Final Air Quality Specialist Report

Transcription

1 Final Air Quality Specialist Report Tonto National Forest Motorized Travel Management Prepared for: Prepared by: United States Department of Agriculture USDA Forest Service Southwestern Region Tonto National Forests 2324 E. McDowell Rd. Phoenix, Arizona Leonard Montenegro NumAIRic, Air Quality Consultants Date: December 20, 2015

2 Contents Introduction... 6 Organization of the Report... 6 Background... 6 Scope of Analysis... 7 Air Pollutants Considered in Analysis... 7 Geographic Reach and Timeline for Analysis Affected Environment Study Area and Time Frame of Analysis Existing Conditions Meteorology Environmental Consequences General Conformity Applicability Analysis Alternative A Alternative B Alternative C Alternative D Direct Effects Alternative A Alternative B Alternative C Alternative D Summary of Direct Effects Indirect Impacts Alternative A Alternative B Alternative C... 22

3 Final Air Quality Specialist Report Tonto National Forest Motorized Travel Management Prepared for: Prepared by: United States Department of Agriculture USDA Forest Service Southwestern Region Tonto National Forests 2324 E. McDowell Rd. Phoenix, Arizona Leonard Montenegro NumAIRic, Air Quality Consultants Date: December 20, 2015 Reviewed by:

4 Alternative D Cumulative Impacts Alternative A Alternative B Alternative C Alternative D References Appendix A: Clean Air Legislation and Regulatory Compliance General Conformity Rule Appendix B: Existing conditions Climate Meteorology Emissions Pollutants Appendix C: General Conformity Applicability Analysis Appendix D: Modeling Direct and Indirect Impacts Using AERMOD Atmospheric Dispersion Modeling System AERMET AERMAP Receptors Emissions AERMOD Appendix E: Cumulative Effects Method for Evaluating Cumulative Effects Study Area and Timeframe of Analysis Air Pollutants Coarse Particulate Matter Nitrogen Oxides Page 3 of 88

5 Impacts to Public Health Past and Present Actions Trends Show Effect of Environmental Regulation Reasonably Foreseeable Actions Effects Tied To Population Growth Effects from Climate Change Environmental Regulations and Other Government Actions Cumulative Impacts Alternative A Alternative B Alternative C Alternative D Appendix F: Climate Change Impact on Air Quality Current conditions and trends in greenhouse gas emissions Assumptions and Methodology Current National Greenhouse Gas Regulations Current Greenhouse Gas Regulations Relevant To Travel Management Climate Change General Effects Anticipated Effects from Increased Air Pollution and Warmer Climate Higher Ambient Temperatures Related to Forest Resources Increasing Temperatures Related to Tropospheric Ozone Worsening Drought Related to Dust The effects of climate change on air quality and public health Mitigation measures Sources Appendix G: Response to public comments Comments Submitted by USEPA Page 4 of 88

6 Comment Comment Comment Comment Comment Comments 8 and Comment Comments Submitted by Center for Biological Diversity Comment Comment Comment Comment Comment Comment and Comments Submitted by U.S. Army Corps of Engineers Comment Comments Submitted by Sierra Club Comment Comments Submitted by J.C. Bush Comment Comment Comment Page 5 of 88

7 Introduction Tonto National Forest has prepared the Final Environmental Impact Statement (FEIS) to examine environmental impacts associated with its Travel Management Plan. With respect to air quality, at question is whether any of the alternatives outlined in the FEIS will result in a significant increase in PM 10 emissions for the Forest s nonattainment and maintenance areas and jeopardize the State of Arizona s ability to attain the National Ambient Air Quality Standards (NAAQS). Before any action occurring within a nonattainment or maintenance area moves forward, the federal agency must apply the applicability requirements to the proposed federal action to determine if a conformity determination is required (General Conformity Guidance, EPA 1994). To comply with General Conformity Regulations, a General Conformity Applicability Analysis is completed to determine if the net change in PM 10 emissions, attributable to each alternative, will not exceed the de minimis levels defined under 40 CFR (b), in which case provisions defined under the General Conformity Regulations are satisfied and no further review is necessary. Atmospheric dispersion modeling is used to determine NAAQS compliance, by modeling downwind 24- hour PM 10 concentrations at three Phoenix area air quality monitors. Results are then compared with the federal air quality standards. Where the predicted 24-hour PM 10 concentration is below the NAAQS, the alternative would not jeopardize the State s ability to attain the NAAQS. Therefore, the objectives of this analysis are summarized as follows: Estimate emissions from off-highway vehicles for each alternative; Compare net emissions to General Conformity Applicability thresholds; and Use dispersion modeling to determine what contribution of PM 10 comes from existing and future OHV use on the Forest to ambient air impacts to nonattainment and class I areas. Organization of the Report This document is a summary of the results from the General Conformity Applicability analysis, and the direct, indirect, and cumulative impacts from the four alternatives. This report contains four main sections and appendices containing technical support documents. Section 1 introduces the purpose and intent for this report. Section 2 introduces the clean air legislation and regulatory compliance that apply to the Travel Management Planning process and analysis requirements for compliance with General Conformity Rule and the National Environmental Policy Act (NEPA). Section 3 describes the existing conditions with respect to air quality and emissions from off-highway vehicles prior to any implementation of the Travel Management Plan. Finally, Section 4 presents the environmental effects associated with each alternative and with respect to particulate emissions and air quality impacts. Section 4 also provides a description of the methods used to develop the emission inventories and for conducting the atmospheric dispersion modeling analysis. Background The Tonto National Forest proposes to designate a system of roads and motorized trails for use by offhighway vehicles to meet requirements of the Travel Management Rule regulations (36 CFR 212, Subpart B). In its Travel Management Plan, the Tonto National Forest presents one no action alternative (Alternative A) and three action alternatives (Alternatives B, C, and D) to the current system of National

8 Forest System roads trails, and areas for motor vehicle use. This report documents emissions associated with each alternative 1. A summary of the alternatives is provided below: Alternative A is the baseline alternative. It has the greatest amount of roads (4, miles) and represents the current conditions, where routes would not be designated and OHV activity would continue unmanaged. It is likely that criteria air pollutants from exhaust and fugitive dust emitted by off-highway vehicle use on unpaved surfaces would continue to contribute to the exceedances of Maricopa County air quality standards. Alternative B has the fewest miles of designated roads and motorized trails open to the public (3, miles) and the most miles of roads proposed for decommissioning. Motor vehicle use for big game retrieval is not permitted and dispersed camping use is restricted to designated sites. Motor vehicle use for fuelwood gathering within designated areas is permitted for up to 300 feet on both sides of all designated motorized routes. Alternative C has the second lowest number of miles of roads designated to be open to the public (3, miles), but has the most miles of motorized trails. Alternative D has the most miles of motorized roads open to travel by the public (4, miles) and the most acres authorized for the purposes of motorized dispersed camping and motorized big game retrieval. Scope of Analysis This report contains the results from quantitative and qualitative assessments into anticipated direct, indirect, and cumulative impacts of the alternatives from sources of course particulate matter (PM 10 ) and oxides of nitrogen (NO X ) pollutants. Allowing cross country travel leads to the greatest negative impact on air quality, yet, its prohibition, as per alternatives B, C, and D, would result in the greatest benefit to air quality. This section presents the goals of this analysis with respect to its regulatory requirements and its geographic reach and timeline of the analysis. Air Pollutants Considered in Analysis Coarse particulate matter and ozone precursors consist of oxides of nitrogen (NO X ) and volatile organic compounds (VOC). NO x and VOC are only considered for conformity purposes. Particulate matter is the main focus since PM 10 impacts tend to be more localized than NO X and ozone, which are pollutants that cause impacts that tend to be more regional. 1 This report has been completely rewritten to respond to comments received during the comment period on the draft EIS. For more detailed information about these comments, see the final EIS. Page 7 of 88

9 Coarse Particulate Matter Particulate matter emissions are both a by-product from internal combustion engines and as fugitive dust lifted by the off-highway vehicle as it is driven on unpaved roadways. The primary National Ambient Air Quality Standard (NAAQS) for PM 10 is 150 micrograms per cubic meter based on the annual second highest concentration averaged over twenty four hours. Nationally, average PM 10 concentrations have been decreasing, but southwestern states have experienced a 13 percent increase in regional average PM 10 between 2000 and 2014 (EPA, 2015). Currently, portions of the Tonto National Forest and Maricopa County experience air quality that exceeds the National Ambient Air Quality Standards (NAAQS) for 24-hour PM 10. These areas are also designated by EPA as nonattainment and require special rules for controlling emissions to bring air quality into compliance with federal air quality standards. Figure 1 shows the number of unhealthy days for Maricopa County and Gila County. Figure 1: Number of Unhealthy Days for Maricopa County and Gila County Scientific studies have linked exposure to coarse particles to a variety of health problems, including hospital admissions for heart disease, hospital admissions, and doctors visits for respiratory diseases, increased respiratory symptoms in children and premature death in people with heart or lung disease. Changes in climate affect air quality by altering weather patterns, which systematically influence dispersion and chemical transformation of air pollutants. As surface temperatures are expected to rise, so is the production of ground-level ozone, which could threaten human health. According to the American Lung Association, about 27 million Americans currently suffer from asthma. Nationally, climate change threatens public health by increasing the likelihood of heat waves, which are associated with increased deaths and illnesses. Children, the elderly, and the poor are among the most vulnerable to these climate-related health effects. (79 FR December 17, 2014) Page 8 of 88

10 Nitrogen Oxides For purposes of environmental regulation and protection Nitrogen Oxides (NO X ) emissions are strictly a byproduct of combustion from industrial sources and internal combustion engines. NOx is emitted to the atmosphere as a mixture of reactive gasses, which are responsible, in part, for the formation of groundlevel ozone, which is also a regulated criteria air pollutant. The NAAQS for ground-level ozone is based on human health effects and equal to 75 parts per billion (ppb), based on the fourth-highest daily maximum 8-hour concentration. NO 2 concentrations have decreased nationally as well as for the Southwest (Figure 2). Figure 2: NOx Emissions by Source Category for Maricopa and Gila Counties While Figure 3 shows that PM 10 concentrations have decreased nationally but have increased by thirteen percent in the Southwest. Figure 3: PM10 Emissions by Source Category for Maricopa and Gila Counties Currently, portions of the Tonto National Forest and Maricopa County experience air quality that exceeds the NAAQS for ozone. These areas are also designated by EPA as nonattainment and require special rules for controlling emissions to bring air quality into compliance with federal air quality standards. Page 9 of 88

11 Breathing ground-level ozone can result in a number of human health effects including chest pain, respiratory irritation, and reduced lung function. Ozone production is greater under warm sunny conditions. Geographic Reach and Timeline for Analysis Areas analyzed include nonattainment and maintenance areas and Class I areas located within the administrative boundary of the Tonto National Forest and the geographic boundaries that define the Lower Salt River airshed 2. In total, nine study areas are examined, comprising five of Arizona s sixteen designated nonattainment and maintenance areas and four Class I wilderness areas. Nonattainment and maintenance areas include the Phoenix, Hayden, Miami, and Payson planning areas for 24-hour PM 10 and the Phoenix 8-hour ozone nonattainment area. The four Class I wilderness areas considered in this analysis include Pine Mountain Wilderness; Mazatzal Wilderness; Sierra Ancha Wilderness; and Superstition Wilderness. Baseline emissions for 2008 are estimated for each alternative and then projected to 2013 future-case OHV emissions for each planning area. Affected Environment This section describes the existing air quality conditions within the forest and areas beyond the forest which may be indirectly impacted by the alternatives. Air quality within the Forest is largely determined by the rate of emissions released to the air and local topography and winds, which drive the advection and dispersion rates of air pollutants. For example, the surrounding mountains, hills and valleys, may create areas of high pollutant concentrations by hindering dispersion, on the other hand, loose soils lifted by high winds may transport dust away from its origin causing indirect impacts to other areas. However, due to its high relative density to air, PM 10 emitted from crustal sources such as unpaved roadways, has a strong tendency for deposition soon after being emitted. Beyond the forest, emissions resulting from the range of alternatives may be transported into one of the many nonattainment areas surrounding the forest or into Class 1 areas which are afforded the most stringent air quality protection under law. Study Area and Time Frame of Analysis The project area includes the geographic boundaries that define the Lower Salt River, beyond which air quality is no longer affected by the range of alternatives (Figure 4), and the geographic areas identified 2 The United States Department of Agriculture Natural Resources Conservation Service defines an airshed as part of the atmosphere that behaves in a coherent way with respect to the dispersion of emissions, and typically forms an analytical or management unit for air quality standards. Page 10 of 88

12 through scoping, which include Superstition Wilderness and the Phoenix PM 10 nonattainment area. The timeframe is from 2011 through Figure 4: Project Area Including Tonto National Forest and Class 1 Areas Existing Conditions Fugitive dust emissions from unpaved roads, windblown dust, and industrial development are the primary contributors to ambient PM 10 concentrations within the Forest and the Phoenix 24-hour PM 10 nonattainment area. Although a small amount of fugitive dust occurs naturally, EPA lists road dust as the largest single source of particulate matter in the air (2015). Beyond the nonattainment areas and in the higher elevations of the Forest, particulate emissions from smoke due to wood burning and prescribed and wild land fires are the primary contributors to poor air quality. Page 11 of 88

13 Particulate emissions from unpaved roads and windblown dust have caused or contributed to numerous violations of federal air quality standards in Maricopa and Pinal Counties, resulting in nonattainment area designations for the 24-hour PM 10 NAAQS. According to State air quality managers, numerous air quality exceedances of the National Ambient Air Quality Standards for 24-hour PM 10 have been measured over the last decade in the Phoenix Metro Area; reportedly due to thunderstorm activity and blowing dust from desert surfaces. Although, active agricultural tilling, dry riverbeds and abandoned agriculture serve as the more prominent examples of anthropogenic causes of windblown dust sources in Maricopa and Pinal Counties. The 2011 emissions inventory published by Maricopa County Air Quality Department (MCAQD) is most recent and applicable inventory of emissions and emission sources for the Phoenix 24-hour PM 10 and 8- hour ozone nonattainment areas. Figure 5 shows the percentage of PM 10 emissions from off-highway vehicles in the PM 10 nonattainment area used for the Phoenix 24-hour PM 10 five percent plan. Contributions from all off-highway vehicles amount to four percent of the total PM 10 emissions. However, this percentage represents the entire Phoenix 24-hour PM 10 nonattainment area and is not subset to nonattainment areas within the Tonto National Forest. It is expected that PM 10 contributions from the nonattainment areas of the forest to Phoenix air quality would be less than four percent. Page 12 of 88

14 Figure 5: Emissions Inventory for PM 10 Nonattainment Area (2008) In order to determine if the alternatives would result in a violation of either of the NAAQS, an emission inventory database containing the amount of PM 10 emissions discharged to the atmosphere by offhighway vehicles was developed for each alternative. Emission rates are presented in tons per year (tpy) emitted by off-highway vehicles traveling on unpaved roads and trails within the Tonto National Forest. Page 13 of 88

15 Figure 6: Gridded Miles per Square Mile - Roads Open to Public for Alternative A Meteorology Wind directions are predominately east-west during daylight hours. When winds are from the east, fugitive dust from off-highway vehicle activity is likely to transport beyond the Forest boundaries and into the Phoenix nonattainment area. Similarly, when winds are from the west, pollution from Phoenix likely contributes to air pollution within the Forest. The wind roses show that Phoenix pollution is more likely transported into the Forest during spring and summer seasons due to higher occurrence of winds and faster wind speeds from the west. Autumn and winter seasons show the opposite, where pollution from the Forest show a higher potential for contributing to Phoenix s air pollution. A closer look at wind shows that pollution is more likely to move away from the Tonto National Forest and into Phoenix between 07:00 AM and 11:00 PM hours, while Phoenix air pollution is more likely to move into the Forest between 2:00 PM and 7:00 PM. For the TMP, this means that riding off-highway vehicles in the afternoon is less likely to cause or contribute to a NAAQS violation at the Phoenix air quality monitors. Page 14 of 88

16 Environmental Consequences General Conformity Applicability Analysis The purpose of General Conformity is to ensure the federal projects don t interfere with air quality planning efforts to attain and maintain federal air quality standards (NAAQS). The General Conformity Applicability Analysis (GCAA) is conducted in order to determine if a federal project would cause or contribute to new air quality violations, increase the frequency or severity of existing violations, or delay attainment of existing air quality goals. If so, the project would be subject to General Conformity requirements. A project is not subject to General Conformity requirements if analysis shows its emissions are below certain thresholds called de minimis thresholds. Results of this analysis show that emissions from this project are below de minimis thresholds (Table 1). No GCAA shows emissions are above the de minimis thresholds. Also, the PM 10 NAA emissions for the current condition (Alternative A) are 220 tpy, but this is already accounted for included in the existing state implementation plan. Threshold is 100 tpy, above which, a general conformity analysis may be needed. The General Conformity Applicability Analysis shows that emissions of PM 10, NO X, and VOC from off-highway vehicles are below the de minimis levels defined under 40 CFR (b) for all action alternatives. Thus, according to the General Conformity Regulations, the Tonto National Forest Travel Management Plan does not require a conformity determination. Table 1: Results from General Conformity Applicability Analysis PM 10 NO x VOC Alternative A Phoenix 24-hour PM10 nonattainment Miami 24-hour PM10 maintenance Hayden 24-hour PM10 nonattainment Payson 24-hour PM10 nonattainment Phoenix 8-hour ozone nonattainment ,734 Alternative B Phoenix 24-hour PM10 nonattainment Miami 24-hour PM10 maintenance Hayden 24-hour PM10 nonattainment Payson 24-hour PM10 nonattainment Phoenix 8-hour ozone nonattainment Alternative C Phoenix 24-hour PM10 nonattainment Miami 24-hour PM10 maintenance Hayden 24-hour PM10 nonattainment Payson 24-hour PM10 nonattainment Phoenix 8-hour ozone nonattainment Page 15 of 88

17 PM 10 NO x VOC Alternative D Phoenix 24-hour PM10 nonattainment Miami 24-hour PM10 maintenance Hayden 24-hour PM10 nonattainment Payson 24-hour PM10 nonattainment Phoenix 8-hour ozone nonattainment Alternative A Under the No-Action Alternative, routes would not be designated and cross country travel would continue unmanaged. Fugitive dust would likely continue to contribute to measured air quality violations in Maricopa and Pinal Counties. Taking no action would result in continued damage to biological or otherwise physical soil crusts which protect soil surfaces from wind erosion and ultimately air quality from the effects of blowing dust. The severity, size, frequency, and timing of blowing dust define its impact, and where the severity of blowing dust is expected to scale with the area of soil crusts damaged. With time, more severe dust storms are anticipated as more forest soil crust is damaged causing local dust emissions to have a greater impact on regional air quality. Alternative B Alternative B has the fewest miles of roads and motorized trails open to the public (3, miles) and the most miles of roads proposed for decommissioning. Motor vehicle use for big game retrieval is not permitted and dispersed camping use is restricted to designated sites. Cross-country travel for fuelwood gathering within designated areas is permitted for up to 300 feet on both sides of all designated motorized routes. The portion of blowing dust attributed to cross-country travel would gradually decline for unroaded areas due to their respective prohibitions on cross-country travel. Unroaded areas may eventually return to natural or near-natural conditions as biological crusts restabilize the damaged soils by gluing loose particles back together (USDOI, 2001). However, more severe warming and drought brought on by climate change may lead to additional worsening of air quality by increasing the rate of NO x conversion to ozone and from a greater chance for wildfires, which produce large amounts of both ozone and PM 10 pollutants. Alternative C Alternative C has the second lowest number of miles of roads designated to be open to the public (3, miles), but has the most miles of motorized trails (2,151 miles). The portion of blowing dust attributed to cross-country travel would gradually decline for unroaded areas due to their respective prohibitions on cross-country travel. Unroaded areas may eventually return to natural or near-natural conditions as biological crusts restabilize the damaged soils by gluing loose particles back together (USDOI, 2001). However, more severe warming and drought brought on by Page 16 of 88

18 climate change may lead to additional worsening of air quality by increasing the rate of NO x conversion to ozone and from a greater chance for wildfires, which produce large amounts of both ozone and PM 10 pollutants. Alternative D Alternative D has the most miles of motorized roads open to travel by the public (4, miles) and the most acres of cross-country travel for the purposes of dispersed camping and big game retrieval. Windblown dust emissions would be greatest for this alternative due to cross-country travel, after the no action alternative. The portion of blowing dust attributed to cross-country travel would gradually decline for unroaded areas due to their respective prohibitions on cross-country travel. Unroaded areas may eventually return to natural or near-natural conditions as biological crusts restabilize the damaged soils by gluing loose particles back together (USDOI, 2001). However, more severe warming and drought brought on by climate change may lead to additional worsening of air quality by increasing the rate of NO x conversion to ozone and from a greater chance for wildfires, which produce large amounts of both ozone and PM 10 pollutants. Direct Effects Alternative A Alternative A is the baseline (No-Action) alternative. Emission density is highest for this alternative. Red cells indicate greater than average roadway density in miles per square mile (Figure 7). Green cells show less than average roadway density. Page 17 of 88

19 Figure 7: Anomaly PM 10 Emissions from Roads Open to Public for Alternative A Alternative B Alternative B has the fewest miles of designated roads and motorized trails open to the public (3, miles) and the most miles of roads proposed for decommissioning. Motor vehicle use for big game retrieval is not permitted and dispersed camping use is restricted to designated sites. Cross-country travel for fuelwood gathering within designated areas is permitted for up to 300 feet on both sides of all designated motorized routes. Emission rates in tons of PM 10 per year for Alternative B are presented in Figure 8. Page 18 of 88

20 Figure 8: Anomaly PM 10 Emissions from Roads Open to Public for Alternative B Alternative C Alternative C has the second lowest number of miles of roads designated to be open to the public (3, miles), but has the most miles of motorized trails (2,151 miles). Modeled air quality concentrations are presented in Figure 9. Page 19 of 88

21 Figure 9: Anomaly PM 10 Emissions from Roads Open to Public for Alternative C Alternative D Alternative D has the most miles of motorized roads open to travel by the public (4, miles) and the most acres of cross-country travel for the purposes of dispersed camping and big game retrieval. Windblown dust emissions would be greatest for this alternative due to cross-country travel, after the No Action Alternative. Emission rates in tons of PM 10 per year for Alternative D are presented in Figure 10. Page 20 of 88

22 Figure 10: Anomaly PM 10 Emissions from Roads Open to Public for Alternative D Summary of Direct Effects Table 2 shows a comparison of the alternatives based on prohibiting cross-country travel and the designation of OHV areas where driving off the designated route system will be permitted. Table 2: Comparison of Alternatives for Direct Effects A B C Alternative Allowing Cross-country Travel Would Result in By taking no action By limiting fuelwood gathering within 300 feet of all designated routes and dispersed camping use at designated sites By limiting fuelwood gathering within 300 feet of all designated routes and motorized big game retrieval within 1 mile of designated routes The Least benefit to air quality and greatest impact from blowing dust caused by damage to soil crusts compared with B, C and D. The greatest benefit to air quality and lowest impact from blowing dust caused by damage to soil crusts compared with A, C and D. A benefit to air quality and lower impact from blowing dust caused by damage to soil crusts compared with A and D. Page 21 of 88

23 D Alternative Allowing Cross-country Travel Would Result in By allocating the most acres of for motorized dispersed camping and motorized big game retrieval and allowing fuelwood gathering within permitted areas The least benefit for air quality and lower impact from blowing dust caused by damage to soil crusts compared with A, B and C. With respect to air quality, Alternative A is the least sustainable options, while Alternative B is the most sustainable option. Indirect Impacts Emissions from OHV use spread beyond the immediate locale and over time may affect air quality beyond its origin. Sensitive areas include PM 10 nonattainment areas and Class 1 wilderness areas. NAAQS are also used as air quality indicators for nonattainment areas such as Maricopa County. Class 1 wilderness areas use different indicators called air quality related values (AQRV), as designated wilderness areas over five thousand acres are designated for the most stringent degree of protection from future degradation of air quality by the Clean Air Act. However, for the purposes of this analysis, AQRVs will also be more likely to be affected as air pollutants from exhaust and fugitive dust emitted by off-highway vehicle use on unpaved surfaces increase. Alternative A Greatest impact to NAA monitors. Alternative A is the baseline (No-Action) alternative. It has the greatest amount of roads (4, miles) and represents the current conditions, where routes would not be designated and OHV activity would continue unmanaged. It is likely that criteria air pollutants from exhaust and fugitive dust emitted by offhighway vehicle use on unpaved surfaces would continue to contribute to the exceedances of Maricopa County air quality standards. Alternative B Lowest impact to NAA monitors. Alternative B has the fewest miles of designated roads and motorized trails open to the public (3, miles) and the most miles of roads proposed for decommissioning. Motor vehicle use for big game retrieval is not permitted and dispersed camping use is restricted to designated sites. Cross-country travel for fuelwood gathering within designated areas is permitted for up to 300 feet on both sides of all designated motorized routes. It is likely that fugitive dust would indirectly contribute to the exceedance of Maricopa County air quality standards, though less than the other alternatives. Alternative C Alternative C has the second lowest number of miles of roads designated to be open to the public (3, miles), but has the most miles of motorized trails (2,151 miles). It is likely that fugitive dust would indirectly contribute to the exceedance of Maricopa County air quality standards, though less than Alternatives A and D. Page 22 of 88

24 Alternative D Alternative D has the most miles of motorized roads open to travel by the public (4, miles) and the most acres of cross-country travel for the purposes of dispersed camping and big game retrieval. Windblown dust emissions would be greatest for this alternative due to cross-country travel, after the No Action Alternative. Therefore, it is likely that fugitive dust would indirectly contribute to the exceedance of Maricopa County air quality standards to a greater degree than the other action alternatives.. Cumulative Impacts Allowing off-highway vehicles uncontrolled access to cross-country travel results in damage to biological and physical soil crusts which protect soils from wind erosion and protect air quality by reducing dust emissions that lead to dust storms. The frequency, timing, and severity of a dust storm determines its impact on air quality. Climate is an important factor in setting the frequency and timing of dust storms, while storm severity scales with the geographic extent of damaged soil crusts. Under Alternative A, taking no action would result in continued damage to biological and physical soil crusts which protect soils from wind erosion and air quality by reducing impacts from blowing dust. With time, as cross-country travel continues to damage soil crusts, more severe dust storms are anticipated causing localized dust emissions to have a greater impact on regional air quality. Under Alternatives B, C and D, the portion of blowing dust attributed to cross-country travel would gradually decline for unroaded areas due to their respective prohibitions on cross-country travel. Unroaded areas may eventually return to natural or near-natural conditions as biological crusts restabilize the damaged soils by gluing loose particles back together (USDOI, 2001). However, more severe warming and drought brought on by climate change may lead to additional worsening of air quality by increasing the rate of NOx conversion to ozone and from a greater chance for wildfires, which produce large amounts of both ozone and PM10 pollutants. Cumulative benefits from both clean air regulations, aimed at reducing emissions, and from travel management planning efforts, are anticipated to reduce criteria pollutant emissions and lead to cleaner air for both the short term and long term scenarios. However, should air quality planning efforts fail to meet their stated goals, then cumulative effects linked to both population growth and climate change may result in adverse effects to vegetation and worsening public health and, thus, the possibility for additional environmental planning may be required in order to reduce air pollution. Alternative A Under the No-Action Alternative, routes would not be designated and cross country travel would continue unmanaged. Fugitive dust would likely continue to contribute to measured air quality violations in Maricopa and Pinal Counties. Taking no action would result in continued damage to biological or otherwise physical soil crusts which protect soil surfaces from wind erosion and ultimately air quality from the effects of blowing dust. The severity, size, frequency, and timing of blowing dust define its impact, and where the severity of blowing dust is expected to scale with the area of soil crusts damaged. With time, more severe dust storms are anticipated as more forest soil crust is damaged causing local dust emissions to have a greater impact on regional air quality. Page 23 of 88

25 Alternative B Alternative B has the fewest miles of roads and motorized trails open to the public (3, miles) and the most miles of roads proposed for decommissioning. Motor vehicle use for big game retrieval is not permitted and dispersed camping use is restricted to designated sites. Cross-country travel for fuelwood gathering within designated areas is permitted for up to 300 feet on both sides of all designated motorized routes. The portion of blowing dust attributed to cross-country travel would gradually decline for unroaded areas due to their respective prohibitions on cross-country travel. Unroaded areas may eventually return to natural or near-natural conditions as biological crusts restabilize the damaged soils by gluing loose particles back together (USDOI, 2001). However, more severe warming and drought brought on by climate change may lead to additional worsening of air quality by increasing the rate of NOx conversion to ozone and from a greater chance for wildfires, which produce large amounts of both ozone and PM 10 pollutants. Alternative C Alternative C has the second lowest number of miles of roads designated to be open to the public (3, miles), but has the most miles of motorized trails (2,151 miles). The portion of blowing dust attributed to cross-country travel would gradually decline for unroaded areas due to their respective prohibitions on cross-country travel. Unroaded areas may eventually return to natural or near-natural conditions as biological crusts restabilize the damaged soils by gluing loose particles back together (USDOI, 2001). However, more severe warming and drought brought on by climate change may lead to additional worsening of air quality by increasing the rate of NOx conversion to ozone and from a greater chance for wildfires, which produce large amounts of both ozone and PM 10 pollutants. Alternative D Alternative D has the most miles of motorized roads open to travel by the public (4, miles) and the most acres of cross-country travel for the purposes of dispersed camping and big game retrieval. Windblown dust emissions would be greatest for this alternative due to cross-country travel, after the no action alternative. The portion of blowing dust attributed to cross-country travel would gradually decline for unroaded areas due to their respective prohibitions on cross-country travel. Unroaded areas may eventually return to natural or near-natural conditions as biological crusts restabilize the damaged soils by gluing loose particles back together (USDOI, 2001). However, more severe warming and drought brought on by climate change may lead to additional worsening of air quality by increasing the rate of NOx conversion to ozone and from a greater chance for wildfires, which produce large amounts of both ozone and PM10 pollutants. Page 24 of 88

26 References Arizona Wilderness Act of Public Law (8/28/1984) U.S. Department of the Interior Air Quality in National Parks Trends ( ) and Conditions ( ) Natural Resource Report NPS/NRSS/ARD/NRR 2013/683 U.S. Department of the Interior Biological Soil Crusts: Ecology and Management. Technical Reference USDI, BLM, and USGS Forest and Rangeland Ecosystem Science Center. United States Department of the Interior Bureau of Land Management National Science and Technology Center Information and Communications Group. Wilderness Act - Public law (9/3/1964) To establish a National Wilderness Preservation System for the permanent good of the whole people, and for other purposes. This public law also includes the following wilderness area(s):

27 Appendix A: Clean Air Legislation and Regulatory Compliance The National Environmental Policy Act (NEPA) and the Clean Air Act as amended (CAA) set provisions for protecting air quality in the US and for local air quality management. NEPA was signed into law on January 1, It establishes national environmental policy and goals to protect, maintain, and enhance the environment. See 42 USC Under NEPA, federal agencies are required to examine the environmental consequences of major proposed actions, including federal land management actions (EPA, 2015). The Clean Air Act requires EPA to establish National Ambient Air Quality Standards (NAAQS) (42 USC 7409) for pollutants considered harmful to public health and the environment (EPA, 2015) and to designate geographic areas within each state as either attainment, nonattainment, or unclassifiable (42 U.S.C 7502). Nonattainment areas are where air quality does not meet the NAAQS. States are required to prepare a state implementation plan (SIP) for assuring that air quality within all designated areas does not exceed the National Ambient Air Quality Standards and to outline how each state will control air pollution within nonattainment areas to bring air quality into compliance with the NAAQS. Federal actions must not interfere with the air quality goals defined in the state implementation plan and any federal action occurring within an area designated as nonattainment or maintenance must be supported by a determination of conformity to the applicable SIP. See General Conformity Regulations under 42 USC General Conformity Rule General Conformity Regulations ensure that federal projects occurring in nonattainment or maintenance areas do not jeopardize a State s ability to attain the NAAQS. Specifically, federal projects must not cause or contribute to any new violation of any standard in any area, interfere with provisions in the applicable SIP for maintenance of any standard, increase the frequency or severity of any existing violation of any standard in any area, or delay timely attainment of any standard or any required interim emission reductions or other milestones in any area including a demonstration of attainment or maintenance plan specified in the applicable SIP. Before a Federal agency can take action, it must perform an applicability analysis to determine whether its Federal action must be supported by a determination of conformity. Federal projects are exempt from submitting a conformity determination if the General Conformity Applicability Analysis shows that total direct and indirect emissions of the criteria pollutants or precursors are de minimis, according to emission threshold screening criteria specified under 40 CFR (b)(1) and (2). Otherwise, Federal actions must demonstrate conformity to any applicable State Implementation Plan (SIP) for each criteria pollutant equal to or exceeding the rates specified under 40 CFR (b). The applicable framework for air quality management in the State of Arizona is the Arizona State Implementation Plan. Currently, Arizona s SIP contains regulations for sixteen air quality planning areas designated by EPA as either nonattainment or maintenance of the NAAQS, with control measures and strategies to attain the NAAQS and are defined for each designated air quality planning area. National attainment of the NAAQS is assured under law through delegation by EPA to states law through a written state implementation plan (SIP). The SIP defines how that State will attain and/or maintain the primary and secondary National Ambient Air Quality Standards (NAAQS) set forth in section 109 of the Page 26 of 88

28 Clean Air Act and 40 CFR parts 50.4 through Five of these planning areas extend to portions of the Tonto National Forest. They include the Phoenix, Hayden, Miami, and Payson planning areas for 24-hour PM 10 and the Phoenix 8-hour ozone nonattainment area. Figure 11: National Ambient Air Quality Standards (NAAQS) Source: Page 27 of 88

29 Appendix B: Existing conditions Climate Meteorology The following wind roses illustrate prevailing wind speed and direction at the Phoenix NWS meteorological monitoring station. Data for wind roses was extracted from AERMET meteorological files used in the dispersion modeling. Hours represented include daylight hours by season averaged between years 2009 and Table 3: Summary of Meteorological Dataset SOURCE MODEL LAT LON UA_ID SF_ID: VERSION THRESH_1MIN ADEQ AERMET N W m/s Source = Arizona Department of Environmental Quality for use in dispersion modeling UA_ID = upper air station id SF_ID = Surface station id - Phoenix NWS meteorological monitoring station Version = AERMET version Table 4: Summary of Meteorological Dataset STATISTIC DATE WIND SPEED WIND DIRECTION Min :00: st Qu :45: Median :30: Mean :30: Max :15: NA Source=Originator of dataset. Arizona Department of Environmental Quality for use in dispersion modeling UA_ID=upper air station id SF_ID=Surface station id Page 28 of 88

30 Figure 12: Proportion of Daylight and Nighttime Winds by Season ( ) Wind speed units: Miles per hour Prevailing seasonal daylight-nighttime wind speed and direction for the Phoenix NWS meteorological monitoring station. Data for wind roses was extracted from AERMET meteorological files used in the dispersion modeling. Winds include daylight hours by season averaged between years 2009 and Plot shows predominately east-west winds for daylight hours and all seasons. Page 29 of 88

31 Figure 13: Seasonal Daylight and Nighttime Winds Capable of Blowing Dust Wind speed units: Miles per hour Seasonal daylight and nighttime winds for years capable of causing windblown dust emissions. Prevailing seasonal daylight-nighttime wind speed and direction for the Phoenix NWS meteorological monitoring station. Data for wind roses was extracted from AERMET meteorological files used in the dispersion modeling. Winds include daylight hours by season averaged between years 2009 and Plot shows predominately east-west winds for daylight hours and all seasons. Page 30 of 88

32 Figure 14: Monthly Winds Wind roses by month for for all wind speeds. Wind speed range 0 to 16 miles per hour. All directions are where the wind blows FROM. Page 31 of 88

33 Figure 15: Monthly Winds Capable of Blowing Dust Wind roses by month for for wind speeds equal to or greater than 12 miles per hour. Page 32 of 88

34 Figure 16: Frequency of Counts by Wind Direction and Season Wind roses illustrate prevailing wind speed and direction at the Phoenix NWS meteorological monitoring station. Data for wind roses was extracted from AERMET meteorological files used in the dispersion modeling. Hours represented include daylight hours by season averaged between years 2001 and Page 33 of 88

35 Figure 17: Frequency of Counts by Wind Direction and Hour of Day Page 34 of 88

36 Emissions Figure 18: 2008 Emissions Inventory for the PM10 Nonattainment Area Source: Nonattainment-Area.pdf Page 35 of 88

37 Pollutants Three monitors were selected for the air quality modeling analysis. They include West 43rd, Apache Junction, and Fort McDowell. Figure 19: PM 10 Monitor Locations Page 36 of 88

38 Figure 20: Daily PM10 Concentrations (1/1/ /31/2012) Page 37 of 88

39 Appendix C: General Conformity Applicability Analysis The General Conformity Applicability analysis is the process of determining if the Federal action must be supported by a conformity determination. For nonattainment or maintenance area, the conformity evaluation for a Federal action involves two steps. First, a threshold applicability analysis is performed to determine whether a conformity determination is required. If this threshold is met, then a conformity determination is performed. As described in 40 CFR , the applicability analysis may find that a conformity determination is not required if, among other things, the Federal action would result in no emissions increase or an increase in emissions that is less than the de minimis rates contained in 40 CFR (b). The analysis was completed using the process outlined in EPA s General Conformity Guidance and The Applicability Analysis was completed using the process outlined in EPA s General Conformity Training Module. Figure 5 in appendix A illustrates the main steps used in the applicability analysis. The method for estimating emissions from off-road recreational vehicles include the following steps: 1. Identify any nonattainment or maintenance areas within the Forest. 2. Develop baseline and future emissions inventories for each nonattainment and maintenance area identified in step 1 and calculate the total direct and indirect emissions for each alternative. 3. If the total direct and indirect emissions from step 2 are below the emissions levels specified under 40 CFR (b)(1) and (2), then the proposed action is not expected to cause significant air quality impacts. In the first step, GIS analysis was used to determine that five air quality planning areas are located within the Forest s administrative boundary. Further, GIS analysis was used to determine the distribution of roadways used by OHV s within the Forest and each air quality planning area. The planning area potentially affected by the alternatives include the following nonattainment and maintenance areas: Phoenix planning area for 24-hour PM 10 Hayden planning area for 24-hour PM 10 Miami planning area PM 10 Payson planning area for 24-hour PM 10 Maricopa County planning area for 8-hour ozone In the second step we estimate the 2008 baseline and 2013 future OHV emissions for each planning area and each alternative. The emissions were estimated using the engineering methods described in AP-42 3 and equation 1 (EQ1) below. 3 EPA AP-42 Compilation of Air Pollutant Emission Factors Unpaved Roads equation (1b) Page 38 of 88

40 Emissions = Activity x Emission Factor EQ1 Where: Emissions = the criteria pollutant emission rate (reported in tons/year) Activity = expressed as Vehicle Miles Traveled (VMT), which is the product of Average Daily Traffic (ADT) and average miles driven per OHV/day. Emission Factor = a representative quantity of air pollutant emissions associated with an activity. For each nonattainment or maintenance area, we require OHV emissions estimates for the no action alternative and OHV estimates for each alternative (A, B and C). The emissions estimates are projected from the 2008 baseline inventory year to the 2013 future baseline inventory year. The no action emissions estimates are representative of OHV activities during the 2013 future baseline year before the proposed action will occur, while the OHV emissions for each alternative are representative of the 2013 future year inventories, after the proposed action will occur. OHV inventories include: 2008 Baseline emissions based on 2008 NVUM statistics 2013 future baseline OHV emissions (Alternative A) future OHV emissions (Alternative B) future OHV emissions (Alternative C) future OHV emissions (Alternative D). Vehicle Miles traveled are the product of Average Daily OHV Traffic (ADT) and average miles traveled by each OHV per day. The value for ADT is formulated from total annual Forest visitors per vehicle and a ratio of OHVs per vehicle. At this writing, the 2008 National Visitor Use Monitoring report (NVUM) is the most recent and available data containing Forest visitation estimates. The 2008 NVUM reports a total of 4,801,000 Forest visitors with a ratio of 2.4 visitors per passenger vehicle, for a total of 5,481 passenger vehicles visiting the Forest daily in A study on emissions within the Tonto National Forest carried out on the weekend of July 4th 2004 by Arizona State University and the Arizona Department of Environmental Quality provided the ratio of OHVs per vehicle used to calculate the ADT. The study found that for every 1,100 vehicles entering the Tonto National Forest, Roosevelt Lake Recreation Area; there were 14 all-terrain vehicles and 8 motorcycles in-tow. Therefore for 2008 there is an estimated maximum of 110 OHVs in daily use throughout the Forest. The daily maximum number of off-highway vehicles in 2008 were then projected to Motorcycle usage increased by 20.12%, while ATV use increased by 21.81% for an estimated maximum of 133 and average of 89 OHVs in daily use throughout the Forest in The growth factors were estimated using Page 39 of 88

41 EPA s nonroad engine growth estimates 4. Table 5 presents the forest wide OHV use estimates for 2008 and Table 5: Estimated Forestwide OHV Activity Levels Used in the Emissions Calculations Average Daily No. OHV ATV Growth Factor > 2013 MC Growth Factor > 2013 NVUM 2008 total park visitors Visitors vehicle Miles per day OHV % 20.12% 4,801, * * From 2004 Roosevelt Lake OHV emissions study Vehicle miles traveled were then calculated according to equation 2 (EQ2). VMT = ADT x Distance Travelled EQ2 The average daily number of OHV s in use is 89 (ADT=89) and the estimated average daily miles driven by each OHV is 25 (Distance Travelled=25). The distance travelled estimate comes from the same 2004 Roosevelt Lake study that provided the ratio of OHV s per vehicle. EPA has also estimated distance travelled for OHV s and motorcycles. In its November 13, 2000 Memorandum titled: Emission Modeling for Recreational Vehicles, EPA estimates that OHV s travel 20 miles per day on average when in use. The value of 25 miles per day reported in the 2004 Roosevelt Lake study is the more conservative of the two estimates, although its basis is unsubstantiated by the report. The daily forest wide VMT for 2013 is 2,225. Fugitive PM 10 emissions were quantified using the AP-42 empirical equation for vehicles traveling on publically accessible unpaved roads. The values used in the following equation (EQ3) are provided in Table 6. EQ3 Where: E = size-specific emission factor (lb/vmt) ss = Silt content (%) MM = Moisture content (%) SS = Mean vehicle speed (mph) kk = 1.8 aa = 1 cc = Nonroad Engine Growth Estimates. EPA420-P April NR-008c 11 EPA420-F Page 40 of 88

42 dd = 0.5 cc = Table 6: Values Used in Fugitive Emission Factor Calculation EF* EF (ATV) EF (MC) ( k ) ( s ) ( S ) ( M ) ( a ) ( d ) ( c ) ( C ) * Average ATV MC (lb/vmt) Emission factors for off-highway recreational vehicles are from EPA s NONROAD2008 model. Actual emissions are estimated by multiplying the estimated annual number of operational hours by their engine rating, equipment load factor, and respective emission factors. A summary of the emission factors is provided in Table 7. Table 7: Exhaust Emission Factors for Off-Highway Vehicles Source HC (pounds/mile) NO x (pounds/mile) PM 10 (pounds/mile) unpaved roads exhaust Once the emissions calculations are completed, the emissions inventories for each alternative (B, C and D) is subtracted from Alternative A to determine the net emissions for each alternative. The total direct and indirect emissions is defined as the net emissions caused by the action considering all the emission increases and decreases that are projected to occur. (EPA, 2013). The emissions for the PM10 nonattainment areas were derived by a ratio method where emissions were scaled to each nonattainment area according to the ratio of its miles to total miles in the forest. Table 8 lists the ratios for scaling the emissions to each planning area. Table 8: Ratio of Miles in Planning Areas to Forest Miles Forest area Alternative A Alternative B Alternative C Alternative D Tonto National Forest % % % % Phoenix 24-hour PM10 nonattainment 10.75% 8.00% 8.52% 9.38% Miami 24-hour PM10 maintenance 4.57% 3.45% 3.24% 3.58% Hayden 24-hour PM10 nonattainment 3.48% 3.95% 3.24% 3.44% Payson 24-hour PM10 nonattainment 5.71% 8.62% 6.75% 5.84% Phoenix 8-hour ozone nonattainment 24.53% 18.38% 22.52% 23.37% Mazatzal Wilderness 3.60% 3.20% 4.24% 2.59% Superstition Wilderness 2.43% 1.67% 3.13% 2.63% Sierra Ancha Wilderness 1.91% 1.02% 2.13% 1.98% Pine Mountain Wilderness 0.83% 1.42% 1.21% 0.89% Page 41 of 88

43 In the third and final step, the total net emissions for each alternative and each nonattainment or maintenance area are then compared to emissions threshold levels to determine if the proposed action would cause or contribute to a NAAQS violation. Table 5 below lists the criteria for determining the significance of the air quality impacts. Table 9: General Conformity Emissions Thresholds by SIP Planning Area Region Pollutant Designation Threshold (tons per year) Phoenix Planning Area Serious Nonattainment 70 Hayden Planning Area Moderate Nonattainment Miami Planning Area Payson Planning Area PM 10 Limited Maintenance Plan and request for redesignation to attainment (ADEQ 2008). Limited maintenance area Maricopa County Ozone Nonattainment Threshold value source: 40 CFR 81, Threshold 40 CFR (b)(1) and (2) (NOx or VOC) Page 42 of 88

44 Figure 21: Process for Completing the General Conformity Applicability Analysis Appendix D: Modeling Direct and Indirect Impacts Using AERMOD Atmospheric Dispersion Modeling System Ambient PM 10 concentrations were modeled using AERMOD. Indirect impacts were modeled for comparison with three PM 10 monitors located within the Maricopa County 24-hour PM10 nonattainment area. Monitor locations include: West 43rd Avenue, Apache Junction Fire Station and Fort McDowell PM 10 monitors. West 43rd Avenue monitor location was selected for modeling because it had the highest recorded number of exceedances between 2008 and Apache Junction Fire Station and Fort McDowell were selected because they are the monitors nearest to the Tonto National Forest. Table 10 presents the receptors used in the modeling and the number of PM 10 exceedances recorded between 2008 and The NAAQS allows one exceedance per year per monitor. Figure 19 in Appendix B shows the Tonto National Forest Boundary with respect to Phoenix area PM 10 monitors. Monitors shown in red Page 43 of 88

45 recorded NAAQS exceedances between 2008 and No exceedances were recorded by the two PM 10 monitors nearest to the Forest (Apache Junction Fire Station and Fort McDowell). Table 10: Modeled PM 10 Concentrations Receptor Alternative A Alternative B Alternative C Alternative D West 43 rd Ave Apache Junction Fort McDowell Superstition Wilderness Sierra Ancha Wilderness Mazatzal Wilderness Pine Mt Wilderness AERMET Meteorological modeling was performed using AERMET. Summary data provided in Table 11 and Table 12. Wind rose plots in Figure 22 through Figure 26, show prevailing wind speed and direction at the Phoenix NWS meteorological monitoring station. Data for wind roses was extracted from AERMET meteorological files used in the dispersion modeling. Plotted wind averages include: hourly daily, monthly, daylight, nighttime, by season averaged between years 2009 and Table 11: Summary of Meteorological Dataset SOURCE MODEL LAT LON UA_ID SF_ID: VERSION THRESH_1MIN ADEQ AERMET N W m/s Source = Arizona Department of Environmental Quality for use in dispersion modeling UA_ID = upper air station id SF_ID = Surface station id - Phoenix NWS meteorological monitoring station Version = AERMET version Table 12: Summary of Meteorological Dataset Statistic Date Wind Speed Wind Direction Min :00: st Qu :45: Median :30: Mean :30: Max :15: NA NA = missing values. NA values removed from wind rose plots. Page 44 of 88

46 Figure 22: Proportion of Daylight and Nighttime Winds by Season ( ) Wind speed units: Miles per hour. All directions are where the wind blows from. Prevailing seasonal daylight-nighttime wind speed and direction for the Phoenix NWS meteorological monitoring station. Data for wind roses was extracted from AERMET meteorological files used in the dispersion modeling. Winds include daylight hours by season averaged between years 2009 and Plot shows predominately east-west winds for daylight hours and all seasons. Table 13: Seasons and Impacts from Nonattainment Area Season Spring Summer Autumn Winter Likely impact May result in indirect impacts to forest from nonattainment area May result in indirect impacts to forest from nonattainment area May result in indirect impacts to forest from nonattainment area May result in indirect impacts to nonattainment area from forest Page 45 of 88

47 Figure 23: Seasonal Daylight and Nighttime Winds Capable of Blowing Dust Wind speed units: Miles per hour. All directions are where the wind blows from. Seasonal daylight and nighttime winds for years capable of causing windblown dust emissions. Data for wind roses was extracted from AERMET meteorological files used in the dispersion modeling. Winds include daylight hours by season averaged between years 2009 and Plot shows predominately east-west winds for daylight hours and all seasons. Page 46 of 88

48 Figure 24: Monthly Winds All directions are where the wind blows from. Wind roses by month for for all wind speeds. Wind speed range 0 to 16 miles per hour. Page 47 of 88

49 Figure 25: Monthly Winds Capable of Blowing Dust All directions are where the wind blows from. Wind roses by month for for wind speeds equal to or greater than 12 miles per hour. Page 48 of 88

50 Figure 26: Frequency of Counts by Wind Direction and Season All directions are where the wind blows from. Wind roses illustrate prevailing wind speed and direction at the Phoenix NWS meteorological monitoring station. Data for wind roses was extracted from AERMET meteorological files used in the dispersion modeling. Hours represented include daylight hours by season averaged between years 2001 and Page 49 of 88

51 AERMAP Source and receptor heights were determined using NED data and AERMAP. National Elevation Dataset (NED) files were downloaded from The National Map 5 by USGS and then processed using AERMAP. CO STARTING ** HILLHTS 1 CO TITLEONE SIERRA CO TITLETWO Dec 2015 CO TERRHGTS EXTRACT CO DATATYPE NED FILLGAPS CO DATAFILE "D:\DATA\TERRAIN\Central_AZ\imgn35w113_13.tif" CO DATAFILE "D:\DATA\TERRAIN\Central_AZ\imgn35w112_13.tif" CO DATAFILE "D:\DATA\TERRAIN\Central_AZ\imgn35w111_13.tif" CO DATAFILE "D:\DATA\TERRAIN\Central_AZ\imgn34w113_13.tif" CO DATAFILE "D:\DATA\TERRAIN\Central_AZ\imgn34w112_13.tif" CO DATAFILE "D:\DATA\TERRAIN\Central_AZ\imgn34w111_13.tif" ** SETTINGS ========================================= ** zone=12 ** datum=nad83 CO ANCHORXY ** ================================================== 5 Page 50 of 88

52 Figure 27: AERMAP Terrain Datasets NED data n34w112, n35w112. Covers forest ectent and full extent of all receptors. Class 1 areas and NAA. Receptors Criteria for selecting NAA receptors: maximum recorded PM10 violation and nearest to forest. Table 14: Air Quality Monitors Used in Modeling Analysis by NAAQS Exceedance Monitor Number of Exceedances W. 43 rd Ave Apache Junction Fire Station Fort McDowell Units: micrograms per cubic meter (µg/m 3 ) Class 1 receptors from NPS Page 51 of 88

53 Emissions Emissions were calculated using maximum capacity per RATM of 15 encounters per trip. 1 trip is 2 hours or 60 miles. So maximum roadway capacity is OHV per mile per hour * 60 miles = 7.5 OHV per hour * 2 hours = 15 OHV per trip * number of miles in cell = OHV per hour per cell (VMT per hour) Gram/mile * VMT = emissions (grams per cell per hour) Travel management is not expected to increase or decrease OHV recreation at the forest-wide level, so vehicle miles traveled do not change among the range of alternatives, hence, forest-wide emissions do not change. Emissions confined to administrative boundary or grid would change with respect to road density. However, as population grows, so too will demand for forest roads by future OHV recreation. Miles include: "AltA_Chang" = '3-Suitable for Passenger Cars' OR "AltA_Chang" = '4-Moderate Degree of Comfort' OR "AltA_Chang" = '5-High Degree of Comfort' OR "AltA_Chang" = '2-High Clearance Vehicles' OR "AltA_Chang" = '1-Basic Custodial Care-Closed' OR "AltA_Chang" = 'D - Decommission' OR "AltA_Chang" = 'Unauthorized' OR "AltA_Chang" ='Unauthorized New' OR "AltA_Chang" ='Unclassified_not_incl' AERMOD Modeling for AERMOD includes: Direct PM10 impacts Indirect PM10 impacts to Phoenix 24-hour nonattainment area Indirect PM10 impacts to Class I areas Emissions included in the Class 1 area modeling are shown in Figure 28. Grid cells located within three miles of the Class 1 boundary are modeled. Page 52 of 88

54 Figure 28: OHV Trails within Three Miles of Each Class 1 Area Boundary Class 1 areas with three-mile buffer. Grey shaded areas represent density of designated OHV trails per square mile. Green shaded areas are Class 1 wilderness area. Class 1 areas with three-mile buffer. PM10 emissions are estimated for each square mile with units of grams per second per square mile. Tan buffer zones extend to three miles beyond the Class 1 area boundary. PM10 emissions are modeled for all sources located within the buffer zones. Page 53 of 88

55 Figure 29: Emissions within Three Miles of Each Class 1 Boundary Class 1 areas with three-mile buffer. Grey shaded areas represent density of designated OHV trails per square mile. PM10 emissions are estimated for each grid cell within the buffer zones and then modeled to estimate indirect impacts to Class 1 areas. Emission units are grams per second per square mile. Grey shaded areas within buffer zones represent OHV emission densities. Green shaded areas are Class 1 wilderness area. Tan buffer zones extend to three miles beyond the Class 1 area boundary. Page 54 of 88

56 Figure 30: Bulldog Permit Zone Emissions and Proximity to Superstition Wilderness Contour map shown the location and extent of the Bulldog permit zone and proximity to Superstition Wilderness. Also shown are area source grids, elevations, designated OHV roads within Bulldog and receptors located within the Superstition Wilderness. AERMOD takes PM10 emissions from Bulldog and predicts the ambient concentration for Pm10 at each receptor indicated on the map. Page 55 of 88

57 Appendix E: Cumulative Effects This section contains the results from a qualitative assessment into anticipated cumulative impacts from sources of course particulate matter (PM 10 ) and oxides of nitrogen (NO X ) pollutants within the Salt River airshed. Allowing cross country travel has a negative impact on air quality for direct and indirect impacts, and yet, through its prohibition per the range of alternatives, would result in the greatest benefit to air quality when compared with other factors associated with the alternatives. Therefore, impacts linked to cross country travel is the focus of this section. Under Alternative A, Allowing off-highway vehicles uncontrolled access to cross-country travel results in damage to biological and physical soil crusts which protect soils from wind erosion and protect air quality by reducing dust emissions that lead to dust storm. The frequency, timing and severity of a dust storm determines its impact on air quality. Climate is an important factor in setting the frequency and timing of dust storms, while storm severity scales with the geographic extent damaged soil crusts. With time, as cross-country travel continues to damage soil crusts, more severe dust storms are anticipated causing localized dust emissions to have a greater impact on regional air quality. Under alternatives B, C and D, the portion of blowing dust attributed to cross-country travel would gradually decline for unroaded areas due to their respective prohibitions on cross-country travel. Unroaded areas may eventually return to natural or near-natural conditions as biological crusts restabilize the damaged soils by gluing loose particles back together (USDOI, 2001). However, more severe warming and drought brought on by climate change may lead to additional worsening of air quality by increasing the rate of NOx conversion to ozone and from a greater chance for wildfires, which produce both ozone and PM10 pollutants in large quantities. Cumulative benefits from both clean air regulations aimed at reducing emissions and from travel management planning efforts are anticipated to reduce criteria pollutant emissions and lead to cleaner air in both the short- and long-term. However, should air quality planning efforts fail to meet their stated goals, then cumulative effects linked to both population growth and climate change may result in adverse effects to vegetation and worsening public health and, thus, the possibility for additional environmental planning may be needed in order to reduce air pollution. Table 15: Anticipated Effects to Air Quality Due to Cumulative Effects Alternative Anticipated effect to air quality Tonto National Forest A Impacts would be greater than Alternatives B, C and D B Impacts would be less than Alternatives A, B and C. C Impacts would be intermediate between Alternatives A and B. D Impacts would be greater than Alternatives B and C but less than A Method for Evaluating Cumulative Effects The five-step approach for developing the cumulative impact analysis is listed below: 1. Define the study area and time frame. 2. Describe the current air quality within the study area. 3. Identify direct and indirect impacts that might contribute to a cumulative impact Page 56 of 88

58 4. Identify other reasonably foreseeable actions that affect air quality 5. Assess and report on any potential cumulative impacts Study Area and Timeframe of Analysis The time frame and geographic areas selected for this analysis are summarized in Table 16. This time frame was selected based on: The most recent county-wide emissions summaries, Climate projections for 2030 from the southwest climate, IPCC and EPA, and Recovery time for soil crusts 6 Table 16: Timeframe and Study Areas Considered for Analysis Time frame Main study area Study areas identified from scoping 1990 thru 2035 Lower Slat River airshed 24-hour PM10 Nonattainment area and Class 1 wilderness areas within the airshed Note: The emissions inventories reflect all past and present actions as quantifiable emissions for each criteria pollutant. For this analysis, 2011 emissions inventories for both Maricopa county and Gila county were used to determine which sources to include in the analysis. This cumulative effects analysis includes the geographic boundaries that define the Lower Slat River, beyond which air quality is assumed to be no longer affected by the range of alternatives. Geographic areas identified through scoping include: Superstition Wilderness and the Phoenix PM10 nonattainment area. Figure 31 below shows the location and extent of the study areas with respect to the Tonto National Forest. Study areas include: the Superstition, Sierra Ancha, Mazatzal, and Pine wilderness areas; and the Phoenix PM10 nonattainment area. 6 Estimated 20 years or more according to research conducted by Belnap and Gillette (1997). Page 57 of 88

59 Figure 31: Geographic Location and Extent of All Areas Considered in Analysis Air Pollutants This section provides general background information about particulates (PM 10 ) and nitrogen oxides (NOx) pollutants. Coarse Particulate Matter With respect to recreational off-highway vehicles, particulate matter emissions are both a by-product from internal combustion engines and a result of their use on unpaved surfaces, which lift loose soils by means of aerodynamic forces caused by the vehicle s motion and break surface crusts, leaving loose soils in its tracks left behind susceptible to wind erosion. The primary National Ambient Air Quality Standard (NAAQS) for PM10 is 150 micrograms per cubic meter based on the annual second highest concentration averaged over twenty four hours. Nationally, average PM10 concentrations have been decreasing, but southwestern states have experienced a thirteen percent increase in regional average PM10 between 200 and 2014 (EPA, 2015). Page 58 of 88

60 Currently, portions of the Tonto National Forest and Maricopa County experience air quality that exceeds the National Ambient Air Quality Standards (NAAQS) for 24-hour PM10. These areas are also designated by EPA as nonattainment and require special rules for controlling emissions to bring air quality into compliance with federal air quality standards. Figure 32 shows the number of unhealthy days for Maricopa County and Gila County. Figure 32: Number of Unhealthy Days for Maricopa County and Gila County Scientific studies have linked exposure to coarse particles to a variety of health problems, including hospital admissions for heart disease, hospital admissions, and doctors visits for respiratory diseases, increased respiratory symptoms in children and premature death in people with heart or lung disease. Nitrogen Oxides With respect to air quality protection, oxides of nitrogen (NOx) are a byproduct of combustion from industrial sources and internal combustion engines. NOx is emitted to the atmosphere as a mixture of reactive gasses, which are responsible, in part, for the formation of ground-level ozone, which is also a regulated criteria air pollutant. The NAAQS for ground-level ozone is based on human health effects and equal to 75 ppb, based on the 4th-highest daily maximum 8-hour concentration. NO 2 concentrations have decreased nationally as well as for the Southwest (Figure 2). Page 59 of 88

61 Figure 33: NOx Emissions by Source Category for Maricopa and Gila Counties While Figure 3 shows that PM 10 concentrations have decreased nationally but have increased by thirteen percent in the Southwest. Figure 34: PM10 Emissions by Source Category for Maricopa and Gila Counties Impacts to Public Health Currently, portions of the Tonto National Forest and Maricopa County experience air quality that exceeds the NAAQS for ozone. These areas are also designated by EPA as nonattainment and require special rules for controlling emissions to bring air quality into compliance with federal air quality standards. Breathing ground-level ozone can result in a number of human health effects including chest pain, respiratory irritation, and reduced lung function. Ozone production is greater under warm sunny conditions. Past and Present Actions Present actions are accounted for in the emissions inventories. County-wide emissions summaries published by EPA for Maricopa County and Gila County, as shown in Figure 2 and Figure 3 serve as the basis for selecting which source types to include in the analysis. Page 60 of 88

62 Trends Show Effect of Environmental Regulation Evidence if past actions and their results are recorded in the monitor concentrations. Trends in air pollutant concentration show the effects over time of regulations aimed at reducing emissions. Nitrogen dioxide (NO 2 ), which is the indicator used by EPA to measure the effects from NOx emissions, shows improvement both nationally and for the southwestern states (Figure 35 and Figure 36). This trend is expected to continue as EPA s engine performance standards continue to reduce pollutants from engine exhausts. Figure 35: NO 2 Trends for Continental and Southwestern United States Figure 36: PM 10 Trends for Southwestern United States Reasonably Foreseeable Actions Actions by the National Park Service (NPS), Bureau of Land Management (BLM), Maricopa County, Gila County and the State of Arizona may affect air quality in the Tonto National Forest. Government actions that may worsen air quality include: actions related to industry permits, construction projects and recreation. Page 61 of 88

63 Table 17: Reasonably Foreseeable Actions Tied to Air Quality Regulations and Permitting ACTION Mining land lease Other industrial permits Travel management on neighboring forests Coal-plant closures to meet EPA's 30% reduction in CO2 by 2030 Coal-plant conversion to natural gas ANTICIPATED EFFECT Increase PM10 and NOx emissions Increase PM10 and NOx emissions decrease PM10 and NOx emissions Decrease CO2 emissions Increase NOx emissions Effects Tied To Population Growth Environmental effects from industry, recreation, and government actions are tied to population growth. Hence, as the population grows, anthropogenic emissions from a variety of source sectors grow as well. Table 18: Source Categories Tied to Population Growth TYPE PM 10 SOURCE CATEGORIES NO X SOURCE CATEGORIES Fugitive dust from unpaved and paved roads and On-road and nonroad mobile sources construction Tailpipe On-road and nonroad mobile sources wildland and prescribed fires Fugitive and stack Industrial mining processes Industrial processes Smoke wildland and prescribed fires Dust Windblown dust from disturbed surfaces Effects from Climate Change Anticipated changes in the global climate over the coming decades could alter weather patterns resulting in higher temperatures, more intense droughts, worsening air quality and greater demand for forest resources. By the end of this century, temperatures are expected to rise approximately five to eight degrees Fahrenheit with the greatest warming to occur during the winter season (IPCC, 2015). This warming trend may lead to shorter winters and a longer season for summer activities (Joyce et al, 2001). Rising temperatures may also lead to higher ground-level ozone concentrations. Ozone forms more readily under high temperatures and in the presence of nitrogen oxides, which may be emitted to the atmosphere in larger amounts as demand for electricity increases, in part from higher demand for air conditioning. More intense droughts may lead to more fugitive dust from areas where OHV use is in high demand. As the climate changes, so does demand for forest resources, thus maintaining forest roadways and managing the use of off-highway vehicles has become an important priority. Human activities can be considered both detrimental and beneficial to air quality. Detrimental effects result from anthropogenic greenhouse gas emissions, which, may change future weather normals and thus air quality. Laws enacted to curb greenhouse gas emissions result in a cumulative benefit. Environmental Regulations and Other Government Actions Rules, regulations, policies, and other government actions by local and federal government agencies can affect air quality in several ways. For example, government funded construction projects cause air pollution, on the other hand, governments take action to improve air quality by reducing anthropogenic emissions. Environmental awareness, conservation, regulation, and enforcement lead to reducing emissions and better air quality. Air emissions tied to air quality permits are managed under State and County air quality rules, regulations and attainment plans, which require emissions reductions within nonattainment areas in order to meet Page 62 of 88

64 federal air quality standards. Therefore, indirect impacts within the nonattainment areas are expected to decrease over time. Also, in many cases, multiple programs may lead to combined effects for the same source category. (EPA, 2015). For example, tailpipe standards, inspection and maintenance programs, as well as transportation initiatives aimed at reducing vehicle miles traveled may have a combined effect on mobile source emissions. An exception being EPA s Exceptional Events rule, where air quality monitoring data affected by exceptional events may be excluded from use in identifying a violation if they meet the criteria for such an exclusion (72 FR 13560). That is, if a the State can demonstrate that the air quality exceedance was due to natural causes beyond regulatory control, then the exceedance would not be counted as a violation. Without proper oversight and transparency, States may rely on provisions allowed under the rule to circumvent federal air quality laws (determinations must be made using credible science that is transparent and reproducible). The cumulative effect of such action may be detrimental to air quality and thus public health and welfare in coming years. If the State cannot clearly demonstrate that, but for the natural conditions, that the air quality exceedance would not have occurred, then the cumulative effect on air quality from other reasonably foreseeable actions may be detrimental. Cumulative Impacts Table 19 summarizes the cumulative impacts of the range of alternatives combined with other past, current, and reasonably foreseeable future actions. With respect to air quality, Alternative A is the least sustainable options, while Alternative B is the most sustainable option. The subsections that follow, describe the cumulative impacts associated with each alternative. Table 19: Comparison of Cumulative Impacts by Alternative For alternative Permitting cross-country travel Would result in The Least benefit to air quality and A greatest impact from blowing dust caused by taking no action by damage to soil crusts compared with B, C and D. B The greatest benefit to air quality and by allowing fuelwood gathering within 300 feet lowest impact from blowing dust caused of all designated routes and dispersed by damage to soil crusts compared with camping use at designated sites A,C and D. A benefit to air quality and lower impact C from blowing dust caused by damage to D by allocating the most acres of for dispersed camping and big game retrieval soil crusts compared with A and D. The least benefit for air quality and lower impact from blowing dust caused by damage to soil crusts compared with A, B and C. Alternative A Under the No-Action Alternative, routes would not be designated and cross country travel would continue unmanaged. Fugitive dust would likely continue to contribute to measured air quality violations in Maricopa and Pinal Counties. Taking no action would result in continued damage to biological or otherwise physical soil crusts which protect soil surfaces from wind erosion and ultimately air quality from the effects of blowing dust. The severity, size, frequency, and timing of blowing dust define its impact, and where the severity of blowing Page 63 of 88

65 dust is expected to scale with the area of soil crusts damaged. With time, more severe dust storms are anticipated as more forest soil crust is damaged causing local dust emissions to have a greater impact on regional air quality. Alternative B Alternative B has the fewest miles of roads and motorized trails open to the public (3, miles) and the most miles of roads proposed for decommissioning. Motor vehicle use for big game retrieval is not permitted and dispersed camping use is restricted to designated sites. Cross-country travel for fuelwood gathering within designated areas is permitted for up to 300 feet on both sides of all designated motorized routes. The portion of blowing dust attributed to cross-country travel would gradually decline for unroaded areas due to their respective prohibitions on cross-country travel. Unroaded areas may eventually return to natural or near-natural conditions as biological crusts restabilize the damaged soils by gluing loose particles back together (USDOI, 2001). However, more severe warming and drought brought on by climate change may lead to additional worsening of air quality by increasing the rate of NO x conversion to ozone and from a greater chance for wildfires, which produce large amounts of both ozone and PM 10 pollutants. Alternative C Alternative C has the second lowest number of miles of roads designated to be open to the public (3, miles), but has the most miles of motorized trails (2,151 miles). The portion of blowing dust attributed to cross-country travel would gradually decline for unroaded areas due to their respective prohibitions on cross-country travel. Unroaded areas may eventually return to natural or near-natural conditions as biological crusts restabilize the damaged soils by gluing loose particles back together (USDOI, 2001). However, more severe warming and drought brought on by climate change may lead to additional worsening of air quality by increasing the rate of NO x conversion to ozone and from a greater chance for wildfires, which produce large amounts of both ozone and PM 10 pollutants. Alternative D Alternative D has the most miles of motorized roads open to travel by the public (4, miles) and the most acres of cross-country travel for the purposes of dispersed camping and big game retrieval. Windblown dust emissions would be greatest for this alternative due to cross-country travel, after the no action alternative. The portion of blowing dust attributed to cross-country travel would gradually decline for unroaded areas due to their respective prohibitions on cross-country travel. Unroaded areas may eventually return to natural or near-natural conditions as biological crusts restabilize the damaged soils by gluing loose particles back together (USDOI, 2001). However, more severe warming and drought brought on by climate change may lead to additional worsening of air quality by increasing the rate of NO x conversion to ozone and from a greater chance for wildfires, which produce large amounts of both ozone and PM 10 pollutants. Page 64 of 88

66 Figure 37: Arizona Airshed Boundaries Page 65 of 88

67 Figure 38: Length of Time for Soil Disturbance Effects to Return to Natural Conditions Resistance of sandy loam soils to wind erosion following disturbance to a well-developed biological soil crust in four time classes. Threshold friction velocity is the force required to detach soil particles from the surface. Time classes indicate the length of time since disturbance to the control. Following determination of threshold friction velocities for controls, treatments were applied as follows: Foot = one pass wearing lug-soled boots; Tire, 1 Pass = one pass of a four-wheel drive vehicle with knobbed tires; Tire, 2 Pass = two passes of a four-wheel drive vehicle with knobbed tires. Within each time sequence, controls were significantly more resistant to wind erosion than treated surfaces. Adapted from Belnap and Gillette (1997). Page 66 of 88

68 Appendix F: Climate Change Impact on Air Quality Anticipated changes in the global climate over the coming decades could alter weather patterns resulting in higher temperatures, more intense droughts, worsening air quality and greater demand for forest resources. By the end of this century, temperatures are expected to rise approximately five to eight degrees Fahrenheit with the greatest warming to occur during the winter season (IPCC, 2015). This warming trend may lead to shorter winters and a longer season for summer activities (Joyce et al., 2001). Rising temperatures may also lead to higher ground-level ozone concentrations. Ozone forms more readily under high temperatures and in the presence of nitrogen oxides, which may be emitted to the atmosphere in larger amounts as demand for electricity increases, in part from higher demand for air conditioning. More intense droughts may lead to more fugitive dust from areas where off-highway vehicle (OHV) use is in high demand. As the climate changes, so does the demand for forest resources. Therefore, maintaining forest roadways and managing the use of OHVs has become an important priority. Current scientific consensus is that climate change is caused by a buildup of atmospheric greenhouse gasses, and that those greenhouse gasses modify the atmosphere s thermal radiative effect on surface temperatures. A review of current literature reveals average global temperatures are expected to increase by 0.5 degrees Fahrenheit to 8.6 degrees Fahrenheit by 2100 and by at least twice as much in the next 100 years as it has during the last 100 years (EPA, 2015). Climate models project an increase in the number of days with maximum temperatures above 90 degrees Fahrenheit for the United States, while precipitation rates will decline by five percent for much of Arizona and as much as ten percent for Arizona s southern half. Climate modelers generally agree that the Southwestern United States is experiencing a drying tend that will continue into the latter part of 21st century. Some potential ecological implications of climate change trends in the Southwestern United States include (U.S. Forest Service, 2010): More extreme disturbance events, including wildfires and intense rain and flashfloods and wind events (Swetnam et al., 1999). Greater vulnerability to invasive species, including insects, plants, fungi, and vertebrates (Joyce et al., 2007). Long-term shifts in vegetation patterns (Westerling et al., 2006; Millar et al., 2007). Cold-tolerant vegetation moving upslope, or disappearing in some areas. Migration of some tree species to the more northern portions of their existing range (Clark, 1998). Potential decreases in overall forest productivity due to reduced precipitation (USDA Forest Service 2005). Shifts in the timing of snowmelt (already observed) in the American West, which, along with increases in summer temperatures, have serious implications for the survival of fish species, and may challenge efforts to reintroduce species into their historic range (Joyce et al. 2007, Millar et al. 2007). Effects on biodiversity, pressure on wildlife populations, distribution, viability, and migration patterns, because of increasing temperatures, water shortages, and changing ecological conditions. Page 67 of 88

69 Current conditions and trends in greenhouse gas emissions Transportation-related emissions from cars, trucks, trains, ships, airplanes, and other vehicles are a major source of both regional air pollution and global climate change. Greenhouse gas emissions from transportation sources, resulting from the combustion of petroleum-based products like gasoline in internal combustion engines, are emitted in the form of carbon dioxide (CO 2 ), water vapor, methane (CH 4 ) and nitrous oxide (N 2 O). In 2013, greenhouse gas emissions from transportation accounted for about 27 percent of total U.S. greenhouse gas emissions, making it the second largest contributor of U.S. greenhouse gas emissions after energy production. Passenger cars and light-duty trucks are the largest sources of transportation-related greenhouse gas emissions in the U.S. and account for over half of the emissions from all mobile sources. The remainder of greenhouse gas emissions comes from other transportation modes such as commercial aircraft, shipping and trains. In 2011, the non-road sector, which is a broad subset of transportation sources that includes recreational off-highway vehicles, contributed approximately one percent of total U.S. emissions of CO 2 and have declined by approximately 25.9 percent between 1990 and The following is a list of equipment categories for the non-road sector 7 : Lawn and Garden Equipment Industrial Equipment Airport Service Equipment Construction Equipment Recreational Equipment Agricultural Equipment Recreational Marine Equipment Logging Equipment Light Commercial Equipment Commercial Marine Vessels Off-highway vehicles are a subset of Recreational Equipment, which includes snowmobiles, dirt bikes, and ATVs. Figure 39 shows the yearly U.S. greenhouse gas emissions from the non-road transportation sector from 1990 to Recreational equipment include snowmobiles, dirt bikes, and ATVs (EPA Non-road Engine and Vehicle Emission Study, 1991). 8 Mobile Non-Road sector includes snowmobiles, dirt bikes, and ATVs (www3.epa.gov/climatechange/ghgemissions/inventoryexplorer/#transportation/allgas/source/all) Page 68 of 88

70 Figure 39: U.S. Greenhouse Gas Emissions, Non-Road Transportation Sector In Arizona, the majority of carbon dioxide (CO2) and nitrous oxide (N2O) emissions come from mobile on-road sources such as passenger vehicles. The non-road sector accounted for approximately two percent of the total CO2 emissions in 2011, while wildfires and prescribed fires were responsible for approximately 92 percent of all methane emissions during the same year. See Figure 40 for percent contributions of greenhouse gasses in Arizona for Figure 40: 2011 Arizona Greenhouse Gas Emissions by Sector The Southwestern Regional Office planning program has summarized some ecological and socioeconomic effects of climate change (U.S. Forest Service, 2010). This document suggests the state of knowledge needed to address climate change at the forest scale is still evolving. Most global climate models are not yet suitable to apply to land management at the forest scale. This limits regional analysis of potential effects especially for a specific project. Assumptions and Methodology The following analysis presents the effects of climate change on air quality and public health, including current regulatory and environmental conditions, relevant to travel management planning on the Tonto National Forest. The four alternatives are evaluated based on their potential to contribute to increased air pollution under projected climate change conditions. Page 69 of 88