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Richard Corsi, PhD, PE (Texas) Profile picture
@CorsIAQ
Sep 19, 2020 • 5 tweets • 2 min read • Read on X
1/ A follow-up on gyms. A couple of months ago I modeled the volume of particles deposited in the respiratory system of those infected in an outbreak in Restaurant X in Guangzhou China with assumed infector emission profiles. More ...
2/ I then placed the infector from Restaurant X in different scenarios w/ ratio of volume deposited in new scenario to that of restaurant X. That ratio (omega) for a specific gym is shown in figure here. The vertical axis is omega for several ventilation/control scenarios. Image
3/ In this analysis, infector X is a staff member in the gym emitting aerosols that are well mixed into the gym. The receptor did 75 minutes of aerobic exercise w/ a heavy breathing rate (greater inhalation dose than if not doing aerobic exercise).
More ...
4/ The under-ventilated gym yields a situation worse than Restaurant X. Even w/ ventilation at ASHRAE 62.1 the volume (deposited) dose is higher than those infected in Guangzhou. Even w/ greater ventilation & controls the ratio is pretty high.
5/ Of course, the more people in the gym and higher the local infection rate the higher the probability that someone in the gym is infected. This analysis did not include an infector doing aerobics, too, which would have led to an even worse condition.

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More from @CorsIAQ

Richard Corsi, PhD, PE (Texas) Profile picture
Aug 7, 2024
Thread on the Corsi-Rosenthal Foundation

The Corsi-Rosenthal Foundation is a tax-exempt 501(c)3 nonprofit organization (EIN: 35-2779639). Our goal is to provide cleaner air in school & other public buildings with particular interest in underserved and/or vulnerable communities.
We do this largely through financial grants, materials, or a combination of the two to build Corsi-Rosenthal boxes (CR Boxes). The Corsi-Rosenthal Foundation is run by consensus of a Board of Directors.
All Board members are volunteers and receive no salary. As such, 100% of donations go directly to grantees for cleaning the air for their communities. No donations are used to purchase materials from companies affiliated with any Board members.
Read 6 tweets
Richard Corsi, PhD, PE (Texas) Profile picture
Jan 21, 2024
The "Sources" chapter of @theNASEM
report on "Health Risks of Indoor Exposure to Fine Particulate Matter & Practical Mitigation Solutions" is approx 60 pages and full of source-specific details. Check out the report here: (some highlights in thread)

nap.nationalacademies.org/catalog/27341/…
Sources considered:

(1) Ambient air (wide range of sources): penetration of fine PM from outdoor to indoor air

(2) Combustion processes: natural gas, propane, wood, oil, coal, candles, incense

Tobacco considered only for comparative purposes as much is already known/reported.
(3) Non-combustion heating processes: cooking, essential oil vaporizers, laser printers, e-cigarettes

Cooking is a very large source, whether heating w/ natural gas, propane, electric. Emissions specific to natural gas for cooking & other heating processes considered in (2)
Read 11 tweets
Richard Corsi, PhD, PE (Texas) Profile picture
Jan 21, 2024
The "Sources" chapter of @theNASEM report on "Health Risks of Indoor Exposure to Fine Particulate Matter & Practical Mitigation Solutions" is approx 60 pages and full of source-specific details. Check out the report here: 👇 (some highlights in thread)

nap.nationalacademies.org/catalog/27341/…
Sources considered:

(1) Ambient air (wide range of sources):
penetration of fine PM from outdoor to indoor air

(2) Combustion processes:
natural gas, propane, wood, oil, coal, candles, incense

Tobacco considered only for comparative purposes as much is already known/reported.
(3) Non-combustion heating processes:
cooking, essential oil vaporizers, laser printers, e-cigarettes …

Cooking is a very large source, whether heating w/ natural gas, propane, electric .. Emissions specific to natural gas for cooking & other heating processes considered in (2)
Read 12 tweets
Richard Corsi, PhD, PE (Texas) Profile picture
Jan 21, 2024
Why is indoor fine particulate matter important?

(Thread)

(1) Americans spend the vast majority of their time indoors. Prior to the pandemic, on average Americans lived to be 79 yo (now lower) & spend almost 70 of those years indoors, 54 years insides residences.
(2) Most fine particulate matter (particles with diameters of 2.5 microns or less) are inhaled indoors. This is true for fine particles of both indoor as well as outdoor origin. (more on sources of fine PM in a future tweet).
(3) There is ample evidence that exposure to fine particulate matter causes a range of adverse health effects (will summarize in a future tweet).
Read 6 tweets
Richard Corsi, PhD, PE (Texas) Profile picture
Jan 20, 2024
Five overarching conclusions of the new @NASEM report on "Health Risks of Indoor Exposure to Fine Particulate Matter" (thread)

(1) There is ample evidence that exposure to indoor PM2.5 causes adverse health effects
(2) Disparities in population exposure to indoor PM2.5 of both outdoor and indoor origin exist

(3) Technological advancements yield great potential for quantifying & reducing exposures
(4) Effective and practical mitigation of exposure to PM2.5 in homes/schools is currently possible

(5) A lack of centralized responsibility for indoor PM2.5 policy is hindering reductions in population exposure and health benefits at scale
Read 4 tweets
Richard Corsi, PhD, PE (Texas) Profile picture
Dec 16, 2023
1/ This CR Box (the one on the right!) has now totaled operational time equivalent to an entire in-classroom school year. Both it and its cohort of three other CR Boxes continue to perform with a high level of effectiveness across a wide range of particle sizes. Image
2/ Four CR Boxes were placed in different indoor settings on the UC Davis campus, from a relatively clean 4-person office suite w/ VCT flooring to a particle-challenged soils lab.
3/ Each CR Box consists of four 20" x 20" x 2" MERV-13 filters (3 boxes w/ filters from the same manufacturer and the 4th from a different manufacturer). A 20" x 20" box fan was used to draw air through each CR Box.
Read 20 tweets

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