When I began researching about how to purify the air in my home, I became very concerned about the fine particles in the air. Fine particles are pollutants that are 2.5 micrometers in size or smaller. You may have seen them abbreviated as particulate matter 2.5 or pm2.5.
Based on my findings, the HEPA (High-Efficiency Particulate Air) filter seemed to be one of the best solutions to clean the air.
A HEPA Filter Guarantees to Capture Fine Particles 0.3 Micrometers and Larger
By definition, a HEPA filter has been tested and proven to be able to filter out 99.97% of particles 0.3 micrometers in diameter and larger. Now, that doesn’t mean that a HEPA filter will absolutely be incapable of trapping those particles that are only 0.1 or 0.2 micrometers in size. It doesn’t mean that it won’t be able to remove these smaller fine particles, but rather, that its testing does not guarantee it.
A HEPA filter employs several mechanisms to trap particles, and all those methods combined are guaranteed to be effective on fine particles that are 0.3 micrometers in size and larger. In case you’re curious, a HEPA filter uses 4 methods – impaction, sieving, interception, and diffusion.
Particles smaller than 0.3 micrometers may escape until they enter the filter again in the next air change cycle. But sooner or later, the HEPA filter will be able to trap them by diffusion. Meaning that in theory many of those particles will naturally get sucked in across the membrane of the HEPA filter and eventually be filtered out by sticking in the mesh with the larger particles.
The research from Smart Air has shown that:
It’s actually easier for HEPA filters to capture particles smaller than 0.3 microns (thanks to Brownian Motion). As just one example, here’s a test from a dedicated nerd (like me) who has a particle counter that measures down to 0.01 microns. He tested seven major purifiers for 10 minutes.
The different purifiers he tested removed about as much of these ultra-fine particles as larger particles .
In the following , i will introduce 5 air purifier that are good for removing PM 2.5.
1,Honeywell HPA100 True HEPA Allergen Remover

This Honeywell HPA100 might not look like much—it has all the visual appeal of a space heater—but Honeywell, no doubt, is hoping you’ll care more about what it can do. This model is designed for medium-sized rooms—about 155 square feet—and features a true HEPA filter for guaranteed removal of 99.97% of airborne particles down to 0.3 microns. Honeywell says that its fan can filter the air in the room five times an hour.
It’s one of the more configurable air purifiers on this list. The control panel on the top of the unit lets you set up to four different cleaning levels (which affects the fan speed and overall noise level) and has an auto-off timer option so it doesn’t run continuously. The panel also indicates when it’s time to change the filter, and it has multiple brightness levels so you can dim it at night or when you don’t need to see it.
2,Levoit Air Purifier

Compact enough to fit on your desk and designed to filter up to about 300 square feet, this compact Levoit model is equipped with a HEPA filter that removes 99.97% of dust, pollen, smoke, odor, mold spores and pet dander. It’s an excellent inexpensive option that eschews technology like UV and ionization more commonly found in this price range. Instead it features a three-stage filtration system that includes a pre-filter, a HEPA filter and an activated carbon filter. And three fan settings let you control the speed and volume of the purifier.
While this air purifier was designed for use in the bedroom (its fan is ultra quiet and it features an optional soft blue night light with two brightness settings), it’s quite portable and can be moved from room to room if needed. Aesthetically, it wouldn’t be out of place on your nightstand, with its white or black case and sleek design. And though its capacity is on the smaller size and it doesn’t have as many features as other air purifiers on this list, it’s hard to beat the price.
The Acekool air purifier D01 helps monitor the air in your surroundings in real-time with multiple sensors. Moreover, the innovative fan blade design contributes to advanced noise reduction to operate quietly while you sleep. With a small size and a modern design, this air purifier is perfect for small areas and bedrooms.
Fitted with a pre-filter, true HEPA filter, and carbon filter, this air purifier can eliminate 99.97% of PM2.5, formaldehyde, bacteria, pollen, smoke, mold spores, dust, odors, and pet dander. There is a built-in LED indicator that will remind you to with a fresh one. Filters must be replaced every 6 months depending on the use and air quality in your home.
4,Blueair Blue Pure 411

If you’re looking for a snazzy-looking device for modestly-sized rooms, this Blueair model may well be the way to go. It’s designed for spaces up to about 160 square feet, and Blueair claims it can filter that space five times an hour.
This three-stage air purifier combines mechanical filtration with an electrostatic filter and, to reduce odors, an activated carbon filter. It comes with two washable pre-filters designed for filtering out particles, pet dander, smoke and more. That said, be aware that while Blueair claims the system filters 99% of pollutants and it’s had its performance independently verified by the AHAM (Association of Home Appliance Manufacturers), the filter itself isn’t HEPA-certified, if you’re looking for that particular seal of approval.
Visually, Blueair made sure that this purifier doesn’t look like an ordinary appliance. It has an interesting design that splits the device into two contrasting colors—colors which you can change depending upon the filter you install. A single button turns it on, off and varies the fan speed, but there’s no display or status on the device, nor is there a way to set an on/off timer.
5,Hathaspace Smart True HEPA Air Purifier 2.0

If you have pets, you need the Hathaspace Smart True HEPA Air Purifier 2.0. This large capacity air purifier—it can replace the air in a 1,500-square-foot room up to 24 times per day—features a 5-in-1 filtration system that eliminates more than 99% of allergens and pollutants, like pet dander and the dust from a litter box. It also has an activated carbon filter that removes smoke, odors and gases and a cold catalyst filter that eliminates VOCs and harmful chemicals found in cleaning products or other household items, like candles or plug-ins.
It has a washable pre-filter that keeps pet hair away from the HEPA filter to improve performance and increase life expectancy. And it’s easy to clean—just take it out, wash it down and it’s ready to start purifying again. It also has a filter replacement reminder that pops up to let you know when it’s time to order new filters, a convenient feature that ensures you never go without clean air.
With these True HEPA Air Purifier, you will no need to be afraid of PM2.5 to harm your health. Breathe easy,every day!