Determination of Particulate Phase Polycyclic Aromatic Hydrocarbons in Ambient Air of Calcutta for Three Years During Winter

Abstract

Twelve species of polycyclic aromatic hydrocarbons were measured in the suspended particulate matter during winter (January and February) in Calcutta for 3 years from 1992 to 1994 both years inclusive. Samples were collected at 5 busy road intersections within the city. Air particulate samples were collected using high volume samplers and glass fibre filters(GFFs). PAH analysis was carried out on an HPLC system. Individual species were identified by retention times and the corresponding response ratios from the fluorescence and UV detectors. The benzene soluble organic matter (BSOM) content of the air particulate samples collected was 10.09 ± 1.92%. The lowest ΣPAH observed was 22.91 ng m⁻³ at Jadavpur in 1993 and the highest was 190.96 ng m⁻³ at Maulali in 1994. The global average ΣPAH of all samples was found to be 77.40± 27.16 ng m⁻³. The compositional pattern of the 12 PAH species monitored were very similar in all the samples. The average BAP concentration was 10.40 ± 4.76 ng m⁻³. BAP concentration was found to be 61 times that of Melbourne and 69 times that of Hong Kong. The BAP/ΣPAH ratio for all samples was 0.12 ± 0.02. There was evidence that the stationary sources like coal burning and numerous industry operating in the city of Calcutta which use coal as fuel, are the major emission sources for PAHs in the air particulate in Calcutta. The compositional profile of the PAHs in the samples were found to be similar to the profile found in air particulate samples collected near a horizontal Soderberg plant used for aluminium smelting.

Keywords:

• Polycyclic aromatic hydrocarbons
• high performance liquid chromatography
• suspended particulate matter
• benzene soluble organic matter
• Calcutta air
• benzo (a) pyzene as an indicator