Air pollution and public health: emerging hazards and improved understanding of risk

Abstract

Despite past improvements in air quality, very large parts of the population in urban areas breathe air that does not meet European standards let alone the health-based World Health Organisation Air Quality Guidelines. Over the last 10 years, there has been a substantial increase in findings that particulate matter (PM) air pollution is not only exerting a greater impact on established health endpoints, but is also associated with a broader number of disease outcomes. Data strongly suggest that effects have no threshold within the studied range of ambient concentrations, can occur at levels close to PM2.5 background concentrations and that they follow a mostly linear concentration-response function. Having firmly established this significant public health problem, there has been an enormous effort to identify what it is in ambient PM that affects health and to understand the underlying biological basis of toxicity by identifying mechanistic pathways-information that in turn will inform policy makers how best to legislate for cleaner air. Another intervention in moving towards a healthier environment depends upon the achieving the right public attitude and behaviour by the use of optimal air pollution monitoring, forecasting and reporting that exploits increasingly sophisticated information systems. Improving air quality is a considerable but not an intractable challenge. Translating the correct scientific evidence into bold, realistic and effective policies undisputedly has the potential to reduce air pollution so that it no longer poses a damaging and costly toll on public health.

Fig. 1

Death toll and pollution concentrations during the 1952 London Smog. Source: Wilkins (1954)

Fig. 2

Predicted average gain in life expectancy (months) for persons 30 years of age and older in 25 Aphekom cities for a decrease in average annual level of PM_2.5 to 10 µg/m³. Source: Aphekom project, InVS (Aphekom 2011)

Fig. 3

Changes in life expectancy for the 1980s–1990s plotted against reductions in PM_2.5 concentrations for 1980–2000. Dots and circles labelled with numbers represent changes in population-weighted mean life expectancies at the county level and metropolitan area level, respectively. The solid and broken lines represent regression lines with the use of county-level and metropolitan-area-level observations, respectively. Reproduced with permission from Pope et al. (2009)

Fig. 4

Biological pathways linking PM exposure with oxidative and inflammatory pathways in the lung and cardiovasculature

Fig. 5

City Air iPhone app. a Advice tailored to specific user groups. b Notification alert when pollution levels change. c 3-D low pollution journey planners