Προηγουμένως, με τον συνεχή ομίχλη σε πολλά μέρη της χώρας, το "PM2.5" έχει γίνει η πιο καυτή λέξη στη λαϊκή επιστήμη. The main reason for the “explosion” of the PM2.5 value this time is the large emissions of sulfur dioxide, nitrogen oxides and dust caused by coal burning. As one of the current sources of PM2.5 pollution, the exhaust gas emissions of coal-fired boilers are very prominent. Among them, sulfur dioxide accounts for 44%, nitrogen oxides account for 30%, and industrial dust and smoke dust together account for 26%. The treatment of PM2.5 is mainly industrial desulfurization and denitrification. On the one hand, the gas itself will pollute the atmosphere, and on the other hand, the aerosol formed by nitrogen oxides is an important source of PM2.5.