Air quality thresholds for natural ventilation

Patty Karapinar

Associate, Director of Sustainability

Architectural Nexus

LEEDuser Basic Member

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November 21, 2019

Hello, what acceptable levels of air quality are you using to evaluate natural ventilation strategies for your projects? In our Living Building we only open windows when PM10, PM2.5, etc. are within LBC and WELL limits. In a seasonally smoggy urban environment, this limits how often we can utilize natural ventilation even if the outside temperatures are frequently within comfort range. However, I'm wondering if there is any consensus about what "healthy" air quality index levels are for natural building ventilation in general, or what levels others may be using and recommending for their projects.

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Luke Leung

Principal

Skidmore, Owings & Merrill LLP

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Thu, 11/21/2019 - 19:54

https://www.epa.gov/criteria-air-pollutants/naaqs-table The above EPA website quantifies ambient air quality, also referenced by ASHRAE. What gets more interesting is when compared to international codes: https://en.wikipedia.org/wiki/Ambient_air_quality_criteria

Patty Karapinar

Associate, Director of Sustainability

Architectural Nexus

LEEDuser Basic Member

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Fri, 11/22/2019 - 18:11

Thanks Luke. Are the EPA levels what your office generally uses as a threshold for natural ventilation or do you use a stricter threshold? We did research the EPA criteria and are also checking with the California Air Resources Board. Surprising that Wikipedia has this kind of information, thanks so much for bringing that to my attention. It will be a good basis of discussion with our client, compared to the WELL and LBC criteria for indoor air quality.

Luke Leung

Principal

Skidmore, Owings & Merrill LLP

LEEDuser Basic Member

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Mon, 11/25/2019 - 04:25

Great discussion! The ambient air quality changes with locations. Different US states, as mentioned above in California, e.g. the Particulate Matters (PM) are different than EPA. https://ww3.arb.ca.gov/research/aaqs/common-pollutants/pm/pm.htm Also, global standards are different, e.g. UN WHO has lower PM 2.5 requirements https://www.who.int/airpollution/publications/aqg2005/en/ Once it is indoor, EPA and WELL also address other contaminants, e.g. Radon. Some countries, e.g. Finland, are not "one size fits all" for air quality indoor, more vulnerable people (older, babies, sick...etc.) have high quality indoor air. https://pdfs.semanticscholar.org/b0d7/32599f21fe23f8d24f4c7d84704dad088701.pdf Yes, we do use the more stringent numbers, where realistically possible. It is interesting that we can not survive for 3 minutes with air, but the world does not agrees on what is as basic as "healthy" air, but we are working with international entities to come up with one.