School of Environment, Guangxi University, Nanning, China,
Arch Environ Contam Toxicol. 2014 May;66(4):594-605. doi: 10.1007/s00244-014-0013-y. Epub 2014 Mar 11.
For the first time, ambient carbonyls were measured in a rural area in southern China from August 2012 to February 2013 to investigate their distribution characteristics and sources. Formaldehyde, acetaldehyde, and acetone were the three most abundant carbonyls, which accounted for 83-95 % of total seven carbonyls identified. The O3 formation potential of carbonyls in summer (59.55 μg/m(3)) was approximately ten times greater than that (6.37 μg/m(3)) in winter, and calculated photolysis rates were significantly faster in summer than those in winter, suggesting intensive photochemical activities in summer. Seasonal and diurnal variations of carbonyls showed that (1) the concentration of total carbonyls in summer (12.62 ± 10.83 μg/m(3)) was approximately five times greater than that in winter (2.33 ± 0.90 μg/m(3)), and a similar trend applied to the three abundant carbonyls; (2) the average summer to winter (S/W) ratio of formaldehyde and acetaldehyde was 10-13, and the S/W ratio of acetone was ~2.59; and (3) the highest concentrations of the three carbonyls and total carbonyls occurred at 14:00-16:00 with high temperature and intensive sunlight, especially in summer. These variations provided direct evidence for significant photochemical production of ambient carbonyls. Average C1/C2 ratios (3.07 ± 1.62) in summer were much greater than those (1.28 ± 0.25) in winter, and average C2/C3 ratios (35.09 ± 58.67) in summer were significantly greater than those (4.75 ± 2.12) in winter, both cases indirectly implying positive photochemical productions in summer. Especially, strong correlations (R(2) = 0.63-0.98) of temperature and sunlight intensity with the three abundant carbonyls and total carbonyls were observed, indicating a similar causal source such as significant photochemical production.
首次在中国南方的一个农村地区测量了环境羰基化合物，以研究其分布特征和来源。甲醛、乙醛和丙酮是三种最丰富的羰基化合物，占总七种鉴定的羰基化合物的 83-95%。夏季（59.55μg/m3）羰基化合物的 O3 形成潜力大约是冬季（6.37μg/m3）的十倍，并且夏季的计算光解率明显快于冬季，表明夏季有强烈的光化学反应。羰基化合物的季节性和日变化表明：（1）夏季（12.62±10.83μg/m3）的总羰基化合物浓度大约是冬季（2.33±0.90μg/m3）的五倍，三种丰富的羰基化合物也呈现类似的趋势；（2）夏季到冬季的甲醛和乙醛的平均 S/W 比值为 10-13，丙酮的 S/W 比值约为 2.59；（3）三种碳酮和总碳酮的最高浓度出现在 14:00-16:00，此时温度高、阳光强烈，尤其是在夏季。这些变化为环境羰基化合物的显著光化学生成提供了直接证据。夏季的平均 C1/C2 比值（3.07±1.62）远大于冬季（1.28±0.25），夏季的平均 C2/C3 比值（35.09±58.67）显著大于冬季（4.75±2.12），这两个比值都暗示了夏季有正的光化学生成。特别是，观察到温度和阳光强度与三种丰富的羰基化合物和总羰基化合物之间存在强烈的相关性（R2=0.63-0.98），表明有类似的因果来源，如显著的光化学生成。
