The Health Effects of Air Pollution in Delhi, India

Abstract

Particulate air pollution has less overall impact on nontraumatic deaths in Delhi, India, than in U.S. cities. But the deaths occur earlier in life in Delhi, which could mean a larger loss in life-years.

Cropper, Simon, Alberini, and Sharma 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 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 than 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 than 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.

This paper-a product of Development Economics Research Group-is part of a larger effort in the group to examine the benefits and costs of pollution control. The study was funded by the Bank's Research Support Budget under research project Measuring the Health Effects of Air Pollution in Developing Countries: The Case of Delhi, India (RPO 679-96). Maureen Cropper may be contacted at [e-mail].