Electronic Air Cleaners and Ozone

February 22nd, 2010 — Filter QA

When the topic of electronic air cleaners comes up it usually doesn’t take long for questions to arise about ozone and whether it is safe or not. So due to several comments on this blog and questions I have received by email I thought I would share a link to a report I found, published by the US Environmental Protection Agency. The report should provide answers to most questions concerning ozone and any health risks associated with it.

The title of the document is "Ozone Generators that are Sold as Air Cleaners: An Assessment of Effectiveness and Health Consequences"

The topics covered are:

  • What is ozone?
  • How is ozone harmful?
  • Is there such a thing as good ozone and bad ozone?
  • Are ozone generators effective in controlling indoor air pollution?
  • If I follow manufacturers directions can I be harmed?
  • Why is it difficult to control ozone exposure with an ozone generator?
  • Can ozone be used in unoccupied spaces?
  • What other methods can be used to control indoor air pollution?

http://www.epa.gov/iaq/pdfs/ozone_generator.pdf

The table below is copied from the report for those who do not want to read the document.

Ozone Health Effects and Standards

Health Effects Risk Factors Health Standards
Potential risk of
experiencing:
 		 Factors expected to
increase risk and
severity of health
effects are: 		The Food and Drug Administration (FDA)
requires ozone output of indoor medical devices to
be no more than 0.05 ppm.
Decreases in lung
function
 		 Increase in ozone air
concentration 		The Occupational Safety and Health Administration (OSHA) requires that workers not be exposed to an average concentration of more than 0.10 ppm for 8 hours.
Aggravation of asthma Greater duration of
exposure for some health effects		 The National Institute of Occupational Safety and Health (NIOSH) recommends an upper limit of 0.10 ppm, not to be exceeded at any time.
Throat irritation and
cough		 Activities that raise the
breathing rate (e.g.,exercise) 
  		The Environmental Protection Agency (EPA)’s National Ambient Air Quality Standard for ozone is a maximum 8 hour average outdoor concentration
of 0.08 ppm.
Chest pain and shortness
of breath 		Certain pre-existing lung
diseases (e.g., asthma) 		 
Inflammation of lung
tissue 		   
Higher susceptibility to
respiratory infection  		  ppm = parts per million

No Comments

Does an Electronic Air Cleaner Create Ozone

April 5th, 2009 — Air Filters

Ozone (O3) is a 3-atom form of oxygen and is a normal trace element in our atmosphere. Ozone is a different chemical than common oxygen (O2) which supports life. Like many substances, ozone is beneficial to life but can also be harmful in excessive concentrations.

Like many household appliances, electronic air cleaners produce ozone when they operate. The amount of ozone produced varies among models.

Ozone is formed when an electric discharge passes through the air and there are many natural sources of ozone. For example, ozone is formed naturally by lightning and is also formed as a by-product of some electric motors and appliances. Ozone is created by air passing through an electrically charged field.

How electronic air cleaners work

Small particles of dust pass through the charging section of the air cleaner and receive a positive electrical charge from a series of tungsten wires. These charged particles then pass by the negatively charged collector plates, which attracts them like a magnet. The particles remain on the collector plates until they are washed away during periodic cleaning of the collector cells.

Can you smell the ozone produced by the electronic air cleaner?

Sensitivity to the smell of ozone varies quite a bit among people. Some people can smell levels at .02 ppm but most people notice the smell of ozone at .03 ppm which is well below the FDA standard. The smell of ozone is not an indicator that the level is above normal, or even near the recommended limit set by the FDA.

Do electronic air cleaners work?

Electronic air cleaners do work. But like all air cleaners and air filters they have their positive and negative characteristics. Many people are very satisfied with their performance and would recommend them to anyone.

4 Comments