1. Health Effects of Diesel Exhaust
Kevin M. Stewart
Director of Environmental Health
American Lung Association of Pennsylvania
May 30, 2003
American Lung Association of Pennsylvania

2. American Lung Association of Pennsylvania
Outline
Diesel Exhaust Composition
Diesel Exhaust Health Effects
Overview
Specifics, notably cancer
Populations at Risk
Key Steps / Conclusion
May 30, 2003
American Lung Association of Pennsylvania

3. American Lung Association of Pennsylvania
What is Diesel Exhaust?
May 30, 2003
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
May 30, 2003
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 …
May 30, 2003
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
May 30, 2003
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
May 30, 2003
American Lung Association of Pennsylvania

8. American Lung Association of Pennsylvania
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
May 30, 2003
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.
May 30, 2003
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
May 30, 2003
American Lung Association of Pennsylvania

11. Diesel Health Effects Overview
May 30, 2003
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
May 30, 2003
American Lung Association of Pennsylvania

13. Diesel Exhaust is a “Quadruple Whammy” for Public Health
Carcinogens
Toxins
Fine Particulate Matter
Nitrogen oxides
May 30, 2003
American Lung Association of Pennsylvania

14. American Lung Association of Pennsylvania
Whammies 1 and 2
Carcinogens
Lung
Bladder
Toxins
Nervous
Endocrine
Reproductive
Immune
Developmental
Liver
Kidney
May 30, 2003
American Lung Association of Pennsylvania

15. American Lung Association of Pennsylvania
Whammy 3
Fine Particulate Matter
Premature death
Increase respiratory illnesses
Exacerbate asthma
Symptom days
Attacks
ER visits
Hospitalization
May 30, 2003
American Lung Association of Pennsylvania

16. American Lung Association of Pennsylvania
Whammy 4
Nitrogen oxides
Ozone precursor …
Increase in respiratory illnesses
Decrease in lung function growth
May 30, 2003
American Lung Association of Pennsylvania

17. Specific Health Effects
May 30, 2003
American Lung Association of Pennsylvania

18. American Lung Association of Pennsylvania
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.
May 30, 2003
American Lung Association of Pennsylvania

19. American Lung Association of Pennsylvania
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).
May 30, 2003
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
May 30, 2003
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
May 30, 2003
American Lung Association of Pennsylvania

22. Diesel Emissions as a Carcinogen
May 30, 2003
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.
May 30, 2003
American Lung Association of Pennsylvania

24. Estimated Cancers from Diesel Particulate
ENTIRE UNITED STATES ,110
20 Largest Metropolitan Areas
Metropolitan Area Cancers
Los Angeles ,250
New York ,360
Chicago ,535
Washington/Baltimore 3,750
San Francisco 3,510
Philadelphia 3,085
Boston ,900
Detroit ,810
Dallas/Fort Worth 2,470
- continued
May 30, 2003
American Lung Association of Pennsylvania

25. Estimated Cancers from Diesel Particulate
20 Largest Metropolitan Areas - continued
Metropolitan Area Cancers
Houston 2,270
Atlanta ,930
Miami/Fort Lauderdale 1,880
Seattle ,765
Phoenix ,510
Cleveland 1,500
Minneapolis 1,460
San Diego 1,430
St. Louis 1,320
Denver ,220
Pittsburgh 1,210
May 30, 2003
American Lung Association of Pennsylvania

26. Cancer Risk Assessments of Diesel Exhaust
ORGANIZATION YEAR CONCLUSION
National Institute for Occupational Safety and Health potential occupational carcinogen
International Agency for Research on Cancer (WHO) probable human carcinogen
State of California known to cause cancer
Health Effects Institute
& World Health Organization consistency in showing weak association between
exposure to diesel exhaust and lung cancer
May 30, 2003
American Lung Association of Pennsylvania

27. Cancer Risk Assessments of Diesel Exhaust
ORGANIZATION YEAR CONCLUSION
California EPA (Staff Recommendation)
“may cause an increase in the likelihood of cancer”
California Air Resources Board
diesel particulate emissions are a toxic air contaminant
National Toxicology Program
“diesel exhaust particulate is reasonably anticipated
to be a human carcinogen”
U.S. Environmental Protection Agency
likely to be carcinogenic to humans by inhalation at
environmental levels of exposure
May 30, 2003
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.
May 30, 2003
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
May 30, 2003
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)
May 30, 2003
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)
May 30, 2003
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, , ,593
210, ,914
PA 12,002, , ,982
315, ,857
DE , , ,666
19, ,557
MD 5,130, , ,642
132, ,593
May 30, 2003
American Lung Association of Pennsylvania

33. Populations at Risk (1998 data) (continued)
State Population Under 14 Years Years and Over
NJ 8,095, ,680, ,106,028
PA 12,002, ,358, ,905,327
DE , , ,809
MD 5,130, ,083, ,273
May 30, 2003
American Lung Association of Pennsylvania

34. The American Lung Association’s Recommended 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.
May 30, 2003
American Lung Association of Pennsylvania

35. American Lung Association of Pennsylvania
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.
May 30, 2003
American Lung Association of Pennsylvania

36. Remember: When You Can’t Breathe, Nothing Else Matters.
May 30, 2003
American Lung Association of Pennsylvania

37. American Lung Association of Pennsylvania
Additional Materials
(Not part of presentation, but for use in responding to questions, if necessary)
May 30, 2003
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)
May 30, 2003
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
May 30, 2003
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 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.
May 30, 2003
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
May 30, 2003
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
May 30, 2003
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
May 30, 2003
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.
May 30, 2003
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
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.”
May 30, 2003
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.
May 30, 2003
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.
May 30, 2003
American Lung Association of Pennsylvania

48. American Lung Association of Pennsylvania
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
The 2000 US EPA Review Draft
May 30, 2003
American Lung Association of Pennsylvania

49. American Lung Association of Pennsylvania
References
The 1998 & 2001 Natural Resources Defense Council Reports
The 2001 OEHHA and American Lung Association of California’s Fact Sheet
May 30, 2003
American Lung Association of Pennsylvania