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Travel Impacts on Air Quality and Greenhouse Gases
Overview:
Data demonstrates that emissions of air pollutants and greenhouse gases increase with vehicle miles driven. Therefore, the more automobile and truck traffic, the greater amount of pollutants emitted.
Research also shows an association between asthma and air quality, as well as life expectancy. Reducing traffic by increasing walkability and bikeability can improve the quality of air that we breathe and cut down on emission of air pollutants and greenhouse gases.
The literature in this section relates to vehicle emissions, air pollution, travel behaviors, and health opportunities.
Research Highlights:
• It is estimated that reductions in air pollution account for as much as 15% of the overall increase in life expectancy in study areas (Pope, et al., 2009).
• In a scenario without buses, city-wide schools (as compared with neighborhood schools) have six times fewer children walking to school, 4.5 times more miles traveled, 4.5 times the system cost and 4.5 times the emissions of criteria air pollutants and greenhouse gases (Wilson, et al., 2007).
• Bus service can decrease miles traveled and resulting emissions by 60-70% compared to no bus service (Wilson, et al., 2007).
• A 5% increase in neighborhood walkability is associated with:
o 6.5% fewer vehicle miles traveled (VMT) per capita
o 5.6% fewer grams of Nitrogen Dioxide per capita
o 5.5% fewer grams of volatile organic compound (VOC) emitted per capita
(Frank, et al., 2006)
• Results demonstrate an association between increased asthma and closer residential distance to a freeway, indicating that respiratory health in children is adversely affected by local exposures to outdoor Nitrogen Dioxide or other freeway-related pollutants (Gauderman, et al., 2005).
• Substitution of cycling for driving for short trips has the potential to reduce gasoline demand up to nearly 34.9% of current domestic oil consumption (Higgins, et al., 2005).
Academic Research Articles and Findings:
“Promoting Physical Activity and Reducing Climate Change: Opportunities to Replace Short Car Trips with Active Transportation” (2009)
• Nearly a third of U.S. greenhouse gas emissions in 2007 were transportation-related; each gallon of gasoline used in transportation emits 20 lbs of CO2 into our atmosphere.
• About half of all car trips in the UK, the Netherlands, and the US, are less than 5 miles.
• This commentary focuses on communication enhancements, marketing enhancements, and policy enhancements that communities can make with relative ease to promote active transport.
• There is strong evidence that communication, social marketing, and policy all have considerable potential to yield significant health, quality of life, economic and environmental benefits to communities willing to implement them.
Maibach, Edward, Steg, Linda, and Anable, Jillian. “Promoting physical activity and reducing climate change: Opportunities to replace short car trips with active transportation.” American Journal of Preventive Medicine. 49 (2009): 326-327.
“Public Health Benefits of Strategies to Reduce Greenhouse-Gas Emissions: Urban Land Transport” (2009)
• This study uses Comparative Risk Assessment methods to estimate the health effects of alternative urban land transport scenarios for London, UK and Delhi, India.
• Transport-related greenhouse-gas emissions are increasing, with a rapid growth projection in low-income and middle-income countries.
• Increase in the distances walked and cycled would lead to large health benefits.
• Creation of safe urban environments for mass active travel will require prioritization of the needs of pedestrians and cyclists over those of motorists. Walking or cycling should become the most direct, convenient, and pleasant option for most urban trips.
Woodcock, James, Edwards, Phil, Tonne, Cathryn, Armstrong, Ben G., Ashiru, Olu, Banister, David, et al. “Public health benefits of strategies to reduce greenhouse-gas emissions: urban land transport” The Lancet. 374 (2009): 1930-1943.
“Creating Physical Activity-Promoting Community Environments: Time for a breakthrough” (2009)
• This article highlights Safe Routes to School as a promising strategy for increasing youth physical activity and improving health equity.
• Joint use agreements to unlock school playgrounds after school and on weekends is another highlighted approach to promote physical activity, especially in poor communities and communities without access to other recreation facilities.
• Finally, this article reminds readers that The Recovery Act includes more than $45.5 billion to employ out of work Americans to improve public transit systems, making our communities more walkable and bikable and investing in projects that reduce reliance on automobiles – the source of close to 30% of total greenhouse gas emissions.
Solomon, Loel S., Standish, Marion B., and Orleans, C. Tracy. “Creating Physical Activity-Promoting Community Environments: Time for a breakthrough.” Preventive Medicine. 49.4 (2009): 334-335.
“Fine Particulate Air Pollution and Life Expectancy in the United States” (2009)
• Exposure to fine-particulate air pollution has been associated with increased morbidity and mortality, suggesting that sustained reductions in pollution exposure should result in improved life expectancy.
• This study directly evaluates the changes in life expectancy associated with differential changes in fine particulate air pollution that occurred in the United States during the 1980s and 1990s.
• Results demonstrate a decrease in the concentration of fine particulate matter with an increase in mean life expectancy. It is estimated that reductions in air pollution accounts for as much as 15% of the overall increase in life expectancy in the study areas.
Pope, Arden C. III, Ezzati, Majid and Dockery, Douglas W. “Fine Particulate Air Pollution and Life Expectancy in the United States.” The New England Journal of Medicine. 360.4 (2009): 376-386.
"The Built Environment, Climate Change, and Health Opportunities for Co-Benefits" (2008)
• Incorporating a health promotion approach in the design and development of the built environment can ease climate change and promote healthier living.
Dannenberg, Andrew L., Morrow Almeida, Heather, Vindigni, Stephen M. and Younger,
Margalit. "The Built Environment, Climate Change, and Health Opportunities for Co-Benefits." American Journal of Preventive Medicine. 35.5 (2008): 517-526.
“The Implication of School Choice on Travel Behavior and Environmental Emissions”(2007)
• This paper examines how children’s travel to school is affected by school choice and providing bus service.
• The number of students who walk to neighborhood schools is calculated at more than 6 times greater than the city-wide school.
• In a scenario without buses, city-wide schools have six times fewer children walking to school, 4.5 times more miles traveled, 4.5 times the system cost and 4.5 times the emissions of criteria air pollutants and greenhouse gases.
• Bus service decreases miles traveled and resulting emissions by 60-70% compared to no bus service.
• The authors suggest policy recommendation for neighborhood walkability consider the implications of specific school district choice programs be addressed in conjunction with traffic patterns.
Wilson, Elizabeth J., Wilson, Ryan and Krizek, Kevin J. “The Implications of School Choice on Travel Behavior and Environmental Emissions.” Transportation Research Part D. 12.7 (2007): 506-518.
“Many Pathways from Land Use to Health” (2006)
• This article examines single-use, low-density land use patterns and reports that a 5% increase in neighborhood walkability is associated with:
o 32.1% more minutes devoted to physically active travel
o About one-quarter point lower BMI (0.228)
o 6.5% fewer vehicle miles traveled (VMT) per capita
o 5.6% fewer grams of Nitrogen Dioxide per capita
o 5.5% fewer grams of volatile organic compound (VOC) emitted per capita
Frank, Lawrence D., Sallis, James F., Conway, Terry L., Chapman, James E., Saelens, Brian E. and Bachman, William. “Many Pathways from Land Use to Health. Associations between Neighborhood Walkability and Active Transportation, Body Mass Index, and Air Quality.” Journal of the American Planning Association. 72.1 (2006): 75-87.
“Multiple Impacts of the Built Environment on Public Health: Walkable Places and the Exposure to Air Pollution” (2005)
• This article focuses on the relationship between the built environment, travel behavior, and public health outcomes.
Frank, Lawrence D. and Engelke, Peter. “Multiple Impacts of the Built Environment on Public Health: Walkable Places and the Exposure to Air Pollution.” International Regional Science Review. 28(2) (2005): 193-216.
“Childhood Asthma and Exposure to Traffic and Nitrogen Dioxide” (2005)
• This study examines the association between traffic-related pollution and childhood asthma among 208 children in 10 communities in Southern California.
• Results demonstrate an association between increased asthma and closer residential distance to a freeway, indicating that respiratory health in children is adversely affected by local exposures to outdoor Nitrogen Dioxide or other freeway-related pollutants.
• The implications of these data are important and relevant because they strengthen emerging evidence that air pollution can cause asthma and that traffic-related pollutants are partly responsible for this association.
Gauderman, James W., Avol, Edward, Lurmann, Fretd, Kuenzli, Nino, Gilliland, Frank, Peters, John, and McConnell, Rob. “Childhood Asthma and Exposure to Traffic and Nitrogen Dioxide.” Epidemiology. 16.6 (2005): 737-743.
“A Healthy Reduction in Oil Consumption and Carbon Emissions” (2005)
• Adoption and maintenance of healthy lifestyles by substituting walking or biking for short trips currently taken by car could simultaneously improve health and reduce oil consumption and carbon dioxide emissions.
• Substitution of cycling for driving for short trips has the potential to reduce gasoline demand up to nearly 34.9% of current domestic oil consumption.
Higgins, Paul A.T. and Higgins, Millicent. “A Healthy Reduction in Oil Consumption and Carbon Emissions.” Energy Policy. 33 (2005): 1-4.
"Travel and Environmental Implications of School Siting" (2003)
• Because of travel behavior differences, school location has an impact on air emissions.
• Centrally located schools that can be reached by walking and bicycling result in reduced air emissions from driving.
"Travel and Environmental Implications of School Siting." October 2003. United States Environmental Protection Agency.
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