气候变化领域集成服务门户(CCPortal): Measurement report: Long-term variations in surface NOx and SO2 mixing ratios from 2006 to 2016 at a background site in the Yangtze River Delta region, China

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DOI	10.5194/acp-22-1015-2022
	Measurement report: Long-term variations in surface NOx and SO2 mixing ratios from 2006 to 2016 at a background site in the Yangtze River Delta region, China
	Yin, Qingqing; Ma, Qianli; Lin, Weili; Xu, Xiaobin; Yao, Jie
发表日期	2022
ISSN	1680-7316
EISSN	1680-7324
起始页码	1015
结束页码	1033
卷号	22 期号:2 页码:19
英文摘要	China has been experiencing rapid changes in emissions of air pollutants in recent decades. Increased emissions of primary particulates and reactive gases caused severe haze in several polluted regions including the Yangtze River Delta (YRD). Measures implemented in recent years for improving air quality have reduced the emissions of NOx, SO2, etc. The emission changes in these gases are reflected by tropospheric columns from satellite observations and surface measurements of surface concentrations from urban sites. However, little is known about the long-term variations in regional background NOx and SO2. In this study, we present NOx and SO2 measurements from the Lin'an station (LAN; 30 degrees 18' N, 119 degrees 440 E; 138.6ma.s.l.), one of the Global Atmosphere Watch (GAW) stations in China. We characterize the seasonal and diurnal variations and study the long-term trends of NOx and SO2 mixing ratios observed at LAN from 2006 to 2016. We also interpret the observed variations and trends in terms of changes in meteorological conditions as well as emission of these gases. The overall average mixing ratios of NOx (NO2) and SO2 during 2006-2016 were 13.6 +/- 1.2 ppb (12.5 +/- 4.6) and 7.0 +/- 4.2 ppb, respectively. The averaged seasonal variations showed maximum values of NOx and SO2 in December (23.5 +/- 4.4 ppb) and January (11.9 +/- 6.2 ppb), respectively, and minimum values of 7.1 +/- 0.8 and 2.8 +/- 2.3 ppb (both in July), respectively. The average diurnal variation characteristics of NOx and SO2 differed considerably from each other, though the daily average mixing ratios of both gases were significantly correlated (R-2 = 0.29, P<0.001). The annual average mixing ratio of NOx increased during 2006-2011 and then decreased significantly at 0.78 ppb/yr (5.16 %/yr, P<0.01). The annual 95th and 5th percentiles of hourly NOx mixing ratios showed upward trends until 2012 and 2014, respectively, before a clear decline. The annual average mixing ratio of SO2 decreased significantly at 0.99 ppb/yr (8.27 %/yr, P<0.01) from 2006-2016. The annual 95th and 5th percentiles of hourly SO2 mixing ratios all exhibited significant (P<0.001) downward trends at 3.18 and 0.19 ppb/yr, respectively. Changes in the total NOx and SO2 emissions as well as the industrial emissions in the YRD region were significantly correlated with the changes in annual NOx and SO2 mixing ratios. The significant decreases in NOx from 2011 to 2016 and SO2 from 2006 to 2016 highlight the effectiveness of relevant control measures on the reduction in NOx and SO2 emissions in the YRD region. A decrease in annual SO2 = NOx ratio was found, suggesting a better efficacy in the emission reduction in SO2 than NOx. We found gradual changes in average diurnal patterns of NOx and SO2, which could be attributed to increasing contributions of vehicle emissions to NOx and weakening impacts of large sources on the SO2 concentration. This study reaffirms China's success in controlling both NOx and SO2 in the YRD but indicates at the same time a necessity to strengthen the NOx emission control.
学科领域	Environmental Sciences; Meteorology & Atmospheric Sciences
语种	英语
WOS研究方向	Environmental Sciences & Ecology ; Meteorology & Atmospheric Sciences
WOS记录号	WOS:000747697200001
来源期刊	ATMOSPHERIC CHEMISTRY AND PHYSICS
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/273836
作者单位	Chinese Academy of Meteorological Sciences (CAMS)
推荐引用方式 GB/T 7714	Yin, Qingqing,Ma, Qianli,Lin, Weili,et al. Measurement report: Long-term variations in surface NOx and SO2 mixing ratios from 2006 to 2016 at a background site in the Yangtze River Delta region, China[J],2022,22(2):19.
APA	Yin, Qingqing,Ma, Qianli,Lin, Weili,Xu, Xiaobin,&Yao, Jie.(2022).Measurement report: Long-term variations in surface NOx and SO2 mixing ratios from 2006 to 2016 at a background site in the Yangtze River Delta region, China.ATMOSPHERIC CHEMISTRY AND PHYSICS,22(2),19.
MLA	Yin, Qingqing,et al."Measurement report: Long-term variations in surface NOx and SO2 mixing ratios from 2006 to 2016 at a background site in the Yangtze River Delta region, China".ATMOSPHERIC CHEMISTRY AND PHYSICS 22.2(2022):19.