Air Purifiers: The Good, The Bad, and the Ugly.

7 min readApr 2, 2018

It may come as a surprise, but not all air purifiers are created equal! Simply putting the word “pure” in a product’s name doesn’t actually mean it’s improving air quality. In fact, several popular air purification options do little to nothing to improve air quality.

Poor air quality can worsen health issues like asthma and allergies, cause sleep problems, and even lead to long-term health effects. If you’re looking to keep your home health-friendly, a quality air purifier is a must! And while many on the market are misleading, we’re here to clear the air (no pun intended). Read on for our reviews of the most popular types of air filters.

  1. HEPA Air Purifiers

High Efficiency Particulate Air Purifiers were developed back in the 1940s. HEPA filters got extremely popular due to their use in medical settings, and trap around 99.97% of particulate matter larger than 0.3 microns. And because the human eye can only see things larger than 10 microns, that means HEPA filters catch what you can’t see. They’ll filter out bacteria, chemicals, and viruses to create a more sanitary living environment. Better yet, it does all of that without relying on harsh chemicals or dangerous byproducts!

You can imagine a HEPA filter as an accordion. Extremely thin pieces of fibrous material are folded to create flaps. These flaps trap particles as air is pushed through by a fan. The particles remain trapped in the filter, however, meaning it decreases in effectiveness over time. You should expect to replace the filter every two to three years.

In more detail, HEPA filters rely on three approaches to prevent particulate matter from passing through. The smallest particles experience what is known as diffusion, which is when particulate matter becomes trapped by gas particles and the fibers. Secondly, slightly larger particles will stick to the fibers upon contact — otherwise known as interception. Larger particles will go through impaction, where they collide with the fibers and become stuck within them.

It’s important to note that HEPA filters will not remove odors, chemicals, or gases. As a result, most incorporate activated carbon materials to address those downsides. If you’ve settled on the HEPA approach, be sure to look at a multi-faceted filter design!

2. Ionizers

Ionizers, also known as negative ion air purifiers, rely on chemical injection to purify the air. Ions are naturally occurring particles that have either positive or negative charges. If you’ve ever shocked yourself after walking around on carpet in socks, ions are to blame.

Negative ions are nothing more than negatively charged oxygen atoms. Because of their charge, these oxygen particles can attack pollen and dust like a magnet. Once the ion is weighed down by the particulate matter, it’s meant to get stuck to the ground or wall.

While this may sound like an amazing, natural solution, it can be far from it. Time and time again, ionizers have proven to be ineffective. Rather than cleaning the air, they often mask smells and visible particulate matter.

This is because ionizers are not able to absorb or eliminate harmful particles. Instead, they move the particles from the air to solid objects such as walls — leaving them for you to be exposed to. Eventually, these particles will become lose and reenter the air.

3. Activated Carbon

Carbon is the building block of everything in our world. From our bodies to the food we eat, every living thing has carbon in it. Activated carbon takes that same building block and improves it. Once “activated” carbon becomes porous and is able to absorb large amounts of pollution.

Activated carbon first became popular in the early twentieth century. It was sold to clean water and take coloring out of sugar-based products. Then, it became even more popular during World War I when researchers found it could protect soldiers when used in gas masks.

Today’s activated carbon filters rely on minuscule doors that are extremely absorbent and can quickly bond with particulate matter chemically. It can capture a wide rang of pollutants, from chemicals to gases, smoke, and odors. And once a pollutant is absorbed, it will never be released.

Activated carbon is particularly useful for those who are extremely sensitive to poor air quality. Children, the elderly, and asthma sufferers have a lot to to gain from this type of filter. This is because activated carbon filters can absorb the chemicals in common household construction and cleaning materials.

It’s important to note that while carbon filters are highly effective in reducing chemicals and odors from the air, they are not extremely effective when it comes to addressing particulate matter and allergens. This is one of the reasons activated carbon is often used in conjunction with a more traditional filter, such as a HEPA filter.

4. Electrostatic Filters

Captures 99% of particles over 1 micron — WYND

Electrostatic filters are one of the most innovative and effective on this list. They are extremely similar to HEPA air purifiers, but lack traditional air filters. Instead, they use an electric charge to trap particles as they travel through the air. These newly charged particles stick to the sides of the purifier, allowing the purified air to escape the filter.

The WYND air purifier is one of the smallest on the market and has been shown to release eight liters of purified air per second. This is a great option if you’re looking to purify your personal space (or a small room) in place of a large house.

Care for clean air?

Better yet, the WYND filter only needs to be replaced roughly every three months — and the cleaner your air gets, the less the filter needs to be replaced. Electrostatic filters also tend to be cheaper to replace, meaning the slightly more frequent replacements don’t come at an inconvenience.

Electrostatic filters such as WYND’s filter can remove everything from pet dander to smog and pollen from the air. They’re among the most diverse air purifiers, extremely convenient, and the most cost effective. If you’re looking to venture into the world of cleaner air, you can’t go wrong here!

5. Ultraviolet Rays

Much like activated carbon filters, UV technology is rarely used as a singular approach to air filtration. Instead, it is commonly paired with other air filters to achieve maximum air quality. While a UV filter will not remove particulate matter, it can eliminate germs, bacteria, and viruses. As microorganisms in the air pass through the filter, UV rays will kill them. This ensures that common allergens and health-risks are eliminated in your home.

Some UV air purifiers can also convert oxygen and water molecules into ozone and hydroxyl. Once converted, the new molecules will react with pollutants, ultimately destroying them. However, ozone can be extremely harmful. Any good UV filter should actually minimize the amount of ozone in the air.

UV air purifiers tend to not be extremely effective, however. Because they can not remove particulate matter, many microorganisms avoid the UV rays due to shielding provided by particles. This is one of the many reason UV filters are best used in conjunction with other approaches. In fact, most air filters that rely on UV will also include activated carbon and HEPA filters as well.

6. Ozone Purifiers

Ozone purifiers live true to their name and simply produce ozone (a molecule consisting of three oxygen atoms). While many companies will brand ozone purifiers as completely safe and effective, they should be avoided at all costs. They have not been demonstrated to have positive effects on air quality, and many governments even ban the sale of these ozone generators.

Being exposed to ozone can trigger asthmatic reactions and even scar the lungs. And this is particularly concerning given that ozone can take years to have an effect on air quality — if any. Furthermore, ozone can not remove particulate matter on its own. As a result, most ozone filters rely on negative ion technology, which, as stated above, is ineffective in itself. Rather than eliminating harmful pollutants, these filters simply mask them.

Some studies have shown that ozone air filters can prevent certain biological containments from multiplying, but other filter types can achieve this without the damaging health effects of ozone. To have any true effect on air quality, ozone would have to be present in higher qualities than deemed safe by most public health standards.

We’re live on Kickstarter. Check out our new ways to breathe clean air at home:




We're a Bay Area startup creating healthy air environments for everyone. We just launched on Kickstarter!