Air quality profile of inorganic ionic composition of fine aerosols at two sites in Mumbai City

The levels of PM10, PM2.5, and NO2 were studied at a kerbsite and ambient site in Mumbai. Measurements were also made for eight inorganic ions (F-, Cl-, NO3-, SO42-, Na+, K+, NH4+, Ca2+, and Mg2+) in the PM2.5 fraction. During the study period, PM2.5, PM10 and NO2 levels ranged between 11-91, 18-125, and 8-64 mu g m(-3) at a ambient site whereas at the kerbsite the ranges were 10 176, 21-189, and 4-55 mu g m(-)3 respectively. Average PM2.5 values were 42 mu g m-3 at ambient and 69 mu g m-3 at the kerbsite. The measured ions accounted for about 50% of the PM2.5 mass. Non-sea-salt (nss) sulfate contributed 91% and 85% of the ionic mass at the ambient and kerbsite sites respectively. Due to biomass sources of K, only about 5% of K+ was from seas salt. The average equivalent ratio of NH4+ to nss- SO42-, and NO3- was over 1, indicating high source strength of ammonia.