Indoor air quality, the quality of the air found inside and around buildings and structures, affects the health and comfort of those who spend a significant amount of time indoors.One primary reason why we should be concerned about indoor air quality is that pathogens can live and spread in areas of poor ventilation. An example of this is the SARS-CoV-2 virus, which causes COVID. Upgrading the ventilation and filtration of buildings was found to decrease COVID-19 transmission. This is a virus that spreads through the air almost exclusively indoors. If we start there, then the building matters,” says Joseph Allen, an associate professor at the Harvard T. H. Chan School of Public Health and director of its Healthy Buildings program.Improving indoor air quality also prevents the risk of infection from other air-borne viruses that cause influenza and other respiratory illnesses.

What is “Acceptable” Air Quality?

The current standards for “acceptable indoor air quality” in the United States are set by The American Society of Heating and Air-Conditioning Engineers (ASHRAE). For nonresidential buildings, acceptable indoor air quality is defined as “air in which there are no known contaminants at harmful concentrations, as determined by cognizant authorities, and with which a substantial majority (80 percent or more) of the people exposed do not express dissatisfaction.”Get more interesting details about air quality check out this site.

For residential buildings, acceptable indoor air quality is defined as “air toward which a substantial majority of occupants express no dissatisfaction with respect to odor and sensory irritation and in which there are not likely to be contaminants at concentrations that are known to pose a health risk. While these ASHRAE standards limit building occupant's exposure to harmful substances such as formaldehyde and other volatile organic compounds, they don't do anything to limit exposure to pathogens. Current minimum ventilation rates—alone—do not provide complete mitigation of airborne disease transmission risk,” said William P. Bahnfleth, chair of the ASHRAE Epidemic Task Force and a professor of architectural engineering at Pennsylvania State University in an interview with Scientific American.

Bahnfleth further said that transmission risk really can't be reduced to zero. Hence, vaccination, mask use, occupancy limits, proper ventilation, filtration, and air disinfection are still the most effective ways to minimize the risk of airborne viruses.

To improve indoor air quality, it's essential to strengthen the four main pillars: source control, ventilation, filtration, and disinfection.

Source Control

Regarding pathogens, source control prevents pathogens from entering the air. For example, someone exposed to COVID-19 should wear a high-quality mask or stay home until they have recovered.

Ventilation

Fresh air dilutes the concentration of virus-laden particles in indoor air. One of the best ways to improve the ventilation of a building is to invest in a good heating, ventilation, and air conditioning system (HVAC). An HVAC system allows a building manager to vary the amount of fresh air circulating.

Filtration

Filtration systems can remove particles and other pollutants from the air. If the building has an HVAC system, it can be fitted with a high-efficiency particulate air filter (HEPA). An alternative to an HVAC system with a HEPA filter for smaller buildings such as homes would be to have one or two portable air cleaners.

Air Disinfection

This involves inactivating viruses using ultraviolet lights. Air disinfection is mainly used for high-risk areas such as hospitals. As UV systems are expensive, homes and small businesses should focus on improving their ventilation and filtration capacities to improve their indoor air quality.