Indoor Air Quality

US EPA Guidance for Air Cleaners In The Home

In 2018, the U.S. EPA updated and substantially revised the national guidance for air cleaners in the home.

Homeowners and apartment dwellers will find the consumer guide useful when selecting and air cleaner to help reduce health risks that come from airborne infectious viruses, wildfire smoke and drifting particulate nearby highways and farm fields.

Professionals will find the technical guide helpful to understanding the technical basis for the recommendations in the consumer guide. The is publication also provides a complete list of the peer-reviewed field and lab studies that support the EPA’s guidance to consumers. The information remains current as of September 2022.

Journal Article Summarizing ASHRAE and EPA IAQ Guidance

As the largest global technical society that is concerned with indoor air quality, ASHRAE has published useful guidance to help professionals and building owners make cost-effective decisions that can measurably improve indoor air quality.

Also, although US Environmental Protection Agency (EPA) is given regulatory authority for maintaining and improving the quality of outdoor air in the US, the organization also monitors and encourages (but does not regulate) state-of-the-art improvements in the quality on the indoor air, since that is where most people spend 90 to 95% of their lives.

This ASHRAE Journal article provides a brief summary of both EPA and ASHRAE guidance for indor air, following the 2018 update to EPA’s Air Cleaner guidance. The information remains current as of September 2022.

Selecting Air Filters for Ventilation And Makeup Air

It’s no secret that in many locations, the outdoor air is not always “clean and fresh.” But there are still very important reasons to ventilate buildings with outdoor air. Lots of nasty pollutants are generated indoors by normal activities of people, by outgassing from materials and by interactions between airborne compounds and normal airborne oxidants and ultraviolet energy. Also, when polluted air is exhausted—as from toilets and kitchen cook tops—outdoor air must be brought into the building to replace it (sometimes called “makeup air”).

This article explains what levels of filtration (which MERV ratings) will be appropriate for incoming outdoor air in different locations throughout the world—when one would like to reduce the fine particle concentration of that incoming air (PM 2.5) to levels that—in the US—are seen as acceptable for long term exposure.