Heavy metals contamination of rainwater is a function of the adsorbed metals present in the particulates of the atmosphere in which the rain was formed from and rainwater chemistry is an alternative way of monitoring urban air pollution for predominant metal species. Three distinct sampling sites (residential, industrial and commercial) were investigated in the south western part of Nigeria for one year. After acid digestion, quantification was done using a double-beam Atomic Absorption Spectrophotometer (AAS). The obtained results showed that heavy metals were predominantly present as free metal ion in the commercial and industrial areas but Mn and As mainly occurred in the suspended fraction. Residential area presented major fractions as bound to organic complexes except Cu and Cd which were principally available as suspended fraction. The health risks associated with the intake of the studied rainwaters indicated susceptibility to possible carcinogens upon consumption due to total RI > 10-4. Ecological risk assessment equally shown a very high level of ecological risks related with the metals due to RI ˃ 600. Sequel upon this, there is need for better sensitization of the citizenry to the sources and control of these pollutants.

Sampling was conducted on Agra-Delhi national highway NH-2. Samples were collected with the help of Sioutas cascade impactor. During the sampling, PM1.0-0.5 (255.85µg/m3) was higher than PM2.5-1.0 (218.96µg/m3). The AQI value for the average PM2.5 concentration also exceeded the severe AQ limit (401-500). These results showed that PM2.5 pollution has a significant influence on the site as a result of a variety of anthropogenic activities. During the summer season, for PM1.0-0.5 and PM2.5-1.0 highest values (µg/m3) of metals followed the same trend and it was observed as Mg(6.52)> Ca(5.89)> Al(3.64)> while for PM2.5-1.0 it was as Mg(10.12)> Ca(9.5)> Al(5.95) respectively. At roadside, most of these metals are emitted from the resuspension of dust and vehicle activities which causes serious diseases to the human being. Cd, Cr, Cu, Pb, and Zn were highly enriched at national highway sampling sites, highlighting the crustal source, which has a major impact on metals concentration, followed by anthropogenic sources. The present research was conducted to find out the concentration level of metals in PM2.5-1.0 and PM1.0-0.5 particles in Agra, India to find out the health risk assessment at highway site.From the results, it was observed that all metals bound to larger size PM has high bioavailability. From the health risk assessment, it was found that all the metals bound smaller size particles showed higher HQ except in the case of Ni and Al. Cr, Pb showed carcinogenic risk to children and adults in both size fraction of PM except in the case of Ni.