1. Agrawal S, Kim H, Lee Y, Sohn J, Lee J, Kim Y (2010) Effect of an air cleaner with electrostatic filter on the removal of airborne house dust mite allergens. Yonsei Med J 51:918-923
2. American Conference of Governmental Industrial Hygienists (ACGIH) (1999) In: Macher J, Ammann HA, Milton DK, Burge HA, Morey PR (Eds.), Bioaerosols: Assessment and Control. American Conference of Governmental Industrial Hygienist, Cincinnati, Ohio
3. Airkorea (2016) Available at: http://www.airkorea.or.kr/
4. Almeida SM, Canha N, Silva A, Freitas MD, Pegas P, Alves C, Evtyugina M, Pio CA (2011) Children exposure to atmospheric particles in indoor of Lisbon primary schools. Atmos Environ 45:7594–7599
5. ANSI/ASHRAE (2004) Ventilation for acceptable indoor air quality, American Society of Heating, Refrigerating and Air-Conditioning Engineers, INC, 1791 Tullie Circle NE, Atlanta, GA 30329. http://isites.harvard.edu/fs/docs/icb.topic256760.files/62_1_2004.pdf . Accessed 1 March 2016