Atmospheric BTEX and carbonyls during summer seasons of 2008–2010 in Beijing

The atmospheric concentrations of carbonyls and BTEX (benzene, toluene, ethylbenzene, m,p-xylene and o-xylene) were measured simultaneously in summers of Beijing from year 2008 to 2010. The total concentrations of formaldehyde, acetaldehyde and acetone in the consecutive summers, which were 33.4 μg m−3, 36.7 μg m−3 and 48.6 μg m−3, respectively, were much lower than those reported in the summers of 2005 (58.4 μg m−3) and 2006 (77.4 μg m−3). The concentrations of BTEX in the summers were 16 μg m−3, 21.5 μg m−3 and 15.4 μg m−3, respectively. The maximal contributions of photochemical reactions to atmospheric formaldehyde and acetaldehyde in the summers were estimated to be around 47.6–60.3%. The average ozone formation potentials (OFPs) for carbonyls and BTEX as well as carbon monoxide in summer of Beijing were calculated as 166.1 μg m−3, 65.4 μg m−3 and 100.8 μg m−3, respectively.