GLOBAL ATMOSPHERIC WATCH ACTIVITIES IN MALAYSIA

THE MONITORING PROGRAMME AT THE GAW STATION IN TANAH RATA

The monitoring programme at the Tanah Rata GAW station includes the following parameters:

- Rainwater chemical composition
- Reactive gases
- Aerosol load and chemical composition
- Surface ozone 
- Meteorology

1. Rainwater Chemical Composition

Precipitation chemistry is the simplest way to obtain an indication of pollution in the lower atmosphere. In essence, air pollutants are scavenged by the precipitation process and delivered to the surface in the rain. In the early part of the century, acidity of precipitation was of major concern in Europe and North America but in recent times the concern has now spread to many regions of the world, especially Asia. Economic development and population growth in developing countries are identified as the main factors contributing to increased emissions and deposition of acidic pollutants. This acidity was known to have adverse effects on terrestrial and aquatic environments, ranging from acidification of soils and inland waters (causing vegetation decline and fish kills) to the damage of buildings and monuments. There is also increasing recognition that the nitrogen nutrients delivered to the surface by precipitation may contribute significantly to the over-enrichment of ecosystems and especially to the eutrophication of coastal waters.

The measurement of rainwater chemical composition at the GAW station in Tanah Rata is to evaluate regional contributions of selected chemical compounds in precipitation, to determine their spatial and temporal distributions, to assess the influence of human activities on the composition of the atmosphere and to improve knowledge of physico-chemical processes related to the atmospheric transport and deposition of acidic pollutants. 

Rainwater is collected using the Ecotech Wet-only Rainwater Sampler. This instrument consists of a tipping bucket precipitation gauge, collection funnel, sample bottles unit and solar panel as power unit. When the sensor detects precipitation, the lid covering the collection funnel opens and initiates sampling of rainwater. The collected rainwater is stored in bottles inside the instrument. The Tanah Rata Wet-only Rainwater Sampler is programmed to collect rainwater samples over a period of 7 days. The samples are sent to the Department of Chemistry for chemical analysis. 

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