Sprawl and Health

Adams 2001 - "Determinants of Fine Particle (PM2.5) Personal Exposure Levels in Transport Microenvironments, London, UK"

Adams, HS; Nieuwenhuijsen, MJ; Colvile, RN
"Determinants of Fine Particle (PM2.5) Personal Exposure Levels in Transport Microenvironments, London, UK"
Atmospheric Environment
September 2001 v.35, n.27; pp.4557-4566
On the Web
Relevance: medium-low

The authors measured concentrations of fine PM on fixed routes using different modes (car, bus, bicycle) in London. They found that route was a significant factor, explaining 20% of the variation, but mode was not. Wind speed explained 18% of the variation. "Personal exposure levels were reasonable correlated with urban background FSM [fixed site monitor] concentrations."

CARB 1998 - "Measuring Concentrations of Selected Air Pollutants Inside California Vehicles"

California Air Resources Board (CARB)
"Measuring Concentrations of Selected Air Pollutants Inside California Vehicles"
December 1998, Contract No. 95-339, Final Report
On the Web
Relevance: medium-low

CARB measured concentrations of various air pollutants inside vehicles as a range-finding experiment. They studied the effect of freeway conditions (rush vs. non-rush), roadway types, vehicle types, air vent settings, time of day, and roadside/ambient air quality.

CARB found that pollutant concentrations were higher:

• in the regular vs. carpool lane
• during rush hour
• when following diesel or other high-emitting vehicles

Other findings include:

• Vent settings and vehicle type did not seem to make a big difference
• "Most pollutants levels, especially the VOC's, were elevated inside and outside the vehicles relative to either the roadside or ambient station concentrations"
• "Particle concentrations were typically significantly higher outside the vehicles than inside, presumably due to losses in the vehicle ventilation systems (and other factors) - while significant differences were not observed between inside and outside levels of gas phase pollutants for the same vehicle."

CAVEAT: this was a preliminary, range-finding study, so we should look at other studies for confirmation and hard numbers.

Rank 2001 - "Differences in Cyclists and Car Drivers Exposure to Air Pollution from Traffic in the City of Copenhagen"

Rank, Jette; Folke, Jens; Jespersen, Per Homann
"Differences in Cyclists and Car Drivers Exposure to Air Pollution from Traffic in the City of Copenhagen"
The Science of the Total Environment
2001; v.279; pp.131-136.
On the Web
Relevance: medium-high

The authors equipt two cyclists and two car drivers with air samplers for 4 hours at a time on 2 days. They found "The concentrations of particles and BTEX in the cabin of the cars were 2-4 times greater than in the cyclists' breathing zone, the greatest difference being for BTEX. Therefore, even after taking the increased respiration rate of cyclists into consideration, car drivers seem tot be more exposed to airborne pollution than cyclists.

Car/bicycle ratio

• Benzene: 2.8
• Toluene: 3.4
• Thylbenzene and Xylenes: 3.7
• Hydrocarbons: 3.7
• Particles (total dust):1.7.

ICTA 2000 - “In-Car Air Pollution: The Hidden Threat to Automobile Drivers"

International Center for Technology Assessment,
“In-Car Air Pollution: The Hidden Threat to Automobile Drivers"
Report No. 4, An Assessment of the Air Quality Inside Automobile Passenger Compartments
Washington, DC: July 2000
On the Web
Relevance: high

This report reviews 23 studies from between 1982 and 1998 covering the main pollutants inside cars: particulate matter, volatile organic compounds, carbon monoxide, nitrogen oxides, and ozone.  For all exhaust pollutants except CO and the largest PM, concentrations are typically higher inside cars in heavy traffic than elsewhere.

Chertok 2004 - “Comparison of Air Pollution Exposure for Five Commuting Modes in Sydney – Car, Train, Bus, Bicycle and Walking”

Chertok, Michael ; Voukelatos, Alexander ; Sheppeard, Vicky ; and Rissel, Chris
“Comparison of Air Pollution Exposure for Five Commuting Modes in Sydney – Car, Train, Bus, Bicycle and Walking”
Health Promotion Journal of Australia
April 2004; v.15,n.1; pp.63-67
On the Web (pdf)
Relevance: high

The study measured the BTEX pollutant and NO2 exposure of 44 subjects on their regular daily commutes, each lasting at least 30 minutes each way.  Car commuters were exposed to the highest levels of BTEX pollutants, while bus commuters were exposed to the highest levels of NO2.  Train (light and heavy rail) commuters were exposed to the lowest levels of all pollutants measured.  Walking and cycling commuters were exposed to significantly lower levels of BTEX than car commuters and of NO2 than bus commuters. 

Batterman 2002 - “Levels and Composition of Volatile Organic Compounds on Commuting Routes in Detroit, Michigan”

Batterman, Stuart A; Peng, Chung-Yu; and Braun, James.
“Levels and Composition of Volatile Organic Compounds on Commuting Routes in Detroit, Michigan”
Atmospheric Environment
December 2002; v.36,n.39-40; pp.6015-6030
On the Web
Relevance: high

Batterman et al measured VOCs in cars and buses during rush hour on commercial, industrial, and residential routes in Detroit, Michigan.  They found that:

• VOC concentrations along roadways and in buses were similar;
• route did not much affect differences in air quality; however, the buses all traveled on congested 4 lane roads during rush hour; and
• VOC concentration varied significantly over time, which the authors attribute to changes in weather, mainly inversions and wind speed and direction;
• vehicle sources dominate industrial sources in influencing urban VOC concentrations, corroborating earlier studies; and
• VOC concentrations on roadways were much higher than concentrations at the two fixed-site monitoring stations in Detroit.  For example, BTEX concentrations measured at the fixed sites were 2-4 times lower than levels measured in traffic.

Kim 2001 - “Concentrations and Sources of VOCs in Urban Domestic and Public Microenvironments”

Kim, Young Min; Harrad, Stuart; Harrison, Roy M.
“Concentrations and Sources of VOCs in Urban Domestic and Public Microenvironments”
Environmental Science and Technology
March 15, 2001; v.35, n.6; pp.997-1004
On the Web
Relevance: high

Concentrations of volatile organic compounds (VOCs) were measured in a wide range of urban microenvironments (including homes, offices, shops, roadsides, buses, trains, and cars) in Birmingham, UK.  Of transportation microenvironments, cars had the highest mean concentrations of most of the VOCs measured; however the automobiles in the study were over 10 years old and smoking occurred in 6 of them during sampling.

Kim 2002 - “Levels and Sources of Personal Inhalation Exposure to Volatile Organic Compounds”

Kim, Young Min; Harrad, Stuart; Harrison, Roy M.
“Levels and Sources of Personal Inhalation Exposure to Volatile Organic Compounds” Environmental Science and Technology
December 15, 2002; v.36,n.24; pp.5405-5410
On the Web
Relevance: medium

Personal exposures to VOCs of 12 urban dwellers (Birmingham, UK) were measured over 5-10 days.  Exposure in the home contributed 50-80% of overall individual exposure to 2 main VOCs, mostly due to the large amount of time spent at home.  Smoking, vehicle use, and heating also contributed noticeably to personal exposure to VOCs.