URBAN AIR-POLLUTION IN BRAZIL - ACETALDEHYDE AND OTHER CARBONYLS

We have measured ambient levels of carbonyls in three major urban areas of Brazil: Sao Paulo, Rio de Janeiro and Salvador. The most abundant carbonyls were acetaldehyde (up to 63 μg m-3, or 35 ppb) followed by formaldehyde (up to 42 μg m-3, or 34 ppb), and acetone (up to 20 ppb). Levels of 10 other aliphatic and aromatic carbonyls were in the range 0-5 ppb. Total carbonyl concentrations were in the range 11-75 ppb. Indoor levels were also measured at several locations in Salvador. High levels of acetaldehyde, 430 μg m-3 or 240 ppb, were measured in a highway tunnel. Using carbonyl/CO concentration ratios, mobile source emissions of carbonyls are estimated for the Sao Paulo area. Ambient levels of acetaldehyde and acetaldehyde/formaldehyde concentration ratios in Brazil are compared to those for other urban areas, and are briefly discussed in relation with the large scale use of ethanol as a vehicle fuel. © 1989.