Assessment Of Respiratory Morbidity Attributable To Particulate Air Pollution In Mexico

Abstract

BACKGROUND: Human exposure to particulate air pollution may result in a variety of health effects including acute respiratory infections (ARI), the leading cause of outpatient visits in Mexico. However, the potential benefits of reducing the exposure to air pollution over the incidence of this disease is unknown. OBJECTIVE: To estimate the outpatients visits due to ARI attributable to particulate air pollution (PM10) under different exposure scenarios using the Health Impact Assessment (HIA) methodology. METHODS: Annual mean PM10 concentrations (µg/m3) and estimations of exposure were determined in each city using existing monitoring network. Concentration-response functions (CRF) reported in epidemiological studies were used to quantify the effects of air pollution. Study area and population at risk were determined considering people who lived within 5 km of an air pollution monitor. The counterfactual concentrations selected to reflect different exposure scenarios were 40 and 20 μg/m3. The target population was 44 Mexican municipalities. Attributable cases to air pollution were estimated for respiratory incidence (all ages) during 2005. RESULTS: Yearly average PM10 concentrations ranged between 41.2 and 121.2 μg/m3. In terms of attributable cases, from 541,212 (CI 95%: 192,147– 859,414) to 980,681 (CI 95%: 355,384 – 152,6724) ARI visits could be prevented annually if long-term exposures to the annual mean PM10 levels were reduced to 40 μg/m3 and 20 μg/m3 respectively in each city. CONCLUSIONS: These data show that the societal burden of urban air pollution in Mexican cities, in terms of respiratory morbidity is very high. Although results should be interpreted with caution when estimating the direct health benefits of reducing PM10 concentrations, the true impact of air pollution is likely to be larger, since only one pollutant has been considered in this study. One limitation is that the analysis has been restricted to selected known CRF.