Trends in ozone levels and identification of visible injuries on agricultural crops in areas in the Metropolitan Zone of Mexico Valley

摘要

Measurements of ozone concentrations were carried out in the ambient air of agricultural areas of the Metropolitan Zone of the Valley of Mexico.Meteorological parameters, processes of synoptic scale and the possible damage to the agricultural crops were related to the ozone levels measured. The project was carried out in two campaigns: the first was carried out in the agricultural areas of the Parres, Tlahuac and San Luis, Xochimilco, in the Federal District from August 9 to August 28 of 2002; and the second was carried out in Huixquilucan, located at Mexico State, during June and July of 2003. The measurements were performed by continuous analyzers, whose principle of operation is the UV-Photometry. In the first campaign (2002), the analysis of the data showed maximum 1-hour concentrations of ozone up to 175 ppb, 169 ppb, and 192.7 ppb in Tlahuac, San Luis Xochimilco, and Parres, respectively. During the second campaign (2003), the maximum average 1-hour ozone concentrations found in Huixquilucan during June and July, were up to 172 ppb and 213 ppb, respectively. It was demonstrated that in the study areas during 2002 and 2003, the 1-hour concentrations of ozone reached harmful values for the agricultural crops. In the agricultural areas of San Miguel de Topilejo, characteristic damages attributable to ozone were identified in potato and oat cultivations.