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Don Oltmann's avatar

So, how can you know if have good ventilation? A CO2 meter will tell you this! CO2 from exhaling builds up in the air. Ambient air is 420 ppm (should be 280, but fossil fuels...) Great ventilation is 600 or lower. Good up to 800. Acceptable up to 1000.

I have an Aranet4. It fits in your pocket. Runs for a year on 2 AA batteries. Has app that connects to your phone via Bluetooth.

Some things I've found... my local supermarkets runs 800-1000 depending on the crowd. Big box home improvement stores about 600. Hotels... 1000-2000 in the rooms, but those aren't "shared air". Airports - 600s in common area like security, 900s in gate lounges. On plane >1000 - but this air is 100% HEPA filtered.

Home HVAC systems rarely have any external ventilation - beware! Your house may have the lowest air quality of anywhere you go.

An cheap DIY alternative to a portables HEPA filter is the Corsi-Rosenthal box. You can make one our of a box fan, MERV 13 furnace filters and duct tape. Higher clean air delivery than many portable HEPA filters. Google it and you'll find tons of instructions and videos.

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Don Oltmann's avatar

We can all thank the "aerosol warriors" for finally winning this battle. They had a hard, upstream battle before the medical community accepted what these engineers knew.

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