Air Purification Techniques

Common Techniques used in air purification, the good the bad and the ugly.

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 healthy, a quality air purifier is a must. While many on the market are misleading, we’re here to clear the air on the different techniques used.

1. 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 attract 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.

2. 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 us very 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 this extremely absorbent quality 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 that can often be triggers. 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.

3. Ultraviolet (UV)

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. UV air purifiers tend to not be extremely effective as 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.

4. 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 containment 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.

5. Electrostatic Filters

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. This is a great option if you’re looking to purify your personal space (or a small room) in place of a large house. Often however, these types of filters require replacement roughly every three months, meaning the more frequent replacements than other more advanced traditional technology filters and you have to clean the collected dust out of the unit. This can be messy and often results in releasing that trapped dust back into your environment. Another downside to Electrostatic filters is that the process of charging ions has the ability to create ozone and Nitrous oxides both of which are know lung irritants.

6. High Efficiency Particulate Air (HEPA)

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! Using tightly packed pleated media the particles remain trapped in the filter and while the filter will continue to filter for long periods the ability of the purifiers fan to draw air through it will decrease over time. You should expect to replace the filter every four 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 is 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.

IQAir HealthPro 250 uses a combination of HEPA filters, activated carbon and impregnated alumina to give the consumer a filtration system that is tried and true with the guaranteed total system efficiency of ≥99.97% @ ≥0.3µm! This means that 99.97% of all fine particles that enter the unit are trapped by the filters inside, no other unit on the market can make that claim! Often you will see the efficiency rating of competitor brands printed on the box, this only refers to the filter itself not the total unit and IQAir have gone to great lengths to make sure that the HealthPro system has as little filter bypass as possible. IQAir have over 50 years in the design and manufacture of personal home air purification systems they have designed a unit that will offer you piece of mind and quality to last. This is extended to their filters with the PreMax filter lasting up to 18 months, the V5-Cell lasting up to 21 months and the HyperHEPA lasting up to 48 months*. IQAir individually test each HealthPro unit that comes off the production line giving it a test certificate that is hand signed to ensure quality is maintained.

If you or anyone in your household suffers from Asthma, allergies or is immuno compromised then the HealthPro unit form IQAir is the unit for you. Allergens in 85 to 90m2 areas will be all but eliminated by the HealthPro units. A study published in the American Journal of Infection Control** in 2010 showed that using the IQAir HealthPro unit could reduce infections rates by 50%! Watch here as one of IQAir's presidents demonstrates he units effectiveness.

*Filter life is based on average daily use of 12 hours on fan speed 3 at a moderate level of pollution. Actual filter life will depend on usage and conditions.

** The Impact of portable high-efficiency particle air filters on the incidence of invasive aspergillosis in a large acute tertiary care hospital, Abdul Salam ZH, Karlin RB, Ling ML et al.; AM J Infect Control 2010; 38:e1-7.

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