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Highway Expansion - Creating Tomorrows Problems Today
22 Scientific Studies Link
Health Risk with Highway Pollution
Sierra Club 2003
The following peer-reviewed and published studies conclude that there is a link between traffic-related air pollution and health risks. The health risks include increased likelihood of asthma, cancer, premature and low birth weight babies, and generally higher risk of death.
These studies show the need to consider these health risks when expanding highways in urban areas with homes and schools, especially when they have more than 150,000 vehicles per day. They also support measures to reduce pollution from trucks and cars and promote cleaner public transportation.
Along with the summaries of the studies, we put contact information for the researchers where possible. Special thanks to the staff of the Environmental Law and Policy Center in Chicago for helping to compile many of these studies. For copies or more information on the studies, call 608-257-4994.
1. Traffic Increased Cancer-Causing Pollution Levels at Tollbooth
A 2003 study published in the Journal of Air & Waste Management shows that there is a “significant association between vehicle traffic and curbside concentrations of the carcinogens benzene, 1,3-butadiene, and particle-bound polycyclic aromatic hydrocarbons (PAH).” The measurements, which were taken at the Baltimore Harbor Tunnel tollbooth, show that much of the daily pollutant variability was explained by traffic volume, class and meteorology. The study provides a model for estimating curbside pollution levels associated with traffic that may be relevant to exposures in the urban environment.
Sapkota, Amir and Buckley, Timothy J. The Mobile Source Effect on Curbside 1,3-Butadiene, Benzene, and Particle-Bound Polycyclic Aromatic Hydrocarbons Assessed at a Tollbooth. Journal of Air & Waste Management. 53:7400748.
Contact: Dr. Timothy J. Buckley, Department of Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, phone: (410) 614-5750, email: tbuckley@jhsph.edu.
2. Increasing Public Transportation and Cutting Traffic Reduces Asthma Attacks
This 2001 Journal of the American Medical Association study found that increasing public transportation along with other traffic control measures during the 1996 Atlanta Olympics reduced acute asthma attacks by up to 44% in children, reduced ozone concentrations by 28% and morning peak traffic by 22.5%. These data provide support for efforts to reduce air pollution and improve health via reductions in motor vehicle traffic.
Friedman, et al, Impact of Changes in Transportation and Commuting Behaviors During the 1996 Summer Olympic Games in Atlanta on Air Quality and Childhood Asthma, JAMA, 2001; 285:897-905.
Contact: Michael S. Friedman, Air Pollution and Respiratory Health Branch, National Center for Environmental Health, Center for Disease Control and Prevention, email: mff7@cdc.gov.
3. Fine Particulate Matter Linked to Lung Cancer, Cardiopulmonary Mortality
A recent study appearing in the Journal of the American Medical Association showed that day-to-day exposure to fine particulate matter, a major component of diesel exhaust increased the risk of various adverse health effects. More specifically the study shows that each 10 microgram/meter3 elevation in fine particulate air pollution leads to an 8% increased risk of lung cancer deaths, a 6% increased risk of cardiopulmonary mortality and 4% increased risk of death from general causes.
Pope, C. Arden III, et al. Lung Cancer, Cardiopulmonary Mortality, and Long-term Exposure to Fine Particulate Air Pollution. Journal of American Medical Association, March 6 2002— Vol. 287, No. 92.
Contact: Clive Arden Pope, Brigham Young University, Phone: (801) 422-2157, email: arden_pope@byu.edu
4. Truck Traffic Linked to Childhood Asthma Hospitalizations
A study in Erie County, New York (excluding the city of Buffalo) found that children living in neighborhoods with heavy truck traffic within 220 yards of their homes had increased risks of asthma hospitalization. The study examined hospital admission for asthma amongst children ages 0-14, and residential proximity to roads with heavy traffic.
Lin, Munsie, Hwang, Fitzgerald, and Cayo. (2002). Childhood Asthma Hospitalization and Residential Exposure to State Route Traffic. Environmental Research, Section A, Vol. 88, pp. 73-81.
5. Pregnant Women Who Live Near High Traffic Areas More Likely to Have Premature and Low Birth Weight Babies
Researchers observed an approximately 10-20% increase in the risk of premature birth and low birth weight for infants born to women living near high traffic areas in Los Angeles County. In particular, the researchers found that for each one part-per-million increase in annual average carbon monoxide concentrations where the women lived, there was a 19% and 11% increase in risk for low birth weight and premature births, respectively.
Wilhelm, Ritz. (2002). Residential Proximity to Traffic and Adverse Birth Outcomes in Los Angeles County, California, 1994-1996. Environmental Health Perspectives. doi: 10.1289/ehp.5688.
Contact: B. Ritz, Department of Epidemiology, School of Public Health, UCLA,
Phone: (310) 206-7458, e-mail: britz@ucla.edu.
6. People Who Live Near Freeways Exposed to 25 Times More Soot Particle Pollution
Studies conducted in the vicinity of Interstates 405 and 710 in Southern California found that the number of ultra-fine particles in the air was approximately 25 times more concentrated near the highways and that pollution levels gradually decrease back to normal (background) levels around 300 meters, or nearly 330 yards, downwind from the highway. The researchers note that motor vehicles are the most significant source of ultra-fine particles, which have been linked to increases in mortality and morbidity. Recent research concludes that ultra-fine particles are more toxic than larger particles with the same chemical composition. Moreover, the researchers found considerably higher concentrations of carbon monoxide pollution near the highways.
Zhu, Hinds, Kim, Sioutas. Concentration and size distribution of ultra-fine particles near a major highway. Journal of the Air and Waste Management Association. September 2002.
Zhu, Hinds, Kim, Shen, Sioutas. Study of ultra-fine particles near a major highway with heavy-duty diesel traffic. Atmospheric Environment. 36(2002), 4323-4335.
7. Air Inside Cars Typically Contains More Dangerous Air Pollutants than Outside
The results of 23 separate scientific studies shows that in-car air pollution levels frequently reach concentrations that may threaten human health. The reports show that the air inside of cars typically contain more carbon monoxide, benzene, toluene, fine particulate matter, and nitrogen oxides than ambient air at nearby monitoring stations. These pollutants are particularly dangerous for children, the elderly and people with asthma or some other respiratory condition.
Kimbrell, Andrew. In-Car Air Pollution: The Hidden Threat to Automobile Drivers. International Center for Technology Assessment. July 2000.
http://www.icta.org/projects/trans/incarexec.htm
Contact: Andrew Kimbrell, Phone: 202-547-9359
8. Children Living Near Busy Roads More Likely to Develop Leukemia, Cancer
A 2000 Denver study showed that children living within 250 yards of streets or highways with 20,000 vehicles per day are six times more likely to develop all types of cancer and eight times more likely to get leukemia. The study looked at associations between traffic density, power lines, and all childhood cancers with measurements obtained in 1979 and 1990. It found a weak association from power lines, but a strong association with highways. It suggested that volatile organic chemical pollution from the roadway may be the cancer promoter causing the problem.
Pearson, Wachtel, et al. (2000). Distance-weighted traffic density in proximity to a home is a risk factor for leukemia and other childhood cancers. Journal of Air and Waste Management Association 50:175-180.
Contact: Professor Howard Wachtel, Department of Electrical Engineering, University of Colorado. Phone: (303) 492-7713. E-mail: wachtel@colorado.edu.
9. Motor Vehicle Pollution Dominate Cancer Risk from Air Pollution
The most comprehensive study of urban toxic air pollution ever undertaken shows that motor vehicles and other mobile sources of air pollution are the predominant source of cancer-causing air pollutants in Southern California. Overall, the study showed that motor vehicles and other mobile sources accounted for about 90% of the cancer risk from toxic air pollution, most of which is from diesel soot (70% of the cancer risk). Industries and other stationary sources accounted for the remaining 10%. The study showed that the highest risk is in urban areas where there is heavy traffic and high concentrations of population and industry.
South Coast Air Quality Management District. Multiple Air Toxics Exposure Study-II. March 2000.
Contact: Steve Barbosa, Phone: (909) 396-2171, sbarbosa@aqmd.gov.
10. Children Exposed to Pollution Shown to have Reduced Lung Function
The Children’s Health Study (CHS), which is a ten year study funded by the California Air Resources Board, was developed to determine the impacts of long-term air pollution exposures on children’s health. Data on children’s health, air pollution exposures and other factors affecting their response to air pollution is being gathered annually. While all parts of the study are not yet completed, researchers have already come to many important conclusions concerning the impacts of pollution on growth and development of the lungs and development of respiratory illnesses based on evidence from the first years of the study.
“Children’s Health Study part of the Long-Term Exposure Health Effects Research Program.” California: 2001 Available online— www.arb.ca.gov/research/chs/chs.htm
Contact: Tracy Hysong, California Air Resources Board, Phone: (916) 445-1324
11. Lung Function Reduced Among Children Living Near Truck Traffic
A European study determined that exposure to traffic-related air pollution, ‘in particular diesel exhaust particles,’ may lead to reduced lung function in children living near major motorways.
Brunekreef B; Janssen NA; de Hartog J; Harssema H; Knape M; van Vliet P. (1997). “Air pollution from truck traffic and lung function in children living near motorways.” Epidemiology. 8(3):298-303.
12. Traffic-Related Air Pollution Associated with Respiratory Symptoms in Two-Year Old Children
This cohort study in the Netherlands found that two year old children who are exposed to higher levels of traffic-related air pollution are more likely to have self-reported respiratory illnesses, including wheezing, ear/nose/throat infections, and reporting of physician-diagnosed asthma, flu or serious cold.
Brauer et al. (2002). Air Pollution from Traffic and the Development of Respiratory Infections and Asthmatic and Allergic Symptoms in Children. Am J Respiratory and Critical Care Medicine. Vol. 166 pp 1092-1098.
Contact: Dr Michael Brauer, School of Occupational and Environmental Hygiene, University of British Columbia, Vancouver, British Columbia, Canada, email: brauer@interchange.ubc.ca, phone: 604-822-9585.
13. Asthma Symptoms Caused by Truck Exhaust
A study was conducted in Munster, Germany to determine the relationship between truck traffic and asthma symptoms. In total, 3,703 German students, between the ages of 12-15 years, completed a written and video questionnaire in 1994-1995. Positive associations between both wheezing and allergic rhinitis and truck traffic were found during a 12 month period. Potentially confounding variables, including indicators of socio-economic status, smoking, etc., did not alter the associations substantially.
Duhme, H., S. K. Weiland, et al. (1996). The association between self-reported symptoms of asthma and allergic rhinitis and self-reported traffic density on street of residence in adolescents. Epidemiology 7(6):578-82.
14. Proximity of a Child’s Residence to Major Roads Linked to Hospital Admissions for Asthma
A study in Birmingham, United Kingdom, determined that living near major roads was associated with the risk of hospital admission for asthma in children younger than 5 yrs of age. The area of residence and traffic flow patterns were compared for children admitted to the hospital for asthma, children admitted for non-respiratory reasons, and a random sample of children from the community. Children admitted with an asthma diagnosis were significantly more likely to live in an area with high traffic flow (> 24,000 vehicles/ 24 hrs) located along the nearest segment of main road.
Edwards, J., S. Walters, et al. (1994). Hospital admissions for asthma in preschool children: relationship to major roads in Birmingham, United Kingdom. Archives of Environmental Health. 49(4): 223-7.
15. Exposure to Carcinogenic Benzene Higher for Children Living Near High Traffic Areas
German researchers compared 48 children who lived in a central urban area with high traffic density with 72 children who lived in a small city with low traffic density. They found that the blood levels of benzene in children who lived in the high-traffic-density area were 71% higher than those of children who lived in the low-traffic-density area. Blood levels of toluene and carboxyhemoglobin (formed after breathing carbon monoxide) were also significantly elevated (56% and 33% higher, respectively) among children regularly exposed to vehicle pollution. Aplastic anemia and leukemia are associated with excessive exposure to benzene.
Jermann E, Hajimiragha H, Brockhaus A, Freier I, Ewers U, Roscovanu A: Exposure of children to benzene and other motor vehicle emissions. Zentralblatt fur Hygiene und Umweltmedizin 189:50-61, 1989.
16. Air Pollution from Busy Roads Linked to Shorter Life Spans for Nearby Residents
Dutch researchers looked at the effects of long-term exposure to traffic-related air pollutants on 5,000 adults. They found that people who lived near a main road were almost twice as likely to die from heart or lung disease and 1.4 times as likely to die from any premature cause compared with those who lived in less-trafficked areas. The authors say traffic emissions contain many pollutants that might be responsible for the health risks, such as ultra-fine particles, diesel soot, and nitrogen oxides, which have been linked to cardiovascular and respiratory problems.
Hoek, Brunekreef, Goldbohn, Fischer, van den Brandt. (2002). Association between mortality and indicators of traffic-related air pollution in the Netherlands: a cohort study. Lancet, 360 (9341): 1203-9.
17. Asthma More Common for Children Living Near Highways
A study of nearly 10,000 children in England found that wheezing illness, including asthma, was more likely with increasing proximity of a child’s home to main roads. The risk was greatest for children living within 90 yards of the road.
18. Most Traffic-Related Deaths Due to Air Pollution, Not Traffic Accidents
Another study analyzed the affect of traffic-related air pollution and traffic accidents on life expectancy in the area of Baden-Wurttemberg, Germany. It estimated that almost five times more deaths in this region resulted from motor vehicle pollution than from traffic accidents.
Szagun and Seidel. (2000). Mortality due to road traffic in Baden-Aurttemberg – air pollution, accidents, noise. Gesundheitswesen. 62(4): 225-33.
19. Cancer Risk Higher Near Major Sources of Air Pollution, Including Highways
A 1997 English study found a cancer corridor within three miles of highways, airports, power plants, and other major polluters. The study examined children who died of leukemia or other cancers from the years 1953-1980, where they were born and where they died. It found that the greatest danger lies a few hundred yards from the highway or pollution facility and decreases as you get further away from the facility.
Knox and Gilman (1997). Hazard proximities of childhood cancers in Great Britain from 1953-1980. Journal of Epidemiology and Community Health. 51: 151-159.
20. A School’s Proximity to Highways Associated with Asthma Prevalence
A study of 1498 children in 13 schools in the Province of South Holland found a positive relationship between school proximity to highways and asthma occurrence. Truck traffic intensity and the concentration of pollutants measured in schools were found to be significantly associated with chronic respiratory symptoms.
Speizer, F. E. and B. G. Ferris, Jr. (1973). Exposure to automobile exhaust. I. Prevalence of respiratory symptoms and disease. Archives of Environmental Health. 26(6): 313-8. van Vliet, P., M. Knape, et al. (1997). Motor vehicle exhaust and chronic respiratory symptoms in children living near freeways. Environmental Research..74(2): 122-32.
21. Exposure to Nitrogen Dioxide (NO2) from Vehicles Exacerbates Asthma Attacks
Researchers at St. Mary’s Hospital in Portsmouth, England determined that while 80 percent of asthma attacks are initially caused by viral infections, exposure to traffic pollution can increase symptoms as much as 200 percent. The team measured the exposure of 114 asthmatic children between ages 8-11 from nonsmoking families over almost a whole year. They found a strong correlation between higher NO2 pollution and the severity of an attack.
Chauhan, A.J., et al. Personal exposure to nitrogen dioxide (NO2) and the severity of virus-induced asthma in children. The Lancet. Volume 361 Issue 9373 Page 1939
22. Diesel Exhaust Linked to Asthma
This study found that particulate matter from diesel trucks can act as an irritant in the airway causing asthma. The authors show that diesel exhaust can trigger asthma attacks in individuals with no pre-existing asthmatic history. When a natural allergen, such as pollen, was added to the situation, the reaction was even more dramatic.
Pandya, Robert, et al. Diesel Exhaust and Asthma: Hypothesis and Molecular Mechanisms of Action.” Environmental Health Perspectives Supplements Volume 110, Number 1, February 2002
For more information on cutting traffic and air pollution, see www.sierraclub.org/sprawl.
HEALTH EFFECTS OF MOTOR VEHICLE POLLUTANTS
Clear Creek County and the Clear Creek I-70 Task Force request that the impacts on public health of pollutants emitted from the I-70 project be included in the EIS as one of the criteria for comparing alternatives, and for the purpose of identifying mitigation measures that may be necessary to eliminate or minimize any adverse effects on public health.
I. Legal Duty To Assess Health Impacts of Emissions from I-70 Project.
NEPA requires that the EIS -
shall provide a full and fair discussion of significant environmental impacts and shall inform decisionmakers and the public of the reasonable alternatives which would avoid or minimize adverse impacts or enhance the quality of the human environment.
40 C.F.R. §1502.1.
In disclosing significant environmental impacts and consideration of alternatives, NEPA requires that the EIS -
shall include discussions of :
(d) The environmental effects of alternatives including the proposed action. The comparisons under § 1502.14 will be based on this discussion. [and]
(h) Means to mitigate adverse environmental impacts (if not fully covered under § 1502.14(f)).
40 C.F.R. §1502.16(d) and (h).
The EIS must consider “the degree to which the proposed action affects public health.”
40 C.F.R. § 1508.27(b)(2); see also § 1508.8.
When a motor vehicle-related pollutant is governed by a standard, NEPA also requires that the EIS determine “whether the action threatens a violation of Federal, State, or local law or requirements imposed for the protection of the environment.”
40 C.F.R. § 1508.27(b)(10).
To satisfy these requirements, FHWA must undertake an investigation of the adverse health effects among populations that will be exposed to air pollutants emitted in the I-70 corridor for each alternative considered, discuss alternatives in the EIS that can avoid or minimize these adverse effects on health, and where the alternatives are not sufficient to avoid adverse impacts, then include additional measures “to mitigate adverse environmental impacts.”
In addition to NEPA, the Federal-Aid Highway Act requires that FHWA consider the “possible adverse effects” of “air pollution” as part of any federal decision to approve a highway project.
23 U.S.C. §109(h).
Section 109(h) of the Federal-Aid Highway Act requires a three-step evaluation of air pollution impacts and mitigation measures to ensure that “final decisions on the project are made in the best overall public interest.” The first step is to determine the “possible adverse economic, social and environmental effects relating to any proposed project.” Id. The second step is to determine “the costs of eliminating or minimizing such adverse effects and … (1) air…pollution.” Id. The third step is to consider “the costs of eliminating or minimizing such adverse effects” together with “the need for fast, safe and efficient transportation” to make a final decision on the project “in the best overall public interest.” Id. FHWA’s implementing regulation further requires that any measures necessary to mitigate these adverse effects be incorporated into the project. 23 C.F.R. § 771.105(d).
Used with the permission of Robert H. Yuhnke, Esq.
FHWA’s assessment of adverse effects under section 109 is not bounded by a condition that the air pollution impacts be “significant” as defined by NEPA and its implementing regulations. Rather, section 109 calls for investigation of “possible adverse . . . environmental effects,” including air pollution. 23 U.S.C. § 109(h) (emphasis added).
This analysis necessitates “the gathering and evaluation of evidence on potential pollution hazards.” D.C. Fed’n of Civic Ass’ns v. Volpe, 459 F.2d 1231, 1242 (D.C. Cir. 1971). Moreover, such hazards must include the motor vehicle-related pollutants for which the EPA has implemented a NAAQS under the Clean Air Act, but are not restricted to criteria pollutants. In applying section 109 to a bridge construction project, the District of Columbia Circuit stated, “[w]e can find no basis in the statute's language or purpose for the conclusion that certain hazards are, as a matter of law, immaterial to the Secretary's evaluation of a project's safety.” D.C. Fed’n, 459 F.2d at 1242.
II. Significance of Air Pollution Impacts on the Human Environment.
NEPA requires that impacts be discussed in an EIS if they “significantly impact the human environment.” The impacts on public health caused by air pollutants emitted from highways may well be the greatest impact from a large highway.
In a 2000 Report to Congress, the Federal Highway Administration (FHwA) estimated that the annual health costs of air pollution from transportation sources in the United States ranges from $40,443,000,000.00 to $64,600,000,000.00.[1] This estimate is based upon health effects of public exposure to emissions from motor vehicles of the pollutants for which NAAQS had been promulgated prior to 1997. The largest portion of the costs result from predicted increases in mortality caused by these pollutants. The Report to Congress did not include health costs for fine particles (particulate matter measuring 2.5 microns in diameter or smaller (PM2.5))[2] or MSAT pollutants emitted by motor vehicles.[3] No other category of air pollution sources has a greater impact on the public health.
Since the FHWA’s Report to Congress, substantial new evidence has emerged showing that pollutants not included in the Report, especially fine particles and toxic air pollutants such as benzene, 1,3 butadiene, formaldehyde, and the mix of pollutants contained in diesel exhaust are associated with significant additional impacts on public health. The general health impacts of fine particles were summarized by U.S. EPA in the 1997 decision to adopt a new NAAQS for PM2.5.
EPA also provided a detailed assessment of the health risks attributable to the 13 mobile source toxic air pollutants included in the Integrated Nation Urban Air Toxics Strategy adopted in 1999, and EPA’s Final Rule adopting more stringent emissions standards for diesel engines. The findings of adverse health effects made by EPA, together with more recent evidence of adverse health effects published in reports of health effects research strongly support the conclusion that the effects on human health from pollutants emitted from highways are a significant impact on the human environment and must be disclosed in an EIS for a highway project.
III. Identifying Air Pollutants to be Investigated.
To satisfy the obligation under §109(h) to identify “possible adverse effects,” FHWA must at least consider the adverse effects of those motor vehicle-related pollutants that have been found by the U.S. EPA to endanger human health, or been shown in credible scientific investigations to be associated with adverse health effects.
a. Criteria Pollutants. When EPA lists a pollutant for promulgation of a NAAQS pursuant to the Clean Air Act (CAA), 42 U.S.C. § 7408(a), a determination has been made that the pollutant endangers public health. Such pollutants presumptively cause “possible adverse effects” that require consideration under § 109(h).
b. MSAT Pollutants. In addition to criteria pollutants, the hazardous air pollutants (HAPs) listed under CAA § 112 also endanger public health. Of the 189 HAPs listed under the Act, the U.S. EPA has identified 21 as “mobile source air toxic” (MSAT) pollutants. Of these 21, EPA included the three statutory MSATs and ten other mobile source-related pollutants on a list of 33 priority pollutants targeted for control under EPA’s Integrated National Urban Air Toxics Strategy. 64 Fed. Reg. 38,706 (July 19, 1999). This Strategy “established a list of urban HAPs [“hazardous air pollutants”] which pose the greatest threats to public health in urban areas, considering emissions from major, area and mobile sources.” Id. at 38,714. EPA observed that “mobile sources are an important contributor to the urban air toxics problem.” Id. at 38,705. The selection of HAPs for listing in the Urban Air Toxics Strategy was based upon modeling to estimate public exposures, and the application of unit risk factors reported in EPA’s Integrated Risk Information System (IRIS). See 64 Fed. Reg. 38,730 (July 19, 1999) (describing the determination of risk factors in the ranking of toxic air pollutants in the development of the Urban Air Toxics Strategy).
EPA’s identification of concentrations of these 13 MSAT pollutants in the ambient air sufficient to present “threats to public health in urban areas” and triggers FHWA’s duty to consider these pollutants as contributing to “possible adverse effects” under § 109(h).
c. DIESEL PM. EPA added diesel exhaust emissions and 7 other pollutants to the 13 MSAT pollutants listed in the Urban Air Toxics Strategy when it published the list of MSAT pollutants required by the CAA. 42 U.S.C. § 7521(l); 66 Fed. Reg. 17229. Diesel exhaust emissions were added to the list because EPA found that “diesel exhaust PM is of special concern because it has been implicated in an increased risk of lung cancer and respiratory disease,” and “that diesel exhaust is likely to be carcinogenic to humans.” 66 Fed. Reg 5007 (January 19, 2001).
EPA also noted that diesel exhaust contains “[s]ome of the toxic air pollutants associated with emissions from heavy-duty vehicles and engines include[ing] benzene, formaldehyde, acetaldehyde, dioxin, acrolein, and 1,3-butadiene.” 66 Fed. Reg. 5008. These findings also trigger the obligation to consider the effects of diesel emissions under § 109(h).
d. Published Health Effects Research.
Peer reviewed scientific research provides compelling evidence that air pollution from highways cause “adverse effects” to public health. The EIS must include an evaluation of the health effects and exposure research to identify levels of exposure to motor vehicle-related pollutants that have been shown to be associated with adverse health effects to sensitive populations.
i. Cancer Risk.
In 2000, the South Coast Air Quality Management District in California made a major contribution to the research showing the link between cancer and mobile source pollution. The final Multiple Air Toxics Exposure Study (MATES-II) measured exposures to 30 toxic air pollutants at 22 locations in the Los Angeles air basin.[7] Using estimates of cancer risk developed for toxic air pollutants by the U.S. Environmental Protection Agency (EPA) and the California Air Resources Board, MATES-II found that cancer risk from the 30 air pollutants averages 1.4 cancers per 1,000 residents. Apportioning air pollution-related cancer risk by pollutant, MATES-II demonstrated that emissions from mobile sources account for 90% of the overall cancer risk attributable to toxic air pollutants in the five-county air district. Id., p. ES-3 ¶1, Fig. ES-2.
The total cancer risk from all sources, including traffic (“on-road mobile”), non-road mobile and stationary sources, averaged across the region was found to be 1400 per million. Id., p. ES-3. On-road vehicle emissions account for half of this risk, or 700 per million. Id., Fig. 4-2. This equates to about 1 cancer for each 1450 exposed people.
MATES-II also demonstrated that higher levels of risk occur near highways. The study found that the range of cancer risks varied significantly across the region, from 1,120 in a million in the cleanest neighborhoods to about 1,740 in a million in the most polluted. Id., p. ES-3 ¶2. The Report found the greatest risk levels at locations where “the dominance of mobile sources is even greater than at other sites.” Id., p. ES-5 ¶3. It also found that “model results, which are more complete in describing risk levels…than is possible with the monitored data, show that the higher risk levels occur… near freeways.” Id., ¶B.2. “Results show that the higher pollutant concentrations generally occur near their emission sources.” Id., ¶4. These findings provide further evidence that neighborhoods near highways would experience higher concentrations than the regional averages. Based on all these observations, MATES-II concluded that “[f]or mobile source compounds such as benzene, 1-3 butadiene, and particulates associated with diesel fuels, higher concentration levels are seen along freeways and freeway junctions.” Id., p. 5-4 ¶5.3.
In an attempt to better quantify the increased cancer risk near the freeway, the Sierra Club enlisted the services of an expert transportation modeler at Resources Systems Group (RSG). RSG reported that based upon its experience in evaluating pollutant concentrations associated with highway emissions—
Modeling conducted by Resource Systems Group for several highway projects shows that exposures to both gaseous and particulate pollution emitted from highways is much greater close to the highway. The results of the modeling showed that air toxics concentrations derived from motor vehicles on the highway were approximately ten times higher at 40 meters from the highway than at 300 meters from the highway.
RSG Report (January 2002), p. 5 ¶1. RSG also reviewed the MATES modeling data, observing that model outputs were reported as average concentrations for each 2 kilometer square receptor grid. “Therefore, the [modeled] estimates are not worst case nor do they represent the exposure levels for residences close to major highways. Exposure levels close to major highways will be higher, and depending on distance, wind direction and other factors, may be considerably higher.” Id. Thus the cancer risks to populations in close proximity to a major freeway will be substantially greater, possibly 10 times greater, than the regional cancer risks attributable to motor vehicle emissions.
ii. Risks to Sensitive Populations.
Particularly important for assessing the adverse health impacts of emissions from highways located near school buildings and residential areas are recent research reports that have focused on the links between motor vehicle emissions and adverse health effects suffered by children.
A new study designed to determine whether the proximity of 10 middle schools to major freeways in California’s East Bay caused adverse health effects among school children aged 10 to 12 found a statistically significant greater prevalence of diagnosed asthma and bronchitis among students at the four schools most affected by motor vehicle emissions.[8] At each school, the study monitored concentrations of a number of motor vehicle-related pollutants, showing that PM2.5 was 25% higher in a school yard 60 meters from a freeway than at monitors located a mile from the freeways.[9] Black carbon, a component of diesel exhaust measured at the schools, was also shown to increase with proximity of the school to a major highway. Carbons levels were 55% higher at the school closest to a freeway compared to schools that were more than a mile distant from a freeway. Air quality at every school complied with national ambient air quality standards (NAAQS).A study in the Bronx, New York, investigated truck traffic, particulate matter and carbon concentrations in the neighborhood around the Hunts Point terminal where one in three children have asthma (compared to one-in-five nationally), and the hospitalization rate for asthma is 12 times the national average.[10] The reported carbon levels used as a surrogate for diesel emissions ranged at six sites from more than two to nearly seven times greater than the levels reported at the school site in the East Bay Children’s Respiratory Health Study with the highest levels.[11] Carbon concentrations were found to correlate strongly with daily diesel truck traffic on the streets nearest the monitor.The data from both the East Bay and the Hunts Point studies strongly suggest that carbon levels associated with diesel emissions may be directly responsible for inducing the allergic response that is asthma, or they are a sound surrogate measure of the mix of chemicals in diesel exhaust that initiate asthma. According to the President's Task Force on Environmental Health, Risks and Safety Risks to Children, America |
