Tips for Final Project

Size: px

Start display at page:

Download "Tips for Final Project"

Harry Henderson
5 years ago
Views:

1 Tips for Final Project Check with us before starting in earnest on your project. Address all parts of the assignment and look at the grading criteria. Provide references for your facts, i.e., crude produced from Canadian oil sands requires 4 times more water than conventional crude, an EV costs $15K more than a similar sized GV. Pre-review option until July 21. Be careful with second-hand quotes. Check the original source (better) or quote the secondary source, i.e., Zenher et al. (date) quotes xyz as concluding that (acceptable) If you cite a fact make sure it supports your argument. Several people mentioned SF6 (a potent GHG) release in the production of solar panels, but no one bothered to check if the full life-cycle GHG emissions for solar power was greater or less than other power sources. Major weaknesses of each study UCS - never mentioned additional up-front cost of purchasing an EV & only focused on GHGs. Zehner - used a variety of facts from a variety of places with no discussion of assumptions or if the entire life-cycle was considered, some of which were used in misleading ways. Note about BW & inhalation

2 Mobile Source Emissions K.E. Kelly

3 Outline Vehicle emissions and health effects Criteria pollutant Toxics Combustion emission control and tradeoffs Emission and fuel-economy standards Non-Combustion emissions Evaporative emissions Tire & breakwear I&M programs

Transportation Emissions are a Big Contributor to Air Pollution In 2013 (highway and non-highway vehicles): 53% of CO (decreasing) 59% of NOx (decreasing) 2% of PM10 5% of PM2.

4 Transportation Emissions are a Big Contributor to Air Pollution In 2013 (highway and non-highway vehicles): 53% of CO (decreasing) 59% of NOx (decreasing) 2% of PM10 5% of PM2.5 2% of Sox 23% of VOCs (decreasing) 3% of NH3 Corresponding decrease in CO and VOCs in urban areas from McDonald et al. (2013) ES&T. from:

5 Health Effects of Vehicle Emissions Vehicle exhaust contains several hazardous air pollutants, including benzene, formaldehyde, and 1,3-butadiene (cancer or cancer-suspect agents). Over 35 million people in the United States living within 300 feet of a major road ( Health effects include: reduced lung function and impaired development in children, asthma, cardiovascular disease, low birth weight, pre-term newborns, and premature death. potential link between childhood leukemia and exposure to high levels of auto exhaust. It is unclear which pollutants are most active near near roadways, how people are exposed to them, the extent of exposure, and the type and severity of health effects. In addition: How do barriers (e.g., walls and vegetation) influence exposure to near-road pollutants? Can pollutants be reduced or eliminated in school buildings by using technologies that modify the ventilation system or reduce infiltration?

6 Per Vehicle Emissions Decrease while VMT Increases

7 Engine Operation and Effect on Pollution Rich Stoichiometric Lean When startup, idling, acceleration 3-way catalysts like this Steady driving at light load, freeway Power Highest Avg Poor Fuel worst avg Best econo CO High Med Low HC High Med Low NOx Low Med High from DeNevers (2000)

8 Tradeoffs between Pollutants Note difference scales Emissions and fuel consumption for a typical IC engine at steady operation (DeNevers 2000)

9 Estimating CO Emissions using Stoichiometry

10 3-Way Catalytic Converter Reduction Catalyst - platinum and rhodium. It converts oxides of nitrogen (NOx) to N2 and O2 via the following reactions: 2NO N2 + O2 2NO2 N2 + 2O2 Oxidation Catalyst - platinum and palladium. It coverts CO and hydrocarbons (HC) in the gases into CO2 and H2O via the following reactions: 2CO + O2 2CO2 HC + O2 CO2 + H2O (where HC is a generic hydrocarbon) 3-way catalytic converter Exhaust with HC, NOx and CO Reduction catalyst NOx removed Oxidation catalyst Exhaust with N2, CO2, and H2O

3-Way Catalytic Converter Operate efficiently in a narrow band of airto-fuel ratios near stoichiometric Too fuel lean and NOx reduction is not favored Too fuel

11 3-Way Catalytic Converter Operate efficiently in a narrow band of airto-fuel ratios near stoichiometric Too fuel lean and NOx reduction is not favored Too fuel rich and too little oxygen remaining to oxidize the HC and CO Ammonia and H2S are unwanted byproduct reactions

12 How do We Really Estimate Mobile Emissions EPA Mobile and Moves Fuel consumption Vehicle fleet information (I&M) Emission factors, which vary with vehicle age (homework) Traffic counts Sophisticated estimates for SIP and regional planning activities

13 Tier 3 Emission Standards More stringent emission control technology and fuel standards. Lowering fuel sulfur content from 30 ppm to 10 ppm sulfur (companywide average) by 2017 (some delays allowed for small refineries). Sulfur poisons the vehicle s catalytic converter. Lowering tailpipe emissions standards for model years 2017 through 2025: for LDVs NMOG and NOx emissions will decrease by 80% compared to today s standards. For HDVs, 60% reduction in NMOG, NOx and PM standards. for LDVs, PM standards will decrease by 70%. Tightening evaporative emissions standards which will result in a 50 % reduction in evaporative emissions. Harmonizes with California standards.

14 Evaporative Emissions & Control Strategies Evaporative emissions - can be responsible for the majority of HC emissions on hot days. Diurnal - as temperature increases, the vapor pressure in the gas tank increases, causing gasoline vapors to vent. Running losses - the hot engine and exhaust system can cause fuel to vaporize Refueling (both vehicles and tankers) - Gasoline vapors are always present in fuel tanks. These vapors are forced out when the tank is filled with liquid fuel.

15 Tier 3 Emission Standards vehicle-emission-and-fuel-standards

16 Projected Change in PM2.5 levels by

17 CAFE Standards Strategies: - Hybrid and electric vehicles - Improving engine and transmission efficiency - Reducing weight - Improving vehicle aerodynamics - Decreasing engine size!

Non-Combustion Emissions Breakwear (iron, copper, antimony, and barium) Reentrained road dust (unpaved roads) Tirewear - primarily carbonaceous material with trace levels of zinc 38% - resuspended

18 Non-Combustion Emissions Breakwear (iron, copper, antimony, and barium) Reentrained road dust (unpaved roads) Tirewear - primarily carbonaceous material with trace levels of zinc 38% - resuspended dust 55% - brake dust 10% - tire dust 10.7 Harrison et al. (2012) Estimation of the Contributions of Brake Dust, Tire Wear, and Resuspension to Nonexhaust Traffic Particles Derived from Atmospheric Measurements. ES&T ,

19 High-Emitting Vehicles and I&M Programs According to the NRC, 50 60% of on-road LDV exhaust emissions are produced by about 10% of the dirtiest LDVs. Estimates vary widely depending on how you define a highemitting vehicle. States and regions have I&M programs, but effectiveness is difficult to measure: Do repaired vehicles maintain acceptable emission levels? Are vehicles just relocated to other areas? But one of the few tools available and states get SIP credit. Evaluating Vehicle Emissions Inspection and Maintenance Programs Maintenance Programs

Tier 3 Vehicle and Fuel Standards: Final Rule. March 2014

Tier 3 Vehicle and Fuel Standards: Final Rule March 2014 1 Overview What is Tier 3? Why Tier 3? Overview of the Program Benefits and Costs 2 What is Tier 3? Systems approach to reducing motor vehicle pollution: