Feb. 2019, Volume 13 Issue 1
Exposure to ambient PM2.5
and its constituents has led to millions of premature death globally. The exposure mainly occurs indoors where people spend over 80% of their time. To better understand health effects of PM2.5
and control indoor PM2.5
exposure, the first step is to accurately characterize indoor PM2.5
and constituents concentrations of outdoor origin. This feature article addresses this from both modeling and measurement perspectives. The key factors in models are air exchange rate, particle penetration factor, and deposition rate. A meta-analysis of measurement data in the past decade shows that sulfate could trace non-volatile species (EC, Fe, Cu, and Mn) and even PM2.5
itself. The indoor-outdoor relationships of semi-volatile species (nitrate, ammonium, and organics) are more complex than those of non-volatile species, especially organics. Future studies on this issue are suggested to help constructing healthy buildings.
(see: Cong Liu & Yinping Zhang, 2019, 13(1): 5)