1.1 This standard (Part XV) covers method for the continuous recording of the mass concentration of particulate matter of known characteristics in the atmosphere in the size range of about 0·05 to 40 υm in diameter. Measurement is based on the light-scattering property of microscopic size solid or liquid particles dispersed in a gaseous medium. The method is specifically used in special situations, such as performance evaluation or atmospheric sampling in special cases. It is used for determination of acid mist or fly ash.
1.2 The maximum range of concentration measured by means of this method is equivalent to 1 to 100 000 υg of particulate matter per cubic metre of air. Calibration within closer concentration limits will permit full-scale readings covering more narrow concentration ranges, thereby increasing the sensitivity of the test over the specific range being measured. The full range of concentration measurable by this method is equivalent to an estimated atmospheric visibility range from 1 500 km to 15 m.
1.3 The mass concentration is strictly proportional to the scattered light intensity only when the particle size, shape, etc, remain constant (see Note under 10.3). For information relative to meteorological and topographical factors affecting the application of this method, reference shall be made to IS : 5182 ( Part XIV )*.
IS 5182 Pt.15-1974 history
1975IS 5182 Pt.15-1974 Air pollution measurement methods Part XV Mass concentration of particulate matter in the atmosphere