Abstract:
The ambient VOCs were sampled in the urban air of Zhaotong from 2018 to 2019. They were analyzed by using the method of Suma sampling, atmospheric preconcentration and gas chromatography-mass spectrometry (GC-MS). The results showed that 48 kinds of VOCs were identified. The concentration of alkanes was the highest (51.52 µg/m
3), followed by aromatics (14.24 µg/m
3). Additionally, the concentration of olefins was the lowest (4.86 µg/m
3), with the highest concentration of propane reaching 10.69 µg/m
3, followed by 3-methylpentane, 2-methylpentane, cumene, isoprene and toluene. From the calculation of ozone generation potential (OFP), it can be seen that the contribution of aromatic hydrocarbons and olefins to OFP in this area was higher than that of alkanes. The OFP performance at different sampling points was Fengxi Hotel > Lanhuan Company > Industrial Park. Through principal component analysis (PCA) was found out that the VOCs in the urban air of Zhaotong were mainly derived from plants and oil-gas volatilization (53.3%), followed by motor vehicle exhaust (27.9%) and solvent/paint sources (17.4%). Through the health risk assessment, it can be known that the non-carcinogenic risk and hazard index of VOCs in the urban air of Zhaotong were less than 1, showing that the non-carcinogenic risk was low. However, the value of cancer risk of the benzene to the human body was higher than the safety threshold of 1×10
−6, showing that there was a risk of cancer.