Morawska, L. Ayoko, G. A. Bae, G. N. Buonanno, G. Chao, C. Y. H. Clifford, S. Fu, S. C. Hanninen, O. He, C. Isaxon, C. Mazaheri, M. Salthammer, T. Waring, M. S. Wierzbicka, A. 2024-01-20T00:04:26Z 2024-01-20T00:04:26Z 2021-09-03 2017-11 0160-4120 https://pubs.kist.re.kr/handle/201004/122125 It has been shown that the exposure to airborne particulate matter is one of the most significant environmental risks people face. Since indoor environment is where people spend the majority of time, in order to protect against this risk, the origin of the particles needs to be understood: do they come from indoor, outdoor sources or both? Further, this question needs to be answered separately for each of the PM mass/number size fractions, as they originate from different sources. Numerous studies have been conducted for specific indoor environments or under specific setting. Here our aim was to go beyond the specifics of individual studies, and to explore, based on pooled data from the literature, whether there are generalizable trends in routes of exposure at homes, schools and day cares, offices and aged care facilities. To do this, we quantified the overall 24 h and occupancy weighted means of PM10, PM2.5 and PN -particle number concentration. Based on this, we developed a summary of the indoor versus outdoor origin of indoor particles and compared the means to the WHO guidelines (for PM10 and PM2.5) and to the typical levels reported for urban environments (PN). We showed that the main origins of particle metrics differ from one type of indoor environment to another. For homes, outdoor air is the main origin of PM10 and PM2.5 but PN originate from indoor sources; for schools and day cares, outdoor air is the source of PN while PM10 and PM2.5 have indoor sources; and for offices, outdoor air is the source of all three particle size fractions. While each individual building is different, leading to differences in exposure and ideally necessitating its own assessment (which is very rarely done), our findings point to the existence of generalizable trends for the main types of indoor environments where people spend time, and therefore to the type of prevention measures which need to be considered in general for these environments. English PERGAMON-ELSEVIER SCIENCE LTD AIR EXCHANGE-RATES SECONDARY ORGANIC AEROSOL ULTRAFINE PARTICLES PARTICULATE MATTER VENTILATION STRATEGIES SOURCE APPORTIONMENT SIZE DISTRIBUTIONS DEPOSITION RATES AMBIENT OUTDOOR Airborne particles in indoor environment of homes, schools, offices and aged care facilities: The main routes of exposure Article 10.1016/j.envint.2017.07.025 1 ENVIRONMENT INTERNATIONAL, v.108, pp.75 - 83 ENVIRONMENT INTERNATIONAL 108 75 83 scie scopus 000411604400008 2-s2.0-85026885239 Environmental Sciences Environmental Sciences & Ecology Review AIR EXCHANGE-RATES SECONDARY ORGANIC AEROSOL ULTRAFINE PARTICLES PARTICULATE MATTER VENTILATION STRATEGIES SOURCE APPORTIONMENT SIZE DISTRIBUTIONS DEPOSITION RATES AMBIENT OUTDOOR Indoor particulate matter Indoor aerosols Indoor ultrafine particles Home indoor particles School indoor particles Office indoor particles Child care indoor particles Aged care indoor particles