Assessment of indoor air exposure among newborns and their mothers: Levels and sources of PM10, PM2.5 and ultrafine particles at 65 home environments

Significant efforts have been directed towards addressing the adverse health effects of atmospheric particles, emphasizing the relevance of indoor exposure. Homes represent an indoor environment where human spend the majority of their time. Thus, the objective of this work was to concurrently assess different matrix of indoor particles considering both mass (PM10, PM2.5) and number (N20-1000) concentrations in indoor and outdoor air of homes (n = 65). Real-time measurements (PM10, PM2.5, UFP) were conducted simultaneously during 48 h in dwellings situated in Oporto, Portugal. In 75% of homes, indoor PM2.5 (mean = 53 mu g m(-3)) exceeded limit of 25 mu g m(-3), for PM10 (mean = 57 mu g m(-3)) 41% of homes demonstrated average levels higher than 50 mu g m(-3), thus indicating potential risks. Indoor PK () was mostly (82-99%) composed of PM 2 . 5 , both PM were highly correlated (vertical bar rs vertical bar>0.9655), thus suggesting the similar origin. Indoor PM originated from infiltrations of outdoor emissions; similar to 70% of homes exhibited indoor to outdoor (I/O) ratio < 1. On the contrary, UFP indoors (mean = 13.3 x 10(3) # cm(-3)) were higher than outdoors (mean = 10.0 x 10(3) # cm(-3)). Indoor UFP spatially varied as follows: kitchens > living rooms > bedrooms. UFP indoors were poorly correlated (vertical bar rs vertical bar = 0.456) with outdoor concentrations, I/O ratios showed that indoor UFP predominantly originated from indoor emission sources (combustions). Therefore, in order to reduce exposure to UFP and protect public health, the primary concerns should be focused on controlling emissions from indoor sources. (C) 2020 Elsevier Ltd. All rights reserved.