At present, China's particulate matter monitoring method adopts GB/T16157-1996 "Measurement of particulate matter in exhaust gas from fixed pollution sources and sampling methods for gaseous pollutants". In the case of low particulate matter concentration and high flue gas humidity, this method is prone to inaccurate monitoring results, mainly due to:

(1) The particles deposited in the sampling nozzle and the front section of the sampling tube cannot be recovered, resulting in low results;

(2) Long term sampling under wet flue gas conditions can easily cause fiber loss or damage to the filter cartridge, resulting in reduced accuracy in particulate matter sampling.

To address these issues and meet the monitoring needs of current pollution source emissions, it is necessary to develop the standard for the determination of low concentration particulate matter in fixed pollution source exhaust gas using the gravimetric method.