Long-Term Trends of Carbon Monoxide Total Columnar Amount in Urban Areas and Background Regions: Ground- and Satellite-based Spectroscopic Measurements

Wang, Pucai; Elansky, N. F.; Timofeev, Yu. M.; Wang, Gengchen; Голицын, Г. С.; Makarova, Maria; Rakitin, V. Yu.; Shtabkin, Yu. A.; Skorokhod, Andrey; Grechko, E. I.; Fokeeva, E. V.; Safronov, A. N.; Ran, Liang; Wang, Ting

doi:10.1007/s00376-017-6327-8

Cited by 23 publications

(11 citation statements)

References 41 publications

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“…After 2012 however, a combination of installation of power plant de-nitration devices and vehicle emissions controls led to a 32 % decrease in NO 2 emissions (Liu et al, 2016;Krotkov et al, 2016;Miyazaki et al, 2017). In Beijing, NO x emissions are decreasing thanks to numerous air pollution control measures implemented since 2000; polluting industries and power plants have been relocated outside of the city, stricter emissions standards for industrial and domestic boilers have been introduced and the fuel type shifted from coal to gas (Wang et al, 2010). Since the introduction of the "Clean Air Action Plan" in Beijing in 2013, 900 000 households in Beijing have converted from using coal to cleaner technologies like gas or electricity.…”

Section: Comparison With An Emissions Inventorymentioning

confidence: 99%

Measurements of traffic-dominated pollutant emissions in a Chinese megacity

et al. 2020

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Abstract. Direct measurements of NOx, CO and aromatic volatile organic compound (VOC) (benzene, toluene, C2-benzenes and C3-benzenes) flux were made for a central area of Beijing using the eddy-covariance technique. Measurements were made during two intensive field campaigns in central Beijing as part of the Air Pollution and Human Health (APHH) project, the first in November–December 2016 and the second during May–June 2017, to contrast wintertime and summertime emission rates. There was little difference in the magnitude of NOx flux between the two seasons (mean NOx flux was 4.41 mg m−2 h−1 in the winter compared to 3.55 mg m−2 h−1 in the summer). CO showed greater seasonal variation, with mean CO flux in the winter campaign (34.7 mg m−2 h−1) being over twice that of the summer campaign (15.2 mg m−2 h−1). Larger emissions of aromatic VOCs in summer were attributed to increased evaporation due to higher temperatures. The largest fluxes in NOx and CO generally occurred during the morning and evening rush hour periods, indicating a major traffic source with high midday emissions of CO, indicating an additional influence from cooking fuel. Measured NOx and CO fluxes were then compared to the MEIC 2013 emissions inventory, which was found to significantly overestimate emissions for this region, providing evidence that proxy-based emissions inventories have positive biases in urban centres. This first set of pollutant fluxes measured in Beijing provides an important benchmark of emissions from the city which can help to inform and evaluate current emissions inventories.

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Section: Comparison With An Emissions Inventorymentioning

confidence: 99%

Measurements of traffic-dominated pollutant emissions in a Chinese megacity

et al. 2020

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“…Ahmed et al (2015) analyzed long-term CO observations at two urban sites in Seoul and reported a downward trend of CO from to 2013. Wang et al (2018) found that from 1998 to 2014, the total column amount of CO over Beijing and Moscow decreased at 1.14% ± 0.87%/yr and 3.73% ± 0.39%/yr, respectively. Cohen et al (2018) analyzed the trends of CO in the upper troposphere from 2001 to 2013.…”

Section: Introductionmentioning

confidence: 99%

Measurement report: Long-term variations in carbon monoxide at a background station in China's Yangtze River Delta region

Chen¹,

Qian²,

Lin³

et al. 2020

Preprint

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Abstract. This study analyzed the long-term variations in carbon monoxide (CO) mixing ratios from January 2006 to December 2017 at the Lin'an regional atmospheric background station (LAN; 30.3° N, 119.73° E, 138 m a.s.l.) in China's Yangtze River Delta (YRD) region. The CO mixing ratios were at their highest (0.69 ± 0.08 ppm) and lowest (0.54 ± 0.06 ppm) in winter and summer, respectively. The average daily variation of CO exhibited a double-peaked pattern, with peaks in the morning and evening and a valley in the afternoon. A significant downward trend of −11.3 ppb/yr of CO was observed from 2006 to 2017 at the LAN station, which was in accordance with the negative trend of the average CO mixing ratios and total column retrieved from the satellite data (the Measurements Of Pollution In The Troposphere, MOPITT) over the YRD region during the same period. The average annual CO mixing ratio at the LAN station in 2017 was 0.51 ± 0.04 ppm, which was significantly lower than that (0.71 ± 0.12 ppm) in 2006. The decrease in CO levels was largest in autumn (−15.7 ppb/yr), followed by summer (−11.1 ppb/yr), spring (−10.8 ppb/yr), and winter (−9.7 ppb/yr). Moreover, the CO levels under relatively polluted conditions (the annually 95th percentiles) declined even more rapidly (−22.4 ppb/yr, α = 0.05, r = −0.68) from 2006 (0.91 ppm) to 2017 (0.58 ppm) and the CO levels under clean conditions (the annually 5th percentiles) were relatively stable throughout the years. The long-term decline and short-term variations in the CO mixing ratios at the LAN station were mainly attributed to the implementation of the anthropogenic pollution control measures in the YRD region and to the events like Shanghai Expo in 2020 and Hangzhou G20 in 2016. The decreased CO level may influence atmospheric chemistry over the region. The average OH reactivity of CO at the LAN station is estimated to significantly drop from 4.1 ± 0.7 s-1 in 2006 to 3.0 ± 0.3 s-1 in 2017.

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“…The peak in concentrations of CO, which has an atmospheric lifetime ranging from weeks to months, is less easily identified. Some studies suggest that trends have been negative potentially throughout the 21 st century (Han et al, 2018;Strode et al, 2016;Wang et al, 2018;Yumimoto et al, 2014;Zheng et al, 2018a), but others suggest that https://doi.org/10.5194/acp-2020-567 Preprint. Discussion started: 16 July 2020 c Author(s) 2020.…”

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confidence: 99%

Changes in satellite retrievals of atmospheric composition over eastern China during the 2020 COVID-19 lockdowns

Field

Hickman

Geogdzhayev

et al. 2020

Preprint

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Abstract. We examined daily Level-3 satellite retrievals of AIRS CO, OMI SO2 and NO2, and MODIS AOD over eastern China to understand how COVID-19 lockdowns affected atmospheric composition, taking into account trends that have occurred since 2005. Over central east China during the January 23–April 8 lockdown window, CO in 2020 was 12 % lower than the 2005–2019 mean, but only 2 % lower than what would be expected given the decreasing CO trend over that period. Similarly for AOD, 2020 was 30 % lower than the 2011–2019 mean, but not distinct from what would be expected from the trend. NO2 in 2020 was 43 % lower than the 2011–2019 mean, but only 17 % lower than what would be expected given the trend over that period. Over southern China, 2020 NO2 was not significantly different from anticipated, and CO and AOD were significantly higher that what would be expected, which we suggest was partly because of an active fire season in neighbouring countries. Over east central and southern China, SO2 was higher than expected, but the magnitude depended strongly on how daily regional values were calculated from individual retrievals. Future work over China, or other regions, needs to take these trends into account in order to separate the effects of COVID-19 on air quality from recent trends, or from variability in other sources.

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Long-Term Trends of Carbon Monoxide Total Columnar Amount in Urban Areas and Background Regions: Ground- and Satellite-based Spectroscopic Measurements

Cited by 23 publications

References 41 publications

Measurements of traffic-dominated pollutant emissions in a Chinese megacity

Measurements of traffic-dominated pollutant emissions in a Chinese megacity

Measurement report: Long-term variations in carbon monoxide at a background station in China's Yangtze River Delta region

Changes in satellite retrievals of atmospheric composition over eastern China during the 2020 COVID-19 lockdowns

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