PM mass concentration variation in urban residential buildings during heating season in severe cold region of China: A case study in Harbin.

Recent years, people pay great attention to fine particle matter (PM) in indoor environment due to its negative impacts on health. Household cooking and severe air pollutant aggravate indoor PM level, especially during heating season in severe cold region of China. To find the variation of actual household PM influenced by both cooking activities and penetration from outdoor environment, a field measurement of PM concentrations in living room of residential buildings was conducted in Harbin, China. Firstly, six households in urban residence were selected to monitor the indoor PM mass concentration sequentially. Simultaneously, outdoor PM concentrations, temperature and indoor occupants' behavior were collected. Secondly, indoor to outdoor (I/O) ratios of PM in each household during monitoring campaigns were calculated. Influence of cooking activities and outdoor penetration on indoor PM concentrations in living room were also analyzed. Thirdly, some discussions were done for explanation of variation of PM in urban residential buildings. Results showed that the average PM mass concentrations varied from 11.7 to 48.6 μg/m indoor, while average I/O ratio value ranged from 0.33 to 1.23. Cooking in kitchen had significant impact on PM mass concentrations in living room, especially when frying, which could lead to peak value of 456.8 μg/m within 10 min from background level. Penetration led to the indoor PM level approximately 2 h behind with outdoor PM concentrations in general residences.