Effect of portable air purifier on indoor air quality: reduced exposure to particulate matter and health risk assessment

We sought to investigate the impact of air purifiers in the removal of particular matter (PM)(10), PM2.5, PM1, and particle number concentration (PNC) in the indoor air of dormitories located at Iran's largest medical university, Tehran University of Medical Sciences. Twelve rooms were selected and randomly assigned to two rooms: sham air purifier system deployed room (SR) and true air purifier system deployed room (TR). All study samples were drawn simultaneously from assigned rooms using portable GRIMM dust monitors for 24 h. The PM monitors of air were positioned in the middle of each room next to the air purifier at the height of the breathing zone (1.5 m in height). The mean PM10, PM2.5, PM1, and PNC removal efficiency in rooms with and without a smoker were measured to be 40.7 vs 83.8%, 31.2 vs 78.4%, 29.9 vs 72.3%, and 44.3 vs 75.6%, respectively. The results showed that smoking is an important influencing factor on the indoor air quality; smoking lowered the removal efficiency of PM10, PM2.5, PM1, and PNC by 43%, 47%, 43%, and 31%, respectively. An air purifier could decline the PM10 and PM2.5 even lower than the WHO 24-h guideline level in non-smoker rooms. This study revealed that using household air purifiers in rooms with smokers and non-smokers significantly reduces the non-carcinogenic risks of exposure to PM10 and PM2.5.