This is a great question, one that gets more interesting the more you think about it. Most of us spend 90% of our time indoors in homes and workplaces that are better insulated and sealed than ever. So any pollutants or particles have a hard time getting out and tend to buildup in the recirculated air. This can lead to an indoor air quality that is worse than the outdoor air quality.
There is overwhelming evidence that particles in the air damage health. Air purifiers used properly can reduce particle count in the air as well as chemicals by 80% or more. There are no long term clinical trials definitely showing air purifiers prolong healthy lifespan but this is absolutely possible.
The effect of particles human health is a fascinating subject. You may not yet realize it, but the epidemiological/clinical data suggests that if you reduced the particle count in your air you would be smarter, happier, and even better looking!
So let us now look at some of these studies and decide are air purifiers worth it.
Health Conditions Related to Particles in the Air
Air pollution has been shown in clinical or epidemiological studies, often multiple studies, to cause-
- Coronary heart disease-heart attacks
- Premature aging of the lungs
- Chronic obstructive pulmonary disease
- Skin problems including skin aging
- Kidney diseas
- Cognitive decline-decrease in thinking ability
- Parkinsons disease
- Vision impairment-age related macular degeneration and glaucoma
- Impairment of sense of smell
- Sleep disturbance
- Increased risk of psychiatric problems
- Decrease in fertility
- Increased miscarriage
- Exposure during pregnancy linked to neurological problems, asthma, lower IQ in child
- Children-lower intelligence and delayed psychomotor development, faster decline in cognitive function in adulthood
- Children-chest infection, asthma
- Children-increased obesity
- Children-increased psychiatric problems
- Children-death rate increased
- Premature aging?-ultrafine particles speed up several processes involve in aging
- Premature death
You may like me be struck by the severity of the effects on the fetus and child. However stroke, dementia, breast cancer, blindness and premature death in adult life are also fairly severe consequences of particle pollution. There are more health conditions related to air pollution, this is a basic list-for further details please see this article.
Parents please note that air filters in classrooms in a US school increased pupils English and Math scores. In China air pollution was found to reduce cognitive (thinking) ability so much it was equivalent to 1 years less schooling.
Air Purifiers Reduce Particle count
There is no doubt that air purifiers reduce airborne particles. A true HEPA filter is the cornerstone of modern air purifiers. UV light and ionic air purifiers do not deal with particles as effectively as a HEPA air purifier does. A HEPA filter easily deals with large particles such as pet dander, mold spores, dust, and dust mite but also fine particulate matter such as tobacco smoke.
To illustrate how well air purifiers can reduce particle count, I performed an experiment. I used an iQair HealthPro Plus air purifier on its maximum setting providing 9.4 air changes per hour, in a room with the door and windows closed. The readings were on normal room air and I used a Trotec PC200 particle counter to count 0.5um diameter particles. This size is the smallest particle size that laser diffraction technology can accurately measure.
So you can see with the air purifier on its maximum setting and providing 9.4 air changes per hour the reduction in particle count only mildly exceeded the EPAs minimum target. This shows that it is best to be careful in buying an air purifier and to check that it really will deliver a minimum of 5 air changes per hour for your room on its second to highest setting. In general, you will never be able to tolerate an air purifier on its maximum setting for long as it is too noisy.
However, there are other airborne pollutants such as chemicals, so nearly all air purifiers also have an activated carbon filter. Activated carbon filters remove a wide range of chemicals particularly volatile organic chemicals and even ozone. Volatile organic compounds are responsible for odor and so an activated carbon filter will remove or at least markedly reduce an unpleasant odor.
An HVAC whole house air purifier is possible but a HEPA specification one will probably need remodeling of your HVAC system. HVAC filters can be very poor at dealing with indoor air pollution. You should check that your HVAC system has a minimum of a MERV13 filter as lower MERV specification filters can be so poor that they remove less than 50% of airborne particulates, as explained in this article. Before you upgrade your HVAC filter to create a whole home air purifier, you should check with an HVAC engineer as an upgraded filter will reduce airflow through the system and may damage it, as explained in this article.
Air Purifiers are Worth Buying For People With Some Medical Conditions and Possibly for Pregnancy/Children
If you have a medical condition, then you should ask your doctor if it could be affected by particles in the air and if so consider using an air purifier. It would be a good idea for anyone who has any condition on the above list of medical conditions or in this article to have air purification at home. Also women who are pregnant or are intending to become pregnant should consider using an air purifier, especially if they are living in a polluted environment. An air purifier should be used especially at home but possibly even at work-there are good desktop personal air purifiers.
There are 24 million people in the U.S. with asthma including 6 million children, it would be wise for these people to at least try a good air purifier with good technique to see if reducing airborne allergens makes their asthma any better. In addition, there are at least 6 million more with seasonal and perennial allergic rhinitis who should at least try an air purifier to reduce airborne allergen to see if this eases their symptoms.
For People Without Medical Conditions
Living in Highly Polluted Areas
If you live in a highly polluted area, it is essential to have an air cleaner/purifier to lower your pollution risk.
Examples of such areas-
- near busy roads
- areas that have forest fires episodically
- near some forms agricultural production
For People in Areas With Low Pollution Levels
Even in low pollution areas there are 1-2 million ultrafine particles per cubic liter of air. A liter is about 1/4 of a gallon. You will be breathing in about 600 litres of air per hour containing about 1 billion ultrafine particles. As explained above ultrafine particles can reach the deepest parts of the lungs and enter our bloodstreams.
So it is not a given that your health would not be improved by using air purifiers even in low pollution areas.
Indeed 2 new medical studies suggest that health effects are seen down to very low PM 2.5 readings indeed. There may be no lower limit in other words anything about zero may start to cause health effects. Personally I run air purifiers and keep my PM 2.5 below 2. You may decide on a different target somewhere in the PM2.5 range of zero to 12g/m3.
Below is a graph of mortality versus PM2.5 particle count illustrating that mortality continues to decline with further reductions in particle count, at counts lower than the EPA’s standard for air quality.
So should people without medical condition living in low pollution level areas consider purifying their air? I would suggest that you buy an air quality sensor/meter and measure the air quality in different rooms in your home. Certainly if the PM 2.5 is above 12 g/m3, the EPA safe level, then it probably would be wise for you to buy air purifiers and reduce particle count in the air. However even if the PM 2.5 is below this level you may wish to look at some of the recent medical evidence outlined in this article.
You may live in an area with particular pollution problems for instance with chemicals, and that may be the main reason that you need to use an air purifier.
If you are going to stake your future health on measuring the air quality in your home, I would recommend the iQair AirVisual Pro.
If you do Decide an Air Purifier is Worth it-5 Rules for Buying the Right Air Purifier
- Do not use the air purifiers maximum setting to size it for your room-it will be too loud!
- You need to use the CADR with the fan on the maximum speed possible that you can tolerate long term. For me this is about 50db. It may be different for you in your room.
- Buy an air purifier with a carbon filter
- Buy an air purifier that can either has a programmable timer, can be controlled by a smart home system or needs controlling
For further information please see this article which goes into much more depth about buying an air purifier.
Once you have one you may be interested in this article about how to use an air purifier.
There is no doubt whatsoever that inhalation of particulate matter harms human health. There is also no doubt that air purifiers when used with good technique lower particle count more than 80%. When particle count is lower in the environment there are fewer heart attacks and strokes. So it may seem a no brainer to use an air purifier.
However, there are no long-term trials showing a benefit from using an air purifier so you may prefer to wait until there are long-term trials of air purifier use. The downside of this approach is you that you may wait 20 years or longer only to find out that you should have been using an air purifier all along.
Now it is not an exact analogy but in another form of pollution there may be parallels. For many years even doctors said that there was no evidence that cigarette smoking harmed health and that there was no evidence that stopping was beneficial. Similarly, there is currently no conclusive evidence that using an air purifier is beneficial although there is overwhelming evidence that particles in the air damage health even at low levels and that air purifiers effectively reduce particle count in the air. Anyway, it would be impossible for conclusive evidence to be available currently as no clinical trials with the right protocol have even been done.
So I hope that this helps you one way or another to decide about whether it is worth buying an air purifier.
Does an air purifier require any maintenance?
An air purifier require the prefilter cleaning usually every 4 weeks, the HEPA filter and activated carbon filter will need changing once a year. The inside of the machine will need cleaning with a damp cloth when the filters are changed. This is for an average air purifier there are machines that need more or less maintenance.
There is an article with further information here.
What is the best air purifier on the market today?
The iQair HealthPro Plus is the machine with the highest specification but is for some people too noisy at high fan speeds needed for large rooms. If you have a room over 290 sq ft the Coway 400s would be the best choice and is a close second on specifications.
There is an extensive article on the iQair HealthPro Plus here.
How do you know if your air purifier is working?
Assuming that air is coming out of the machine the only way of telling is to measure the air quality in the room at the point at which you are breathing the air. You should get a drop in particle count or PM2.5 reading of at least 80% comparing the air with the air purifier off to that with it switched on. You should always buy an air quality meter whenever you buy your first air purifier as you cannot tell what the particle count is with your senses. In medical studies people using air purifiers often did not achieve even a 50% reduction in particle count. It is harder to hit the EPAs target than you may realise and without an air quality meter you are very unlikely to succeed.
What settings should you run an air purifier on?
You should run the air purifier on its maximum setting for 30-45 minutes before you step into the room. Then when you are in the room you should run it on the maximum speed that you find the noise it makes alright to live with. You should check the air quality on this speed to see if it is fine. Then usually you should leave it on this speed if you have a room that is very well sealed you could try reducing the speed and checking the airborne particle count on lower speeds.
Should air purifiers run all the time?
You should run the air purifier for 30-45 minutes before you step into the room and then continuously whilst you are in the room
For further information on using an an air purifier please see this article.
How long does it take to notice a difference with an air purifier?
As a general rule about 30-60 minutes to notice a reduction in odors. You may not notice any difference in particle count unless you have asthma or some other upper or lower respiratory tract problems, that is why it is essential to buy an air quality sensor/meter when you first buy an air purifier. If you do have asthma or for instance allergic rhinitis it will probably take at least 3 hours to notice a difference. If you do not it is very important to measure the air quality as it is possible that you have the air purifier incorrectly set up or you have not brought a powerful enough air purifier. Of course if you have not reduced the particle count you will not notice a difference.
I had a patient who was a very severe asthmatic and her husband brought her an expensive air purifier that was very unlikely to be successful because it has a hidden problem (I will not recomend it on this website except possibly for small rooms). So she thought that an air purifier did not help her asthma. I tried to persuade them to buy a more effective air purifier to give the wife a proper trial of an air purifier but I doubt that they did.
Why are air purifiers able to blow out cold air?
The air leaving an air purifier is basically the same temperature as that entering. Like any moving air it makes your skin feel colder because of evaporation from your skin and also the air current increases heat loss by convection from the skin.
What are the other ways you can improve air quality in your home?
There are not any other ways that you can remove particles from the air. Plants do not work to remove pollution. You can ventilate the house but this will only be helpful if there are more airborne particles in your indoor air than the outdoor air. Particles are the aspect of pollution most likely to damage human health.
For further information about using plants to reduce indoor pollution please see this article.