Spatial oscillation of the particle pollution in eastern China during winter: Implications for regional air quality and climate

Exploring the relationship between environmental air quality (EAQ) and climatic conditions on a large scale can help better understand the main distribution characteristics and the mechanisms of EAQ in China, which is significant for the implementation of policies of joint prevention and control of regional air pollution. In this study, we used the concentrations of six conventional air pollutants, i.e., carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), fine particulate matter (PM2.5), coarse particulate matter (PM10), and ozone (O3), derived from about 1300 monitoring sites in eastern China (EC) from January 2015 to December 2018. Exploiting the grading concentration limit (GB3095-2012) of various pollutants in China, we also calculated the monthly average air quality index (AQI) in EC. The results show that, generally, the EAQ has improved in all seasons in EC from 2015 to 2018. In particular, the concentrations of conventional air pollutants, such as CO, SO2, and NO2, have been decreasing year by year. However, the concentrations of particulate matter, such as PM2.5 and PM10, have changed little, and the O3 concentration increased from 2015 to 2018. Empirical mode decomposition (EOF) was used to analyze the major patterns of AQI in EC. The first mode (EOF1) was characterized by a uniform structure in AQI over EC. These phenomena are due to the precipitation variability associated with the East Asian summer monsoon (EASM), referred to as the “summer–winter” pattern. The second EOF mode (EOF2) showed that the AQI over EC is a north–south dipole pattern, which is bound by the Qinling Mountains and Huaihe River (about 35° N). The EOF2 is mainly caused by seasonal variations of the mixed concentration of PM2.5 and O3. Associated with EOF2, the Mongolia–Siberian High influences the AQI variation over northern EC by dominating the low-level winds (10 m and 850 hPa) in autumn and winter, and precipitation affects the AQI variation over southern EC in spring and summer.

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Description and Evaluation of the Fine Particulate Matter Forecasts in the NCAR Regional Air Quality Forecasting System

Atmosphere ◽

10.3390/atmos12030302 ◽

2021 ◽

Vol 12 (3) ◽

pp. 302

Author(s):

Rajesh Kumar ◽

Piyush Bhardwaj ◽

Gabriele Pfister ◽

Carl Drews ◽

Shawn Honomichl ◽

...

Keyword(s):

Particulate Matter ◽

Air Quality ◽

Information Dissemination ◽

Fine Particulate Matter ◽

Model Errors ◽

Air Quality Forecast ◽

Fine Particulate ◽

Regional Air Quality ◽

Forecasting System ◽

Air Quality Forecasting

This paper describes a quasi-operational regional air quality forecasting system for the contiguous United States (CONUS) developed at the National Center for Atmospheric Research (NCAR) to support air quality decision-making, field campaign planning, early identification of model errors and biases, and support the atmospheric science community in their research. This system aims to complement the operational air quality forecasts produced by the National Oceanic and Atmospheric Administration (NOAA), not to replace them. A publicly available information dissemination system has been established that displays various air quality products, including a near-real-time evaluation of the model forecasts. Here, we report the performance of our air quality forecasting system in simulating meteorology and fine particulate matter (PM2.5) for the first year after our system started, i.e., 1 June 2019 to 31 May 2020. Our system shows excellent skill in capturing hourly to daily variations in temperature, surface pressure, relative humidity, water vapor mixing ratios, and wind direction but shows relatively larger errors in wind speed. The model also captures the seasonal cycle of surface PM2.5 very well in different regions and for different types of sites (urban, suburban, and rural) in the CONUS with a mean bias smaller than 1 µg m−3. The skill of the air quality forecasts remains fairly stable between the first and second days of the forecasts. Our air quality forecast products are publicly available at a NCAR webpage. We invite the community to use our forecasting products for their research, as input for urban scale (<4 km), air quality forecasts, or the co-development of customized products, just to name a few applications.

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The implication of the air quality pattern in South Korea after the COVID-19 outbreak

Scientific Reports ◽

10.1038/s41598-020-80429-4 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Ja-Ho Koo ◽

Jhoon Kim ◽

Yun Gon Lee ◽

Sang Seo Park ◽

Seoyoung Lee ◽

...

Keyword(s):

Air Quality ◽

South Korea ◽

Social Impact ◽

Social Activity ◽

Satellite Measurements ◽

Ordinary Life ◽

The Social ◽

Regional Air Quality ◽

Long Lifetime ◽

Positive Effect

AbstractBy using multiple satellite measurements, the changes of the aerosol optical depth (AOD) and nitrogen dioxide (NO2) over South Korea were investigated from January to March 2020 to evaluate the COVID-19 effect on the regional air quality. The NO2 decrease in South Korea was found but not significant, which indicates the effects of spontaneous social distancing under the maintenance of ordinary life. The AODs in 2020 were normally high in January, but they became lower starting from February. Since the atmosphere over Eastern Asia was unusually stagnant in January and February 2020, the AOD decrease in February 2020 clearly reveals the positive effect of the COVID-19. Considering the insignificant NO2 decrease in South Korea and the relatively long lifetime of aerosols, the AOD decrease in South Korea may be more attributed to the improvement of the air quality in neighboring countries. In March, regional atmosphere became well mixed and ventilated over South Korea, contributing to large enhancement of air quality. While the social activity was reduced after the COVID-19 outbreak, the regional meteorology should be also examined significantly to avoid the biased evaluation of the social impact on the change of the regional air quality.

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Dynamic evaluation of regional air quality model’s response to emission reductions in the presence of uncertain emission inventories

Atmospheric Environment ◽

10.1016/j.atmosenv.2011.03.030 ◽

2011 ◽

Vol 45 (24) ◽

pp. 4091-4098 ◽

Cited By ~ 34

Author(s):

Sergey L. Napelenok ◽

Kristen M. Foley ◽

Daiwen Kang ◽

Rohit Mathur ◽

Thomas Pierce ◽

...

Keyword(s):

Air Quality ◽

Emission Inventories ◽

Emission Reductions ◽

Dynamic Evaluation ◽

Regional Air Quality

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Assessing the regional impacts of Mexico City emissions on air quality and chemistry

Atmospheric Chemistry and Physics ◽

10.5194/acp-9-3731-2009 ◽

2009 ◽

Vol 9 (11) ◽

pp. 3731-3743 ◽

Cited By ~ 35

Author(s):

M. Mena-Carrasco ◽

G. R. Carmichael ◽

J. E. Campbell ◽

D. Zimmerman ◽

Y. Tang ◽

...

Keyword(s):

Air Quality ◽

Mexico City ◽

Ozone Production ◽

Anthropogenic Aerosol ◽

Near Surface ◽

Mixing Ratios ◽

Regional Impacts ◽

Photolysis Rates ◽

Regional Air Quality ◽

The Impact

Abstract. The impact of Mexico City (MCMA) emissions is examined by studying its effects on air quality, photochemistry, and on ozone production regimes by combining model products and aircraft observations from the MILAGRO experiment during March 2006. The modeled influence of MCMA emissions to enhancements in surface level NOx, CO, and O3 concentrations (10–30% increase) are confined to distances <200 km, near surface. However, the extent of the influence is significantly larger at higher altitudes. Broader MCMA impacts (some 900 km Northeast of the city) are shown for specific outflow conditions in which enhanced ozone, NOy, and MTBE mixing ratios over the Gulf of Mexico are linked to MCMA by source tagged tracers and sensitivity runs. This study shows that the "footprint" of MCMA on average is fairly local, with exception to reactive nitrogen, which can be transported long range in the form of PAN, acting as a reservoir and source of NOx with important regional ozone formation implications. The simulated effect of MCMA emissions of anthropogenic aerosol on photochemistry showed a maximum regional decrease of 40% in J[NO2→NO+O], and resulting in the reduction of ozone production by 5–10%. Observed ozone production efficiencies are evaluated as a function of distance from MCMA, and by modeled influence from MCMA. These tend to be much lower closer to MCMA, or in those points where modeled contribution from MCMA is large. This research shows that MCMA emissions do effect on regional air quality and photochemistry, both contributing large amounts of ozone and its precursors, but with caveat that aerosol concentrations hinder formation of ozone to its potential due to its reduction in photolysis rates.

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