The pollution status of atmospheric carbonyls in a highly industrialized area.

The concentrations of 12 carbonyls in ambient air were measured from multiple locations of an urban area in the surroundings of a large industrial complex (August 2004 to September 2005). According to our field study, acetaldehyde (19.5+/-10.6 ppb) and formaldehyde (19.3+/-10.1 ppb) were found to be the two most abundant species followed by propionaldehyde (19.0+/-23.2 ppb), acetone (15.9+/-15.2 ppb) and butyraldehyde (13.0+/-19.8 ppb). An examination of spatial variation patterns of carbonyls, when compared between industrial sites versus non-industrial sites, indicates that the mean values for each site type are statistically insignificant in most cases. In contrast, a comparison of temporal variation patterns indicates a fairly distinctive trend with the relative enhancement during summer (over winter) and/or daytime (over nighttime). The computation of the concentration ratios between some indicative species (e.g., formaldehyde/acetaldehyde and acetaldehyde/propionaldehyde) is unique enough to describe the pollution status of carbonyl species in the study area. Moreover, the relative contribution of several offensive odorous components (e.g., acetaldehyde, propionaldehyde, and butyraldehyde) is fairly strong, while their emissions are suspected to come from a substantial use of ethanol. The results of the present study thus confirm that the acquisition of ambient carbonyl concentration data is fairly useful for distinguishing the pollution status and the associated odor-related impacts.