Breath of Fresh Air for Indoor Air Quality

The U.S. Centers for Disease Control and Prevention (CDC) has released updated guidance for building ventilation to help prevent indoor transmission of airborne viral particles such as SARS-CoV-2 and influenza. In a related action, the American Society of Heating, Refrigerating and Air-Conditioning Engineers has released a first draft of ASHRAE Standard 241P, Control of Infectious Aerosols. Both actions are considered to be significant public health protection measures.

The CDC guidance includes recommendations to upgrade heating, ventilation and air conditioning (HVAC) filters to a minimum efficiency report value (MERV) of 13 or better and a goal of five air changes per hour. Other suggestions include keeping fans in the “on” position, adding as much fresh air as possible, and using properly sized air cleaners, ultraviolet air treatment systems and carbon dioxide monitoring systems.  The ASHRAE standard outlines minimum requirements for HVAC systems to reduce contagious disease exposure risk in homes and commercial and public buildings.

Indoor air quality experts say older buildings in the U.S. were constructed to meet minimal air-quality standards and that the recommended measures will help reduce the spread of disease and minimize exposure to particles that can trigger asthma and cause allergy symptoms.