Air quality assessment and its relation to potential health impacts in Delhi, India

The main objective of the air quality index (AQI) system is to interpret air quality in a standardized indicator to enable the public to understand the likely health and environmental impacts of air pollutant concentration levels monitored on any given day. The daily averaged concentration data of air pollutants of monitoring sites under the National Ambient Air Quality Monitoring Programme of Delhi were analysed for the period 2001-2010 using the AQI system. This study was undertaken to (i) evaluate the trends of air quality for the past 10 years, (ii) ascertain the association of air quality with mortality and respiratory morbidity rate of Delhi, and (iii) examine the seasonal variation of air quality. The air quality status was found to be varying from 'moderate' to 'unhealthy for sensitive group' category from the health impact point of view. Non-trauma mortality (r = 0.877, P < 0.01) as well as respiratory morbidity were found to be significantly correlated with AQI values. The present study increases public awareness of the health implications of air pollution and helps assess pollution trends in a more meaningful way.