According to a systemic review, portable air filters and cleaners are effective for reducing the concentration of indoor particulate matter by 40-82%. These findings are based on real-life situations instead of laboratory and occupational setting therefore, they give clearer concept of reducing indoor pollutants. Systemic reviews about the efficacy of portable air filters and cleaners are short term and included small number of participants. Most of the participants were healthy. Long term studies with consideration of susceptible population will prove more helpful.