Policy Guidelines for ReducingVehicle Emissions in Asia

APPENDIX

Adverse Health andEnvironmental Effectsfrom Vehicle Emissions

Asian Development Bank 2003All rights reserved

This publication was prepared by staff of the Asian Development Bank. Thefindings, interpretations, and conclusions expressed in it do not necessarilyrepresent the views of ADB or those of its member governments. ADB does notguarantee the accuracy of the data included in this publication and accepts noresponsibility whatsoever for any consequences of their use.

The term “country” does not imply any judgment by ADB as to the legal or otherstatus of any territorial entity.

Publication Stock No. 020203

Published by the Asian Development BankP.O. Box 789, 0980 Manila, Philippines

Preface ivAbbreviations vi

Carbon monoxide 1

Nitrogen oxides 2

Photochemical oxidants 2

Gaseous air toxics 3

Benzene 3

Formaldehyde 4

Acetaldehyde 4

1,3 Butadiene 4

Lead 4

Lead scavengers 5

Particulate 6

Diesel emissions 7

Sulfur dioxide 9

Visibility and regional haze 10

Acid deposition 10

Climate change 11

Eutrophication 12

Notes 14

Contents

POLICY GUIDELINES FOR REDUCING VEHICLE EMISSIONS IN ASIAiv

Concerned with the increasing levels of air pollution caused by

motor vehicles in Asia’s major cities, Asian Development Bank

initiated a project on Reducing Vehicle Emissions in November

2000. The project collected and disseminated information on

policies to reduce vehicle emissions through the Reducing Ve-

hicle Emissions in Asia website (http://www.adb.org/vehicle-

emissions), an information portal on international, regional, na-

tional and city level experiences in reducing vehicle emissions.

Through five workshops, the project provided a venue for the

sharing of experiences between countries in Asia and the intro-

duction of best practices on reducing vehicle emissions from

other regions—

■ Fuel Quality, Alternative Fuels, and Advanced Vehicle

Technology held on 2–4 May 2001 in New Delhi, India,

■ Reducing Emissions from Two and Three Wheelers held

on 5–7 September 2001 in Hanoi, Viet Nam,

■ Strengthening Vehicle Inspection and Maintenance

held on 7–9 November 2001 in Chongqing, PRC,

■ Transport Planning, Demand Management and Air

Quality held on 26–27 February 2002 in Manila, Philip-

pines, and

■ Concluding Workshop on Reducing Vehicle Emissions

held on 28 February–1 March 2002 in Manila, Philippines.

The project supported the formation of multi-sector action

plan groups and the formulation of three action plans—”Inte-

grated Vehicle Emission Reduction Strategy for Greater Jakarta,

Indonesia,” “Strengthening Vehicle Inspection and Maintenance

in Chongqing, People’s Republic of China,” and “Integrated Ac-

tion Plan to Reduce Vehicle Emissions in Viet Nam.” It provided

Preface

APPENDIX v

resources for two studies—“Study on Air Quality in Jakarta, Indo-

nesia: Future Trends, Health Impacts, Economic Value and Policy

Options” and “Pricing and Infrastructure Costing for Supply and

Distribution of CNG and ULSD to the Transport Sector in Mumbai,

India.”

The Policy Guidelines for Reducing Vehicle Emissions in Asia con-

sist of five main books with these titles:

■ Reducing Vehicle Emissions in Asia

■ Cleaner Fuels

■ Cleaner Two and Three Wheelers

■ Vehicle Emissions Standards and Inspection and Mainte-

nance

■ Transport Planning and Traffic Management for Better Air

Quality

These books come with a common appendix on the Adverse

Health and Environmental Effects from Vehicle Emissions printed

as a separate book to clearly demonstrate the health and envi-

ronmental impacts caused by air pollution from vehicles.

These policy guidelines, which are based on the five workshops

organized by the project, provide an in-depth analysis of the dif-

ferent components of an integrated strategy to reduce pollution

from vehicles in Asia. Policymakers in Asia will have to combine

the general principles outlined in the policy guidelines with their

knowledge of the local situation in their countries and cities to

arrive at effective strategies.

The Reducing Vehicle Emissions project produced its final re-

port in a CD-ROM containing the workshop presentations, action

plans, studies, and policy guidelines.

POLICY GUIDELINES FOR REDUCING VEHICLE EMISSIONS IN ASIAvi

ADB Asian Development Bank

CFC chlorofluorocarbons

CO carbon monoxide

HC hydrocarbon

NOx

nitrogen oxides

NO2

nitrogen dioxide

ODS ozone-depleting substance

PM particulate matter

SO2

sulfur dioxide

US EPA US Environmental Protection Agency

Abbreviations

APPENDIX 1

Vehicles emit significant amounts of several pollutants with vary-

ing effects as summarized in Table 1.

Adverse health andenvironmental effectsfrom vehicle emissions

Carbon monoxide1

Carbon monoxide (CO)—an odorless, invisible gas created when

fuels containing carbon are burned incompletely—poses a seri-

ous threat to human health. Fetuses and persons afflicted with

heart disease are especially at risk. Because the affinity of blood

hemoglobin is 200 times greater for carbon monoxide than for

oxygen, CO hinders oxygen transport from the blood into the tis-

sues. Therefore, more blood must be pumped to deliver the same

amount of oxygen. Numerous studies in humans and animals

Table 1Adverse Healthand EnvironmentalEffects of VehicleEmissions

CO = carbon monoxide, HC = hydrocarbon, NOx = nitrogen oxides, PM = particulate matter, SO

x = sulfur oxide

a Ozone

Health Effect Climate Change

Pollutant Direct Indirect Acid Rain Eutrophication Visibility Direct Indirect

CO X

HC X Xa X

NOx

X Xa X X X X X

PM X X X

SOx

X X X X

POLICY GUIDELINES FOR REDUCING VEHICLE EMISSIONS IN ASIA2

demonstrate that individuals with weak hearts are placed under

additional strain by the presence of excess CO in the blood. In

particular, clinical health studies have shown a decrease in time

to the onset of angina pain in individuals suffering from angina

pectoris and exposed to elevated levels of ambient CO.

Healthy individuals are also affected, but only at higher levels.

Exposure to elevated CO levels is associated with the impairment

of visual perception, work capacity, manual dexterity, learning

ability and the performance of complex tasks.

Nitrogen oxides2

As a class of compounds, the oxides of nitrogen are involved in

a host of environmental concerns that adversely impact human

health and welfare. Nitrogen dioxide (NO2) has been linked with

increased susceptibility to respiratory infection, increased air-

way resistance in asthmatics, and decreased pulmonary func-

tion. It has been shown that even short-term NO2 exposures have

resulted in a wide-range of respiratory problems in school chil-

dren; cough, runny nose and sore throat are among the most

common.

Nitrogen oxides (NOx)

also contribute to acid deposition, which

damages trees at high elevations and increases the acidity of lakes

and streams, which results in severe damage to aquatic life. Fi-

nally, NOx emissions can contribute to increased levels of particu-

late matter by changing into nitric acid in the atmosphere and

forming particulate nitrate.

Photochemical oxidants (Ozone)3

Ground level ozone, the main ingredient in smog, is formed by

complex chemical reactions of volatile organic compounds and

NOx in the presence of heat and sunlight.

Ozone can cause harmful respiratory effects including chest

pain, coughing, and shortness of breath, which affect people with

compromised respiratory systems most severely. When inhaled,

APPENDIX 3

ozone can cause acute respiratory problems; aggravate asthma;

cause significant temporary decreases in lung function of 15 to

over 20% in some healthy adults; cause inflammation of lung tis-

sue; may increase hospital admissions and emergency room vis-

its; and impair the body’s immune system defenses, making

people more susceptible to respiratory illnesses. Children and

outdoor workers are likely to be exposed to elevated ambient

ozone levels during exercise and, therefore, are at greater risk of

experiencing adverse health effects.

In addition to the effects on human health, ozone is known to

adversely affect the environment in many ways. These effects in-

clude reduced yields for commodity crops, fruits, vegetables, and

commercial forests; ecosystem and vegetation effects in parks;

damage to urban grass, flowers, shrubs, and trees; reduced yield

in tree seedlings and noncommercial forests; increased suscepti-

bility of plants to pests; materials damage; and impaired visibility.

Gaseous air toxicsIn addition to their contribution to ozone levels, certain hydro-

carbon (HC) emissions contain toxic air pollutants that may have

a significant effect on public health.

Benzene

The United States Environmental Protection Agency (US EPA) has

recently reconfirmed that benzene is a known human carcino-

gen by all routes of exposure.4 Long-term respiratory exposure

to high levels of ambient benzene concentrations has been

shown to cause cancer of the tissues that form white blood cells.

Exposure to benzene and/or its metabolites has also been linked

with genetic changes in humans and animals,5 and increased

proliferation of mouse bone marrow cells.6 The occurrence of

certain chromosomal changes in individuals with known expo-

sure to benzene may serve as a marker for those at risk of con-

tracting leukemia.7

POLICY GUIDELINES FOR REDUCING VEHICLE EMISSIONS IN ASIA4

Formaldehyde

The US EPA has classified formaldehyde as a probable human

carcinogen based on limited evidence for carcinogenicity in hu-

mans and sufficient evidence of carcinogenicity in animal stud-

ies on rats, mice, hamsters, and monkeys.8 Epidemiological stud-

ies in occupationally-exposed workers suggest that long-term

inhalation of formaldehyde may be associated with tumors of the

nasopharyngeal cavity (generally the area at the back of the

mouth near the nose), nasal cavity, and sinuses. Research has dem-

onstrated that formaldehyde produces mutagenic activity in cell

cultures.9

Acetaldehyde

The atmospheric chemistry of acetaldehyde is similar in many

respects to that of formaldehyde.10 Like formaldehyde, it is pro-

duced and destroyed by atmospheric chemical transformation.

Acetaldehyde emissions are classified as a probable human car-

cinogen.

1,3-Butadiene

1,3-Butadiene was classified by the US EPA as a Group B2 (prob-

able human) carcinogen in 1985.11 This classification was based

on evidence from two species of rodents and epidemiologic data.

Lead12

Over the past century, a range of clinical, epidemiological and

toxicological studies have continued to define the nature of lead

toxicity, to identify young children as a critically susceptible popu-

lation, and to investigate mechanisms of action of lead toxicity.

In summary, lead affects many organs and organ systems in the

human body, with sub-cellular changes and neurodevelopmental

effects appearing to be the most sensitive. The most substantial

APPENDIX 5

evidence from cross-sectional and prospective

studies of populations with lead levels generally

below 25 µg/deciliter of blood relates to decre-

ments in intelligence quotient (IQ).

Existing epidemiological studies do not provide

definitive evidence of a threshold. Below the range

of about 10–15 µg/deciliter of blood, the effects of

confounding variables and limits in the precision

of analytical and psychometric measurements in-

crease the uncertainty attached to any estimate of

effect. However, there is some evidence of an asso-

ciation below this range. Animal studies provide support for a

causal relationship between lead and nervous system effects, re-

porting deficits in cognitive functions at lead levels as low as 11–

15 µg/deciliter of blood, which can persist well beyond the ter-

mination of lead exposure. Other effects that may occur include:

� impaired sensory motor function

� impaired renal function

� a small increase in blood pressure has been associated with

lead exposure

� some, but not all, epidemiological studies show a dose-

dependent association of pre-term delivery and some in-

dices of fetal growth and maturation at blood lead levels

of 15 µg/deciliter or more.

Airborne lead can be deposited on soil and water, thus reach-

ing humans through the food chain and drinking water. Atmo-

spheric lead is also a major source of lead in household dust.

Lead scavengersWhen lead additives were first discovered to improve gasoline

octane quality, they were also found to cause many problems with

vehicles. Notable among these was a very significant build up of

deposits in the combustion chamber and on spark plugs, which

caused durability problems. To relieve these problems, lead scav-

engers were added to gasoline at the same time as lead to en-

In summary, lead affects

manyorgans and organ

systems in the human body,

with sub-cellular change

and neurodevelopmental

effects appearing to be the

most sensitive

POLICY GUIDELINES FOR REDUCING VEHICLE EMISSIONS IN ASIA6

courage greater volatility in the lead combustion by-products so

they would be exhausted from the vehicle. Unfortunately, the

National Cancer Institute has found these lead scavengers, most

notably ethylene dibromide, to be carcinogenic in animals and

they have been identified as potential human carcinogens.13

ParticulateParticulate matter (PM) represents a broad class of chemically and

physically diverse substances that exist as discrete particles (liq-

uid droplets or solids) over a wide range of sizes. Human-gener-

ated sources of particles include a variety of stationary and mo-

bile sources. Particles may be emitted directly to the atmosphere

or may be formed by transformations of gaseous emissions such

as sulfur dioxide or nitrogen oxides. The major chemical and physi-

cal properties of PM vary greatly with time, region, meteorology,

and source category, thus complicating the assessment of health

and welfare effects as related to various indicators of particulate

pollution. At elevated concentrations, particulate matter can ad-

versely affect human health, visibility, and materials. Components

of particulate matter, such as sulfuric or nitric acid, contribute to

acid deposition.14

The key health effects categories associated with PM include

premature death; aggravation of respiratory and cardiovascular

disease, as indicated by increased hospital admissions and emer-

gency room visits, school absences, work loss days, and restricted

activity days; changes in lung function and increased respiratory

symptoms; changes to lung tissues and structure; and altered

respiratory defense mechanisms. Most of these effects have been

consistently associated with ambient PM concentrations, which

have been used as a measure of population exposure in a large

number of community epidemiological studies.

Sensitive populations include the following:

� Individuals with respiratory disease (e.g. chronic obstruc-

tive pulmonary disease, acute bronchitis) and cardiovas-

cular disease (e.g. ischemic heart disease) are at greater

APPENDIX 7

risk of premature mortality and hospitalization due to ex-

posure to ambient PM.

� Individuals with infectious respiratory disease (e.g. pneu-

monia) are at greater risk of premature mortality and mor-

bidity (e.g. hospitalization, aggravation of respiratory symp-

toms) due to exposure to ambient PM. Also, exposure to

PM may increase an individual’s susceptibility to respira-

tory infections.

� Elderly individuals are also at greater risk of premature

mortality and hospitalization for cardiopulmonary prob-

lems due to exposure to ambient PM.

� Children are at greater risk of increased respiratory symp-

toms and decreased lung function due to exposure to

ambient PM.

� Asthmatic individuals are at risk of exacerbation of symp-

toms associated with asthma, and increased need for medi-

cal attention, due to exposure to PM.

There are fundamental physical and chemical differences be-

tween fine and coarse fraction particles. The fine fraction con-

tains acid aerosols, sulphates, nitrates, transition metals, diesel

exhaust particles, and ultrafine particles, and the coarse fraction

typically contains high mineral concentrations, silica and resus-

pended dust. Exposure to coarse fraction particles is primarily

associated with the aggravation of respiratory conditions such

as asthma. Fine particles are most closely associated with health

effects such as premature death or hospital admissions, and for

cardiopulmonary diseases.

Diesel emissionsThe US EPA has concluded that diesel particulate is a probable

human carcinogen based largely on the consistent association

that has been observed between increased lung cancer and die-

sel exhaust exposure in certain occupationally-exposed workers.

Approximately 30 individual epidemiological studies show in-

creased lung cancer risks of 20 to 89% within the study popula-

POLICY GUIDELINES FOR REDUCING VEHICLE EMISSIONS IN ASIA8

tions depending on the study. Analytical results of pooling the

positive study results show that on average, the lung cancer risks

were increased by 33 to 47%. While not all studies have demon-

strated an increased risk (6 of 34 epidemiological studies sum-

marized by the Health Effects Institute15 reported relative risks of

less than 1.0), the fact that an increased risk has been consistently

noted in the majority of epidemiological studies strongly sup-

ports the determination that exposure to diesel exhaust is likely

to pose a carcinogenic hazard to humans.

The concern for the carcinogenic health hazard resulting from

diesel exhaust exposures is widespread, and several national and

international agencies have designated diesel exhaust or diesel

particulate matter as a “potential” or “probable” human carcino-

gen.16 The International Agency for Research on Cancer (IARC) in

the late 1980s concluded that diesel exhaust is a “probable” hu-

man carcinogen.17 Based on IARC findings, the State of California

identified diesel exhaust in 1990 as a chemical known to the State

Children are atgreater risk ofincreasedrespiratorysymptoms anddecreased lungfunction due toexposure toambient PM

APPENDIX 9

The fact that an increased risk

has been consistently noted

in the majority of epidemiological

studies strongly supports the

determination that exposure to

diesel exhaust is likely to pose a

carcinogenic hazard to humans

to cause cancer, and after an extensive review

in 1998, listed diesel exhaust as a toxic air

contaminant.18 The National Institute for Oc-

cupational Safety and Health has classified

diesel exhaust as a “potential occupational

carcinogen.” The World Health Organization

recommends that “urgent efforts should be

made to reduce [diesel engine] emissions,

specifically of particulates, by changing ex-

haust train techniques, engine design and

fuel composition.”

Another aspect of diesel particulate that is a cause for con-

cern is its size. Approximately 80 to 95% of diesel particle mass is

in the 0.05 to 1.0 micron size range with a mean particle diam-

eter of about 0.2 microns. These fine particles have a very large

surface area per gram of mass which makes them excellent carri-

ers for adsorbed inorganic and organic compounds that can ef-

fectively reach the lowest airways of the lung. Approximately 50

to 90% of diesel exhaust particles are in the ultrafine size range

from 0.005-0.05 microns, averaging about 0.02 microns. While

accounting for the majority of the number of particles, ultrafine

diesel particulate matter accounts for 1 to 20% of the mass of

diesel particulate matter.

Sulfur dioxideHigh concentrations of sulfur dioxide (SO

2)

can result in tempo-

rary breathing impairment for asthmatic children and adults who

are active outdoors. Short-term exposures of asthmatic individu-

als to elevated SO2

levels while at moderate exertion may result

in reduced lung function that may be accompanied by such symp-

toms as wheezing, chest tightness, or shortness of breath. Other

effects that have been associated with longer-term exposures to

high concentrations of SO2, in conjunction with high levels of PM,

include respiratory illness, alterations in the lungs’ defenses, and

aggravation of existing cardiovascular disease. The subgroups of

POLICY GUIDELINES FOR REDUCING VEHICLE EMISSIONS IN ASIA10

the population that may be affected under these conditions in-

clude individuals with cardiovascular disease or chronic lung dis-

ease, as well as children and the elderly.

Visibility and regional hazeVisibility impairment is the haze that obscures what we see, and

is caused by the presence of tiny particles in the air. These par-

ticles cause light to be scattered or absorbed, thereby reducing

visibility. Visibility impairment, also called regional haze, is a com-

plex problem that relates to natural conditions and to several

pollutants. The principal cause of visibility impairment is fine par-

ticles, primarily sulphates, but also nitrates, organics, and elemen-

tal carbon and crustal matter. Particles between 0.1 and one mi-

crometers in size are most effective at scattering light, in addi-

tion to being of greatest concern for human health. Of the pol-

lutant gases, only NO2 absorbs significant amounts of light; it is

partly responsible for the brownish cast of polluted skies. How-

ever, it is responsible for less than 10% of visibility reduction.

Acid deposition19

Acid deposition, or acid rain as it is commonly known, occurs when

SO2 and NO

x react in the atmosphere with water, oxygen, and

oxidants to form various acidic compounds that later fall to earth

in the form of precipitation or dry deposition of acidic particles.

It contributes to tree damage at high elevations and, in extreme

cases, may cause lakes and streams to become so acidic that they

cannot support aquatic life. While fish species vary in their sensi-

tivities to acidification, those with low tolerance decline in popu-

lation at times to the point of extinction. This not only affects the

species directly harmed, but damages the ecosystem as a whole

due to the loss of species diversity. Effects on soil include reduc-

ing the availability of nutrients and enhancing the solubility of

metals. In addition, acid deposition accelerates the decay of build-

ing materials and paints, including irreplaceable buildings, stat-

APPENDIX 11

ues, and sculptures that are part of many nations’ cultural heri-

tage. Much research has been devoted to studies in North America

and Western Europe, while relatively little has been done in Asia—

where most of the growth in acid-depositing emissions is ex-

pected over the next few decades.

Climate changeGreenhouse warming occurs when certain gases allow sunlight

to penetrate the earth but partially trap the planet’s radiated in-

frared heat in the atmosphere. Some such warming is natural and

necessary. If there were no water vapor, carbon dioxide, meth-

ane, and other infrared absorbing (greenhouse) gases in the at-

mosphere trapping the earth’s radiant heat, our planet would be

about 60ºF (33ºC) colder, and life as we know it would not be pos-

sible. Naturally occurring greenhouse gases include water vapor,

carbon dioxide, methane (CH4), nitrous oxide (N

2O), and ozone.

Several classes of halogenated substances that contain fluo-

rine, chlorine, or bromine are also greenhouse gases, but they are

for the most part, solely a product of industrial activities. Chlorof-

luorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are

halocarbons that contain chlorine; while halocarbons that con-

tain bromine are referred to as halons. Other fluorine containing

halogenated substances include hydrofluorocarbons (HFCs), per-

fluorocarbons (PFCs), and sulfur hexafluoride (SF6).

There are also several gases that, although they do not have a

direct global warming effect, do influence the formation and

destruction of ozone, which does have such a terrestrial radia-

tion absorbing effect. These gases include carbon monoxide (CO),

oxides of nitrogen (NOX), and nonmethane volatile organic com-

pounds.

Aerosols, extremely small particles or liquid droplets often pro-

duced by emissions of sulfur dioxide (SO2), can also affect the

absorptive characteristics of the atmosphere.

Although CO2, CH

4, and N

2O occur naturally in the atmosphere,

the atmospheric concentration of each has risen, largely as a re-

POLICY GUIDELINES FOR REDUCING VEHICLE EMISSIONS IN ASIA12

sult of human activities. Since 1800, atmospheric concentrations

of these greenhouse gases have increased by 30%, 145%, and

15%, respectively (Intergovernmental Panel on Climate Change

1996). This build up has altered the composition of the Earth’s

atmosphere, and may affect the global climate system.

Beginning in the 1950s, the use of CFCs and other ozone-de-

pleting substances (ODSs) increased by nearly 10% a year, until

the mid-1980s when international concern about ozone deple-

tion led to the signing of the Montreal Protocol. Since then, the

consumption of ODSs has rapidly declined as they are phased-

out. In contrast, use of ODS substitutes such as HFCs, PFCs, and

SF6 has grown significantly; all of which have strong greenhouse-

forcing effects.

In late November 1995, the Intergovernmental Panel on Cli-

mate Change (IPCC) Working Group 1 concluded, “the balance of

evidence suggests that there is a discernible human influence

on global climate.”20 The transportation sector is responsible for

approximately 17% of global carbon dioxide emissions and these

emissions are increasing in virtually every part of the world.

The potential global warming benefits of diesel vehicles, due

to their substantial fuel economy benefits relative to gasoline-

fuelled vehicles, have been undercut by recent studies. These in-

dicate that diesel particles may, by reducing cloud cover and rain-

fall, more than offset any CO2 advantage. As noted by NASA’s Dr.

James Hansen, “Black carbon reduces aerosol albedo, causes a

semi-direct reduction of cloud cover, and reduces cloud particle

albedo.”21

EutrophicationNitrogen oxides also result in nitrogen deposition into sensitive

nitrogen-saturated coastal estuaries and ecosystems, causing in-

creased growth of algae and other plants.22 Long-term monitor-

ing in the United States, Europe, and other developed regions of

the world shows a substantial rise of nitrogen levels in surface

waters, which are highly correlated with human-generated in-

APPENDIX 13

puts of nitrogen to their watersheds. Fertilizers and atmospheric

deposition dominate these nitrogen inputs.

Human activity can increase the flow of nutrients into those

waters and result in excess algae and plant growth. This increased

growth can cause numerous adverse ecological effects and eco-

nomic impacts, including nuisance algal blooms, dieback of un-

derwater plants due to reduced light penetration, and toxic plank-

ton blooms. Algal and plankton blooms can reduce the level of

dissolved oxygen, which adversely affect fish and shellfish popu-

lations. This problem is of particular concern in coastal areas with

poor or stratified circulation patterns. In such areas, the “overpro-

duced” algae tends to sink to the bottom and decay, use all or

most of the available oxygen and thereby reduce or eliminate

populations of bottom-feeder fish and shellfish, distort the nor-

mal population balance between different aquatic organisms, and

in extreme cases, cause dramatic fish kills.

Collectively, these effects are referred to as eutrophication.

POLICY GUIDELINES FOR REDUCING VEHICLE EMISSIONS IN ASIA14

1 United States Environmental Protection Agency (US EPA). 1999. Sec-

ond External Review Draft, Air Quality Criteria for Carbon Monoxide.

USA.2 US EPA. 1993. Air Quality Criteria for Oxides of Nitrogen, EPA/600/8-91/

049aF. USA; US EPA. 1995. Review of National Ambient Air Quality Stan-

dards for Nitrogen Dioxide, Assessment of Scientific and Technical Infor-

mation. OAQPS Staff Paper, EPA-452/R-95-005. USA.3 US EPA. 1996. Review of National Ambient Air Quality Standards for

Ozone, Assessment of Scientific and Technical Information. OAQPS

Staff Paper, EPA-452/R-96-007. USA; US EPA. 1996. Air Quality Crite-

ria for Ozone and Related Photochemical Oxidants. EPA/600/P-93/

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dustrial chemicals and dyestuffs. In IARC monographs on the evalua-

tion of carcinogenic risk of chemicals to humans. Vol. 29. World Health

Organization, Lyon, France: 345-389.6 Irons, R.D., W.S. Stillman, D.B. Colagiovanni, and V.A. Henry. 1992. Syner-

gistic action of the benzene metabolite hydroquinone on myelopoietic

stimulating activity of granulocyte/macrophage colony-stimulating fac-

tor in vitro. Proc. Natl. Acad. Sci. 89:3691-3695.7 Lumley, M., H. Barker, and J.A. Murray. 1990. Benzene in petrol. Lancet

336: 1318-1319.8 US EPA. 1987. Assessment of health risks to garment workers and certain

home residents from exposure to formaldehyde. Office of Pesticides and

Toxic Substances.April 1987.9 US EPA. 1993. Motor Vehicle-Related Air Toxics Study. Office of Mobile

Sources. Ann Arbor, MI. EPA Report No. EPA 420-R-93-005, April 1993.

Notes

APPENDIX 15

10 Ligocki, M.P., G.Z. Whitten. 1991. Atmospheric transformation of air toxics:

acetaldehyde and polycyclic organic matter. Systems Applications In-

ternational, San Rafael, CA, (SYSAPP-91/113).11 US EPA. 1985. Mutagenicity and carcinogenicity assessment of 1,3-buta-

diene. Office of Health and Environmental Assessment.EPA/600/8-85/

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ylene Dibromide. Society of Automotive Engineers, #820786.14 US EPA. 1996. Air Quality Criteria for Particulate Matter. EPA/600/P-95/

001aF.15 Health Effects Institute. 1995. Diesel Exhaust: A Critical Analysis of Emis-

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genic effects of exposure to diesel exhaust. NIOSH Current Intelligence

Bulletin 50. DHHS (NIOSH) Publication No. 88-116. Centers for Disease

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Air Contaminant Appendix III Part A: Exposure Assessment. California Air

Resources Board. April 22, 1998.19 US EPA, Office of Air and Radiation, Acid Rain Division. 1995. Human

Health Benefits from Sulfate Reduction. Written under Title IV of the 1990

Clean Air Act Amendments. Washington, DC.

POLICY GUIDELINES FOR REDUCING VEHICLE EMISSIONS IN ASIA16

20 In its most recent draft report, the IPCC has changed the wording to

“there is a discernable human influence on global climate.”21 Hansen, J., NASA Goddard Institute for Space Studies Research. Global

Warming in the 21st Century: An Alternative Scenario. Available:

www.giss.nasa.gov/research/impacts/altscenario/22 Vitousek, Pert M., John Aber, Robert W. Howarth, Gene E. Likens, et al.

1997. Human Alteration of the Global Nitrogen Cycle: Causes and Conse-

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