Preliminary study of the determination of ambient carbonyls in Xalapa City, Veracruz, Mexico

A preliminary study of ambient carbonyls was performed in Xalapa City to measure carbonyls in the atmosphere of this City, because it has an explosive increase in population and traffic density, but few industries. The city is located at the eastern flanks of the Sierra Madre Oriental, between 1350 and 1550m above sea level. Acetone was the most abundant carbonyl in June, followed by formaldehyde and acetaldehyde, whereas acetaldehyde was the most abundant one in November. Higher concentrations were observed in autumn than in spring, probably due to stagnation conditions in autumn and heavy rains from late spring to early autumn. The very high concentrations of acetaldehyde found in November could have been caused by an accidental leak or spill from a truck, since no stationary sources were identified and acetaldehyde concentrations steeply rose and constantly decreased after Few days. Moreover, a highly transited highway traverses Xalapa. The most important ozone and carbon monoxide concentrations were below the Mexican Air Quality Standards; 216 mug m(-3) (0.11 ppm) for 1 h average and 12.6 mg m(-3) (11 ppm) for 8 h moving average, respectively. The low concentrations of the main carbonyls, compared with the values reported for other urban areas, and of carbon monoxide, seem to indicate that air quality is still satisfactory in Xalapa City. (C) 2001 Elsevier Science Ltd. All rights reserved.