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Rain Quality Monitoring in Metropolitan Manila Using an Automated Acid Rain Monitor

This report gives the results obtained in the monitoring of air quality in the Metropolis by the measurement of the quality of rain from 1998 to 2000. The Kimoto Acid Rain Monitor acquired by the Chemical Engineering Department through the DOST-ESEP Programme was used. The rain quality parameters measured by the said instrument are pH, conductivity, sulfate and nitrate. They are measured automatically by the monitor located at the roof deck of the STRC building located within DLSU compound. Five (5) sampling sites within Metro Manila were chosen. Sibata rain collectors acquired through DOST-ESEP programme were installed in Pasig, San Juan, Malabon, Muntinlupa, and inside the South Power Plant compound. Samples are collected, refrigerated and transported to the Environmental Engineering Laboratory for analysis using the monitor. At the same time, the monitor allows the continuous sampling and analysis of rain samples collected in STRC (Manila). Results obtained that for almost a year, rain samples collected are most of the time acidic with higher concentration of sulfates than nitrates. Rain samples collected from the Power Plant is more acidic than those collected away from the power plant. Rain pH is lower in the site nearer the power plant like Manila than the others. Acidic rain collected in Malabon may be attributed to the many industries located within its vicinity. At the same time, motor vehicles contribute to the acidification in the sites like San Juan, Pasig, and Muntinlupa. Wind transports pollutants like SOX from its source to these places that are affected by acidification. Meteorological data from PAGASA shows that wind movement taken from Science Garden in Quezon City has an average in 1999 of 1 m/s in the direction going to the north while from NAIA, it is 3 m/s East-Southeast and from the Port Area, it is 3 m/s West-Southwest. The results are important in the management of air quality. These data may be used in acid rain models that have been developed for the Asian region. At the same time, control of pollutants like SOX and NOX becomes significant to reduce the problem of acidification. Finally, the results should be verified by continuing monitoring of wet deposition but also dry deposition, effect of lakes and effect on soil vegetation.


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