We use air purifiers to improve our indoor air quality. But can an air purifier actually prevent you from getting sick? Bacteria and viruses settle on surfaces in our homes, but they also float in the air, where they can be inhaled. This means that an air purifier can potentially remove them from the air. Some air purifiers will do a better job of this than others. If you already have a cold or flu, an air purifier will not eliminate the illness, but it could ease some of the symptoms by improving the air quality. In this post, we will look at which air purifiers can help with colds, which ones are most effective at removing germs from the air, and which ones will not help much at all.
Indoor air quality and germs
Bacteria and viruses are microscopic organisms that vary in size depending on the species. The smallest bacteria are around 0.2 micrometers in size, although most species are larger, in the 1-10 micrometers range (for reference, the width of a human hair is about 70 micrometers). Viruses are generally smaller than bacteria, with the smallest ones being less than 0.01 micrometers in size. Germs are also small enough to become suspended in the air, although they will eventually settle onto surfaces.
Small particles like bacteria and especially viruses can be a challenge for air purifiers. However, because they have a positive or negative electrical charge, these germs tend to cling to other particles in the air, such as dust, pet dander, skin flakes, cockroach feces, and other larger forms of particulate pollutants. These larger particles also tend to stick to ones with the opposite charge even if the charge is weak, which makes it easier for filters to capture them. However, they also settle out of the air more quickly.
So, exactly how do germs get into the air in the first place? They might float in from outside when a door is opened, but they are more likely to be carried in on someone’s hands before getting deposited onto a surface when someone touches it. Later, air flow from the furnace, a broom, vacuum, a pet or person walking by, or even a sneeze or cough will stir these germs into the air. This is why it is very important to cover your mouth with a tissue or your elbow (and not your hand) when you sneeze or cough.
Maintaining the right humidity
Humidity is another important aspect of indoor air quality because it has a direct effect on germs in the air. You are more likely to catch a cold or flu in the winter because the air is cold and dry, with very low humidity. Studies have found that viruses and bacteria thrive in low humidity, but if the relative humidity is increased to between 40 and 60 percent, it will inactivate about 70 percent of the viruses in the air (Noti et al., 2013). Therefore running a humidifier in your house during the winter can keep the air from becoming too dry. Make sure to keep the humidity between 30 and 50 percent, as excess humidity can increase the risk of mold and mildew growth.
As stated above, improving the air quality in your home will not rid you of your illness, but it can ease some of your symptoms. If you have a stuffy nose or a bad cough, particles and toxins in the air, including dust, pet dander and other allergens, gaseous pollutants, particles from wood smoke and tobacco smoke, can further irritate your respiratory system. Maintaining a moderate humidity level of 30 to 50 percent may help keep your nasal passages and throat more comfortable.
How air purifier technologies stack up against germs
Different air purification technologies have their own strengths and weaknesses, and some are better at removing germs from the air than others.
Ultraviolet light – A UV lamp exposes microbes in the air to ultraviolet light, which theoretically can kill or inactivate them. The EPA reports that residential UV air purifiers work to some extent, but high power and long exposure are needed to truly eliminate all germs from the air, conditions that are difficult to achieve with an off-the-shelf UV unit. UV light can also produce ozone as a side effect. Ozone is a known lung irritant that you should not be exposed to for long periods because it could make your symptoms even worse.
HEPA filters – The designation of HEPA (High Efficiency Particulate Air) describes filters that have been certified to trap 99.97 percent of particles 0.3 micrometers in size, so they may reduce the amount of small particles that carry bacteria and viruses in the air. However, be aware that not all virus and bacteria particles in the air will be trapped by a HEPA filter alone, and if the filter is not changed regularly, microbes can collect and grow on it and get released back into the air.
Ionizers – These impart an electrical charge to particles, causing them to clump together and settle out of the air (basically accelerating the clumping process that happens naturally). Some viruses or bacteria may be removed from the air, but they will simply settle onto surfaces. Ionizers also create ozone as a side effect, which does not improve your air quality.
Ozone generators – These air purifiers generate ozone, which causes a chemical reaction with gaseous pollutants. They do not work on particles at all, so they are useless against germs. Ozone is also a harmful pollutant and lung irritant, which is why the EPA does not recommend the use of ozone generators in enclosed spaces. If you have a cold, an ozone generator can make things worse for your symptoms.
PECO – The Molekule air purifier contains a brand-new technology that goes beyond trapping particles on filters to actually destroying them through a chemical process. The proprietary Photo Electrochemical Oxidation (PECO) technology has been proven by an independent laboratory to destroy bacteria and viruses. Small particles that may otherwise pass through traditional particle filters, or multiply on the filter surface, are broken down into safe substances like water vapor and carbon dioxide.
Best practices for preventing colds
While an air purifier can reduce the amount of germs floating in the air of your house, there are also other steps you can take to keep your family healthy throughout the cold and flu season.
Since bacteria and viruses settle out of the air onto surfaces, you should wipe them down to prevent illness. A 70 percent isopropyl alcohol solution is a proven method for disinfecting surfaces because it kills bacteria and viruses with great efficiency. A HEPA vacuum can collect dust particles, which may help reduce microbe particles that have settled onto carpets and upholstery.
Finally, it is important to follow proper hygiene practices. Remember to wash your hands vigorously and cover your mouth when you sneeze or cough. If you are really worried about getting sick, wearing a face mask can also help. Studies have found that while masks might not prevent you from inhaling airborne particles, they seem to reduce how often you touch your face, preventing you from spreading germs from your hands to your mouth or nose.
Preventative steps are especially important if someone in the house is already sick. Careful hygiene and the use of an effective air purifier technology can help reduce the concentration of germs in the air, as part of a comprehensive approach to promote the health and well-being of you and your family.