AROMATIC-HYDROCARBONS AND ALDEHYDES IN THE ATMOSPHERE OF GRENOBLE, FRANCE

Ambient levels and night and day profiles of aromatic hydrocarbons (be nzene, toluene, (m+p)xylene, o-xylene and ethyl benzene) and aldehydes (formaldehyde, acetaldehyde, n-butanal, n-pentanal, n-hexanal and ben zaldehyde) were measured in Grenoble, France, during a selected week f rom May, 4, 1995 to May, 11, 1995. Most abundant aromatic hydrocarbons observed were toluene (up to 3.5 ppbv), benzene and (m+p)-xylene (0-3 ppbv). Formaldehyde was the most abundant aldehyde with concentration s ranging from 2 to 18 ppbv followed by acetaldehyde with levels from 2 to 10 ppbv. Gas phase concentrations of four other aldehydes were in the range 0-2 ppbv. Results are discussed with respect to direct emis sions and photochemical production. Formaldehyde appears to come mainl y from exhaust car emissions but acetaldehyde from other primary sourc es. (C) 1998 Elsevier Science Ltd. All rights reserved.