Levels, sources and health risks of carbonyls and BTEX in the ambient air of Beijing, China
Abstract
The atmospheric concentrations of carbonyls and BTEX (benzene, toluene, ethylbenzene, m,p-xylene and o-xylene) were measured
simultaneously at a same sampling site in Beijing from September 2008 to August 2010. The average concentrations of the total
measured carbonyls during autumn, winter, spring, and summer were 37.7, 31.3, 39.7, 50.5 g/m3, respectively, and maximal values for
their diurnal variations usually happened at noontime. In contrast to carbonyls, the average concentrations of the total measured BTEX
during the four seasons were 27.2, 31.9, 23.2, 19.1 g/m3, respectively, and minimal values for their diurnal variations always occurred
in the early afternoon. The average concentration for carbonyls increased about 24% from September 2008–August 2009 to September
2009–August 2010, for BTEX, increased about 15%. Integrated life time cancer risks for three carcinogens (benzene, formaldehyde and
acetaldehyde) in Beijing exceeded the value of 1E-06, and the hazard quotient (HQ) of non-cancer risk of exposure to formaldehyde
exceeded unity.