If there has been a sick person or someone who tested positive for COVID-19 in your facility within the last 24 hours, you should clean and disinfect the spaces they occupied immediately. Close off areas used by the person who is sick and do not use those areas until after cleaning and disinfecting. Do not deactivate central HVAC systems as these systems provide better filtration capabilities and introduce outdoor air into the areas that they serve. Call on a Remediation Contractor and make sure they use products from  the U.S. Environmental Protection Agency (EPA) List N according to the instructions on the product label.