Ambient Air quality Monitoring Guidlines. - Maharashtra Pollution ...

1. AIR SAMPLING – GASEOUS
1.0 TITLE
Method for Air Sampling - Gaseous.
2.0 PURPOSE
The purpose is to lay down a uniform and reliable method for the sampling of
gaseous pollutants.
3.0 PRINCIPLE
For determination of concentration of gaseous pollutant in air, it is necessary to
obtain representative samples of air at a number of strategic points. The
concentrations are likely to vary with time and distance from the source of
pollution depending upon the nature of release, meteorological factors and local
conditions such as topography and presence of buildings and vegetation. The
measured concentrations are also known to depend upon the average time
namely, the period of sampling. These aspects are required to be taken into
account for sampling and interpretation of the measured values.
4.0 SCOPE
This method of sampling is applicable to the gaseous pollutants in the air such as
oxides of nitrogen and sulphur, ozone and other pollutants, which react with
liquid absorbing reagents at atmospheric temperature and pressure when air is
bubbled through the absorbing solution in the impinger.
5.0 INTERFERENCES
The interferences are governed by the following factors.
5.1 Chemical changes such as chemical interactions among the components of the
collected sample or photochemical decomposition.
5.2 Adsorption of the gases from the sample on to the walls of the container and
leaks
5.3 The interval between collection and analysis of samples as short as possible,
protect the samples from light and heat.
6.0 SAMPLE PRESERVATION
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