Gaseous/particulate bound polycyclic aromatic hydrocarbons (PAHs), seasonal variation in North central part of rural India

The concentration of twenty-three polycyclic aromatic hydrocarbons (PAHs) were measured in the outdoor environment of rural homes in the North central part of India during three consecutive season winter, summer and rainy (November 2006–October 2007). The gaseous phase PAHs were collected by using XAD-2 resin tubes (600 mg) followed by a PTFE filter paper (37 μm dia) for particulate bound PAHs at a flow rate of 3 Lpm for 24 h. The individual PAHs were identified by using a gas chromatograph with mass spectrometry detector (GC/MS). The results showed that average concentration of (gas + particulate) PAHs varied with season. It ranged from (21.91–1290.50 ng/m3) being the highest in winter, lower in summer (11.18–613.00 ng/m3) and lowest in the rainy season (13.10–272.50 ng/m3) respectively. The total PAHs concentrations in the air were 32.56% and 61.97% higher in winter season from summer and rainy season respectively. It was indicated that the two, three and four rings PAHs were predominantly in gaseous phase while the five and six rings PAHs were primarily associated with the particulate phase. Among the 23 PAHs, naphthalene was the most abundant PAH. It contributed 30.99–55.81% to the sum of PAHs in three different seasons. The trend of the concentrations of the major PAHs found in present study were Nap > 2 methyl Nap > 1 methyl Nap > biphenyl > acenapthylene at all the sampling locations. The average BaP equivalent exposure, calculated by using toxic equivalent factors was approximately 27.95 ng/m3. Correlation and factor analysis was applied to identify the probable sources of PAHs.