Particulate matter concentrations and their related metal toxicity in rural residential environment of semi-arid region of India

The concentration of PM10, PM5.0, PM2.5 and PM1 were measured in the indoor–outdoor environment of rural homes of North central part of India during winter, summer and rainy seasons for the time duration of October 2007 to March 2009. Seven trace metals (Pb, Cd, Ni, Fe, Cr, Mn and Cu) were also determined in PM2.5 from October 2007 to March 2009 in the indoor–outdoor environment. During the study period the annual average concentration for PM10, PM5.0, PM2.5 and PM1 in indoor and outdoor were 242.53 μg m−3 and 217.76 μg m−3, 203.57 μg m−3 and 180.42 μg m−3, 164.60 μg m−3 and 143.07 μg m−3, 106.23 μg m−3 and 105.17 μg m−3 respectively. Concentrations of PM10 and PM2.5 have been compared with prescribed WHO standards and NAAQS standards of India and were found to be much higher. Significant seasonal variations of particulate pollutants were obtained using the monthly average concentration of coarse and fine particulate matter. Indoor/outdoor ratios at the rural sites were also determined with the meteorological parameters like temperature, humidity, wind speed and air exchange rate. Chromium was found to have the highest excess cancer risk in a risk evaluation using an Integrated Risk Information System. Three factors each in indoor and outdoor environment of rural site have been identified using Principal Component Analysis & Positive Matrix Factorization.