Entity

Time filter

Source Type


Wang Z.,Beijing Municipal Environmental Monitoring Center | Zhang D.,Beijing Municipal Environmental Monitoring Center | Chen T.,Beijing Environmental Protection Bureau | Li Y.,Beijing Municipal Environmental Monitoring Center | And 3 more authors.
Huanjing Kexue Xuebao/Acta Scientiae Circumstantiae | Year: 2015

NO2 data from 35 automatic air quality monitoring stations in Beijing in 2013 were analyzed to investigate spatiotemporal characteristics of NO2 and also correlation between NO2, PM2.5 and also atmospheric oxidation. The results showed that the average concentration of NO2 is the highest in winter followed by autumn, spring and summer with the average concentration of 66.6, 58.3, 54.7 μg·m-3 and 45.8 μg·m-3, respectively. The average concentration of NO2 is the highest at the traffic station, followed by the urban station, the suburban station and the regional station with the average concentration of 78.6, 57.9, 48.5 μg·m-3 and 40.3 μg·m-3, respectively. Monthly average concentration of NO2 changes in a wave-shape curve with peak values during January, March, May and also October. Generally, diurnal variation of NO2 at the regional station showed unimodal distribution, while other stations showed bimodal distribution. Concentrations of NO2 were higher during weekends most of the time, which indicated anti weekend effect. Annual average concentration of NO2 in different regions show different concentrations at different stations. The highest concentration can be found at the central six districts, while lower concentration at the southwest, southeast, northwest and northeast. Concentrations of NO2 were significantly positively correlated with concentrations of PM2.5 and OX, which indicated that NO2 could be the factor behind increase in PM2.5 concentrations by increasing precursor concentrations and enhancing atmospheric oxidation. ©, 2015, Science Press. All right reserved. Source


Wang Z.,Chinese Research Academy of Environmental Sciences | Li Y.,Beijing Municipal Environmental Monitoring Center | Chen T.,Beijing Environmental Protection Bureau | Zhang D.,Tsinghua University | And 5 more authors.
Bulletin of the American Meteorological Society | Year: 2016

An examination of the major air pollution control measures leading to the improvement in air quality in Beijing from 2008 to 2014. © 2016 American Meteorological Society. Source


Wang Z.,Beijing Municipal Environmental Monitoring Center | Wang Z.,Chinese Research Academy of Environmental Sciences | Li Y.,Beijing Municipal Environmental Monitoring Center | Chen T.,Beijing Environmental Protection Bureau | And 8 more authors.
Journal of Geophysical Research: Atmospheres | Year: 2015

Five sites were selected to investigate the impact of regional-scale air pollutant control strategies during the Asia-Pacific Economic Cooperation (APEC) conference (1-12 November 2014) in and around Beijing. Concentrations of most of the air pollutants in the APEC period were significantly lower than those in the adjacent time period, especially when the enhanced reduction measures were implemented. Compared with the same time period in the previous 5 years (PM2.5 was compared with the last year), average concentrations of SO2, NO2, PM10, and PM2.5 in the five sites during the APEC period decreased by 62%, 41%, 36%, and 47% respectively, whereas average concentration of O3 increased by 102%. A possible cause of the increase of O3 concentrations is the stricter reduction measure on NOx compared to that applied to volatile organic compounds. Compared with the non-APEC period in autumn 2014, concentrations of most of the chemical compositions of PM2.5 decreased significantly in the APEC period, especially SO4 2-, NO3 -, and NH4 + (sulfate, nitrate, and ammonium). The aerosol optical depth and the columnar NO2 in the area of 39.5°-40.5°N, 116°-117°E showed a changing pattern similar to the typical gas pattern. The net effectiveness of the emission reduction measures was calculated through a comparison of concentrations of air pollutants under similar meteorological conditions. Through the reduction measures imposed during the APEC period, concentrations of CO, SO2, NO, NO2, PM10, and PM2.5 decreased by 54%, 74%, 64%, 48%, 67%, and 65%, respectively, whereas concentrations of O3 increased by 189%. © 2015. American Geophysical Union. All Rights Reserved. Source


Cheng N.-L.,Airborne | Cheng N.-L.,Beijing Normal University | Cheng N.-L.,Chinese Research Academy of Environmental Sciences | Li Y.-T.,Airborne | And 7 more authors.
Huanjing Kexue/Environmental Science | Year: 2016

The spatial-temporal distribution characteristics of O3 and the correlations between O3 and meteorological elements in Beijing urban area were investigated based on the hourly O3 monitoring data from January to December in 2014 released by Beijing Municipal Environmental Monitoring Center. The annual concentration of O3 in Beijing was about 56.18 μg·m-3 in 2014. In the over polluted days during May and September, the O3 concentration could reach as high as 148.05 μg·m-3. The diurnal distribution of ozone presented a clear unimodal pattern with its peak appearing at 15:00 or 16:00 and trough at 06:00 or 07:00 and the concentrations of O3 during 09:00 and 23:00 was significantly higher than those in the Summer time. For the spatial distribution of O3, the concentration was lower in central urban area with the highest concentration appearing at plant garden site in the west of the urban area. Ground weather type of O3 over polluted days was divided into three categories including high-pressure, low-pressure, equalizing field, which accounted for 16%, 36%, 48%, respectively. The concentration of O3 was negatively correlated with the air pressure, humidity and visibility while it was positively correlated with the wind speed and temperature. In one heavy pollution episode of O3 caused by local photochemical pollution and regional transport from May 29th to June 1st in 2014 in Beijing, regional transport showed a very important influence on the concentration of O3 in Beijing. © 2016, Science Press. All right reserved. Source


Cheng N.-L.,Airborne | Chen T.,Beijing Environmental Protection Bureau | Zhang D.-W.,Airborne | Li Y.-T.,Airborne | And 5 more authors.
Huanjing Kexue/Environmental Science | Year: 2015

To analyze the impacts of emissions from fireworks on the air quality, monitoring data of PM2.5, PM10, SO2, NO2 chemical compositions of PM2.5 of automatic air quality stations in Beijing during Spring Festival(February 18th-24th) in 2015 were investigated. Moreover, we also estimated the fireworks on the New Year's Eve produced based on the ratio of PM2.5 to CO. Analysis results showed that the concentrations of PM2.5, PM10, SO2, NO2 during 2015 Spring Festival was 116.85, 184.71, 22.14, and 36.27 μg·m-3, respectively, which raised 52.61%, 92.41%, -40.15%, -0.46% respectively compared to the same period in 2014; the concentration peaks of PM2.5, PM10, SO2, NO2at 1:00 am on 19th was 412.69, 541.63, 152.73, 51.09 μg·m-3, respectively, which was increased 19.02%, 14.37%, 76.57%, 11.35% compared to that of 2014; the concentration peaks at dense population area were significantly higher than that in other districts; fireworks had great influence on the chemical compositions of PM2.5especially on the concentrations of chloride ion, potassium ion, magnesian ion, which were 18.85, 66.72, and 70.10 times than that in 2013-2014; fireworks resulted in severe air pollution in a short time and the estimated fireworks on the New Year's Eve was approximately 2.13×105 kg of PM2.5. Reduction of pollutants during Spring Festival had a positive significant impact on air quality in Beijing. ©, 2015, Science Press. All right reserved. Source

Discover hidden collaborations