Thread by @joeyfox85

Ventilation vs. Filtration vs. UVGI vs. Electronic Air Cleaning
What are they and what do they do?

Ventilation - Exchanging indoor air with outdoor air (slight oversimplification)

Filtration - passing air through a filter

1/7

Ultraviolet germicidal irradiation (UVGI) - kill or inactivate microorganisms with UV light.

Electronic Air Cleaning (EAC) - charge particles and discharge them into the space.

2/7

They all do different things with different types of indoor pollutants. There are many pollutants, but I'll deal with 3 types:

Gasses - carbon dioxide, carbon monoxide, radon
Particulate Matter (PM) - dust, smoke, pollen
Microbes (type of PM) - Viruses, Bacteria, Mold

3/7

VENTILATION

It removes indoor gasses, microbes and particulate matter. Mechanical ventilation includes filtration. Natural ventilation (eg. windows) doesn't have filtration and could bring in outdoor pollution.

4/7

FILTRATION

It removes particulate matter from the air. Efficient filters (HEPA, MERV-13) can remove viruses and bacteria. Less efficient filters (MERV-8) removes dust and pollen. It does nothing for gasses.

5/7

UVGI

It kills microbes. It can kill viruses at a higher rate than ventilation or filtration. It does nothing for gases or particulate matter (besides microbes).

EAC

Poor evidence of effectiveness. It can create harmful chemical compounds.
medium.com/open-letter-to…

6/7

SUMMARY

- Avoid EAC
- The rest all work against viruses.
- Ventilation is the most important.
- UVGI is very good for microbes but not other pollutants.
- Filtration still important. Normally, with good ventilation, extra filtration not required.

fin/7

Correction - not all electronic air cleaners discharge charged particles, although many do. Here’s a more thorough explanation.