A. It’s all about air flow!
Most air conditioner systems primarily recirculate indoor air without introducing that much air from the outside. Unfortunately, if viral particles are already inside the air-conditioned space, the particles continue to be recirculated, potentially infecting others.
One of the early case studies about air conditioning investigated an air-conditioned windowless restaurant in Guangzhou in which diners from 3 different tables became infected from a single patron. In that case, stagnant air, rather than air conditioning per se, was the bigger problem. In fact, in a room without windows running the air conditioning is possibly preferable considering that HVAC systems provide at least some ventilation and filtration. Thankfully, there’s not much evidence that the virus is traveling through HVAC systems in apartment buildings.
If you are already practicing good social distancing, the effects of air conditioning shouldn’t worry you. Your indoor time should already be limited to people who are within your household or pod. If you are going indoors to an air-conditioned store or workplace with other people, please wear a mask.
If you must share an indoor space with people outside your household or pod, consider ways to improve ventilation. Open doors and windows. Fans blowing in air from the outside can also help. Add or improve a filter on your HVAC system — the NYT blog linked below recommends MERV-12. Use a portable HEPA air purifier. Keep your distance and use the biggest room possible. It is particularly important that small spaces like bathrooms be well ventilated. Remember back in April when we posted about toilet plumes? Close that lid before you flush!
As with many Dear Pandemic posts, we will repeat our Stay SMART reminder: Space, Mask, Air, Restrict, and Time. The advice applies to spaces with and without air conditioning.
SPACE –> Keep your distance from people outside of your household, both in and out of air-conditioned spaces.
MASK –> Keep it on! If you need to enter an enclosed space with people outside your pod, please wear your mask and keep it on.
AIR –> Get as much airflow as possible. Windows and fans can help indoors, but outdoor options are preferred.
RESTRICT –> Stick with your household or pod as much as possible.
TIME –> Keep your time in shared spaces short.