Songjun Guo

Carbonyl compounds and BTEX in the special rooms of hospital in Guangzhou, China

The occurrence of carbonyl compounds and benzene, toluene, ethylbenzene and xylenes (BTEXs) was assessed in the indoor and outdoor air of a hospital in Guangzhou, China. The pharmacy room, the preparing traditional Chinese medicine room, the supply room (where the medical appliances are disinfected), the laundry and the garbage room were selected as sampling sites. Acetaldehyde (ranging from 4.56 to 66.8 microg m(-3)) was in all samples the most abundant among the 18 carbonyls detected, and toluene (ranging from 33.5 to 264 microg m(-3)) among the BTEXs. The indoor/outdoor (I/O) concentration ratios of BTEXs in the morning were always >1.0, and close to 1.0 or slightly <1.0 in the afternoon, while the concentration ratios of carbonyls in the afternoon showed large variation. These ratios demonstrate the significance of outdoor emissions that deteriorate the indoor air quality at the various rooms of the hospital. The possible sources of BTEXs and carbonyls in these rooms are discussed with the use of specific ratios and with the use of statistical methods, like principal components analysis.

Characteristics of atmospheric non-methane hydrocarbons during haze episode in Beijing, China

This study firstly focused on non-methane hydrocarbons (NMHCs) during three successive days with haze episode (16–18 August 2006) in Beijing. Concentrations of alkanes, alkenes, aromatic hydrocarbons, and ethyne all peaked at traffic rush hour, implying vehicular emission; and alkanes also peaked at non-traffic rush hour in the daytime, implying additional source. Especially, alkanes and aromatics clearly showed higher levels in the nighttime than that in the daytime, implying their active photochemical reactions in the daytime. Correlation coefficients (R2) showed that propane, n-butane, i-butane, ethene, propene, and benzene correlated with ethyne (R2 = 0.61–0.66), suggesting that their main source is vehicular emission; 2-methylpentane and n-hexane correlated with i-pentane (R2 = 0.61–0.64), suggesting that gasoline evaporation is their main source; and ethylbezene, m-/p-xylene, and o-xylene correlated with toluene (R2 = 0.60–0.79), suggesting that their main source is similar to that of toluene (e.g., solvent usage). The R2 of ethyne, i-pentane, and toluene with total NMHCs were 0.58, 0.76, and 0.60, respectively, indicating that ambient hydrocarbons are associated with vehicular emission, gasoline evaporation, and solvent usage. The sources of other hydrocarbons (e.g., ethane) might be natural gas leakage, biogenic emission, or long-range transport of air pollutants. Measured higher mean B/T ratio (0.78 ± 0.27) was caused by the more intensive photochemical activity of toluene than benzene, still indicating the dominant emission from vehicles.