Atmospheric Particulate Pollutants and their Relationship with Meteorology in Ahmedabad

Urban air pollution is rapidly becoming an environmental problem of public concern worldwide. It can influence public health and local/regional weather and climate. In the present study, airborne particulate pollutants data were collected for a period of 4 years (2005-2008) at 13 locations in Ahmedabad, a mega city in Gujarat State in western India. The particulate pollutants data were collected by the Gujarat Pollution Control Board with respirable dust samplers (RDSs). The observed Suspended Particulate Matter (SPM) concentrations varied from 66.0 to 786.0 mu g/m(3), and concentrations of Particulate Matter of aerodynamic diameters less than 10 microns (PM10) ranged between 17.0 to 327.0 mu g/m(3). The seasonal-and annual-average concentrations of the two pollutants were mostly above Indian air quality standards and were generally comparable with those observed in most other Indian urban areas. During this study period, there was a continuous decrease of particulate pollutants concentrations within Ahmedabad; however, the concentrations were just above the permissible limits set by the Central Pollution Control Board (CPCB). These particulate pollutants concentrations were compared with meteorological variables such as rainfall, humidity, temperature, and wind speed. Both SPM and PM10 showed significant negative correlations with rainfall. An Air Quality Index (AQI) was calculated for all stations for all months. AQI values varied from 25 to 193.3. AQI was high in summer season and low in monsoon season. AQI values varied from Good (0-50) to Hazardous (300-500). On the basis of the AQI scale, it is found that the atmospheric environment of Ahmedabad is moderately polluted to unhealthy range.