Evaluation of building characteristics in 27 dwellings in Denmark and the effect of using particle filtration units on PM_2.5 concentrations

Exposure to airborne particulate matter in homes is associated with the risk of cardiovascular diseases and respiratory problems. Due to the extended time people spend at home, reducing the particle concentration in homes may be a means to reduce the risk of cardiovascular diseases and respiratory problems. Use of particle filtration units (PFU´s) might be an effective way for rapid removal of indoor PM.In a randomised cross-over design, the custom built PFU´s ran for two weeks in each of two modes: with or without the inclusion of a HEPA filter.We assessed the association between the concentration levels of particulate matter and building characteristics; and the use of PFU as a way to effectively reduce the levels of PM2.5 indoors.The results obtained from the study have shown that a small room area, wooden floor material, or the use of gas for cooking is strongly associated with high PM2.5 mass concentrations. Furthermore, the winter period and a location farther from a trafficked street were associated with increased PM2.5 mass. Overall, the use of PFU led to a decrease in the concentrations of PM2.5 of 54.5% (median value). We assessed the PFU particle-removal efficiency by using the amount of infiltrated air, size of the controlled room and filtration effectivenes