Air Purification Versus Air Ventilation

Air Quality Management

Everyone wants to breathe clean air. Unfortunately, pollution is everywhere, even indoors. All building structures can harbor airborne impurities like dust, dander, odors, and allergens. Different industries carry their own set of indoor air pollution problems. For example, manufacturing establishments have the added risk of chemical and other harmful emissions. In any enclosed space where people are present – be it a hospital, airport, school, or office – bacteria and viruses present a threat of transmission. All these scenarios of poor IAQ are why indoor air cleaning products were invented.

The EPA states (1) that there are three basic strategies in combatting poor IAQ: Source Control, Ventilation, and Air Cleaning.

Source Control is the removal of emissions at the source of the pollution, but before they can enter someone’s breathing space. This is accomplished by manually cleaning an area or using specialized equipment.

Ventilation uses mechanical or natural means to remove stale air, exhaust it outside, and replace it with fresh outdoor air.

Air Cleaning uses specialized equipment to run air through a filter to extract pollutants and recirculate fresh air.

Both Source Control and Air Cleaning capture dirty air, remove contaminants, and then distribute clean air back into the indoor environment, making these two options preferable in many situations.

Recirculating vs Exhaust Systems

Clean air and ventilation in tandem are critical to maintaining a healthy IAQ. A naturally clean IAQ has minimal contaminants and a proper baseline of ventilation such as open windows and doors. But as long as humans enter and exit buildings and live and work within them, more will need to be done to promote good health for a building’s occupants.

Air Purification, or Recirculation, removes airborne contaminants through filtration and then recirculates newly cleaned air within the building environment.

Air Ventilation, or an Outside Exhaust System, exchanges indoor air with outdoor air before ushering it back inside the building.

In other words, an air purifier removes contaminants and a ventilation system dilutes them.

How They Work

Purification and ventilation are often confused as interchangeable but have different impacts and considerations that make them distinct.

Let’s begin with air purification.  An air purifier (or source capture machine) is a portable unit that collects undesirable particles from a specific room and uses a powerful internal fan to push the contaminants through a filter (such as HEPA) and redistribute them back into the room.  This process is repeated several times an hour, continually refreshing the quality of the indoor air.

An outdoor exhaust system, by contrast, draws air through its intake vent. The collected air runs through a filter, trapping contaminants. The cleaned air is sent outdoors where it is mixed with outside air and then vented back inside.

Pros and Cons

While both air purification and air ventilation contribute to improved IAQ, they serve distinct purposes and are often used in tandem to create the healthiest possible indoor environment.

Consider the following:

Exhaust Systems require cutting holes in the roof or walls and usually require one or more building permits to do the work.

Recirculating Air Cleaners do not usually require any retrofitting to existing walls or roofing.

With Exhaust Systems, cooled, heated, and ducted air can escape in the exchange which reduces overall efficacy and will increase costs to a building’s owner.

With Recirculating Air Cleaners, no air is lost in a ducted transfer. All air remains indoors.

Exhaust Systems are installed for use in large areas, or entire buildings.

Recirculating Air Cleaners are flexible mobile devices that are well-suited to a specific room or workspace.

Which System is Right for You?

While Exhaust Systems clean and expel filtered air away from a person’s breathing space and then vent it outdoors, Recirculating Air Cleaners are particularly effective in spaces where a consistently controlled indoor climate is important or where external venting is impractical. In these cases, our Extract-All® SP-800 Portable Fume Extractor is ideal. It specializes in direct source capture and filtration of airborne contaminants such as welding fumes, paint overspray, and dust particulates from powder-mixes.

For over thirty years, AIRSInc has provided top-quality products for our customers’ air cleaning needs. Our skilled and experienced indoor air quality specialists can meet with you to discuss your specific IAQ application and provide a free air quality assessment. Contact us today to make an appointment.