Mobile Source Air Toxics: Overview and Regulatory Background Melanie Zeman USEPA Region 2 Northern Transportation & Air Quality Summit August 14, 2008
About MSATs More than 1000 compounds have been identified in exhaust and evaporative emissions from onroad and nonroad mobile sources A number of these compounds have cancer and noncancer health effects in animals and humans. We have identified 93 compounds listed in EPA IRIS database. No formal MSAT list. 2001 MSAT rule identified list of 21 MSATs, but 2007 rule eliminated it in favor of more flexible and expansive approach EPA s identification of key MSATs changes over time. 2
Key MSATs Diesel exhaust Benzene 1,3-Butadiene Acrolein Formaldehyde Acetaldehyde Naphthalene Polycyclic organic matter (POM) 3
Health Effects of MSATs MSATs are also part of the mixture of pollutants near major roads Exposure to near-road pollutants has been linked with adverse health effects, such as: Respiratory effects Adverse birth outcomes Premature mortality Cardiovascular effects Childhood cancer 4
Why Are We Concerned About MSATs? According to 1999 National Air Toxics Assessment (NATA) Mobile sources responsible for 50% of risk from outdoor sources of air toxics 110 million people live in areas where the combined upper-bound lifetime cancer risk from air toxics emitted by mobile sources > 10 in a million. 220 million live in areas where mobile source acrolein levels are above the health benchmark. 5
Public Health Risks Trend in U. S. cancer risk from MSATs emitted by mobile and stationary sources, 1999 to 2030 (not including diesel exhaust) -- Includes recent MSAT rule, but not locomotive and marine rule Average Nationwide Cancer Risk 3.0E-05 2.5E-05 2.0E-05 1.5E-05 1.0E-05 5.0E-06 0.0E+00 1999 2015 2020 2030 Year All MSATs Benzene 6
2020 Cumulative Cancer Risk from Exposure to MSATs from All Sources Risk (N in a million) 1.4-6.4 6.5-12.0 12.1-21.2 21.3-41.9 42.0-101.8 7
Public Health Risks Average respiratory hazard index for chronic noncancer effects from exposure to MSATs for U. S. population Hazard Index 7 6 5 4 3 2 1 mobile stationary background 0 1999 2015 2020 2030 Year Hazard Index(HI) = sum of hazard quotients (HQ) for compounds that affect the same target organ. HQ = Exposure/RfC Respiratory HI mostly due to acrolein exposure 8
Public Health Risks Large reductions through 2015 Cancer and noncancer risks from MSATS increase slightly after 2015 More people with higher cancer risk in future years Mostly due to population growth Much progress is being made, but: Potential cancer and noncancer health risks remain a concern 9
MSAT Rule Signed February 9, 2007 Elements Gasoline benzene content standard Annual refinery average benzene standard: 0.62 vol% National average today about 1.0 vol% Averaging, banking, & trading (ABT) program Effective January 1, 2011 Maximum annual refinery average benzene standard: 1.3 vol% Upper limit on benzene in a refinery s actual production Credits cannot be used to comply with this standard Effective July 1, 2012 10
Elements of EPA s s Recent Vehicle standards MSAT Rule New exhaust hydrocarbon standards for cold temps Cold temperature CO certification data showed high cold temperature NMHC emissions in Tier 2 vehicles Standard for NMHC also reduces benzene, 1,3-butadiene, formaldehyde, etc. Copollutant benefits: PM 2.5 Evaporative standards Harmonized with CA Codifies approach manufacturers are already taking Phase in from 2009-2015 11
Elements of EPA s s Recent MSAT Rule Gas cans, diesel and kerosene containers Hydrocarbon standard starting in 2009 Reduces evaporation, permeation, spillage Durable permeation barriers Automatically closing spouts Well-sealed cans Consistent with revised California program Attached garages contribute significantly to personal exposure to benzene 12
What Other Actions has EPA Taken to Address MSATs? Emission standards that reduce VOC, PM, and diesel emissions also reduce toxics Low-sulfur gasoline and Tier 2 emission standards Low-sulfur diesel and 2007/2010 HD emission standards Recent locomotive and marine engine rule Small gasoline engine proposal Voluntary programs in OTAQ National Clean Diesel Campaign Retrofit engines with emission control technology Cleaner fuels Funding and other incentives Idling reduction 13
Addressing Local Impacts National scale assessments have difficulty capturing localized impacts of mobile source pollution. Port Roads Spatial distribution of modeled annual average benzene concentrations in New Haven, CT 14
Measured Air Toxics Near Roads and Other Sources in Elizabeth, NJ Major urban arterials Gas stations Kwon et al. (2006) ES&T 15
Addressing Localized Impacts Steep spatial gradients are associated with transportation facilities such as roads. SoCal PM Center 16
Near Road In >>100 studies since late 1990s, living, working or going to school in proximity to heavy traffic is associated with significant increases in: Cardiovascular effects Prevalence of respiratory conditions and symptoms Adverse birth outcomes (LBW, etc.) Premature mortality Concentrations of criteria and hazardous air pollutants are elevated near roadways 12.6% of U.S. housing units within 300 feet of 4+ lane highway, railroad, or airport according to 2003 American Housing Survey 17
Near Source Impacts of Major Transportation Facilities Marine ports, rail yards J. R. Davis Rail yard and Port of Long Beach Studies Modeling showed substantially elevated diesel PM within 5000 meters of railyard EPA Analysis for Locomotive and Marine Rule at least 13 million people living in vicinity of railyards and ports are being exposed to elevated ambient diesel PM levels. 18
Contact Information Melanie Zeman EPA Region 2 Mobile Source Team (212) 637-4022 zeman.melanie@epa.gov 19