Periodic Assessment of Human Exposure to Air Pollution from Mobile Sources: A Potential Indicator of

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Periodic Assessment of Human Exposure to Air
Pollution from Mobile Sources A Potential
Indicator of the Effectiveness ofEmission
Control Programs in Asia

• Peter Flachsbart, Ph.D., AICP
• Associate Professor
• Department of Urban and Regional Planning
• University of Hawaii at Manoa

November 16-17, 2006
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What is an Integrated Approach?
(Source Lovei, 2003)
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Three Major Periods of AQM
Source Larssen et al., 2003
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Urbanization in Asia

• Asia has 10 mega-cities (gt 10 million people) or
  50 of the worlds mega-cities.
• By 2020, 1 of every 2 people will live in a city
  in Asia.
• Asia has giant urban agglomerations (Delhi,
  Jakarta, Manila).
• In Delhi and Manila, car population doubles in
  size every 7 years growth of two-wheelers is
  even more rapid.

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Bangkok
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Manilas Unique Modes of Transport
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Mobile Sources in Developing Countries

• Mobile sources contribute over 60-80 of urban
  air pollution in developing countries.
• Many cities have high levels of traffic
  congestion, accidents and air pollution, because
  of rapid growth in motor vehicle populations.
• Long life of vehicles, slow turn-over of fleet,
  many old vehicles without emission controls.
• Fuel quality and fuel alternatives
• Many countries converting to unleaded gasoline.
• Photochemical smog potential may be increased in
  the transitional period

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Air Pollution Terminology
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Mobile-Source Air Pollutants

• Aromatic hydrocarbons (e.g., benzene, toluene,
  ethyl benzene, the xylenes, and the
  trimethyl-benzenes)
• Carbon monoxide (CO)
• Lead (Pb)
• Nitrogen oxides (NOx)
• Ozone(O3)
• Particulate matter (PM)
• Sulfur oxides (SOx), sulfuric acids and reduced
  sulfur compounds

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Factors Affecting Tailpipe Emissions

• Motor vehicle population which is affected by
  population and economic growth
• Exhaust emission standards, motor vehicle fuel
  technologies, inspection and maintenance (I/M)
  programs
• How people travel (e.g., by walking, biking,
  motorcycle, automobile, truck, bus, rail, etc.)
• Travel distance which is affected by land use
  patterns, density, and the social and economic
  characteristics of trip-makers

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Elements of a Successful I/M Program
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Research Question

• Can periodic measurements of personal exposure to
  mobile-source air pollutants over time be used to
  assess the effectiveness of motor vehicle
  emission control programs?

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Exposure to Air Pollution

• An exposure to an air pollutant occurs when a
  person comes in contact with the pollutant in
  ambient air and in various microenvironments.
• Exposure f (air pollutant concentration and
  duration of exposure).
• Exposures are typically reported as average
  concentrations measured over a specified time
  period (e.g., while commuting in traffic).

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Individual Exposure as a Function of Time
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Approaches for Measuring Personal Exposure

• Direct
• Ordinary people use personal monitors to measure
  exposure to air pollutants while performing their
  daily activities and keep a diary of time spent
  doing those activities.
• Indirect
• Technicians use personal monitors to measure
  air pollutant concentrations in
  micro-environments that ordinary people visit.

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Lady Carrying a CO Personal Exposure Monitor (PEM)
Personal Exposure Monitor (PEM)
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Page of a Diary from a CO Exposure Study
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Duans Model for Estimating Total Exposure to an
Air Pollutant in a Population
k Ei S Ck (Tik) k1

• Ei the total integrated exposure of person i
  over some period of interest (e.g., 24 hours)
• Ck the air pollutant concentration in
  microenvironment type k (e.g., indoor, outdoor,
  in-vehicle)
• Tik the amount of time spent by person i in
  microenvironment type k
• k the number of microenvironment types
  encountered by person i over the period of
  interest

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The Integrated CO Exposure of a Hypothetical
Person for a 24-hour Period
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Hypothetical Histogram of Exposure to Carbon
Monoxide of 200,000 People on Given Date
(Source Ott et al. 1981. A research plan for
population exposure monitoring methodology
Vehicular air pollutants. Washington, D.C. US
EPA. p. 9.)
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U.S. EPAs Direct Studies of Urban Population
Exposure to Carbon Monoxide (CO)

• Representative samples of adults (18 to 70 years
  of age) in two cities during fall of 1982 and
  winter of 1983
• 454 people in Denver carried a PEM and kept a
  diary for 48 hours.
• 712 people in Washington, DC, carried a PEM and
  kept a diary for 24 hours.
• In both cities
• fixed-site monitors overestimated the 8-hour
  exposures of people with low-level personal
  exposures and underestimated the 8-hour exposures
  of people with high-level personal exposures.
• Over 10 of the daily maximum 8-hour personal
  exposures exceeded the National Ambient Air
  Quality Standard (NAAQS) of 9 ppm for CO in
  Denver, and about 4 did so in Washington.

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Results of Direct Studies (continued)

• Indoor mean CO exposure increased
• 2.6 ppm when operating a gas stove
• 1.6 ppm when smokers were present
• 0.4 ppm if a parking garage was attached to the
  home
• Higher CO exposures occurred for travel by motor
  vehicles (motorcycle, bus, car, and truck) than
  for pedestrian or bicycle modes of travel.
• Commuting 6 hours or more per week resulted in
  higher average CO exposures.
• Above 9 ppm observed in garages, service
  stations, and vehicle repair shops.
• Jobs with high CO exposure included taxi drivers,
  policemen, and chauffeurs.
• (Source Akland et al., 1985)

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Diurnal CO Exposure Profile of a Denver, Colorado
Respondent using a Personal Monitor along with
Predicted Blood Carboxyhemoglobin (COHb)
(Source Ott, 1995 Duan et al., 1990)
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Exposure Studies on U.S. Roadways
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Spatial Variation in CO Concentrations at
Breathing Level (approximately 2 meters high)
in an Urban Area
(Source Ott, 1977)
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Relative Concentrations of Three Air Pollutants
on I-405 Freeway in West Los Angeles(Zhu et al.,
2002)
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Exhaust Emissions from Motor Vehicles on Roadway
(Source Ingalls and Garbe, 1982)
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Arie J. Haagen-Smit, professor of bio-organic
chemistry at Caltech, adjusts an instrument used
to measure CO concentrations while commuting in
traffic in Los Angeles in the mid-1960s.
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Results of Haagen-Smits StudyVariation in CO
Concentrations while Commuting
Source Haagen-Smit, 1966
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Kalanianaole Highway in Honolulu, Hawaii
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Traffic Lanes Subject to Transportation System
Managementon Kalanianaole Highway
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Kalanianaole Highway Exposure StudyShow
Benefits of Express Lane
Source Flachsbart, 1989
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Previous Question

• Can periodic measurements of personal exposure to
  mobile-source air pollutants over time be used to
  assess the effectiveness of motor vehicle
  emission control programs?

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Plot of Typical Ambient and In-Vehicle CO
Concentrations for 16 Studies, 1965-1992

• Source Flachsbart 1995, p. 488.

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Findings of Review of 16 Exposure Studies

• Downward trends in both the mean in-vehicle CO
  concentration (top line) and the concurrently
  measured ambient CO concentrations (bottom line)
  of these studies.
• Typical CO exposures of U.S. commuters fell
  approximately 92 from 1965 to 1992.
• The mean in-vehicle CO concentration of a given
  study was typically 3.5 times greater than the
  concurrently measured mean ambient CO
  concentration at the nearby fixed-site monitor.
• Typical commuter CO exposures varied by
• study approach (direct vs. indirect) and even by
  researcher for the more common type of study
  (i.e., the indirect approach)
• city where surveys were performed
• season of the year
• roadway type (freeway, expressways/arterials,
  residential streets)
• location of survey (central city, suburb, rural)
• travel mode (automobile, bus, rail transit, etc.)
• ventilation settings of the test vehicle
• Source Flachsbart, 1995.

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U.S. Exhaust Emission Standardsby New Vehicle
Model Year
(Source U.S. Department of Energy. 1997.
Transportation Energy Databook Edition 17. Table
7.12. American Automobile Manufacturers
Association. 1997. Motor Vehicle Facts and
Figures. pp. 83-84.)
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Longitudinal Study in San Francisco Bay Area
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Map of Survey Site El Camino Real (State Route
82)
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Rooftop Fixed-Site Monitoring Station
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Download Data to a Computer
Source Langan, 2000
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Number of Trips Taken by Survey Period
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Series 1 1980-81 Trips Series 2 1991-92 Trips
Series 3 2001-02 TripsSource
Flachsbart, Ott and Switzer, 2004.
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Light-Duty Vehicle Exhaust Emission Standards for
Carbon MonoxideEmission rates by (or adjusted to
equivalent) 1975 Federal Test Procedure

• (a) Federal Tier 1 CO standards, which were
  phased in beginning 1994, include a cold
  temperature standard of 10 grams/mile measured at
  20 F rather than at 75 F under the Federal Test
  Procedure. California included an identical cold
  temperature CO requirement beginning with the
  1996 model year.
• (b) The emission standards in parenthesis are
  phase-in standards for the 1993 and 1994 model
  years. The first standard applies to the
  vehicles first 5 years or 50,000 miles, and the
  second standard applies for 10 years or 100,000
  miles. Manufacturers must certify a minimum of
  40 of their vehicles to the phase-in standard or
  to the more stringent standards of test
  procedures.
• (Sources U.S. DOT, 1999 Air Resources Board,
  1997 Godish, 1991)

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Comparison of Current Inspection and Maintenance
(I/M) Programs in California
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One-Minute Average Net CO Concentrations
forMatched Trips in Early June of Each Survey
Period
Note In 2001, two monitors were operating
side-by-side and are plotted together.
Source Flachsbart, Ott and Switzer, 2004.
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Carbon Monoxide Exposure in Bangkok
(Source Walsh, M. 1991. Urban transport and the
environment in the Asia-Pacific Region)
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Hypothetical CO Exposure of a Person in an Asian
Cityfor a 24-hour period
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Does CO exposure contribute to traffic accidents?

• One-hour peak exposures ( 5 COHb in the blood)
  can affect a persons central nervous system,
  visual perception, hearing ability, and manual
  dexterity. Such exposures may diminish a healthy
  persons vigilance and ability to drive a vehicle
  in traffic. (U.S. EPA, Air Quality Criteria for
  Carbon Monoxide, 2000)
• 5 - 17 COHb is associated with statistically
  significant reductions in visual perception,
  manual dexterity, ability to learn, and/or
  performance of complex sensorimotor tasks (e.g.,
  driving a motor vehicle). (World Health
  Organization, 1987)

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International Comparison Typical Net Mean
In-Vehicle CO Concentrations by Travel Mode for
Cities in Three Countries a,b,c
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Timetable for Automobile Emissions Standards in
Asia
Note e gasoline vehicle f diesel
vehicles (Source Walsh, 2003 HEI, 2004, p. 39.)
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EU Emission Standards for Passenger Cars
(Category M1), g/km
Excluding cars over 2,500 kg, which meet N1
Category standards Values in brackets are
conformity of production (COP) limits.a - until
1999.09.30 (after that date Direct Injection (DI)
engines must meet the InDirect Injection (IDI
limits)) Source http//www.dieselnet.com/standa
rds/eu/ld.html
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Recommendation
To chart trends over time in Asian cities, we
need standardized, periodic studies of personal
exposure to motor vehicle air pollutants given

• Asias rapidly growing motor vehicle population
• Still nascent motor vehicle emission control and
  inspection programs

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Some Recent Traffic-Related Exposure Studiesin
Asian Countries

• Roadside exposure to PM10 in Hong Kong, China
  (Chan et al., 2000)
• Occupational exposure to VOCs in Taegu, Korea (Jo
  and Yu, 2001 Jo and Song, 2001)
• Roadside exposure to PAHs in Bangkok and Tokyo
  (Chetwittayachan et al., 2002)
• Roadside exposure to VOCs in Guangzhou, Macau,
  and Nanhai, China (Wang et al., 2002)
• In-vehicle exposure to PM10, PM2.5, CO, VOCs in
  Guangzhou, China (Chan et al., 2002, 2003)
• In-vehicle exposure to VOCs in Hong Kong, China
  (Lau and Chan, 2003)
• In-vehicle exposure to PAHs in Taichung, Taiwan,
  China (Kuo et al., 2003)
• In-vehicle exposure to VOCs in Hong Kong, China
  (Lau and Chan, 2003)
• Source Han and Naeher, Environment International
  32, 2006, 106-120.

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CO Dose (mg) Inhaled during Commuting in Delhi
(Prasad et al., 2003)
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RSP dose (mg) Inhaled during Commuting in Delhi,
India (Prasad et al., 2003)
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2005 Pilot Study of Exposure in Bangalore,
IndiaCO monitor (left) and PM10 monitor (right)
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• Thank you !
• flachsba_at_hawaii.edu