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Comment by throw0101c | Hacker News Reader

In 2023 there was a conference about Chemistry of Indoor Environments (CIE) that looked at the research that was done over a ten-year period; opening presentation:

* https://www.youtube.com/watch?v=vt0GLbi20Q4

* https://indoorchem.org/publications/

Playlist of the various presentations from the conference:

* https://www.youtube.com/watch?v=J2iHOCI2hz4&list=PLsc2-5fAgM...

Generally: avoid any use of electronics to 'do stuff' to the air or pathogens (e.g. UV) and just use high-MERV / HEPA filters, and use an ERV to vent stale air and bring in (filtered, conditioned) outside air.

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Even HEPA isn’t a requirement, you just need a high CADR. Doesn’t matter if the filter doesn’t catch a particle on the first pass as long as it does one a subsequent one and the flow rate is high!

Yeah the whole 'just use HEPA' has been what's worked for us after about a half dozen different air purifiers of experimentation. I noticed the positive ionization things changed my heart rate variability which was spooky.

Empirically, the ionizer is good for wildfire season, but the rest of the year HEPA is good.

> Empirically, the ionizer is good for wildfire season, but the rest of the year HEPA is good.

Smoke can be dealt with via a carbon filter and you don't have to do a chemistry experiment in your house.

* https://shop.aprilaire.com/search?q=Carbon+Air+Filter

Empirically, no it doesn't, at least not for the quantities of smoke we get in wildfire season. It's probably enough for most "abandoned industry on fire again" fires, if that's all you get?

Per the EPA:

> Upgrading to a filter rated MERV 13 or higher can be especially important during smoky periods to effectively remove fine particle pollution from smoke in the indoor air.

* https://www.epa.gov/wildfire-smoke-course/preparing-fire-sea...

The carbon is for the smell. The EPA also points to this California list, which include "mechanical" types which do not use electronic measures:

* https://ww2.arb.ca.gov/list-carb-certified-air-cleaning-devi...

The main challenge is the resistance to airflow (US: inches w.c.) that can be a problem with for HVAC equipment, which is why you want a large surface area, e.g.:

* https://electronicaircleaners.com/docs/aprilaire_2416_2216_a...

* https://www.aprilaire.com/whole-house-products/air-purifiers...

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