Air purifiers have become increasingly popular as people seek to improve their indoor air quality. But with various types available, it’s essential to understand What Does An Air Purifier Do and how each technology works. This article will explore the different types of air purifiers, their effectiveness, and potential drawbacks, helping you make an informed decision about whether an air purifier is right for you.
Different Types of Air Purifiers and Their Functions
Air purifiers employ diverse technologies to clean indoor air. Some are effective in removing pollutants, while others may be less efficient or even pose health risks. Let’s delve into the common types:
1. Mechanical Filters: The Power of Physical Trapping
Mechanical air purifiers are the most common type and rely on mechanical filters to capture airborne particles. These devices use fans to draw air through a dense network of fine fibers that physically trap pollutants.
HEPA filters (High-Efficiency Particulate Air) are a prime example of mechanical filters. They feature a very fine mesh designed to capture microscopic particles effectively. While HEPA filters excel at removing tiny particles, they can also trap larger particles like dust, pollen, and mold spores when these are suspended in the air.
It’s worth noting the distinction between “HEPA-type” or “HEPA-like” filters and certified HEPA filters. While the former may offer adequate performance, they haven’t undergone certification to meet the stringent requirements of a true HEPA filter.
Limitations of Mechanical Filters:
- No gas or odor removal: Mechanical filters are not designed to tackle gases or odors.
- Maintenance costs: Filters need regular replacement, typically every 6 to 12 months, and can range in price, sometimes reaching up to $200 per filter, though a more typical cost is around $80.
2. Activated Carbon Filters: Targeting Gases and Odors
In contrast to mechanical filters, activated carbon filters utilize activated carbon to adsorb certain types of gases, including odor-causing molecules. The porous nature of activated carbon provides a large surface area to trap these gaseous pollutants.
However, activated carbon filters are not universally effective against all gases. They are less efficient at removing formaldehyde, ammonia, or nitrogen oxide.
Due to their focus on gases and odors and lack of particle removal, activated carbon filters are often combined with mechanical filters in air purifiers to provide comprehensive air cleaning.
Considerations for Activated Carbon Filters:
- Faster saturation: Activated carbon filters become saturated more quickly than mechanical filters.
- Frequent replacement: They require replacement more often, typically every three months.
- Replacement costs: Activated carbon filters usually cost up to $50 each.
3. Ozone Generators: A Potentially Harmful Approach
Ozone generators produce ozone, a molecule that can react with pollutants to alter their chemical structure. While this sounds promising, ozone itself is a lung irritant and can be harmful to health.
Consumer Reports and other health organizations do not recommend ozone generators for home use. Despite manufacturers’ claims of safe ozone levels, tests have shown that even low settings on some ozone generators can exceed the FDA’s limit for medical devices.
Furthermore, the EPA has reviewed studies indicating that low ozone levels are ineffective at destroying indoor pollutants. Research links ozone exposure to decreased lung function and increased risks of respiratory issues like throat irritation, coughing, chest pain, and lung tissue inflammation. Ozone can also worsen conditions like asthma, emphysema, and bronchitis.
4. Electrostatic Precipitators and Ionizers: Charged Particles and Ozone Concerns
Electrostatic precipitators and ionizers are electronic air purifiers that work by charging airborne particles. These charged particles then adhere to oppositely charged plates within the machine or nearby surfaces, effectively removing them from the air.
However, Consumer Reports generally does not test or recommend electronic air purifiers due to their potential to generate ozone as a byproduct. As discussed earlier, ozone poses health risks and is not an ideal air purification method.
5. Ultraviolet Germicidal Irradiation (UVGI): Targeting Biological Contaminants
Ultraviolet germicidal irradiation (UVGI) air purifiers use UV lamps to kill airborne viruses, bacteria, and fungal spores. The high-energy UV light damages the DNA or RNA of these microorganisms, rendering them inactive.
While UVGI can be effective against certain biological contaminants, it may not eliminate all of them. Some bacteria and mold spores exhibit resistance to UV radiation.
For UVGI to be effective, the UV light needs to be sufficiently powerful, and the exposure time must be long enough – ranging from minutes to hours, rather than the brief seconds typical of many UVGI air purifiers.
Consumer Reports does not specifically test UVGI technology in air purifiers, although some mechanical air purifiers they test may include UVGI as an additional feature.
6. Photocatalytic Oxidation (PCO): Potential Byproducts and Limited Effectiveness
Photocatalytic oxidation (PCO) air purifiers utilize ultraviolet radiation and a photocatalyst, such as titanium dioxide, to generate hydroxyl radicals. These radicals then oxidize gaseous pollutants.
A significant concern with PCO technology is the potential for harmful byproducts. Depending on the pollutant and reaction, PCO can generate ozone, formaldehyde, nitrogen dioxide, and carbon monoxide.
Consumer Reports does not currently evaluate air purifiers using PCO technology. Research into the effectiveness of PCO air purifiers is limited. One laboratory study from Syracuse University found that PCO devices were ineffective at removing common indoor volatile organic compounds (VOCs).
7. Photoelectrochemical Oxidation (PECO): A Newer Technology with Mixed Results
Photoelectrochemical oxidation (PECO) is a variation of PCO, notably used by the manufacturer Molekule, emerging in 2017.
Consumer Reports testing of the Molekule Air purifier showed poor performance in removing dust, smoke, and pollen. The more expensive Molekule Air Pro performed better at higher settings but still did not excel in other air purifier test categories and received unfavorable ratings in Consumer Reports member surveys.
Do You Need an Air Purifier?
Understanding what does an air purifier do and the different technologies available is crucial for deciding if you need one. Air purifiers can be beneficial for individuals with allergies, asthma, or respiratory sensitivities, as well as for those living in areas with poor air quality.
However, it’s important to choose the right type of air purifier based on your specific needs and concerns, avoiding potentially harmful technologies like ozone generators. Mechanical and activated carbon filters are generally considered safe and effective options for improving indoor air quality.
By considering the information presented here, you can make an informed decision about whether an air purifier is a worthwhile investment for your home or workspace.
