Levels, characteristics and health risk assessment of VOCs in different functional zones of Hefei.

In order to study the characteristics and health risk of VOCs in the ambient air in the typical developing cities in China, the research was conducted in five functional zones in Hefei from September 2016 to January 2017. The average concentrations of total measured VOCs in traffic zone was the largest (85.94 μg m-3), followed by industrial zone (64.84 μg m-3), development zone (58.92 μg m-3), resident zone (57.31 μg m-3), and background zone (54.94 μg m-3). Cl-VOCs were most abundant species in chlorinated VOCs (85.06%), which showed much higher level in industrial zone. the mean value of BTEX found in presented study was 65.19 μg m-3. Based on the specific VOC ratio method (B/T), the observed sites were greatly affected by the traffic emissions. The ratios of T/B, E/B and X/B were 1.15, 1.35 and 0.47, respectively, possibly due to the aging air mass. Carcinogenic risks for benzene, carbon tetrachloride, trichloroethylene, 1, 2-dichloroethane and chloroform were higher than the general acceptable risk level of 1.00 × 10-6. Potential non-carcinogenic risk assessment showed that hazard quotient (HQ) of 10 VOCs not exceeded unity, but the hazard risk index (HI) at site ED, LY, YH and HD were both higher than 1.