Surface Transportation Environmental Research A Long-Term Strategy -- Special Report 268 (2002) / Chapter Skim
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2 Research Area 1: Human Health
2 Research Area 1: Human Health
Pages 32-57
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From page 32... ...
through vehicle emissions; road dust; degra dation of drinking and stream water by road runoff from substances in vehi cles, deicing chemicals, or other substances; exposure to toxic contaminants through vehicle and battery scrappage (either directly or through contami nation of ground or surface water) ; and engine and tire noise.1 The effects of these emissions, pollutants, and wastes on health occur at different spatial scales.
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From page 33... ...
Under the Clean Air Act, the Environmental Protection Agency (EPA) is responsible primarily for estimat ing emissions from mobile, area, and stationary sources, linking emissions to concentrations of air pollutants, and linking the resulting air quality to human health.
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From page 34... ...
. In addition, mobile source air toxics from the com bustion of gas and diesel fuel pose potential human health risks.2 Air toxics are 2Mobile source air toxics include the aggregate emissions of acetaldehyde, benzene, 1,3-butadi ene, formaldehyde, and polycyclic organic matter (POM)
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From page 35... ...
Each of these linkages is explored in great detail in EPA's regulatory impact analyses of its ambient air quality standards and in both the prospective and retrospective analyses of the costs and benefits of the Clean Air Act and its 1990 amendments (EPA 1997a; EPA 1997b; EPA 1999a)
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From page 36... ...
While policy discussion has focused historically on the long-term health effects of global warming, research has indicated that reductions in mobile source greenhouse gas emissions -- provided these reductions are based on lowered fossil-fuel combustion -- may provide immediate health benefits. In a study of four major cities, Cifuentes et al.
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From page 37... ...
An important point to note with respect to transportation is that ozone concentrations evidence a strong association with daytime hours because of their dependence on sunlight; emissions of ozone pre cursors at night will not create much ozone, but will be available for downwind ozone formation in the morning. Also important for transportation, ozone and fine particulates travel long distances, so emissions in one location can affect human health in downwind locations even 1,000 miles away (TRB 1995)
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From page 38... ...
While monitoring for air quality changes is a principal means of demon strating how well an area is doing in meeting the National Ambient Air Qual ity Standards, linking monitored changes in concentrations to mobile source emissions is not a simple matter. Complex air quality models are used to make "source attributions," relating emissions from various source types and source locations to concentration changes in particular receptor locations (EPA 2001b)
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From page 39... ...
PM2.5 consists largely of particles from fuel combustion by motor vehicles or from power generation, as well as fine crustal particles from road dust and soils (Laden et al.
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From page 40... ...
note that individ uals spend a small percentage of their time outside, making personal exposure levels highly dependent on the ability of pollutants to penetrate indoor spaces and on the quality of indoor air. It is perhaps even more difficult to estimate the percentage of an individual's total level of exposure to air toxics that is due to vehicle emissions, which surely varies with distance from roads and traffic density, among other factors.
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From page 41... ...
Based on elasticities computed from various epidemiological studies (where the elasticity is the percentage change in mortality risk per average percentage change in pollution concen tration across the study sample) , acute PM10-related mortality appears to be about four to five times more potent than that related to ozone.9 9To estimate these elasticities, the percent change in mortality rate per 1 µg/m3 (the relative risk coefficient minus 1)
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From page 42... ...
. Sensitive populations were identified in the process of setting the National Ambient Air Quality Standards under the Clean Air Act.
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From page 43... ...
. Routine vehicle operations involve leak age of brake fluid, antifreeze compounds, lubricating oil, engine oil, grease, and gasoline onto the highway surface, which can lead to the contamination of surface water and groundwater, as can the washing of fine particles from tires and road surfaces into water supplies.
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From page 44... ...
People become subject to negative health effects of water pollution by drinking contaminated water (either surface or groundwater) , swimming in or otherwise contacting contaminated water, or eating fish or other organisms that have come in contact with contamination or have bioaccumulated contam ination in their tissues.
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From page 45... ...
. Strategies to address the problem include redesign of vehicles to reduce noise from engines and tires; redesign of pave ments to reduce noise production; location and design of transportation infra structure to avoid or minimize noise transmission; installation of barriers or other devices to deflect noise away from populations; and design and retro fitting of buildings and outdoor areas to reduce indoor noise exposure, mask noise, or cancel out noise (TRB 1987; TRB 1990)
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From page 46... ...
11The repository of accepted information about emissions from mobile sources is embodied in EPA's MOBILE model, which is required for use in developing State Implementation Plans to meet the National Ambient Air Quality Standards. This model has a number of major limitations, both in its goals and in its information base, which represent research needs.
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From page 47... ...
However, better, more detailed characterizations of these vehicle emissions are needed in light of the increasing attention being paid to the VOCs in gasoline and the various fine particulates in diesel fuel, as well as the growing aware ness of mobile source air toxics in general as possible carcinogens and con tributors to a variety of respiratory ailments, immune and nervous system disorders, and birth defects. Recommendation 1-3.
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From page 48... ...
While the use of additives reduces emissions and thus the health effects of more conventional pollutants, a better understanding of any potential risk trade-offs is necessary. Finally, road dust entrained by mobile sources has been found to contribute up to 60 to 70 percent of the inventory of total suspended particulates from mobile sources.
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From page 49... ...
Special concern: Particulate matter measured by mass. EPA's newly pro mulgated standard for fine particulates is stated in terms of the weight of the particles in the air, i.e., µg/m3.
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From page 50... ...
A comprehensive accounting is needed of the many pathways by which surface transportation activities affect human health through contact with polluted water or contaminated fish or through linkages with solid waste from vehicle or parts scrappage. Greater understanding is also needed of the social and economic consequences of attempts to limit such contact, for example, through fish con sumption advisories or the creation of more comprehensive recycling markets.
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From page 51... ...
Special concern: Regulatory constraints. Conformity requirements in the Clean Air Act were intended to incorporate air quality considerations into transportation planning.
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From page 52... ...
REFERENCES Abbreviations EIA Energy Information Administration EPA Environmental Protection Agency FHWA Federal Highway Administration HEI Health Effects Institute NRC National Research Council OECD Organization for Economic Cooperation and Development TRB Transportation Research Board Balachandran, C
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From page 53... ...
1994. Air Toxics from Motor Vehicles.
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From page 54... ...
1999a. The Benefits and Costs of the Clean Air Act, 1990 to 2010.
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From page 55... ...
2000. Association of Fine Par ticulate Matter from Different Sources with Daily Mortality in Six U.S.
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From page 56... ...
2002. Lung Cancer, Cardiopulmonary Mortality, and Long-Term Exposure to Fine Particulate Air Pollution.
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From page 57... ...
1997. Motor Vehicle Exhaust and Respiratory Symptoms in Children Living Near Freeways.
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