Diurnal variations of air pollution over metropolitan Manila

I. ISIDRO VALEROSO, C. A. MONTEVERDE, MARIANO A. ESTOQUE

Abstract

The diurnal variations of the concentrations of atmospheric pollutants in the Metropolitan Manila area is studied. The pollutants included in the study are SO2, CO, NO2, NO, HC, Ox and particulate matter. The data consist of hourly observations from five (5) monitoring stations at selected urban centers for the period covering 1975-1978. The results show two types of concentration variations exhibited by the pollutants depending upon whether they are photochemically reactive (N0x, SO2, HC and Ox) or non-photochemically reactive (CO and particulate matter). The variation corresponding to non-photochemically reactive pollutants show two maxima, one in the morning at 8:00 am and a secondary in the evening from 8:00-9:00 pm. However, the photochemically reactive pollutants exhibit only a single maximum at about noontime or early afternoon. The dependence of the diurnal variation with respect to the season has also been studied. In general, the trend of the variations for all pollutants are similar but the concentration of the pollutants is lower during the southwest monsoon season.

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