The Health Effects of Motor Vehicle Emissions

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The Health Effects of Motor Vehicle Emissions

• Daniel S. Greenbaum, President
• Health Effects Institute
• Concluding WorkshopReducing Vehicle Emissions
• Manila
• 28 February 2002

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Assessing the Health Effects of Vehicles

• Health Effects Institute
• A brief Introduction
• Air Pollution Levels and Health
• Emissions and Exposure
• Vehicle emissions
• Special Exposure Situations
• Health Effects
• Trends/Possibilities for Control

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The Health Effects Institute

• Founded in 1980 to provide impartial,
  high-quality science on health effects of vehicle
  and other emissions
• Joint and Equal Core Funding from
• Government (U.S. EPA)
• Industry (28 Worldwide Vehicle Manufacturers)
• Also partnerships with WHO, California, Other
  Industries
• Independent Board and Expert Science Committees
  oversee and review all research
• Over 200 studies - Americas, Europe, China,
  Mexico - ozone, carbon monoxide, particulate
  matter, diesel exhaust, benzene, butadiene,
  methanol, others

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PM10 in residential areas of cities in developing
countries Many cities exceed safe standards
Krzyzanowski Schwela, in AIR POLLUTION AND
HEALTH, Holgate, Samet, Koren Maynard (Eds), AP
1999
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The Contribution of Vehicles to Ambient Levels
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Special Population Exposures

• Average Annual Levels Can Be Misleading
• In Urban Areas, there are Hot Spots
• Street canyons, roadsides, urban centers
• Often more older cars and trucks
• Exposure levels for PM, diesel, CO, air toxics
  can be 2 to 10 times higher than average
• Exposure levels for Ozone will be somewhat lower
  (NOx scavenges the ozone)
• In these settings, vehicle contribution will be
  higher

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Vehicle Emissions and ExposureThe ADB Workshops

• Must consider all effects of the system
• Vehicle plus fuels (and fuel components)
• ADB India Workshop
• Different vehicle types including 2 and 3
  wheelers
• ADB Hanoi Workshop
• The full mix of vehicles on the road (new and
  old, poorly maintained vehicles
• ADB Chongqing Workshop
• The growth in travel
• ADB Manila Workshop

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Major Vehicle/Fuel Emissions

• Carbon Monoxide
• Carbon Dioxide (Climate Change)
• Diesel Exhaust
• Particulate Matter (PM)
• Lead
• Nitrogen Oxides (NOx) and Hydrocarbons (HC)
• Precursors to Ozone and PM
• Nitrogen Dioxide

• Air Toxics
• Aldehydes
• formaldehyde
• acetaldehyde
• others
• Benzene
• 1,3-butadiene
• Methanol
• Polycyclic organic matter (e.g. PAHs)

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Effects

• Different Pollutants have Different Effects
• Carbon Monoxide - circulatory system, heart
• Ozone - respiratory system, lung
• Lead - nervous system, brain
• PM - lung, potential effects on heart
• Diesel, Air Toxics - cancer, respiratory effects
• There are potential effects of the Mixture
• Carbon Dioxide and Carbon Particles - climate
  change

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Health Effects

• Some Populations more sensitive than others
• Children
• Elderly
• people with heart and lung disease
• Asthma is growing
• 150 million asthmatics worldwide
• Increasing in most countries (2 to 5 per year)
• Asthmatics much more sensitive to air pollution

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PM Health Effects

• High levels of PM (e.g. 500 ?/m3) known to cause
  premature death
• e.g. London 1952
• Recent studies in US, Europe, Asia, South America
  have found association of PM with death at much
  lower levels
• no evidence of a threshold (safe level)
• To date, a plausible biological mechanism for
  these effects has not been found

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PM - The Epidemiology Studies

• A Number of Epidemiology Studies
• Europe Studies Harvard 6 Cities
  Study
• Growing Number of Asian Studies (Bangkok, Seoul,
  HK)

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PM Health Effects - India, ThailandSource
Chhabra 2001, Pande 2001, Vichit-Vadakan, 2001
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PM Health Effects - China(Source Zhang, et al,
2001)
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PM Health Effects

• Recent Reanalyses by HEI have generally confirmed
  the results of key studies
• WHO, EPA and others have estimated effects on
  mortality
• WHO analysis (Lancet, 2000) estimated 20,000
  annual deaths due to traffic pollution in 3
  countries (Fr, Aus, Switz)
• New WHO global estimate underway
• Much work underway to understand effects of PM
  components (e.g. ultrafines, metals, chemicals
  on particles)

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Carbon Monoxide Effects

• Known to cause death at high levels of exposure
• raises levels of carboxyhemoglobin in the blood,
  blocking transport of oxygen to heart and brain
• In humans, effects have been shown even at low
  levels of exposure
• accelerates angina (chest pain) in people with
  coronary artery disease

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Lead Health Effects

• Excessive exposure can severely damage nervous
  system
• At low doses, lead is associated with
• nerve damage in fetuses and infants
• learning deficits
• lowered Intelligence Quota (IQ)

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Ozone Health Effects

• Known to cause inflammation in respiratory tract
• reduces ability to breathe (lung function) for
  some people
• Increases hospitalization for asthma, other lung
  diseases
• Effects have been demonstrated for short term,
  long term effects are less certain
• some people appear to develop tolerance

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Ozone Health Effects

• Some humans have been shown to have reduced lung
  function (measured as FEV1) after exposure to
  ozone

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Diesel Health Effects

• Diesel Engines have substantial advantages
• higher fuel efficiency
• lower CO and CO2 emissions
• However, they also emit high levels of
• particulate matter, NOx, and chemicals attached
  to the particles (e.g. PAHs)
• Two major types of health effects
• acute effects (e.g. exacerbating asthma)
• cancer effects

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Diesel Effects on Childhood Illness Association
between truck traffic and symptoms(Brunekreef,
et al Study in 24 Dutch schools)
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Assessing Diesel Cancer Risk

• In general, some 30 studies of effects on workers
  have provided best data
• Consistent small (20-40) increase in lung
  cancer associated with exposure
• Some questions about each study
• It is a challenge to quantify the risk

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Studies in Railroad Workers HEI,1995
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Diesel Risk Assessment Today

• Many Agencies have reviewed
• Most (WHO, IARC, US) have concluded diesel a
  probable human carcinogen
• California calculated unit risk per 1 ?/m3 of
  exposure
• 3 excess cancer deaths in 10,000 people (3x10-4)
• US EPA 2000 draft risk assessment
• a range of risk (10-3 to 10-5)

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Applying Risk Estimates (Source South Coast Air
Quality Management District)
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Air Toxics Health Effects

• Benzene
• levels of exposure a function of how much
  benzene, aromatics in the fuel
• a known human carcinogen
• studies in U.S. and Chinese workers have shown
  link between exposure and increased leukemia

• 1,3 Butadiene
• a product of combustion
• vehicles the major environmental source
• a probable or known human carcinogen
• studies in laboratory animals and US and Czech
  workers have shown effects

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Air Toxics Health Effects II

• Aldehydes
• emitted from vehicles and other sources also
  formed in the air
• Many different aldehydes (acetaldehyde,
  formaldehyde, others)
• most are probable human carcinogens
• also can be nose and respiratory irritants

• PAHs
• polycyclic aromatic hydrocarbons
• many different toxic compounds
• known or probable carcinogens
• Much higher levels from high emitters
• maintained vehicles lower emissions

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Effects on Climate Change

• Transport a significant contributor
• More than 30 of CO2
• Growing evidence that carbon soot also a
  significant contributor
• absorbs sun and heat
• diesel a major source
• Transport contribution likely to grow with rapid
  motorization

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Looking AheadTrends and Possibilities for
Control

• In reducing the health effects from vehicle
  emissions, one fact is clear
• Even if the emissions from each vehicle and its
  fuel are reduced,
• the use of vehicles will increase,
• vehicles will age and need maintenance.
• This can offset, in whole or in part, the
  pollution reductions and health benefits

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Looking Ahead

• In countries with high use of vehicles today
  (e.g. US, Europe) continued improvement in air
  quality has required continual improvements in
  technology and fuels
• First, through unleaded fuel, electronic fuel
  injection, inspection and maintenance, and
  catalysts
• Today, through enhanced I and M, low benzene/low
  sulfur fuel, advanced catalysts, and particle
  filters

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Progress on Lead and Health
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But Global Trends in the Total Vehicle Population
Point Upward(Excludes Motorcycles Source M.
Walsh)
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Conclusions

• Vehicle effects on health result from both engine
  emissions and fuel
• In general, as economies develop, vehicles will
  contribute 25 to 40 of most pollutants
• more for some pollutants and in urban settings
• There are a variety of health effects caused by
  vehicle emissions, including cancer, premature
  death, and increased hospitalization
• Also a significant contributor to climate change
• With increasing travel, health effects will only
  be reduced with continual improvement in fuels,
  emissions controls, and better maintenance

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Thank You!

• Dan Greenbaum
• dgreenbaum_at_healtheffects.org
• www.healtheffects.org