Metropolitan Transit. Prepared for. Original Submittal: May 28, Resubmitted: November 10, 2010 January 21, aq5-28

Transcription

1 Criteria Pollutant Air Dispersion Modeling Analysis for Metro Transit s Existing Hiawatha Light Rail Vehicle Operation & Maintenance Facility, Proposed Paint Booth, and Proposed Light Rail Support Facility Prepared for Metropolitan Transit Original Submittal: May 28, 2010 Resubmitted: November 10, 2010 January 21, 2011 aq5-28

2 Criteria Pollutant Air Dispersion Modeling Analysis for Metro Transit s Existing Hiawatha Light Rail Vehicle Operation & Maintenance Facility, Proposed Paint Booth, and Proposed Light Rail Support Facility Wenck File # Phases 13 Prepared for: METROPOLITAN TRANSIT th Avenue North Minneapolis, MN Original Submittal: May 28, 2010 Prepared by: WENCK ASSOCIATES, INC Wooddale Drive Suite 100 Woodbury, MN (651) Resubmitted: November 10, 2010 January 21, 2011

3 Table of Contents 1.0 INTRODUCTION MODEL INPUT Model Selection Model Options Building Downwash Receptor Grid Meteorological Data AIR EMISSION SOURCES ANALYSIS OF RESULTS TABLES (included throughout the text) 3-1 Modeling Source Parameters 4-1 Estimated Criteria Pollutant Ambient Air Concentrations FIGURES (included throughout the text) 2.1 Air Dispersion Modeling Receptor Grid 2.2 Near-Field Air Dispersion Modeling Receptors 4.1 NO2 1-Hour Average High Modeled Concentrations 4.2 PM Hour Average High Modeled Concentrations APPENDICES A Criteria Pollutant Air Dispersion Modeling T:\0141\89\tech\Phase 13 - Revised Reports\Modeling\Criteria Pollutant Modeling Report doc i

4 1.0 Introduction Air dispersion modeling was completed for Metro Transit s existing Hiawatha Light Rail Vehicle Operations & Maintenance (HLRV O&M) Facility and the proposed Light Rail Support (LRS) Facility. The two facilities are considered a single stationary source for air permitting by the MPCA. The HLRV O&M site includes a proposed paint booth and expansion of the building footprint. This air dispersion modeling supports the air permit application for the facilities. In addition, air dispersion modeling was completed to support the Screening-Level Air Emissions Risk Analysis (AERA) conducted for the facilities; please refer to the AERA for details. Modeling was submitted in April, May, and November Following those submittals, plans for the HLRV O&M expansion had matured to the extent that they were able to be included in this modeling report. This report updates earlier modeling to incorporate MPCA comments as well as the proposed expansion. T:\0141\89\tech\Phase 13 - Revised Reports\Modeling\Criteria Pollutant Modeling Report doc 1-1

5 2.0 Model Input 2.1 MODEL SELECTION The Metro Transit modeling used the AMS/EPA Regulatory Model with Plume Rise Model Enhancements (AERMOD), version 09292, to estimate criteria pollutant concentrations at and around the HLRV O&M and LRS facilities. AERMOD is a preferred air dispersion model in the United States Environmental Protection Agency s (EPA) Guideline on Air Quality Models, 40 CFR 51 Appendix W. Pollutant specific concentrations were entered for PM 2.5, PM 10, CO, NO x, lead, and SO MODEL OPTIONS All options within AERMOD recommended by the EPA as regulatory defaults were used. These options include: 1) using elevated terrain algorithms that require the input of terrain height data; 2) using stack-tip downwash as applicable; 3) using routines to process averages during calm winds; and 4) using algorithms to handle missing meteorological data. Averaging periods with an applicable National Ambient Air Quality Standard (NAAQS), Minnesota Ambient Air Quality Standard (MAAQS), or Significant Impact Level (SIL) were modeled. In accordance with EPA s March 19, 2009, AERMOD Implementation Guidance, the Urban Mode was selected. The Urban Mode estimates the effects of urban heat islands. Current EPA guidance is to use the Urban Mode for all sites within urban statistical areas regardless of whether nearby land uses would be considered urban or not, and regardless of the location of the meteorological data site. A population of 1,000,000 will be entered for the Minneapolis/St. Paul area, obtained from MPCA on other recent air dispersion modeling. Selection of the Urban Mode is a change from earlier modeling submitted for the facility, in response to MPCA s comments dated August 19, T:\0141\89\tech\Phase 13 - Revised Reports\Modeling\Criteria Pollutant Modeling Report doc 2-1

6 2.3 BUILDING DOWNWASH The Building Profile Input Program with Plume Rise Model Enhancements (BPIP-PRIME), version 04274, was used to calculate building downwash parameters for the modeling analysis. Elevations of stacks and buildings were input into BPIP-PRIME. 2.4 RECEPTOR GRID A Cartesian receptor grid was used in the modeling analysis to determine concentrations for the modeling analysis. The grid extended 1.5 kilometers from the property line in each direction, in accordance with MPCA s RASS guidance for stacks less than 50 meters tall. The receptors were placed at 100 meter spacings. In addition, receptors were located at every 25 meters along the facility property line as well as along the bike path running through the northeast side of the facility. Receptor locations are shown in Figures 1 and 2. In response to MPCA comments, elevated (or flagpole ) receptors were placed at the nearest point to the HLRV site for the three apartment buildings located between Franklin Avenue and 22 nd St., just west of Hiawatha Avenue. The buildings appear to be 12 stories tall from aerial photographs of the site, not including the penthouses. The penthouses do not appear to include residences. A height of 120 feet was assumed for each building. Flagpole heights were included at ground level, 30 ft, 60 ft, 90, ft, and 120 ft for each building. Flagpole receptors will also be included for the senior housing located on Cedar Avenue and Sixth Street, north/northwest of the facility. The senior housing appears to be 26 stories tall from aerial photographs. Flagpole heights were included at heights of ground level, 65 ft, 130 ft, 195 ft, and 260 ft at the corner of the building closest to the Metro Transit property line. The modeling results predict that concentrations are lower at the elevated flagpole heights than at ground level. High concentration occurs along the facility property lines and, therefore, the 1.5 kilometer grid captures high facility concentrations. Receptor elevations were determined using the AERMOD Terrain preprocessor (AERMAP), version 09040, and USGS National Elevation Dataset (NED) files. The option T:\0141\89\tech\Phase 13 - Revised Reports\Modeling\Criteria Pollutant Modeling Report doc 2-2

7 of NADA=4 was used to reference the North American Datum (NAD) of 1983 anchor coordinates based on the AERMAP User s Guide. 2.5 METEOROLOGICAL DATA Minneapolis/St. Paul, Minnesota surface meteorological data was selected for the years 2000 through Processed meteorological data was provided by MPCA. The Minneapolis/St. Paul site is the closest meteorological data site to the area of interest for this project, and is the most urban of the available upper Midwestern meteorological data. Therefore, the Minneapolis/St. Paul data is believed to be the most representative. Upper air data for the corresponding years were obtained from the Minneapolis National Weather Service station. T:\0141\89\tech\Phase 13 - Revised Reports\Modeling\Criteria Pollutant Modeling Report doc 2-3

8 Metro Transit Wenck Associates, Inc Pioneer Creek Center Maple Plain, MN November 2010 Air Dispersion Modeling Receptor Grid Figure 2-1 T:\0141\89\tech\Phase 3 - Modeling\Expansion Modeling\Criteria Pollutant Report Figures and Tables.doc

9 Property line receptors are shown as a purple +. Discrete receptors are shown as a yellow +. Property lines are shown in red. Building footprints are shown in blue. Metro Transit Near-Field Air Dispersion Modeling Receptors T:\0141\89\tech\Phase 3 - Modeling\Expansion Modeling\Criteria Pollutant Report Figures and Tables.doc Wenck Associates, Inc Pioneer Creek Center Maple Plain, MN Nov Figure 2-2

10 3.0 Air Emission Sources The modeled source parameters are attached in Table 3-1. Supporting calculations for criteria pollutants are included with the AERA report and are not repeated here. The facilities Make-up Air Units (MAUs) nos. 1-4 exhaust indoors. The exhaust fans that are interlocked with these MAUs were modeled as the exhaust points for the MAUs. Material use emissions that occur throughout the facility were included in the AERA. The only criteria pollutant emissions from material use are VOCs and, therefore, are not included in the criteria pollutant modeling analysis. Correspondence with MPCA indicated that it is reasonable to exclude insignificant sources from the air dispersion modeling and health risk assessment. These excluded emission units include the combustion units with a capacity of less than 1% of the total facility heat input for the AERA. Emission units excluded from the AERA were also excluded from the criteria pollutant analysis. Criteria pollutant sources with emissions less than 0.1 lb/hr such as the facility s sand silo were also excluded. The facility sand silo has no toxic emissions and has particulate emissions less than 0.1 lb/hr. A Tier 2 NO 2 ambient concentration of 75% of total NO x emissions is proposed for 1-hour NO 2 modeling. The Tier 2 value is the national default value for the average annual ambient concentration of NO 2 versus total NO x, obtained from 40 CFR 51 Appendix W. A significant fraction of NO x from combustion sources is emitted as NO. NO is converted to NO 2 in the atmosphere. The conversion time and fraction is dependent upon a number of variables such as temperature and ozone concentrations, and is not instantaneous. For comparison to the annual (as opposed to 1-hour) NO 2 National Ambient Air Quality Standard, the Tier 2 value was not used. Instead, the conservative Tier 1 assumption of 100% conversion of NO x to NO 2 was used. For the 1-hour NO 2 National Ambient Air Quality Standard, EPA s Tier 2 NO 2 /NO x ratio of 75% was applied to the NO x emission rates so that 1-hour NO 2 concentrations were estimated by AERMOD. Since emissions are directly proportional to concentrations in AERMOD, the same results would be obtained by entering total NO x emission rates and multiplying the predicted NO x concentration T:\0141\89\tech\Phase 13 - Revised Reports\Modeling\Criteria Pollutant Modeling Report doc 3-1

11 by 75% to obtain 1-hour NO 2 concentrations. The 75% value applies to estimated ambient concentrations rather than the emission rates that would be expected in-stack. EPA indicated in the June 28, 2010 memorandum on The Applicability of Appendix W Modeling Guidance for the 1-Hour NO 2 National Ambient Air Quality Standard that for low-level sources with limited plume rise that the 75% Tier 2 value will likely be conservative. High 1-hour concentrations in the previously submitted Metro Transit modeling occurred at the property line. The highest proposed stack height at the facility is 60 feet above ground and all exit velocities are below 10 m/s. Therefore, the facility sources can be characterized as low-level with limited plume rise. The NO 2 modeling, for all five meteorological years, each of the 1 st high and 8 th high 1-hour NO 2 concentrations occurred either during the night or in winter morning hours (such as 6:00 am in January and February). EPA also noted in the June 28, 2010 memorandum that stable nighttime conditions would limit the entrainment of ozone and, therefore, the 75% concentration is expected to be conservative for these meteorological conditions. Wenck does not expect additional modeling will change which meteorological conditions predict the highest ambient concentrations. Therefore, the 75% NO 2 /NOx value appears to be conservative for estimation of 1-hour NO 2 ambient concentrations. The ratio of ambient NO 2 to NO x concentrations is effected more by atmospheric conversion of NO to NO 2, compared to the in-stack concentrations of NO 2, since the majority of NO x is emitted as NO rather than NO 2 from uncontrolled combustion sources. For the Ozone Limiting Method (OLM) in Tier 3 NO 2 modeling, a 0.10 NO 2 /NO x in-stack ratio is often used as a default in the absence of stack test data, therefore, EPA s discussion of ambient and stack discharge conditions where the Tier 2 value is conservative is applicable to the Metro Transit modeling. Criteria pollutant emission rates for the modeling are presented in the facility s air permit application. The calculations are also included electronically in Appendix A. The modeled emission rates include a daily paint booth coatings limit, an annual paint booth coatings limit, and a proposed annual natural gas limit. T:\0141\89\tech\Phase 13 - Revised Reports\Modeling\Criteria Pollutant Modeling Report doc 3-2

12 Table 3-1 Point Source Exhaust Parameters Location Exhaust Height Height Exit Exhaust Base Exit from Ground Above Temperature Flowrate Diameter UTM East UTM North Elevation Velocity Source Source Description Roof (ft) (K) ( o F) (acfm) (m/s) (ft) (ft) SV001 HLRV Paint Booth Vent 1 (EF-11) 480, ,979, , SV002 HLRV Paint Booth Vent 2 (EF-26) 480, ,979, , SV003 HLRV Paint Booth Vent 3 (EF-27) 480, ,979, , SV005 HLRV Welding 480, ,979, SV006 HLRV Water Heater 480, ,979, SV007 HLRV Bryan B-1 Boiler 480, ,979, SV008 HLRV RTU-5 480, ,979, SV009 HLRV Pressure Washer 480, ,979, SV010 HLRV South Air Curtain Furnace 480, ,979, SV011 HLRV North Air Curtain Furnace 480, ,979, SV012 HLRV Gun Cleaning 480, ,979, Side of Bldg SV013 HLRV MAU1 Vent 1 (EF-1) 480, ,979, , SV014 HLRV MAU1 Vent 2 (EF-2) 480, ,979, , SV015 HLRV MAU1 Vent 3 (EF-3) 480, ,979, , SV016 HLRV MAU1 Vent 4 (EF-4) 480, ,979, SV017 HLRV MAU1 Vent 5 (EF-5) 480, ,979, , SV018 HLRV MAU1 Vent 6 (EF-6) 480, ,979, , SV019 HLRV MAU2 (EF-9) 480, ,979, , SV020 HLRV MAU3 (EF-11) 480, ,979, , SV021 HLRV MAU4 Vent 1 (EF-13) 480, ,979, , SV022 HLRV MAU4 Vent 2 (EF-14) 480, ,979, , SV023 HLRV MAU4 Vent 3 (EF-15) 480, ,979, SV024 HLRV MAU5 480, ,978, SV025 HLRV MAU6 480, ,979, SV026 HLRV MAU7 480, ,978,

13 Source Source Description UTM East Location UTM North Table 3-1 Point Source Exhaust Parameters Base Elevation Exhaust Height Height Exit Exhaust Exit from Ground Above Temperature Flowrate Diameter Velocity Roof (ft) (K) ( o F) (acfm) (m/s) (ft) (ft) SV027 HLRV MAU8 480, ,979, SV028 HLRV VP-1 480, ,978, SV029 HLRV VP-2 480, ,979, SV030 LRS HVAC RTU-1 480, ,978, SV031 LRS MAU1 480, ,978, SV032 LRS Boiler B-1 480, ,978, SV033 LRS Boiler B-2 480, ,978, Source Source Description UTM East Location Table 3-2 Area Source Exhaust Parameters UTM North Base Elevation (ft) Release Height Easting Side Length Northing Side Length Angle of Rotation (deg) HLRVMSC1 HLRV Misc. Maint. Act , ,978, HLRVMSC2 HLRV Misc. Maint. Act , ,979, HLRVMSC3 HLRV Misc. Maint. Act , ,979, HLRVMSC4 HLRV Misc. Maint. Act , ,979, HLRVMSC5 HLRV Misc. Maint. Act , ,979, LRSMSC1 LRS Misc. Maint. Act , ,978, LRSMSC2 LRS Misc. Maint. Act , ,978, LRSMSC3 LRS Misc. Maint. Act , ,978, Initial Vertical Dimension 3-4

14 4.0 Analysis of Results Estimated ambient air concentrations from the modeling analysis are shown in Table 4-1. Following MPCA s guidance for Minn. Stat Subd. 4a, the Prevention of Significant Deterioration (PSD) Significant Impact Levels (SILs) were used as an acceptable ambient concentration for the HLRV O&M and LRS impacts without background. In addition, background concentrations were added to the high modeled concentrations to obtain total ambient impacts for comparison to the National and Minnesota Ambient Air Quality Standards. Background concentrations were obtained from MPCA s SAM spreadsheet, unless otherwise noted. Option 1 values were selected. Option 1 values are for sites that do not include nearby sources in the air dispersion modeling. Concentrations were selected for Minneapolis if available, or for the Twin Cities where separate Minneapolis values were not listed by the MPCA. Lead and 1-hour NO 2 background concentrations were not included in the SAM spreadsheet. MPCA recommended an NO 2 urban background 1-hour average concentration of 83 ug/m 3 for 1- hour NO 2 based on the Blaine monitoring station on another recent project. The Blaine NO 2 concentration is higher than other NO 2 monitoring sites in Minnesota. The lead background concentration was obtained from MPCA s 2011 Annual Air Monitoring Network Plan, page 26, indicating the majority of sites in Minnesota have monitored lead concentrations below 0.01 ug/m 3. Figure 16 from this monitoring network plan shows that the nearby th Ave S., Chase Anderson School monitoring site (No. 963) has concentrations at this level. T:\0141\89\tech\Phase 13 - Revised Reports\Modeling\Criteria Pollutant Modeling Report doc 4-1

15 To minimize run times for the project, a multi-cpu processor computer was used for this analysis. Lakes Environmental has developed a version of AERMOD that is designed to minimize run times on multi-cpu processor computers that are now commonly available. The version is called AERMOD MPI. The modeling completed in this analysis utilized Lakes Environmental s AERMOD MPI executable. AERMOD MPI reduced the run-times for this analysis by approximately eight-fold. In past projects approved by MPCA, Wenck completed a comparison of the design concentrations using the US EPA SCRAM AERMOD version and Lakes Environmental s AERMOD MPI. The demonstration showed that the results were identical using both versions. Therefore, Wenck believes it is valid to rely upon Lakes Environmental s AERMOD MPI executable for this modeling demonstration. The modeling shows that the HLRV O&M and LRS facilities meet all ambient air quality standards both at and beyond the facilities property lines. The site meets most SILs with the exception of the interim NO 2 1-hour SIL and the final PM hour SIL. Isopleth contour figures are included, showing the areas with predicted concentrations above the SILs. The larger of the two areas, the NO 2 impact area, is being addressed in the cumulative impacts analysis. EPA sets the NAAQS to be protective of human health. EPA reviewed the NO 2 and PM 2.5 NAAQS in 2010 and 2006, respectively. Therefore, the scientific background data used by EPA for the NAAQS health risk assessments is expected to be up-to-date. The SILs are not based on health risk criteria but are typically used to demonstrate a source does not have culpability towards a high concentration, or that a full air quality analysis is not required. The SILs are applied to the Metro Transit facility to identify the area that will be discussed in the cumulative impacts analysis. T:\0141\89\tech\Phase 13 - Revised Reports\Modeling\Criteria Pollutant Modeling Report doc 4-2

16 Pollutant PM 2.5 Averaging Period and High Selected Table 4-1. Estimated Criteria Pollutant Ambient Air Concentrations HLRV and PSD Estimated LRS Significant Background Ambient Air Modeled Impact Concentration Concentration Level ( g/m 3 Concentration ) ( g/m 3 ) ( g/m 3 ( g/m 3 ) ) National Ambient Air Quality Standard ( g/m 3 ) Minnesota Ambient Air Quality Standard ( g/m3) 24-Hour, 1 st High Annual, High PM Hour, 1 st High Annual, High CO 1-Hour, 1 st High ,565 3,631 40,000 35,000 8-Hour, 1 st High ,760 2,799 10,000 10,000 SO 2 1-Hour, 1 st High ,300 3-Hour, 1 st High , Hour, 1 st High Annual, High Lead 3-Month Average (rolling), High Month Identified 2 NO 2 /NO x 1-Hour, 1 st High Annual, High Separate model runs including proposed annual throughput limits were not completed for SO 2 since the estimated annual concentrations for this pollutant is below the applicable significant impact level or ambient air quality standard. Including annual limits would reduce predicted annual average concentrations. 2 For the 1-hour NO 2 analysis, the 40 CFR 51 Appendix W NO 2 /NO x fraction of 0.75 was used to estimate the fraction of NO x in the form of NO 2 in the ambient air. For the annual NO 2 analysis, all NO x emissions were assumed to form NO 2 in the ambient air. T:\0141\89\tech\Phase 13 - Revised Reports\Modeling\Criteria Pollutant Modeling Report doc 4-3

17 Contours are in units of g/m 3. The NO 2 1-Hour Interim Significant Impact Level (SIL) of 7.5 g/m 3 is shown in bold. Metro Transit Wenck Associates, Inc Pioneer Creek Center Maple Plain, MN November 2010 NO 2 1-Hour Average High Modeled Concentrations Figure 4-1 T:\0141\89\tech\Phase 3 - Modeling\Expansion Modeling\Criteria Pollutant Report Figures and Tables.doc

18 Contours are in units of g/m 3. The PM Hour Average Significant Impact Level (SIL) of 1.2 g/m 3 is shown in bold. Metro Transit Wenck Associates, Inc Pioneer Creek Center Maple Plain, MN Nov PM Hour Average High Modeled Concentrations Figure 4-2 T:\0141\89\tech\Phase 3 - Modeling\Expansion Modeling\Criteria Pollutant Report Figures and Tables.doc

19 Appendix A Electronic Dispersion Modeling Files (CD-ROM)