UV air purifiers: Pros, cons, and effectiveness

Introduction

Air is a mixture of dust particles, dirt, pathogens, microbes, gases, and many other things. The amounts of harmful air components are surpassing the innocuous ones. Furthermore, the continuous rise in air pollution levels is now a global phenomenon. 

While one may not be able to control the outdoor air quality, the manufacturers of air purifiers claim that they can improve indoor air quality drastically. Air purifiers may be of different types, the most common being High-Efficiency Particulate Air (HEPA) purifiers, Adsorbent purifiers, Ionic purifiers, UV purifiers, and Ozone generators. These mainly vary in terms of their respective air filtration systems.   

What Are UV Air Purifiers? 

UV Air purifiers use short-wave UV light technology to destroy harmful microbes and pathogens in the air. They are available as standalone units and part of an air purifier with a multi-stage filtration system. UV air purifiers may be of different types, depending on the space size, function, and consumer requirements. 

What Does UV Light Do On Air Purifiers?

When the air passes through the filter of a UV air purifier, it reaches an internal chamber where UV light treats unwanted airborne components such as microbes and pathogens, including viruses, bacteria, and mold spores. UV light destroys the chemical bonds between the molecules of such harmful components through the ultraviolet germicidal irradiation (UVGI) process. Once the chemical bonds break, the microbes and pathogens become inactive. 

The treated air then passes through another filter before returning to the room.  The method of treating air using UV rays is known as UV air sterilization. 

What are the Pros And Cons of UV Air Purifiers?

The pros and cons of UV air purifiers are listed below.

Pros

1. UV air purifiers destroy toxic or harmful airborne components, including viruses, bacteria, and mold spores.
2. They operate silently. 
3. They do not need the machine to push the air to continue treating it non-stop constantly.
4. The internal UV light chamber does not accumulate dust particles or grime and, therefore, never gets blocked. 
5. Since UV air purifiers target airborne microbes, they have extensive applications in healthcare, especially as an antiviral disinfectant. 
6. They are available in portable form.
7. They use less energy.

Cons

1. While UV air purifiers destroy airborne microbes and pathogens, they do not remove most allergens, smoke, or fumes. 
2. Production of UV air purifiers is expensive as the technology is relatively new, and manufacturers are finding the best possible method. 
3. You may not need to change the UV filters regularly, but they will need some maintenance. You may need to replace the UV light bulb regularly as the intensity of UV radiation deteriorates over time. 
4. UV filters, if used with HEPA filters, may emit ozone.
5. They might kill good bacteria.
6. They need careful installation, as it has potential health risks.
7. UV bulbs may contain toxins such as mercury, which may leak out if broken and cause harm. 

Are UV Air Purifiers Effective?

There is not enough evidence that UV air purifiers protect against respiratory diseases. UV air purifiers combined with HEPA filters may effectively destroy and restrict the reproduction of harmful and toxic pathogens. Still, they do not eliminate volatile organic compounds (VOCs) from the air.

Further, with the limited airflow, there is a high chance that the pathogens will not stay in the UV chamber for sufficient time for sanitization. UV air filters can work better with other filtration systems to treat indoor air effectively instead of standalone units. 

Since UV purifiers may emit harmful ozone gas, they may cause coughing, sore throat, inflammation of the airways, or worsening lung diseases. 

The other factors that may play a role in determining the effectiveness of the UV air purifier include:

1. UV light exposure - The longer the pathogens stay inside the UV chamber, the more they become inactive.
2. Distance from the UV light bulb - The closer the pathogens are to the bulb, the sooner and better they sterilize.
3. The material and type of lightbulb - While old models use mercury bulbs, the latest ones use light-emitting diodes (LED), which are relatively safer.
4. The number of UV bulbs - The larger the number, the more efficient the purifier is.
5. Size of the UV air purifier - The larger the unit, the stronger the impact of UV. 
6. The intensity of UV light - UV intensity tends to reduce over time; therefore, it is necessary to replace the bulb regularly to sustain its effectiveness. 
7. The strain of pathogens - Different bacteria and viruses require different exposure times and UV light to penetrate the cell. 

Conclusion

UV air purifiers are effective against airborne microbes and pathogens but would need additional filtration systems to work efficiently. As long as you are not directly exposed to UV light from the air purifier, it is safe to use.