Periodic Assessment of Human Exposure to Air Pollution from Mobile Sources: A Potential Indicator of the Effectiveness of Emission Control Programs in Asia : Periodic Assessment of Human Exposure to Air Pollution from Mobile Sources: A Potential Indicator of the Effectiveness of Emission 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
What is an Integrated Approach?: What is an Integrated Approach? (Source: Lovei, 2003)
Three Major Periods of AQM: Three Major Periods of AQM Source: Larssen et al., 2003
Urbanization in Asia: Urbanization in Asia Asia has 10 mega-cities (> 10 million people) or 50% of the world’s 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.
Bangkok: Bangkok
Manila’s Unique Modes of Transport: Manila’s Unique Modes of Transport
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 Mobile Sources in Developing Countries
Air Pollution Terminology: Air Pollution Terminology
Mobile-Source Air Pollutants : 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
Factors Affecting Tailpipe Emissions: 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
Elements of a Successful I/M Program: Elements of a Successful I/M Program
Research Question: 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?
Exposure to Air Pollution: 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).
Individual Exposure as a Function of Time: Individual Exposure as a Function of Time
Approaches for Measuring Personal Exposure: 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.
Lady Carrying a CO Personal Exposure Monitor (PEM): Lady Carrying a CO Personal Exposure Monitor (PEM) Personal Exposure Monitor (PEM)
Page of a Diary from a CO Exposure Study: Page of a Diary from a CO Exposure Study
Duan’s Model for Estimating Total Exposure to an Air Pollutant in a Population: Duan’s Model for Estimating Total Exposure to an Air Pollutant in a Population 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 k
Ei = S Ck (Tik)
k=1
The Integrated CO Exposure of a Hypothetical Person for a 24-hour Period: The Integrated CO Exposure of a Hypothetical Person for a 24-hour Period
Hypothetical Histogram of Exposure to Carbon Monoxide of 200,000 People on Given Date: 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.)
U.S. EPA’s Direct Studies of Urban Population Exposure to Carbon Monoxide (CO): U.S. EPA’s 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.
Results of Direct Studies (continued): 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)
Diurnal CO Exposure Profile of a Denver, Colorado Respondent using a Personal Monitor along with Predicted Blood Carboxyhemoglobin (COHb): 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)
Exposure Studies on U.S. Roadways: Exposure Studies on U.S. Roadways
Spatial Variation in CO Concentrations at “Breathing Level” (approximately 2 meters high) in an Urban Area: Spatial Variation in CO Concentrations at “Breathing Level” (approximately 2 meters high) in an Urban Area (Source: Ott, 1977)
Relative Concentrations of Three Air Pollutants on I-405 Freeway in West Los Angeles (Zhu et al., 2002): Relative Concentrations of Three Air Pollutants on I-405 Freeway in West Los Angeles (Zhu et al., 2002)
Slide29: (Source: Ingalls and Garbe, 1982) Exhaust Emissions from Motor Vehicles on Roadway
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.: 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.
Results of Haagen-Smit’s Study: Variation in CO Concentrations while Commuting: Results of Haagen-Smit’s Study: Variation in CO Concentrations while Commuting Source: Haagen-Smit, 1966
Kalanianaole Highway in Honolulu, Hawai’i: Kalanianaole Highway in Honolulu, Hawai’i
Traffic Lanes Subject to Transportation System Management on Kalanianaole Highway: Traffic Lanes Subject to Transportation System Management on Kalanianaole Highway
Kalaniana’ole Highway Exposure Study Show Benefits of Express Lane : Kalaniana’ole Highway Exposure Study Show Benefits of Express Lane Source: Flachsbart, 1989
Previous Question: 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?
Plot of Typical Ambient and In-Vehicle CO Concentrations for 16 Studies, 1965-1992: Plot of Typical Ambient and In-Vehicle CO Concentrations for 16 Studies, 1965-1992 Source: Flachsbart 1995, p. 488.
Findings of Review of 16 Exposure Studies: 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.
U.S. Exhaust Emission Standards by New Vehicle Model Year: U.S. Exhaust Emission Standards by 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.)
Longitudinal Study in San Francisco Bay Area: Longitudinal Study in San Francisco Bay Area
Map of Survey Site: El Camino Real (State Route 82): Map of Survey Site: El Camino Real (State Route 82)
Rooftop Fixed-Site Monitoring Station: Rooftop Fixed-Site Monitoring Station
Download Data to a Computer : Download Data to a Computer Source: Langan, 2000
Number of Trips Taken by Survey Period: Number of Trips Taken by Survey Period
Slide45: Series 1: 1980-81 Trips Series 2: 1991-92 Trips Series 3: 2001-02 Trips Source: Flachsbart, Ott and Switzer, 2004.
Light-Duty Vehicle Exhaust Emission Standards for Carbon Monoxide Emission rates by (or adjusted to equivalent) 1975 Federal Test Procedure: Light-Duty Vehicle Exhaust Emission Standards for Carbon Monoxide Emission 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 vehicle’s 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)
Comparison of Current Inspection and Maintenance (I/M) Programs in California: Comparison of Current Inspection and Maintenance (I/M) Programs in California
One-Minute Average Net CO Concentrations for Matched Trips in Early June of Each Survey Period: One-Minute Average Net CO Concentrations for Matched 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.
Carbon Monoxide Exposure in Bangkok: Carbon Monoxide Exposure in Bangkok (Source: Walsh, M. 1991. Urban transport and the environment in the Asia-Pacific Region)
Hypothetical CO Exposure of a Person in an Asian City for a 24-hour period: Hypothetical CO Exposure of a Person in an Asian City for a 24-hour period
Does CO exposure contribute to traffic accidents?: Does CO exposure contribute to traffic accidents?
One-hour peak exposures (≥ 5% COHb in the blood) can affect a person’s central nervous system, visual perception, hearing ability, and manual dexterity. Such exposures may diminish a healthy person’s 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)
International Comparison: Typical Net Mean In-Vehicle CO Concentrations by Travel Mode for Cities in Three Countries a,b,c: International Comparison: Typical Net Mean In-Vehicle CO Concentrations by Travel Mode for Cities in Three Countries a,b,c
Timetable for Automobile Emissions Standards in Asia: Timetable for Automobile Emissions Standards in Asia Note: e: gasoline vehicle; f: diesel vehicles
(Source: Walsh, 2003; HEI, 2004, p. 39.)
EU Emission Standards for Passenger Cars (Category M1*), g/km : 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/standards/eu/ld.html
Recommendation: Recommendation Asia’s rapidly growing motor vehicle population
Still nascent motor vehicle emission control and inspection programs To chart trends over time in Asian cities, we need standardized, periodic studies of personal exposure to motor vehicle air pollutants given:
Some Recent Traffic-Related Exposure Studies in Asian Countries: Some Recent Traffic-Related Exposure Studies in 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.
Slide58: CO Dose (mg) Inhaled during Commuting
in Delhi (Prasad et al., 2003)
Slide59: RSP dose (mg) Inhaled during Commuting
in Delhi, India (Prasad et al., 2003)
2005 Pilot Study of Exposure in Bangalore, India CO monitor (left) and PM10 monitor (right): 2005 Pilot Study of Exposure in Bangalore, India CO monitor (left) and PM10 monitor (right)
Slide61: Thank you !
flachsba@hawaii.edu