ISEE/ISEA 2006 Conference Abstracts Supplement: Symposium Abstracts: Abstracts
To meet its goal of assessing the health effects of air pollution across key and often understudied areas, in a collaborative study for Public Health and Air Pollution in Asia (PAPA), a common protocol was developed among 3 cities in China and a city in Thailand in the first wave and another 3 cities in India in the second wave. Individual teams followed the guidelines for development of core models and assessment of the effects, taking into account city-specific conditions. The objectives were to 1) establish a common protocol and estimate the short-term effects of air pollution in Asian cities, and to 2) assess the effects of air pollutants on mortality within each city and the pooled effects in all the participating cities.
Daily counts of mortality for nonaccidental causes (all ages, 0–4, 5–44, 45–64, and 65+ age groups) and cardiorespiratory diseases (all ages) were modeled by Poisson regression. Trend and seasonality using smoothers of natural spline with 4–6 degrees of freedom (df), temperature, and relative humidity using smoothing spline each with 3 or 4 df, days of the week, and other city-specific conditions using dummy variables were adjusted for in a core model for each health outcome. Adequacy of the core models was evaluated by partial autocorrelation of the residuals. The effects of daily air pollutant concentrations of PM10, NO2, SO2 (24-hour average), and O3 (8-hour average) were estimated.
Preliminary findings were that ambient concentrations for PM10 varied across the 4 first wave cities with mean levels of 52.1 μg/m3 (Bangkok), 51.6 μg/m3 (Hong Kong), 102.0 μg/m3 (Shanghai), and 141.8 μg/m3 (Wuhan). Statistically significant excess risks were observed across the 4 cities, ranging from 0.2% to 1.1% per 10-μg/m3 increase of PM10 for nonaccidental causes in all ages with highest excess risk found in Bangkok followed by Hong Kong, Wuhan, and Shanghai. Similar studies with a modified common protocol were developed for the 3 Indian cities, Ludhiana, Chennai, and Delhi in the second wave.
Discussion and Conclusions:
Asian cities, like many cities in other parts of the world, experience similar effects of excess mortality associated with increased air pollution. Despite regulations put in place from local agencies to control air quality, there is clear evidence of the need for legislation to support a comprehensive program of air-quality controls to reduce adverse health effects associated with pollution.