成都郊区(新津)夏季甲醛污染特征分析

甲醛（HCHO）是大气光化学重要污染物之一，为研究西南地区郊区大气夏季甲醛污染特征选取了四川省成都市新津区进行大气甲醛观测，结合NO_x、O₃、PAN、J-value、温湿度、风速风向、天气数据进行分析.观测期间成都市新津区夏季甲醛浓度为0.76×10^-9~12.50×10^-9（V/V），均值为3.47×10^-9±2.05×10^-9（V/V），呈现明显的日变化规律.结合数据分析可知，一次人为排放源在成都郊区夏季日间甲醛贡献中占比较低.观测期间甲醛受光照的影响较大，与O₃、PAN、J-value普遍呈现一致的变化规律，因此成都市夏季日间甲醛主要来源为甲醛前体物的二次光化学反应.

Analysis on the characteristics of formaldehyde pollution observed in summer in suburb of Chengdu(Xinjin)

Formaldehyde (HCHO)is an important photochemical pollutant in atmosphere. A comprehensive field study for investigating the atmospheric behavior of HCHO was performed in Chengdu suburban in southwest China in summer 2019. HCHO was measured simultaneously with NO_x, O₃, PAN, and meteorological parameters(including photolysis frequencies, temperature, relative humidity, wind speed, and wind direction). The observed HCHO concentration ranged from 0.7×10^-9 to 12.50×10^-9(V/V) with a mean value of 3.47×10^-9±2.05×10^-9(V/V), and shows clear diurnal variation. It is found that anthropogenic emissions have little contribution to the HCHO formation. In contrast, HCHO concentration was largely influenced by solar radiation, resulting in similar temporal variation as O₃, PAN, and photolysis frequencies. This suggests that HCHO observed during summer time in Chengdu suburban is mainly originated from photochemical oxidations of its precursors.