Photochemical Production of Atmospheric Carbonyls in a Rural Area in Southern China

Abstract

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.

Atmospheric Levels of Benzene and C1-C2 Carbonyls in San Nicolas de los Garza, Nuevo Leon, Mexico: Source Implications and Health Risk

“…The formaldehyde and acetaldehyde concentrations in the present study were lower than those reported in downtown Monterrey, Nuevo Leon, Mexico by Menchaca-Torre et al [42] and similar to those reported in Chendu (China) [49], but higher than those reported in Longmen Southern China during 2012-2013 by Guo et al [50].…”

Determination and Characteristic Analysis of Atmospheric Carbonyl Compounds in a North China Plain Hub City

“…It was also higher than coastal cities such as Qinzhou and Yantai [22,23] of China. The concentration of acetone in Jinan is higher than that in rural and forest areas [24], especially in the similar mountainous area of Guiyang [25]. Compared with mega cities affected by photochemical smog processes, such as Beijing, Shanghai and Guangzhou [26][27][28], the concentration levels of formaldehyde and acetaldehyde in Jinan were much lower.…”

Characterization of Odorous Compounds (VOC and Carbonyl Compounds) in the Ambient Air of Yeosu and Gwangyang, Large Industrial Areas of South Korea

“…In addition to odor, the carbonyl compounds have also attracted the attention of researchers to measure their concentrations in ambient air because of their ozone formation potential by means of photochemical reactions and their adverse health effects on humans [ 14 , 15 ].…”