Abstract:filtering loads of outdoor PM2.5 for all province capital of China are determined with the method of un-guarantee days. Filtering Concentration Days(FCD) is proposed with the analogy of the CDD and HDD. Based on PM2.5 concentrations dynamic data and the base concentration, the FCDs of all province capital are calculated. The relationship between FCD and the filtering load of outdoor PM2.5 is analyzed with a statistical way. The result shows: FCD is highly linear correlated with the filtering load of outdoor PM2.5 with P<0.01. And FCD can be used as the climatic indicator of the demand for filtering services. Besides it can provide a straightforward basis for the filtering system design.
