CORRELACIÓN PAN-O3 EN EL SUROESTE DE LA CIUDAD DE MÉXICO

Abstract

Peroxyacetyl nitrate (PAN) and NO 2 (true) were measured during two short campaigns in June and October, 2017 with a gas chromatography-luminol detection method in southwest Mexico City. The maximum and total hourly mixing ratio measured averages of PAN were 5.2 and 1.3 ppb v in June and 3.3 and 0.6 ppb v in October, respectively, being these values slightly lower than those reported in 2003 suggesting that PAN precursor levels have only partially decreased during the last 15 years. PAN hourly averages of the two campaigns were correlated with O 3 , NO 2 (by chemiluminescence), solar radiation, temperature, and wind speed measured in the same monitoring site in order to obtain a combined empirical model (CEM) for the diagnosis of PAN concentrations for other periods of the year. The resulting CEM was integrated with several multiple linear correlations which are applied depending on the period of the day and the ambient temperature. The correlation between both, the simulated and measured PAN resulted in a coefficient R 2 = 0.87. The CEM was applied to records of the above mentioned variables measured at the Centro de Ciencias de la Atmosfera monitoring station at Ciudad Universitaria for the 2017 ozone season. A positive temperature dependent correlation was obtained between PAN and ozone, but the correlation was weaker as ambient temperature exceeded the 20 oC.