Estimating the public health burden attributable to air pollution: an illustration using the development of an alternative air quality index.
The example of the development of an alternative air quality index (AQI) is used to illustrate issues related to quantifying the public health burden attributable to air pollution. These issues include: (1) appropriately representing the weight of evidence; (2) extrapolation of risk measures over time and space; (3) attribution of health effects to air pollution versus other risk factors and to individual pollutants versus the rest of the mix; (4) application of complementary approaches from health economics; and (5) effective risk communication. A no-threshold, multipollutant AQI was developed, based on the relationship of CO, NO(2), O(3), SO(2) and PM(2.5) with mortality in Canadian cities in a daily time-series study. Risk coefficients were applied to daily air pollution concentrations to calculate multipollutant percent excess mortality, and results were scaled to a 0 to 10 range. The observed distribution of values was used to characterize days as low, medium, high, or extreme risk. Considerable day-to-day variability in the index value was observed, and the percent of days falling in the high or extreme risk categories ranged from 0.3 to 33.2 among the cities considered. The new index was moderately correlated with conventionally derived AQIs. Results did not appear to be sensitive to an alternative choice of risk coefficients based on a worldwide meta-analysis. Additional efforts will be required to validate this AQI formulation against one based on the association between air pollution and other health outcomes, and to most effectively utilize the AQI as a communication tool regarding acute health risks associated with air pollution.
Stieb
David M
DM
Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, Ontario, Canada. dave_stieb@hc-sc.gc.ca
Doiron
Marc Smith
MS
Blagden
Philip
P
Burnett
Richard T
RT
D000393:Air Pollutants / Q000592:standards*; D000397:Air Pollution / Q000009:adverse effects* / Q000706:statistics & numerical data*; D003142:Communication; D006801:Humans; D011634:Public Health; D011788:Quality of Life; D012306:Risk
D000393:Air Pollutants