华北区域大气中羰基化合物体积分数水平及化学反应活性

为了解华北区域光化学污染特征，于2018年5月至2019年4月在石家庄和兴隆地区利用2，4-二硝基苯肼（DNPH）对空气中的羰基化合物进行采样，并利用高效液相色谱对采集样品进行分析，以了解该区域羰基化合物的组成、体积分数、来源、·OH损耗速率和臭氧生成潜势.本研究共测定了13种含羰基的挥发性有机物，其中体积分数最高的3种物质为丙酮、甲醛和乙醛石家庄地区：（6.46±5.25）×10^-9、（3.76±2.29）×10^-9和（2.65±1.74）×10^-9；兴隆地区：（1.85±1.27）×10^-9、（1.29±1.02）×10^-9和（0.72±0.48）×10^-9]；C1/C2和C2/C3值表明石家庄地区工业化水平较高，受机动车尾气和化石燃料燃烧等人为排放影响较明显；兴隆地区采样点处于背景区域，受自然源影响较大；石家庄地区对L_·OH贡献最大的3种物质分别为乙醛（1.77 s^-1）、甲醛（1.57 s^-1）和丁醛（0.42 s^-1）；兴隆地区对L_·OH贡献最大的3种物质为分别为甲醛（0.53 s^-1）、乙醛（0.47 s^-1）和丁醛（0.12 s^-1）；对O₃生成贡献最大的羰基化合物物种为甲醛和乙醛石家庄地区：34.61×10^-9（以O₃计，下同）和16.73×10^-9；兴隆地区：11.77×10^-9和4.47×10^-9]，且甲醛的最大臭氧生成潜势估算（OFP）远高于乙醛.

Concentration and Reactivity of Carbonyl Compounds in the Atmosphere of North China

To reveal the characteristics of photochemical pollution in North China, adsorbing columns with 2, 4-dinitrophenylhydrazine(DNPH) were used to sample carbonyl compounds in Shijiazhuang and Xinglong between May 2018 and April 2019. The samples were analyzed by high-performance liquid chromatography to understand the composition, volume fraction, source, ·OH loss rate, and ozone formation potential of the carbonyl compounds. A total of 13 carbonyl compounds containing carbonyl groups were determined, of which acetone, formaldehyde, and acetaldehyde were highest at(6.46±5.25)×10^-9, (3.76±2.29×10^-9), and(2.65±1.74)×10^-9 in Shijiazhuang compared to(1.85±1.27)×10^-9, (1.29±1.02)×10^-9, and(0.72±0.48)×10^-9 in Xinglong, respectively. The estimated maximum ozone formation potential(OFP) of formaldehyde was much higher than that of acetaldehyde; the C1/C2 and C2/C3 ozone formation potential(OFP) of formaldehyde was much higher than that of acetaldehyde; and the C1/C2 and C2/C3 values showed that vehicle exhaust and fossil fuel combustion were the main sources in Shijiazhuang in association with the higher level of industrialization. In Xinglong, the carbonyl compounds mainly originated from natural sources. Acetaldehyde(1.77 s^-1), formaldehyde(1.57 s^-1), and butyraldehyde(0.42 s^-1) contributed most to L_·OH in Shijiazhuang, and formaldehyde(0.53 s^-1), acetaldehyde(0.47 s^-1), and butyraldehyde(0.12 s^-1) were the three main contributors to L_·OH in Xinglong. The carbonyl compounds contributing most to O₃ production were formaldehyde and acetaldehyde at(34.61×10^-9 O₃) and (16.73×10^-9 O₃) in Shijiazhuang, compared to (11.77×10^-9 O₃) and (4.47×10^-9 O₃) in Xinglong, respectively.