Influences of characteristic meteorological conditions on atmospheric carbonyls in Beijing, China

Abstract

Atmospheric pollutants are controlled not only by their production rates but also by meteorological conditions. The influences of dust storm, sauna weather (haze with high temperature and high humidity), wet precipitation and wind speed on atmospheric carbonyls in Beijing were investigated. During a severe dust episode (April 17, 2006), the mixing ratios of carbonyls were significantly elevated to 13-27 ppbV from 7 to 13 ppbV in the previous non-dust days (April 15 and 16) with the increasing extents of 38-154%. The accumulating effect and the lower photolysis rate in the dust day may be responsible for the increases of carbonyls' levels. Additionally, the contribution from heterogeneous reactions occurring on dust particles to formaldehyde and acetaldehyde cannot be ruled out. During the period of typical sauna weather, the concentrations of atmospheric carbonyls increased to 18-60 ppbV from 10 to 17 ppbV before the sauna days. The air mass over Beijing during the sauna days was controlled by a subtropical anticyclone and the boundary layer became quite stable, which was beneficial to the rapid accumulation of air pollutants including carbonyls. Wet precipitation was found to be an effective removal process to the atmospheric carbonyls. After one-hour of rain in summer, the total concentrations of atmospheric carbonyls decreased to less than half of that before the rainfall. The similar temporal varying patterns of carbonyls and inorganic ions in rainwater indicated that carbonyls were mainly washed out from the atmosphere into rainwater as inorganic ions were. Strong wind could evidently dilute atmospheric carbonyls and a negative correlation was found between wind speeds and the concentrations of carbonyls in spring in Beijing.

Pollution Characteristic of Atmospheric Carbonyls during One Haze Event in Nanning, South China

“…Meteorology can affect air components and has been recognized as being associated with the worst air pollutant episodes (Kang et al, 2004;Sun et al, 2006;Pang et al, 2009;Guo et al, 2011). Fig.…”

“…Weather conditions are crucial for the distribution of carbonyls (Pang et al, 2009). Nanning is surrounded by mountains on the east and west.…”

“…In particular, meteorological conditions significantly influence the distributions of atmospheric carbonyls, such as temperature, wind speed, and solar irradiation (Pang et al, 2009).…”

Seasonal and Diurnal Characteristics of Carbonyls in Urban Air in Qinzhou, China

“…Ambient carbonyl levels are influenced by multiple factors such as direct emissions, photochemical process (Moussa et al, 2006;Pang and Mu, 2006;Cerón et al, 2007;Pang et al, 2009;Pang and Lee, 2010;Duan et al, 2012), and metrological conditions (Ho et al, 2002;Pang and Mu, 2006;Pang et al, 2009). To estimate the possible impacts from these factors, seasonal and diurnal variations of carbonyls in Qinzhou are presented in Table 5.…”

“…Studies have been performed to evaluate carbonyls' levels and sources (Kean et al, 2001;Seco et al, 2007;Pal et al, 2008), distributions (Moussa et al, 2006;Cerón et al, 2007;Pang et al, 2009), photochemical formations (Wiedinmyer et al, 2001;Duane et al, 2002;Guo et al, 2013), health risks (Cavalcante et al, 2006;Noisel et al, 2007;Weng et al, 2009), and analytical approaches (Guo et al, 2007;Kim and Pal, 2010;Ho et al, 2011;Pang et al, 2011;Saha et al, 2012;Xie et al, 2013). However in China, investigation on carbonyls in developing regions (e.g., in Guangxi) is very limited due to the poor economic capabilities compared to economically developed regions (Feng et al, 2005;Duan et al, 2008;Lü et al, 2010;Guo et al, 2011;Zhang et al, 2012), resulting in that our current knowledge of carbonyls remains weak in these developing regions.…”