Air samples were collected from two rural sites and an urban site. Rural site I (Village 35/2L) was 15 km away from District Okara (30.80◦N 73.45◦E). Rural site II (Bhaun) was located in District Chakwal (32.55◦N 72.51◦E), 12 km from the major town. Lahore (31.55◦ N 74.34◦ ), the capital of Punjab province was the urban site.