| Volatile organic compounds?VOCs?,especially formaldehyde?HCHO?,are widespread,diverse,highly toxic and can leave a long time in the atmospheric environment,raising concern by the society.Several typical public places were selected to take sample including living rooms,restaurants and shopping malls in Lanzhou.Samples in outdoor and indoor air were analyzed by high-performance liquid chromatography?HPLC?and portable VOC and formaldehyde detector respectively.After analyzing of the pollution characteristics of TVOC and formaldehyde as well as health risk assessment for distinct people exposed to formaldehyde,several research findings are as follow:?1?Spatial distribution difference of indoor and outdoor TVOC and formaldehyde concentrations existed in Lanzhou.The average concentration of indoor TVOC is 2.13 mg/m3 in heating period,appeared as mixed district>rural district>industrial district.The average concentration of indoor formaldehyde is 0.03 mg/m3 in the heating period,appeared as the industrial district is higher than the mixed district and the rural district.The average concentration of indoor formaldehyde is 0.05 mg/m3 in the non-heating period,appeared as the rural district is higher than the mixed district and the industrial district.The pollution level of indoor and outdoor formaldehyde in rural area appeared as non-heating period>heating period,and the outdoor formaldehyde in mixed district appeared as non-heating period>heating period,while industrial district is just the opposite.?2?The cancer risk and non-cancer risk of formaldehyde exposure in the population existed in Lanzhou.The cancer risk and non-cancer risk all appeared as the rural district>mixed district>industrial district,and female>male.The cancer risk of age group appeared as 60 years old and above group>1844 years old>4559 years old,the non-cancer risk appeared as 1844 years old crowd>60 years old and above>4559 years old.?3?The indoor TVOC and formaldehyde concentration of kitchen and dining room have different characteristics in different restaurants?scale,fuel and edible oil?in Lanzhou.The level of TVOC and formaldehyde pollution in kitchen of small and medium-sized restaurants were higher than that in the large-sized restaurants and canteens,were 2.46 mg/m3 and 0.07 mg/m3respectively.The pollution level of TVOC and formaldehyde in bio-oil restaurants is higher than that in other fuel restaurants,were 3.71 mg/m3 and 0.10 mg/m3 respectively.The restaurant TVOC with rapeseed oil as edible oil has more serious pollution,which is 3.90 mg/m3,while the restaurant with soybean oil and mixed oil as edible oil has heavy formaldehyde pollution,which is0.08 mg/m3.?4?Indoor TVOC and formaldehyde pollution in malls shows different pollution characteristics in Chengguan District of Lanzhou City.Pollution level of TVOC on different floors:third>fourth>ground>fifth,Pollution level of formaldehyde presents fourth>ground and fifth>third floor.The concentration of TVOC in different commodity regions presents as shoes>clothing>cosmetics>jewelry>specialty products.The pollution level of TVOC and formaldehyde in weekend is higher than week.Temperature,humidity and flow of people in indoor maybe affect pollution of TVOC and formaldehyde.?5?The range of the lifetime cancer risk of formaldehyde exposure in the catering industry cooks and the large shopping malls was 3.83×10-59.13×10-5,surpassing the cancer risk limits recommended by US EPA.The non-cancer hazard index of the working group in malls is greater than 1,and there is a non-cancer and chronic health risk.In summary,the family room,catering industry and shopping mall indoor TVOC pollution is serious in Lanzhou.The cancer risk of formaldehyde exposure of different groups of people?ordinary people,chef,shop assistant?more than EPA recommended 10-6,and have the risk of carcinogenesis. |
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