Pollution Characteristics of Atmospheric Carbonyls in Urban Linfen in Winter

Fanxiu Li,Xuezhong Wang,Hengyuan Wang,Xuan Chen,Liqin Duan,Yujie Zhang,Yongjun Kou,Zhigang Xue

doi:10.3390/atmos11070685

Abstract

Atmospheric carbonyls (aldehyde and ketone compounds) can be precursors for ozone and PM2.5, and they play an essential role in atmospheric chemistry. Linfen is a basin between mountains on the east and west, and there are many coking plants on the north and south sides of its urban area. The special topography and unfortunate industrial layout have frequently contributed to serious air pollution in Linfen. In order to investigate the pollution characteristics of atmospheric carbonyls in winter in urban Linfen, the carbonyl compounds were collected from the Municipal Committee site (MC) and the Yaowangtai site (YWT) from 16 to 25 January 2019, and their concentrations were analyzed by a high performance liquid chromatography-ultraviolet detector (HPLC-UV). The results show that formaldehyde, acetaldehyde, and acetone were the most abundant compounds, accounting for more than 70% of the total mass concentration of carbonyls in urban Linfen. Levels of these three carbonyls increased during the morning and evening traffic rush hours. The mass concentration of formaldehyde at both sites reached peak values at around noon (10:00–14:00). In addition, the mass concentrations of formaldehyde, acetaldehyde, and acetone were positively correlated with CO mass concentrations, whereas only formaldehyde and acetaldehyde were positively correlated with temperature. Therefore, atmospheric formaldehyde in urban Linfen’s winter mainly came from vehicle exhaust emissions and the secondary generation of photochemical reactions. Most of the acetaldehyde came from vehicle exhaust emissions, and photochemical reactions also partially contributed to it. For acetone, vehicle exhaust emissions were the main source. In addition, coking industry emissions from Northern Linfen′s Hongtong County may also have contributed to the atmospheric carbonyls in the urban area of Linfen. For the first time, this study found that formaldehyde showed different behavior to acetaldehyde and acetone; that is, the nighttime decrease in formaldehyde mass concentration was greater than that of acetaldehyde and acetone.

Highlights

IntroductionCalled carbonyl compounds or carbonyls, are oxygenated volatile organic compounds (OVOCs) that are commonly found in the atmosphere [1]
Aldehyde and ketone compounds, called carbonyl compounds or carbonyls, are oxygenated volatile organic compounds (OVOCs) that are commonly found in the atmosphere [1]
The results showed that vehicle exhaust emissions and photochemical reactions are important sources; the atmospheric concentration of aldehyde and ketone compounds in the Bohai Sea was significantly lower than that in Tianjin (15.93 ± 4.49 μg/m3, 15.71 ± 7.50 μg/m3, 25.58 ± 5.96 μg/m3, and 15.68 ± 3.65 μg/m3, respectively) but higher than that of other sea areas

Summary

Introduction

Called carbonyl compounds or carbonyls, are oxygenated volatile organic compounds (OVOCs) that are commonly found in the atmosphere [1]. The sources of aldehyde and ketone compounds in the atmosphere include primary emissions and secondary generation. Secondary generation refers to the photochemical reactions of volatile organic compounds (VOCs) which are emitted into the atmosphere from human and natural sources [2]. Due to their unstable carbonyl group, these compounds are chemically active and play an important role in the process of photochemistry. Studies have shown that compounds such as formaldehyde, acetaldehyde, and acrolein are highly biologically toxic. In high concentrations, they can cause upper respiratory tract discomfort and even cancer [5]. In October 2017, the World Health Organization’s International Agency for Research on Cancer announced that formaldehyde is classified as a Grade 1 carcinogen, while acetaldehyde, 2,4-hexadienal, and benzophenone are Grade 2 carcinogens, and cyclohexanone and pyruvaldehyde are Grade 3 carcinogens

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