Good ventilation (circulation of clean air) is an important part of preventing COVID-19 spread. 

Ventilation can be increased by opening doors and windows or proper use of a heating, ventilation, and cooling (HVAC) system. 

In certain situations where good ventilation isn’t possible, a portable air filter or purifier may also help to reduce COVID-19 spread. 

Increasing ventilation, when combined with other environmental measures like masking and limiting time in crowded indoor spaces can help reduce airborne exposure to contaminants including viruses.  Simple measures like opening windows and using fans can increase air circulation in your home.  Portable air cleaners can filter air in a single room where vulnerable people spend the most time, acting as a supplement to other control measures.  Be mindful of potential safety and health risks.

  • Don’t open windows if doing so creates a window fall risk for your child. Properly installed window guards can prevent such falls. If you live in New York City, landlords must install window guards in apartments with a child 10 or younger in buildings with three or more units or when requested regardless of building size. Window screens are not a substitute for window guards. Window Guard Tenant Factsheet: Are Your Window Guards Installed Safely 
  • Don’t open windows on poor air quality days, especially if doing so could trigger an asthma attack for you or your child.
  • When using fans, be sure that they are out of reach of small children. Make sure fans are stable so they don’t tip over and blades are completely shielded.

If you have central air conditioning or an HVAC system, consult with a professional about how to optimize air exchange and filtration.  Do not try to install a new filter or upgrade your system yourself. 

Some air filters or purifiers may be able to remove very small virus particles from the air, and may be effective in areas with poor ventilation and air exchange.  However there is little evidence for efficacy of portable air filters for reducing COVID transmission in homes, and they should not be used as a primary method of prevention. 

The best ways to reduce transmission of COVID and many other viruses are to remain physically distant from those not in your household, wear a mask, wash your hands for at least 20 seconds with soap and warm water, and safely disinfect high-touch surfaces (door knobs, light switches, etc).

Air purifiers can effectively remove indoor air pollutants like dust, pollen, and some gases. If you do choose to use an air purifier, choose one with a HEPA (High Efficiency Particulate Air) filter that is properly rated for the size of your space.. We do not recommend PECO or PCO filters or other emerging ionizing technologies as these have been shown to be less effective than HEPA filters at capturing Sars-CoV-2 (COVID viral) particles. In addition, some of these devices generate ozone which can irritate the lungs.


World Health Organization, Ventilation and airborne diseases.  [Accessed 22 April, 2020].

Atkinson J, Chartier Y, Pessoa-Silva CL, et al., editors. Natural Ventilation for Infection Control in Health-Care Settings. Geneva: World Health Organization; 2009. Annex C, Respiratory droplets. Available from:

Environmental Protection Agency, Will an air cleaner or air purifier help protect me and my family from COVID-19 in my home?.  [Accessed 28 May, 2020].