DIY Air Purification
Cheap, DIY tools for reducing PM2.5 concentrations during fire season

Table of Contents

Making a cheap air purifier


Affix the MERV 13 filter to the front of the fan (not behind). (source).

For positioning the air purifier, consensus seems to be to stay away from tight corners. Intuitively, you want the intake to be pointed toward dirty stuff. You also want the outake clean side to be pointing air toward a clear space, not toward a tight corner.

Ideally, you will want to leave all windows and doors closed (seal the house). You are trying to recirculate your own air multiple times.

Total cost: $30 per purifier.

Detecting air purity

The Temptop P10 will measure PM2.5 and estimate AQI based on that concentration.1 It's doesn't connect to the Internet.

Using your forced-air heating system

If you have a forced-air heating system in your house, you can turn it into a passive, 24/7 air filter.

First, find the intake. There will be a vent somewhere in your house, which feeds into a fan. Open that up and measure the opening.

For myself, I used a 14x30x1 MERV 13 filter. Just make sure to get the airflow direction right.

Finally, use your thermostat to turn the heat off, and instead run the fan.



AQI is typically computed across several types of pollutants; since this one only detects PM2.5, it's not really an AQI at all, but does convert the PM2.5 concentrations into a more familiar range of values.

Date: 2020-08-22 Sat 00:00

Author: ffff

Created: 2020-09-25 Fri 20:54