Visibility characteristics and the impacts of air pollutants and meteorological conditions over Shanghai, China

Abstract

In China, visibility condition has become an important issue that concerns both society and the scientific community. In order to study visibility characteristics and its influencing factors, visibility data, air pollutants, and meteorological data during the year 2013 were obtained over Shanghai. The temporal variation of atmospheric visibility was analyzed. The mean value of daily visibility of Shanghai was 19.1 km. Visibility exhibited an obvious seasonal cycle. The maximum and minimum visibility occurred in September and December with the values of 27.5 and 7.7 km, respectively. The relationships between the visibility and air pollutant data were calculated. The visibility had negative correlation with NO2, CO, PM2.5, PM10, and SO2 and weak positive correlation with O3. Meteorological data were clustered into four groups to reveal the joint contribution of meteorological variables to the daily average visibility. Usually, under the meteorological condition of high temperature and wind speed, the visibility of Shanghai reached about 25 km, while visibility decreased to 16 km under the weather type of low wind speed and temperature and high relative humid. Principle component analysis was also applied to identify the main cause of visibility variance. The results showed that the low visibility over Shanghai was mainly due to the high air pollution concentrations associated with low wind speed, which explained the total variance of 44.99 %. These results provide new knowledge for better understanding the variations of visibility and have direct implications to supply sound policy on visibility improvement in Shanghai.

The Impact of Selected Parameters on Visibility: First Results from a Long-Term Campaign in Warsaw, Poland

“…The changes in its concentration mainly resulted from the changes in the weather conditions (insolation intensity, air temperature) and the participation of the O3 precursors (e.g., nitrogen oxides, hydrocarbons and other pollutants participation in the O3 formation) in the atmospheric air [30,39]. Since the visibility is strongly affected by air pollutants [1,40,41], the presence of its' weaker variation over Warsaw from 2004-2013 is found. In Poland, considerable changes in air pollution were observed from 1980-2000 [42].…”

“…PC1, PC2, PC3 and PC4 can be interpreted as major factors that control visibility [1,6,17,40]. Visibility (Vis), O3 concentration (O3), NO2 concentration (NO2), CO concentration (CO), air temperature (T), relative air humidity (RH), PM10 concentration (PM10) and insolation intensity (Rad) were most strongly correlated with PC1.…”

Long-Term Atmospheric Visibility Trends and Characteristics of 31 Provincial Capital Cities in China during 1957–2016

“…To understand the characteristics and factors affecting AV, studies have been carried out in highly developed regions all over the world [3][4][5][6][7][8][9][10][11][12][14][15][16][17][18][19][20][21][22]. Wang et al (2009) revealed that since the mid-1980s, AV has increased in Europe and North America, but has decreased substantially over south and east Asia, South America, Australia, and Africa [14].…”

“…Sabetghadam et al (2012) analyzed AV data collected during 1958-2008 from the historical airport AV database in Tehran, Iran, and found decreasing trends in AV from all of the database's monitoring stations [17]. In recent years, studies that have occurred in China (e.g., Shanghai [18,19], Beijing [20][21][22], and Guangzhou [22]) have shown increasing trends of AV. Overall, previous studies have revealed that developed countries display a general increasing trend of AV after the mid-1980s, whereas developing countries display substantially decreasing trends of AV due to rapid economic development-this is especially true in China [18][19][20][21][22].…”

Generation and Analysis of Gridded Visibility Data in the Arctic

“…At the same time, their study suggested that visibility and microphysical parameters are nonlinearly related to each other and RH and Nd, LWC are most important parameters for fog visibility calculation [5,22]. Xue et al [24] studied the effects of air pollution and meteorological elements on visibility in Shanghai, China; their results showed that air temperature and wind speed are positively correlated with visibility, while relative humidity is negatively correlated with visibility. Hong [25] studied the relationship between visibility and its influencing factors based on binary correlation and partial correlation methods.…”