13 Sep Do HEPA Air Purifiers Remove PM2.5?
Do HEPA Air Purifiers Remove PM2.5?
Yes, they do. According to ScienceDirect, HEPA air purifiers can reduce PM2.5 by 29 percent in settings with very high concentrations. While 29% may not seem like much, it’s significant. However, one shouldn’t rely on portable room air cleaners exclusively to push down PM2.5 levels. Air quality experts recommend that air purifiers be used alongside other effective measures. These measures include improving ventilation and addressing the source of the pollutants.
Other Research on PM2.5 Elimination
Air purifier manufacturers have always marketed their devices as being able to filter out contaminants down to 0.3 microns. Quite naturally, I’ve always imagined that these machines don’t remove particles that are smaller than 0.3 microns. But I was wrong if the findings from the following two experiments are anything to go by.
The first “researcher” cobbled together a DIY air purifier and used an air quality monitor to test its efficacy. The particle counter used could test the machine’s effectiveness down to 0.5 microns. Note that the AQI in the room read “Very Unhealthy.” Also, 4 regular air purifiers were tested alongside the homemade contraption. These were Blue Air, Philips, IQ Air, and Cannon air purifiers.
After 1 hour, the reading had improved to somewhere between “Unhealthy” and “Good.” Another 1 hour after that, the number stood at “Moderate.” Between the 4th and 7th hours, the counter showed that the air quality was “Good.” You can view the findings via the link above.
For the 4 regular air purifiers, the results didn’t significantly deviate from the findings described above. In these tests, the air purifiers removed 80 to 90 percent of particles smaller than 0.5 microns!
The researcher leaned another astounding truth. Shockingly, they found that air purifiers are actually better at eliminating particles that are smaller than 0.3 microns. Our researcher reasoned that Brownian motion was probably responsible for that effect. Chandrasekhar (1943) defined Brownian motion as the stochastic motion that particles made after being randomly bombarded by molecules.
While researching for this post, I discovered another “researcher” who’d performed a similar experiment. This person tested 10 air purifiers, and the particle counter used detected particle pollution down to 0.01 microns. The experiment took 10 minutes.
Interestingly, the air purifiers in question removed as many PM2.5 as they did PM10 particles!
These two findings are the best answers I’ve seen to the question: do HEPA air purifiers remove PM2.5? Admittedly, these tests aren’t exactly scientific research. I mean, the sample size is too small. But in my opinion, these results trump all the personal testimonies we hear or read about all the time.
What Does PM2.5 Mean?
PM2.5 refers to particles whose diameter is equal to or smaller than 2.5 microns. Now, these particles are microscopic. You just can’t see them, unless you’re viewing them under a powerful electron microscope.
But how small is 2.5 microns? You can learn about particle sizes in this comprehensive guide to buying the best air purifier. In that guide, you’ll find a detailed chart that lists more than 10 common particles and their respective sizes.
Indoor air pollution particles are so small that expressing them in inches wouldn’t make much sense. A diameter of 1 micron is the same as 0.00004 inches. See, it’s hard to visualize 0.00004″. Human hair is 30 times thicker than a PM2.5 particle.
But you shouldn’t confuse PM2.5 with PM10. Learn more about these two types of particles in the section that follows.
PM2.5 Vs PM10, What’s the Difference and Which is More Dangerous?
Both categories of particles are dangerous. However, PM2.5 is more lethal than PM10. That’s because these particles are much smaller and harder to detect. In addition, they’re way more difficult to remove or control. The human eye can detect particles as small as 10 microns. You should be able to see some PM10 particles.
Inhaling PM2.5 is extremely dangerous to your health. Mounting evidence finds that breathing these particles can lead to serious health-related issues. In fact, a recent comprehensive review of particle pollution linked it to a whole range of deadly diseases. Some of these diseases include diabetes, Parkinson’ disease, Alzheimer’s disease, heart disease, obesity, and asthma.
But what are PM10 particles? These are particles whose diameter stays in the 2.5–10 microns range. They’re relatively larger than PM2.5. Still, you won’t be able to see the vast majority of them without an electron microscope. PM10 are sometimes referred to as course particles and PM2.5 called fine particles.
Examples of PM2.5 and PM10 Particles
Combustion particles, viruses, tobacco smoke, fine metallic dust, and organic compounds are examples of PM2.5 particles. Household dust, pollen, and various types of mold, tobacco smoke, mold spores, dust mites, and lint are examples of PM10.
Why have I listed cigarette smoke particles as both PM2.5 and PM10? It’s because their size is a range rather than a single number. The size of tobacco smoke particles ranges from 0.01 to 4 microns.
What Causes PM2.5?
PM2.5 particles originate from many different sources. They’re mainly the result of combusting fossil fuels, organic materials, and other types of materials.
Power plants, automobiles, planes, wildfires, and burning organic matter during land preparation produce these particles. Volcanic eruptions and dust storms also contribute immensely to particle pollution.
Some of these particles are directly released into the atmosphere, such as during a dust storm or volcanic eruption. Or, when you’re installing a new countertop in your kitchen during a renovation.
Also, these particles get formed when particles and gases in the atmosphere react with one another. An example of this is when SO2 (sulfur dioxide) from sulfur-rich sources reacts with water droplets and oxygen. The resulting pollution is sulfuric acid, or acid rain.
What’s a Healthy PM2.5 Concentration?
First off, it’s best to track the 24-hour PM2.5 number as it provides more reliable info than a shorter duration. Concentration levels are critical, but the length of exposure determines a lot. A shorter-duration reading may not tell you everything you should know regarding whether you should take action.
Healthy PM2.5 Concentration Level
According to the EPA, a 24-hour PM2.5 reading of anywhere between 0 and 12 μg/m3 is ok. If that’s where your reading is, you don’t need to take any action. That level of exposure translates into “little to no risk.”
If your 24-hour reading lies between 12.1 and 35.4 μg/m3, the EPA considers that to be moderate exposure. At that exposure level, sensitive people will likely experience a few respiratory symptoms. If that’s you, it’s time to start reducing your exposure. Studies have demonstrated that using a HEPA air purifier might also help.
Unhealthy for Sensitive People
Between 35.5 and 55.4 μg/m3, you’re looking at a level of exposure that’s unhealthy for sensitive people. Those with asthma or other respiratory challenges may experience more pronounced symptoms.
Also, elderly people with cardiopulmonary disease may see premature mortality. People grappling with heart or respiratory diseases, children, and the elderly should try reducing their exposure.
Unhealthy PM2.5 Concentration for Everyone
If your reading hovers between 55.5 and 150.4 μg/m3, that’s considered unhealthy for everyone. At this level, even healthy people may experience increased respiratory effects.
Everyone, not just children, the elderly, and those battling respiratory conditions, should do everything possible to minimize exposure.
Next, any reading between 150.5 and 250.4 μg/m3 is deemed very unhealthy. Anyone exposed to this level of concentration might see their respiratory symptoms worsen significantly. Again, reducing prolonged exposure to these pollutants is the way to go.
Finally, readings between 250.5 and 500.4 μg/m3 are said to have hit hazardous levels. At this exposure level, there might serious aggravation of respiratory disease. Also, elderly people living with cardiopulmonary disease may see a seriously increased premature mortality.
In addition, children and everyone else face a serious risk of respiratory effects. Children and elderly people living in areas with such particle pollution levels should stay indoors. Everyone else must stay away from outdoor exposure as much as possible.
What’s the Best Air Purifier for Removing PM2.5 ?
The best air purifier for tackling PM2.5 is one that uses a True HEPA filter. Amazon and other online retailers carry a wide variety of such devices.
What’s a Normal AQI (Air Quality Index)?
According to the EPA, an Air Quality Index between 0 and 50 μg/m3 means “Good” air quality. 51 to 100 μg/m3 is moderate while 101 to 150 μg/m3 is unhealthy for sensitive people.
Next, readings between 151 and 200 μg/m3 shows that the pollution level is unhealthy for everyone. AQIs between 201 and 300 μg/m3 indicate that pollution has reached a very unhealthy level for everyone. Finally, readings between 301 and 500 μg/m3 say you’re dealing with a hazardous level of indoor air pollution.
Do HEPA Air Purifiers Remove PM2.5?
Yes. Studies show that portable air purifiers help reduce PM2.5 pollution. But they may not remove 100% of these microscopic particles. While installing an air purifier in your rooms is advisable, it’s not enough to resolve particle pollution. People should incorporate air cleaning devices into a wider indoor air pollution reduction strategy.
You now know what PM2.5 and PM10 particles are and what harm they’re capable of causing. Now, it’s time to take steps to protect yourself against the adverse consequences of inhaling polluted indoor air.