The carbon components in indoor and outdoor PM2.5 in winter of Tianjin

To study the carbon components in indoor and outdoor PM 2.5 , the samples of PM 2.5 were collected from Nankai University in December 2015. The contents of eight carbon components were analyzed to use the thermo-optical reflection method. The results indicated that organic carbon (OC) mass concentration was 17.01, 19.48 and 18.92 µg/m 3 in outdoor, dormitory and laboratory; elemental carbon (EC) mass concentration was 7.97, 3.56 and 3.53 µg/m 3 in outdoor, dormitory and laboratory; and the total carbon aerosol was the proportion of more than 23% of PM 2.5 samples. Lower wind speed and higher relative humidity were helpful to the accumulation of PM 2.5 . The ratio of OC/EC was > 2, and the SOC/OC ratio was > 30%, indicating that SOC was a crucial component indoors and outdoors. About 72% and 85% of the outdoor OC entering dormitory and laboratory environment, and about 59% and 71% of the outdoor EC entering dormitory and laboratory environment. Factor analysis of the eight carbon fractions indicated that the sources of OC and EC in outdoor, dormitory and laboratory is different.