From Good Intentions to Proven Interventions: Effectiveness of Actions to Reduce the Health Impacts of Air Pollution

Article excerpt

BACKGROUND: Associations between air pollution and a multitude of health effects are now well established. Given ubiquitous exposure to some level of air pollution, the attributable health burden can be high, particularly for susceptible populations.

OBJECTIVES: An international multidisciplinary workshop was convened to discuss evidence of the effectiveness of actions to reduce health impacts of air pollution at both the community and individual level. The overall aim was to summarize current knowledge regarding air pollution exposure and health impacts leading to public health recommendations.

DISCUSSION: During the workshop, experts reviewed the biological mechanisms of action of air pollution in the initiation and progression of disease, as well as the state of the science regarding community and individual-level interventions. The workshop highlighted strategies to reduce individual baseline risk of conditions associated with increased susceptibility to the effects of air pollution and the need to better understand the role of exposure duration in disease progression, reversal, and adaptation.

CONCLUSION: We have identified two promising and largely unexplored strategies to address and mitigate air pollution-related health impacts: reducing individual baseline risk of cardiovascular disease and incorporating air pollution--related health impacts into land-use decisions.

KEY WORDS: air pollution, antioxidant, cardiovascular, exposure, intervention, public health, respiratory, urban planning. Environ Health Perspect 119:29-36 (2011). doi:10.1289/ehp.1002246 [Online 20 August 2010]

Associations between air pollution and multiple health effects are now well established (Pope 2007; Pope and Dockery 2006; Pope et al. 2002). For key pollutants such as particulate matter (PM) and ozone (Green et al. 1999), there are no established thresholds of exposure below which population health impacts are absent. Given that everyone is exposed to some level of air pollution, the attributable health burden can be high, particularly for vulnerable subpopulations. Recent evidence that air pollution leads to inflammatory processes that mediate a variety of diseases suggests an expanding range of health impacts related to air pollution exposure. Consequently, the population health burden may be greater than previously believed.

A discussion of the biological mechanisms by which air pollution leads to cardiovascular and respiratory disease has been covered in detail elsewhere (Brook et al. 2010; Ko and Hui 2009; Mittleman 2007; Nogueira 2009; Patel and Miller 2009) and is beyond the scope of this review. However, a mechanistic understanding provides information on the effects of timing and exposure duration on disease development and progression, how pollutants interact with other stressors, and potential mitigating factors such as nutritional supplementation or medications. Ambient PM affects respiratory and cardiovascular disease development and exacerbation via pulmonary (neurologic) reflexes and pulmonary inflammation. Under some circumstances, these responses result in systemic inflammation, oxidative stress, and altered vascular function. Collectively, these processes can contribute to cardiovascular and pulmonary diseases, including atherosclerosis.

Evidence from natural experiments (Clancy et al. 2002; Parker et al. 2008; Pope 2007) and from analyses of long-term trends (Laden et al. 2006; Pope et al. 2009) indicates that reducing air pollution has clear health benefits. Traditionally, air quality management has focused on emissions-based pollution control. Although regulations promoting cleaner vehicle engine technology, power production, and industrial combustion processes have clearly led to decreased emissions, increases in vehicle-kilometers traveled and overall power generation and industrial activity may offset their effectiveness. Interventions separating people from pollution, which reduce exposure independent of emissions controls and mitigate health impacts, have largely been overlooked as components of formal strategies. …