Sprawl and Health

Handy 2005 - "Correlation or Causality Between the Built Environment and Travel Behavior? Evidence from Northern California"

Handy, Susan; Cao, Xinyu; Mokhtarian, Patricia
"Correlation or Causality Between the Built Environment and Travel Behavior? Evidence from Northern California"
Transportation Research Part D
November 2005; v.10, n.6; pp.427-444
On the Web
Relevance: medium

Handy et al surveyed residents of traditional and suburban neighborhoods on their travel habits, travel attitudes, perceived neighborhood attributes, and socio-economic status. They found that while residents of traditional neighborhoods drove 18% fewer miles than suburban residents, the variation in this cross-section could be better explained by differences in attitudes and SES factors than in the built environment.

When the authors separated out those who had moved in the past year for a quasi-longitudinal study, differences in the built environment (mainly in accessibility) appeared significant. The built environment seemed to affect increased walking more than decreased driving.

I'm a bit wary of the quasi-longitudinal part of this study. Why would the built environment be significant there but not in the cross-sectional analysis?

Riediker 2004 - "Particulate Matter Exposure in Cars is Associated with Cardiovascular Effects in Healthy Young Men"

Riediker, Michael; Cascio, Wayne; et al.
"Particulate Matter Exposure in Cars is Associated with Cardiovascular Effects in Healthy Young Men"
American Journal of Respiratory and Critical Care Medicine
April 15, 2004; v.168, n.8; pp.934-940
On the Web
Relevance: medium-low

Part of a larger research project measuring air quality in cars, the authors measured the effects of exposure to PM2.5 on the cardiovascular functions of nine young, healthy patrol officers in North Carolina. They concluded that in-vehicle PM2.5 negatively affected inflammation, coagulation, and cardiac rhythm in slight but significant amounts. However, they also measured PM2.5 concentrations to be lower in the vehicles than on the side of the road or at the ambient location.

This study suggests to me that even a small amount of PM2.5 from vehicles is bad.

Ebelt 2005 - "Exposure to Ambient and Nonambient Components of Particulate Matter"

Ebelt, Stefanie T; Wilson, William E; Brauer, Michael.
"Exposure to Ambient and Nonambient Components of Particulate Matter: A Comparison of Health Effects"
Epidemiology
May 2005; v.16, n.3; pp.396-405
On the Web
Relevance: medium

Intro: Using a small sample of pulmonary patients in Vancouver, the authors measured exposure to particulate matter and health effects, trying to separate out influence of ambient and nonambient particles on lung function, heart rate, and blood pressure.

Findings: They found that ambient exposure was not correlated with nonambient or personal exposure. They also found that ambient exposure was a better predictor of health effects. In contrast nonambient and personal exposures were not associated with health effects, except in the wrong direction for lung function. The authors caution that this is a small study and the results are not conclusive.