Ozone air pollution in Mendoza, Argentina

摘要

Observations of air quality are rather rare in Argentinal. The city of Mendoza is located in a semi-arid region at the eastern edge of the Cordilleres. In Mendoza the high concentration of ozone precursors and the strong solar radiation may contribute to high levels of summersmog. Series of continuous ambient tropospheric ozone, temperature and wind measurements were taken for a period of one year starting in November 1995 and analyzed in terms of diurnal and annual variation. Indications were found of the strong impact of the mountain-valley circulation system, which ventilates and considerably cleans the air in Mendoza. THe low level jet is mainly active during the summer. It lowers the peak mid-day ozone concentration and produces a temporary concentration increase at night. The WHO standard of 0.113 mg ozone/m~3 (56.5 ppb) is only rarely exceeded during winter. Thanks to the existing natural ventilation, ozone pollution is not expected to have any critical adverse health effects. Nevertheless, the elevated ozone concentrations during calm periods in winter highlight the necessity of reducing precursors from vehicle emissions. It is essential that the ventilation paths should be left open during future urban development.