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Health Effects of Diesel Exhaust

Health Effects of Diesel Exhaust. Kevin M. Stewart Director of Environmental Health American Lung Association of Pennsylvania. Outline. Diesel Exhaust Composition Diesel Exhaust Health Effects Overview Specifics, notably cancer Populations at Risk Key Steps / Conclusion.

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Health Effects of Diesel Exhaust

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  1. Health Effects of Diesel Exhaust Kevin M. Stewart Director of Environmental Health American Lung Association of Pennsylvania American Lung Association of Pennsylvania

  2. Outline • Diesel Exhaust Composition • Diesel Exhaust Health Effects • Overview • Specifics, notably cancer • Populations at Risk • Key Steps / Conclusion American Lung Association of Pennsylvania

  3. What is Diesel Exhaust? American Lung Association of Pennsylvania

  4. Composition of Diesel Exhaust • Complex mixture of thousands of chemicals • Gases and fine particles • Over forty air contaminants recognized as toxicants, carcinogens, reproductive and developmental hazards, endocrine disruptors American Lung Association of Pennsylvania

  5. Composition of Diesel Exhaust • Gas phase Oxygen Carbon dioxide Nitrogen Carbon monoxide Water vapor Nitrogen Oxides (especially NO) Sulfur Compounds (especially Sulfur Oxides) Volatile Organic Compounds Low MW Hydrocarbons … American Lung Association of Pennsylvania

  6. Composition of Diesel Exhaust • Gas phase components of toxicological significance Aldehydes (formaldehyde, acetaldehyde, acrolein) Benzene 1,3-butadiene nitrosamines polycyclic aromatic hydrocarbons (PAHs) nitro-PAHs American Lung Association of Pennsylvania

  7. Composition of Diesel Exhaust • Particulate phase • Mostly elemental carbon (soot) • About 20% to 40% adsorbed organic compounds • Also sulfate, nitrate, metals, other trace elements • The most toxicologically relevant adsorbed compounds (less than 1% of PM by mass): - PAHs - Nitro-PAHs - Oxidized PAH derivatives • 92% of mass is in particles smaller than 1 micron American Lung Association of Pennsylvania

  8. Substances in Diesel Exhaust Listed by the California Air Resources Board as Toxic Air Contaminants acetaldehyde cobalt compounds nickel acrolein cresol isomers 4-nitrobiphenyl aniline cyanide compounds phenol antimony compounds dibutylphthalate phosphorus arsenic dioxins and dibenzofurans POM, including PAHs benzene ethyl benzene and their derivatives beryllium compounds formaldehyde propionaldehyde biphenyl hexane selenium compounds bis[2-ethylhexyl]phthalate lead (inorganic) styrene 1,3-butadiene manganese compounds toluene cadmium mercury compounds xylene isomers, mixtures chlorine methanol o-xylenes chlorobenzene methyl ethyl ketone m-xylenes chromium compounds naphthalene p-xylenes American Lung Association of Pennsylvania

  9. Diesel Emissions Inventory • Nationwide, 2001 data show diesel emissions at ~ 4% of PM2.5 inventory. (~11% excluding natural and miscellaneous sources) • Urban Centers Diesel PM estimated up to 10% to 36% in some western cities. • Nitrogen Oxides – nearly one third! • Over decades, nonroad diesel has over- taken decreasing onroad diesel emissions. • Recent diesel emissions trends have been relatively stagnant. American Lung Association of Pennsylvania

  10. Estimating Exposure to Diesel Exhaust • Use of particulate phase as surrogate for all: • Typical indoor level about half of higher risk areas • Near-highway exposures up to about 5 times average outdoor levels • On school buses, average PM2.5 concentrations often 5 to 10 times higher than ambient, especially when buses are queued and idling. • PM10 concentrations average ~ 2 mcg/m3 but has been detected at 125 mcg/m3 above background (w/ windows closed) following an urban transit bus American Lung Association of Pennsylvania

  11. Diesel Health Effects Overview American Lung Association of Pennsylvania

  12. Weight of Evidence Approach to Understanding Risk • biological plausibility • supporting evidence from animal studies, genotoxicity • consistency of response • broad-based evidence • upward trend in exposure-response • detectable association at environmental levels • effects remain after adjusting for potential bias • strong association for highest exposure groups • confounding cannot explain association American Lung Association of Pennsylvania

  13. Diesel Exhaust is a “Quadruple Whammy” for Public Health • Carcinogens • Toxins • Fine Particulate Matter • Nitrogen oxides American Lung Association of Pennsylvania

  14. Whammies 1 and 2 • Carcinogens • Lung • Bladder • Toxins • Nervous • Endocrine • Reproductive • Immune • Developmental • Liver • Kidney American Lung Association of Pennsylvania

  15. Whammy 3 • Fine Particulate Matter • Premature death • Increase respiratory illnesses • Exacerbate asthma • Symptom days • Attacks • ER visits • Hospitalization American Lung Association of Pennsylvania

  16. Whammy 4 • Nitrogen oxides • Ozone precursor … • Increase in respiratory illnesses • Decrease in lung function growth American Lung Association of Pennsylvania

  17. Specific Health Effects American Lung Association of Pennsylvania

  18. Specific Highlights • Diesel emissions are a significant source of the fine particulate matter that may be responsible for about 50,000 premature deaths in the U. S. every year. • Nationwide, expected lifetime cancers from diesel particulate in the U. S. population have been conservatively estimated at about 125,000. • EPA has estimated that the diesel engine and fuel rule approved in February of 2001 will prevent 8,300 premature deaths, 360,000 asthma attacks, and 1.5 million lost work days annually. American Lung Association of Pennsylvania

  19. Specific Highlights STAPPA and ALAPCO estimated in 2002 that if EPA were to adopt and implement a NONROAD heavy duty diesel rule consistent with those organizations’ recommendations: • Approximately 8,500 premature deaths per year could be avoided. • In 2030 the total annual monetized health-related benefits associated with reductions in particulate matter emissions reductions would be more than $67 billion (1999 dollars). American Lung Association of Pennsylvania

  20. Non-cancer Health Effects from Short-term Exposure • Acute irritation • Respiratory symptoms (e.g., cough) • Neurophysiological symptoms (e.g., nausea) • Compromised pulmonary function • Increase in biochemical markers associated with allergy • Asthma exacerbation • Insufficient data for specifying “guidance” level American Lung Association of Pennsylvania

  21. Non-cancer Health Effects from Long-term Exposure • Greater cough and phlegm • Asthma induction • Animals also show decreased resistance to infection, increased chronic lung inflammation and tissue changes • Insufficient human data for specifying “guidance” level, but US EPA has set Reference Concentration at 5 micrograms/m3 American Lung Association of Pennsylvania

  22. Diesel Emissions as a Carcinogen American Lung Association of Pennsylvania

  23. Estimated Cancers from Diesel Particulate State and Territorial Air Pollution Program Administrators and Association of Local Air Pollution Control Officials (STAPPA/ALAPCO) Cancer Risk from Diesel Particulate: National and Metropolitan Area Estimates for the United States, March 15, 2000. American Lung Association of Pennsylvania

  24. Estimated Cancers from Diesel Particulate ENTIRE UNITED STATES 125,110 20 Largest Metropolitan Areas Metropolitan Area Cancers Los Angeles 16,250 New York 10,360 Chicago 4,535 Washington/Baltimore 3,750 San Francisco 3,510 Philadelphia 3,085 Boston 2,900 Detroit 2,810 Dallas/Fort Worth 2,470 - continued American Lung Association of Pennsylvania

  25. Estimated Cancers from Diesel Particulate 20 Largest Metropolitan Areas - continued Metropolitan Area Cancers Houston 2,270 Atlanta 1,930 Miami/Fort Lauderdale 1,880 Seattle 1,765 Phoenix 1,510 Cleveland 1,500 Minneapolis 1,460 San Diego 1,430 St. Louis 1,320 Denver 1,220 Pittsburgh 1,210 American Lung Association of Pennsylvania

  26. Cancer Risk Assessments of Diesel Exhaust ORGANIZATION YEAR CONCLUSION National Institute for Occupational Safety and Health 1988 potential occupational carcinogen International Agency for Research on Cancer (WHO) 1989 probable human carcinogen State of California 1990 known to cause cancer Health Effects Institute 1995 & World Health Organization 1996 consistency in showing weak association between exposure to diesel exhaust and lung cancer American Lung Association of Pennsylvania

  27. Cancer Risk Assessments of Diesel Exhaust ORGANIZATION YEAR CONCLUSION California EPA (Staff Recommendation) 1998 “may cause an increase in the likelihood of cancer” California Air Resources Board 1998 diesel particulate emissions are a toxic air contaminant National Toxicology Program 1998 “diesel exhaust particulate is reasonably anticipated to be a human carcinogen” U.S. Environmental Protection Agency 2002 likely to be carcinogenic to humans by inhalation at environmental levels of exposure American Lung Association of Pennsylvania

  28. Carcinogenic Potential of Diesel Emissions • Known carcinogens in vapor phase • Benzene • Formaldehyde • 1,3-butadiene • Ethylene dibromide • Adsorbed onto particles • 3 PAHs (including BAP) classified as probably carcinogenic to humans • At least 16 hydrocarbons classified as possibly carcinogenic to humans • These do not account for all of the cancer risk associated with diesel exhaust. American Lung Association of Pennsylvania

  29. Carcinogenic Potential of Diesel Emissions • Meta-analysis by California Office of Environmental Health Hazard Assessment on diesel exhaust and lung cancer: • Clear positive relationship between occupational diesel exhaust and lung cancer • Cigarette smoking removed as confounder • Consistent with causal relationship • Association with 40% increase in relative risk American Lung Association of Pennsylvania

  30. Carcinogenic Potential of Diesel Emissions • A similar meta-analysis on diesel exhaust and bladder cancer (January, 2001 by Boffetta and Silverman in Epidemiology): • Found an increased risk of between 18% and 76% among occupationally exposed individuals (bus and truck drivers, railroad and shipyard workers) American Lung Association of Pennsylvania

  31. Carcinogenic Potential of Diesel Emissions • People are exposed to hundreds of times the amount of carcinogens the Clean Air Act recognizes as a reasonable precaution (one-in-a-million): • In 1996 the national average lifetime cancer risk from breathing outdoor hazardous pollutants was 1 in 2,100. • Mobile sources: 93% of this risk • Diesel emissions: 89% of the risk: • 28% from on-road sources (e.g., trucks) • 60% from nonroad sources (industrial, construction and farm equipment) American Lung Association of Pennsylvania

  32. Populations at Risk (1998 data) State Population Emphysema Chronic Bronchitis Adult Asthma (>= 18 yr) Pediatric Asthma (< 18 yr) NJ 8,095,542 91,513 277,593 210,480 105,914 PA 12,002,329 137,136 415,982 315,416 151,857 DE 744,066 8,461 25,666 19,460 9,557 MD 5,130,072 57,572 174,642 132,420 68,593 American Lung Association of Pennsylvania

  33. Populations at Risk (1998 data) (continued) State Population Under 14 Years 65 Years and Over NJ 8,095,542 1,680,818 1,106,028 PA 12,002,329 2,358,803 1,905,327 DE 744,066 150,327 96,809 MD 5,130,072 1,083,642 591,273 American Lung Association of Pennsylvania

  34. The American Lung Association’sRecommended Key Steps • Implement the clean air standards for trucks and buses and fuels – completely and on time. • Adopt strong equivalent standards for all nonroad diesel equipment. • Close the loophole for diesel electric generators. • Implement retrofit programs now. American Lung Association of Pennsylvania

  35. Conclusion Approximately one in ten Americans has a chronic lung disease and is at risk from air pollution. Infants, children, and the elderly are at increased risk, too. These are not faceless statistics, but people close to you: Your friends, your coworkers. Your parents, your children. Your aunt with emphysema struggling to breathe. Your coworker who can't make it in for that important task. Your child taking that frightening trip to the emergency room. Maybe even yourself. American Lung Association of Pennsylvania

  36. Remember:When You Can’t Breathe, Nothing Else Matters. American Lung Association of Pennsylvania

  37. Additional Materials • (Not part of presentation, but for use in responding to questions, if necessary) American Lung Association of Pennsylvania

  38. Factors Affecting Composition of Diesel Emissions • Engine types (light-duty to heavy-duty as they appear in passenger vehicles to off-road vehicles, in locomotives to electric generators) • Engine operating conditions (idle, accelerate, decelerate) • Fuel formulations (e.g., sulfur or aromatic content) American Lung Association of Pennsylvania

  39. Factors Affecting Fate of Diesel Emissions • Dilution • Chemical & physical changes Example: Diesel exhaust “aging” results in secondary PM formed from gas phase components • Transport • Weather (sunlight, temperature, humidity, precipitation) • Other (interacting) pollutants • Interactions with ground-level environment American Lung Association of Pennsylvania

  40. Example of Study from Current Research • Study in April 3, 2002 issue of Immunotherapy Weekly presented at annual meeting of the American Academy of Allergy, Asthma and Immunology (AAAAI). • Prior evidence showed that Diesel Exhaust Particulate (DEP ) could increase immune system response and airway inflammation associated with various allergens. • This study examined hospital emergency room visits and inpatient admissions between 1995 to 2000. Asthma exacerbations for children under 18 years old increased 1.4 times in the fall compared with the spring, significantly correlated with higher levels of DEP. American Lung Association of Pennsylvania

  41. Reproductive and Developmental Effects • Some possibilities in animal studies • Neurobehavioral and neurophysiological effects in neonatal rodents • Organ systems not yet evaluated American Lung Association of Pennsylvania

  42. Immunological Effects • Several observed effects in immune system biochemical mediators, inflammation, cytological changes • Diesel exhaust as potentiator for known allergens • Insufficient data to determine reference level American Lung Association of Pennsylvania

  43. Genotoxic Effects of Diesel Particulates or Extracts • Mutagenic in several mammalian cell systems • Aberrations in chromosomes or cell division • Free radical inhibition of antioxidant enzymes • Separately, substances in diesel exhaust have been identified as genotoxic • Questions remain about the level of bioavailability American Lung Association of Pennsylvania

  44. Carcinogenic Potential of Diesel Emissions • Lifetime lung cancer risks per microgram of diesel exhaust: • Cancer risk per microgram of diesel exhaust particulate per cubic meter of air: Scenarios range on the order of 100 to 1000 per million population after 70 years of exposure. American Lung Association of Pennsylvania

  45. Major Report on Particulate Air Pollution:March 6, 2002 of JAMA • “Lung Cancer, Cardiopulmonary Mortality, and Long-term Exposure to Fine Particulate Air Pollution” by Pope, C. A., et al. • Prospective mortality study of 500,000 adults in 156 cities, followed over the years 1982-98. • Conclusion: “Each 10-µg/m3 elevation in fine particulate air pollution was associated with approximately a 4%, 6%, and 8% increased risk of all-cause, cardiopulmonary, and lung cancer mortality, respectively.” American Lung Association of Pennsylvania

  46. Important Public Health News from Last Year • Dec. 21, 2000: EPA issues rule for diesel fuel and heavy duty diesel vehicles. • Feb. 28, 2001: EPA agrees to enforce rule. • May 3, 2002: Ruling by U. S. Circuit Court of Appeals for the District of Columbia Circuit upholds the rule. American Lung Association of Pennsylvania

  47. Important Public Health News from Last Year • Rule to take effect in 2007. • EPA estimates that annually the rule will prevent 8,300 premature deaths, more than 9,500 hospitalizations, 5,500 cases of chronic bronchitis, 17,600 cases of acute bronchitis in children, 360,000 fewer asthma attacks, and more than 1.5 million lost workdays. The rule also will prevent cancers from diesel exhaust, which EPA has found to be a likely carcinogen in humans. American Lung Association of Pennsylvania

  48. References … where you can find links to this same information – and more: • The 1998 California Environmental Protection Agency’s Office of Environmental Health Hazard Assessment (OEHHA) Report www.arb.ca.gov/regact/diesltac/diesltac.htm • The 2000 US EPA Review Draft www.epa.gov/ncea/dieslexh.htm American Lung Association of Pennsylvania

  49. References • The 1998 & 2001 Natural Resources Defense Council Reports www.nrdc.org/air/transportation/ • The 2001 OEHHA and American Lung Association of California’s Fact Sheet www.californialung.org/downloads/diesel010501/ALA-OEHHA_diesel.pdf American Lung Association of Pennsylvania

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