Indoor PM_(2.5) and its chemical composition during a heavy haze-fog episode at Jinan, China

摘要

PM_(2.5) samples were collected in both a typical laboratory (indoors) and adjacent courtyard (outdoors) in Jinan, China from 12 January to 4 February 2013. The samples were analysed for 10 inorganic water-soluble ions, 14 elements and carbonaceous species to investigate their chemical characteristics and relationships with indoor and outdoor PM_(2.5) during a severe haze-fog (HF) episode and a normal (NHF) period. The average indoor and outdoor PM_(2.5) concentrations during the HF episode were 236 μg/m~3 and 409 μg/m~3, respectively, whereas the corresponding figures for the NHF period were 62 μg/m~3 and 87 μg/ m~3. The predominant component was (NH_4)_2SO_4, which accounted for 55.07% and 44.43% of the total measured species of indoor and outdoor PM_(2.5), respectively, in the HF episode, and 40.31% and 32.93%, respectively, in the NHF period. The indoor NH_4NO_3 level was significantly lower than the outdoor level due to volatility. The indoor and outdoor concentration ratios, infiltration rates, and indoor-generated concentration of PM_(2.5) and chemical compounds (SO_4~(2-), NO_3~- and EC) indicate that the aforementioned species had primarily outdoor sources, whereas NH_4~+ and OC and all the measured elements appear to have indoor sources, Cu in particular.