Rapid decline in carbon monoxide emissions and export from East Asia between years 2005 and 2016

Zheng, Bo; Chevallier, F.; Ciais, Philippe; Yin, Yi; Deeter, Merritt N.; Worden, H. M.; Wang, Yilong; Zhang, Qiang; He, Kebin

doi:10.1088/1748-9326/aab2b3

Cited by 128 publications

(108 citation statements)

References 44 publications

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“…Considering larger scales, their distribution is similar, while for smaller scales, the distribution is different because the life cycle of NO 2 and SO 2 is indeed much shorter than CO. However, the vertical column densities of CO show a clear interannual downward trend ( Figure 5(d)) [50,51], which is different from the trends of NO 2 and SO 2 . During the first phase (2005-2011), CO decreased at an average rate of (0.03 ± 0.03) × 10 18 molec·cm − 2 ·yr − 1 , and during the second phase (2012-2016), it decreased faster, with an average rate of (0.05 ± 0.05) × 10 18 molec·cm − 2 ·yr − 1 .…”

Section: Interannual Summer Variation and Trends Of Relevantmentioning

confidence: 76%

Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China

Li-hua

Zhang

Zheng

et al. 2019

Advances in Meteorology

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Compared with other regions in China, air pollution on the North China Plain (NCP) is serious. Fine particle pollution has been studied in-depth, but there is less research on long-term troposphere ozone (O 3 ) variation. is study focuses on the summer interannual tropospheric O 3 variation on the NCP and its influential factors. Our analysis relies on satellite observations (O 3 , nitrogen dioxide (NO 2 ), sulfur dioxide (SO 2 ), carbon monoxide (CO), and formaldehyde (HCHO), determined as vertical column density of the troposphere) and dynamical processes (El Niño-Southern Oscillation (ENSO), potential vorticity (PV), the quasibiennial oscillation (QBO), and East Asian summer monsoon index (EASMI)). Our results show the vertical column density of tropospheric O 3 has a transition from the increasing trend to decreasing trend during the summer of 2005-2016. e summer series of tropospheric O 3 show two distinct phases: the first phase (2005)(2006)(2007)(2008)(2009)(2010)(2011), with an average growth rate of 0.55 ± 0.20 DU/yr, and a second phase (2012)(2013)(2014)(2015)(2016), with an average reduction rate of 0.16 ± 0.23 DU/yr. e tropospheric NO 2 column in the NCP also has a transition from the increasing trend to decreasing trend during the summer of 2005-2016. Tropospheric NO 2 and CO column concentrations obtained from satellite observations indicate that emission reductions might be the main cause of the tropospheric O 3 decrease. Particularly, the reduction of nitrogen oxides (NO x ) is more significant, and NO 2 decreased by (0.45 ± 0.11) × 10 15 molec·cm − 2 per year in summer since 2012. However, tropospheric column HCHO shows an increase of 0.05 × 10 15 molec·cm − 2 per year during the whole period of 2005 to 2016. An O 3 -NO x -VOC sensitivity experiment in the NCP showed that the O 3 is still in a NO x -saturated state in some heavily polluted cities, although the NO x emissions are decreasing overall. In addition to the chemical reactions, atmospheric dynamic processes also have an effect on tropospheric O 3 . Finally, we built a model to analyze the contributions of chemical processes and dynamic processes to the tropospheric O 3 column in the NCP. For the chemical process variables, 69.73% of the observed trend of tropospheric O 3 could be explained by the NO 2 tropospheric column. erefore, the reduction of tropospheric O 3 since 2012 is associated with the reduction of NOx. For the dynamical process variables, ENSO, PV, and EASMI can explain 60.64% of the observed trend of tropospheric O 3 . is result indicates that the atmospheric circulation of the western Pacific Ocean in summer has a significant impact on the interannual trends of tropospheric O 3 in the NCP. It is also found that chemical processes had a more important impact on interannual tropospheric O 3 than dynamic processes, although the dynamic processes cannot be neglected.

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Section: Interannual Summer Variation and Trends Of Relevantmentioning

confidence: 76%

Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China

Li-hua

Zhang

Zheng

et al. 2019

Advances in Meteorology

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“…However, the emissions ratios expected from the inventory are higher than what we see in the ∆CO/∆CO 2 ratio distributions, with power generation the only category with an expected ratio below 1% CO/CO 2 , and the residential emissions above 11% CO/CO 2 . Recent work on pollution trends in East Asia by Zheng et al () indicate that CO emissions have decreased in China while fossil fuel consumption has held steady or increased and attribute this decrease in CO to increasing emission controls within China. Assessing the change in Chinese emissions is beyond the scope of the current work, but motivates the use of this technique as a method for assessing inventory comparisons to top‐down measurements, especially in areas like China where there are rapidly changing emissions characteristics.…”

Section: Discussionmentioning

confidence: 99%

“…Globally, vehicle combustion efficiency has increased with time as compliance with emissions standards has improved (Popa et al, 2014;Singer & Harley, 1996), but standards vary between countries (Huo et al, 2011). South Korea has generally had stronger vehicle emissions standards than China (Wang et al, 2014), although combustion efficiency has been increasing in China with improved emissions control technology and government incentivized implementation of improved standards (Zhang et al, 2009;Zheng et al, 2018).…”

Section: Supporting Informationmentioning

confidence: 99%

“…However, the emissions ratios expected from the inventory are higher than what we see in the ΔCO/ΔCO 2 ratio distributions, with power generation the only category with an expected ratio below 1% CO/CO 2 , and the residential emissions above 11% CO/CO 2 . Recent work on pollution trends in East Asia by Zheng et al (2018) indicate that CO emissions have…”

Section: Comparisons To Korean Emission Inventoriesmentioning

confidence: 99%

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Using Short‐Term CO/CO₂ Ratios to Assess Air Mass Differences Over the Korean Peninsula During KORUS‐AQ

et al. 2019

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One‐second in situ measurements of CO and CO2 mole fractions were made aboard the National Aeronautics and Space Administration DC‐8 aircraft during the 2016 KORUS‐AQ joint air quality and atmospheric chemistry field campaign in South Korea. The ratio of CO to CO2 enhancement is used to characterize regional combustion source signatures. Calculations of the ∆CO/∆CO2 ratio were made with a short duration rolling window (60 s), filtered by the coefficient of determination (R2), and plotted as distributions to characterize air masses measured from the aircraft during the campaign. The KORUS‐AQ sampling domain was divided into analysis regions to facilitate the analysis. Over Seoul, the boundary layer shows a low‐ratio signature in the ∆CO/∆CO2 ratios, with more than 50% of the correlated slopes in the boundary layer falling below 1% ∆CO/∆CO2, and 80% of the slopes between 0% and 2% ∆CO/∆CO2. However, this behavior changes to a larger ratio distribution at higher altitudes. The West Sea receptor region was divided into three analysis sectors, by meteorological regime, and used in conjunction with measurements collected over China during the KORUS‐AQ campaign time period to characterize the Chinese ∆CO/∆CO2 ratio signature. Chinese‐type emissions have a slope distribution that is shifted to higher ratios and broadened compared to measurements over Seoul, with the bulk of the measurements between 2% and 4% ∆CO/∆CO2, with few negative slopes. The measured ratio trends over South Korea are consistent with inventoried CO and CO2 emissions.

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“…The a priori emissions of fires are derived from GFED 4.1 s, and the other input data are summarized in Figure S1 and Table S1 (Olivier et al, 2003;Granier et al, 2011;Sindelarova et al, 2014;González Abad et al, 2015). Detail of the current version of the inversion system is given by Zheng et al (2018). Here we provide a brief summary.…”

Section: Inversion Analysis Of Co Emissionsmentioning

confidence: 99%

On the Role of the Flaming to Smoldering Transition in the Seasonal Cycle of African Fire Emissions

Zheng

Chevallier

Ciais

et al. 2018

Geophysical Research Letters

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Satellite estimates of burned area, associated carbon monoxide (CO) emission estimates, and CO column retrievals do not agree on the peak fire month in Africa, evident in both Northern and Southern Africa though distinct in the burning seasonality. Here we analyze this long‐standing problem using (1) a top‐down Bayesian inversion of Measurements Of Pollution In The Troposphere CO columns during 2005–2016 into surface CO emissions and (2) the bottom‐up Global Fire Emissions Database 4.1 s. We show that Global Fire Emissions Database 4.1 s underestimates CO emissions by 12–62% in the late fire season and hypothesize that this is partly because it assumes seasonally static emission factors. However, the degree to which emission factors would have to vary through the season to bring top‐down and bottom‐up in agreement cannot be confirmed by past field‐based measurements. Improved observational constraint on the seasonality of burned area, fuel combustion, and emission factors would further reduce the discrepancy between bottom‐up and top‐down emission estimates.

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Rapid decline in carbon monoxide emissions and export from East Asia between years 2005 and 2016

Cited by 128 publications

References 44 publications

Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China

Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China

Using Short‐Term CO/CO₂ Ratios to Assess Air Mass Differences Over the Korean Peninsula During KORUS‐AQ

On the Role of the Flaming to Smoldering Transition in the Seasonal Cycle of African Fire Emissions

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Rapid decline in carbon monoxide emissions and export from East Asia between years 2005 and 2016

Cited by 128 publications

References 44 publications

Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China

Impacts of Chemical and Synoptic Processes on Summer Tropospheric Ozone Trend in North China

Using Short‐Term CO/CO2 Ratios to Assess Air Mass Differences Over the Korean Peninsula During KORUS‐AQ

On the Role of the Flaming to Smoldering Transition in the Seasonal Cycle of African Fire Emissions

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Using Short‐Term CO/CO₂ Ratios to Assess Air Mass Differences Over the Korean Peninsula During KORUS‐AQ