scholarly journals Significant wintertime PM<sub>2.5</sub> mitigation in the Yangtze River Delta, China from 2016 to 2019: observational constraints on anthropogenic emission controls

2020 ◽  
Author(s):  
Liqiang Wang ◽  
Shaocai Yu ◽  
Pengfei Li ◽  
Xue Chen ◽  
Zhen Li ◽  
...  
Keyword(s):  
Yangtze River ◽  
Emission Control ◽  
Yangtze River Delta ◽  
Control Measures ◽  
Anthropogenic Emissions ◽  
Observational Constraints ◽  
Anthropogenic Emission ◽  
The Yangtze River Delta ◽  
Emission Control Measures

Abstract. Ambient fine particulate matter (PM2.5) mitigation relies strongly on anthropogenic emission control measures, the actual effectiveness of which is challenging to pinpoint owing to the complex synergies between anthropogenic emissions and meteorology. Here, observational constraints on model simulations allow us to derive not only reliable PM2.5 evolution but also accurate meteorological fields. In this study, we isolate meteorological factors to achieve reliable estimates of surface PM2.5 responses to both long-term and emergency emission control measures from 2016 to 2019 over the Yangtze River Delta (YRD), China. The results show that long-term emission control strategies play a crucial role in curbing PM2.5 levels (> 14 μg/m3, 19 %), especially in the megacities and other areas with abundant anthropogenic emissions. The G20 summit hosted in Hangzhou in 2016 provides a unique and ideal opportunity involving the most stringent, even unsustainable, emergency emission control measures. For the winter time periods from 2016 to 2019, the most substantial declines in PM2.5 concentrations (~ 35 μg/m3, ~ 59 %) are thus achieved in Hangzhou and its surrounding areas. The following hotspots also emerge in megacities, especially in Shanghai (32 μg/m3, 51 %), Nanjing (27 μg/m3, 55 %), and Hefei (24 μg/m3, 44 %). Compared to the long-term policies from 2016 to 2019, the emergency emission control measures implemented during the G20 Summit achieve more significant decreases in PM2.5 concentrations (17 μg/m3 and 41 %) over most of the whole domain, especially in Hangzhou (24 μg/m3, 48 %) and Shanghai (21 μg/m3, 45 %). By extrapolation, we derive insight into the magnitude and spatial distributions of PM2.5 mitigation potentials across the YRD, revealing significantly additional rooms for curbing PM2.5 levels.

scholarly journals Significant wintertime PM<sub>2.5</sub> mitigation in the Yangtze River Delta, China, from 2016 to 2019: observational constraints on anthropogenic emission controls

2020 ◽  
Vol 20 (23) ◽  
pp. 14787-14800
Author(s):  
Liqiang Wang ◽  
Shaocai Yu ◽  
Pengfei Li ◽  
Xue Chen ◽  
Zhen Li ◽  
...  
Keyword(s):  
Yangtze River ◽  
Emission Control ◽  
Yangtze River Delta ◽  
Control Measures ◽  
Anthropogenic Emissions ◽  
Observational Constraints ◽  
The Yangtze River Delta ◽  
Emergency Measures ◽  
Emission Control Measures

Abstract. Ambient fine particulate matter (PM2.5) mitigation relies strongly on anthropogenic emission control measures, the actual effectiveness of which is challenging to pinpoint owing to the complex synergies between anthropogenic emissions and meteorology. Here, observational constraints on model simulations allow us to derive not only reliable PM2.5 evolution but also accurate meteorological fields. On this basis, we isolate meteorological factors to achieve reliable estimates of surface PM2.5 responses to both long-term and emergency emission control measures from 2016 to 2019 over the Yangtze River Delta (YRD), China. The results show that long-term emission control strategies play a crucial role in curbing PM2.5 levels, especially in the megacities and other areas with abundant anthropogenic emissions. The G20 summit hosted in Hangzhou in 2016 provides a unique and ideal opportunity involving the most stringent, even unsustainable, emergency emission control measures. These emergency measures lead to the largest decrease (∼ 35 µg m−3, ∼ 59 %) in PM2.5 concentrations in Hangzhou. The hotspots also emerge in megacities, especially in Shanghai (32 µg m−3, 51 %), Nanjing (27 µg m−3, 55 %), and Hefei (24 µg m−3, 44 %) because of the emergency measures. Compared to the long-term policies from 2016 to 2019, the emergency emission control measures implemented during the G20 Summit achieve more significant decreases in PM2.5 concentrations (17 µg m−3 and 41 %) over most of the whole domain, especially in Hangzhou (24 µg m−3, 48 %) and Shanghai (21 µg m−3, 45 %). By extrapolation, we derive insight into the magnitude and spatial distribution of PM2.5 mitigation potential across the YRD, revealing significantly additional room for curbing PM2.5 levels.

scholarly journals Space borne tropospheric nitrogen dioxide (NO<sub>2</sub>) observations from 2005–2020 over the Yangtze River Delta (YRD), China: variabilities, implications, and drivers

2022 ◽  
Author(s):  
Hao Yin ◽  
Youwen Sun ◽  
Justus Notholt ◽  
Mathias Palm ◽  
Cheng Liu
Keyword(s):  
Yangtze River ◽  
Industrial Structure ◽  
High Energy ◽  
Yangtze River Delta ◽  
Anthropogenic Emission ◽  
Tropospheric No2 ◽  
Increasing Trends ◽  
The Yrd ◽  
The Yangtze River Delta

Abstract. Nitrogen dioxide (NO2) is mainly affected by local emission and meteorology rather than long-range transport. Accurate acknowledge of its long-term variabilities and drivers are significant for understanding the evolutions of economic and social development, anthropogenic emission, and the effectiveness of pollution control measures on regional scale. In this study, we quantity the long-term variabilities and the underlying drivers of NO2 from 2005 to 2020 over the Yangtze River Delta (YRD), one of the most densely populated and highly industrialized city clusters in China, using OMI space borne observations and the multiple linear regression (MLR) model. We have compared the space borne tropospheric results to the surface in-situ data, yielding correlation coefficients of 0.8 to 0.9 over all megacities within the YRD. As a result, the tropospheric NO2 column measurements can be used as representatives of near-surface conditions, and we thus only use ground-level meteorological data for MLR regression. The inter-annual variabilities of tropospheric NO2 vertical column densities (VCDs) from 2005 to 2020 over the YRD can be divided into two stages. The first stage was from 2005 to 2011, which showed overall increasing trends with a wide range of (1.91 ± 1.50) to (6.70 ± 0.10) × 1014 molecules/cm2·yr−1 (p < 0.01) over the YRD. The second stage was from 2011 to 2020, which showed over all decreasing trends of (−6.31 ± 0.71) to (−11.01 ± 0.90) × 1014 molecules/cm2·yr−1 (p < 0.01) over each of the megacities. The seasonal cycles of tropospheric NO2 VCDs over the YRD are mainly driven by meteorology (81.01 % – 83.91 %) except during winter when anthropogenic emission contributions are pronounced (16.09 % – 18.99 %). The inter annual variabilities of tropospheric NO2 VCDs are mainly driven by anthropogenic emission (69.18 % – 81.34 %) except for a few years such as 2018 which are partly attributed to meteorology anomalies (39.07 % – 91.51 %). The increasing trends in tropospheric NO2 VCDs from 2005 to 2011 over the YRD are mainly attributed to high energy consumption associated with rapid economic growth which cause significant increases in anthropogenic NO2 emissions. The decreasing trends in tropospheric NO2 VCDs from 2011 to 2020 over the YRD are mainly attributed to the stringent clean air measures which either adjust high energy industrial structure toward low energy industrial structure or directly reduce pollutant emissions from different industrial sectors.

scholarly journals China’s emission control strategies have suppressed unfavorable influences of climate on wintertime PM2.5 concentrations in Beijing since 2002

2020 ◽  
Author(s):  
Meng Gao ◽  
Kaili Lin ◽  
Shiqing Zhang ◽  
Ken kin lam Yung
Keyword(s):  
Control Strategies ◽  
Emission Control ◽  
Field Measurements ◽  
Meteorological Conditions ◽  
Control Measures ◽  
Anthropogenic Emissions ◽  
Recent Climate ◽  
Decadal Variations ◽  
Haze Days ◽  
Emission Control Measures

&lt;p&gt;Severe wintertime PM2.5 pollution in Beijing has been receiving increasing worldwide attention, yet the decadal variations remain relatively unexplored. Combining field measurements and model simulations, we quantified the relative influences of anthropogenic emissions and meteorological conditions on PM2.5 concentrations in Beijing overwinters of 2002-2016. Between the winters of 2011 and 2016, stringent emission control measures resulted in a 21% decrease in mean mass concentrations of PM2.5 in Beijing, with 7 fewer haze days per winter on average. Given the overestimation of PM2.5 by model, the effectiveness of stringent emission control measures might have been slightly overstated. With fixed emissions, meteorological conditions over the study period would have led to an increase of haze in Beijing, but the strict emission control measures have suppressed the unfavorable influences of recent climate. The unfavorable meteorological conditions are attributed to the weakening of the East Asia Winter Monsoon associated particularly with an increase in pressure associated with the Aleutian low.&lt;/p&gt;

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