Influence of circulation types on temporal and spatial variations of ozone in Beijing.

This study analyzes the impact of circulation types (CTs) on ozone (O) pollution in Beijing. The easterly high-pressure (SWW) circulation occurred most frequently (30%; 276 day), followed by northwesterly high-pressure (AN) circulation (24.3%; 224 day).

On-road mobile mapping of spatial variations and source contributions of ammonia in Beijing, China.

Ammonia (NH) measurements were performed with a mobile platform deploying a cavity ring-down spectroscopy NH analyzer in Beijing. The transect and loop sampling strategy revealed that the Beijing urban area is more strongly affected by NH emissions than surrounding areas. Although average enhancements of on-road NH were small compared to background levels, traffic emissions clearly dominated city enhancements of NH, carbon dioxide (CO), acetaldehyde and acetone.

[Characteristics of Two Pollution Episodes Before and After City Heating in Beijing from February to March of 2019].

The characteristics of meteorological conditions and pollutant concentrations were analyzed based on two pollution episodes before and after city heating in Beijing during February to March of 2019. The backward trajectory and WRF-CAMx models were used to analyze the evolution of pollutants before and after city heating, and the influences of meteorological conditions, regional transport, and secondary transformation on the episodes were discussed. There was little difference in the average (PM) between February 21-24 (episode 1) and March 18-20 (episode 2), with concentrations of 100.

[Differences in Pollution Characteristics Under the Southerly and Easterly Wind in Beijing].

In this study, the hourly meteorological factors and PM concentrations during 2014-2019 in Beijing were analyzed, in order to explore the characteristics of the prevailing wind direction of pollution, and the corresponding long-term tendency. During the study period, 67% of pollution in Beijing occurred under the influence of southerly and easterly wind, and pollution was most likely to occur in winter, followed by spring and autumn. The average pollution probability of winter, spring, autumn and summer was 45.

Contributions of inter-city and regional transport to PM concentrations in the Beijing-Tianjin-Hebei region and its implications on regional joint air pollution control.

Regional transport plays an important role in the serious PM pollutions in the Beijing-Tianjin-Hebei (BTH) region, China. Practical regional joint emission control strategies require quantitative assessments of the transport contribution among cities and regions. The Community Multiscale Air Quality model equipped with the Integrated Source Apportionment Model is used to simulate the contributions from 5 major emission sectors in 13 cities of the BTH region, and 4 surrounding provinces outside BTH for the year 2014.

Estimating the contribution of regional transport to PM air pollution in a rural area on the North China Plain.

PM air pollution in metropolises as well as some medium-sized cities in the North China Plain have aroused many researchers' interest, but less attention has been paid to the rural areas of this region. In this study, four months of daily PM samples were collected from a rural site in Lingcheng (a district of Dezhou City in Shandong Province) during different seasons in 2013 and 2014. Analysis of the samples indicates that the PM air pollution was severe over this area with the four-month average concentration of 105.