The Health Effects of Air Pollution in Delhi, India

report the results of a time-series study of the impact of particulate air pollution on daily mortality in Delhi. They find: • A positive, significant relationship between particulate pollution and daily nontraumatic deaths, as well as deaths from certain causes (respiratory and cardiovascular problems) and for certain age groups. • In general, these impacts are smaller than those estimated for other countries, where on average a 100-microgram per cubic meter increase in total suspended particulates (TSP) leads to a 6-percent increase in nontraumatic mortality. In Delhi, such an increase in TSP is associated with a 2.3 percent increase in deaths. • The differences in magnitudes of the effects are most likely explained by differences in distributions of age at death and cause of death, as most deaths in Delhi occur before the age of 65 and are not attributed to causes with a strong association with air pollution. • Although air pollution seems to have less impact on mortality counts in Delhi, the number of life-years saved per death avoided is greater in Delhi that in U.S. cities-because the age distribution of impacts in these two places varies. In the United States particulates have the greatest influence on daily deaths among persons 65 and older. In Delhi, they have the greatest impact in the 15-to-44 age group. That means that for each death associated with air pollution, on average more life-years would be saved in Delhi that in the United States. Large differences in the magnitude of effects do call into question the validity of the "concentration-response transfer" procedure. In that procedure, concentration-response relationships found for industrial countries are applied to cities in developing countries with little or no adjustment, to estimate the effects of pollution on daily mortality.