By now, we all know the effect that cigarette secondary smoke can have on our lungs, which has led to a huge fight against public smoking around the world. Similarly, society is increasingly concerned about the effect of traffic pollution on our health, especially in city centres. But ultimately, we spend much more time in our homes than in public spaces. Therefore, it makes sense to focus on achieving clean air quality there as well.
After all, our front doors aren't magical barriers that keep pollutants and allergens out of our living space. Even if they were, we ourselves also generate pollutants within our homes, from things like cooking, cleaning, building materials, products and furniture.
Indoor air pollutants come in the form of tiny particles, such as PM2.5 and PM10, formaldehyde, mold and pollen. They can also appear as gases, such as volatile organic compounds (VOCs). That's why it makes sense to reduce them in the air we breathe. That's why the best air purifiers are becoming more and more popular.
But how do air purifiers work? Are they really effective? Read on as we answer these questions and explain how to find the right product for you.
How do air purifiers work?
The basic principle behind air purifiers is quite simple. They draw in air from their surroundings, pass it through one or more filters to remove contaminants, and then return the clean air to the room. That's all.
There are several different types of filters they use, but the most common (and most effective) is the high-efficiency particulate air (HEPA) filter. These filters are designed to trap 99.97% of particles 0.3 microns in diameter or larger. To give you an idea of scale, a human hair is typically between 50 and 70 microns in diameter. So here we are talking about very small particles.
The effectiveness of a HEPA filter is usually expressed as a MERV rating (which stands for Minimum Efficiency Reporting Values). They typically range between 12 and 17, and your air purifier should have a MERV rating of at least 13 to be worth using.
Do air purifiers work?
The million dollar question is: do Do air purifiers really work? The answer is yes, in some circumstances. According to the Environmental Protection Agency: “Some air cleaners, under the right conditions, can effectively remove certain respirable-sized particles.”
When equipped with activated carbon filters, some air purifiers have also been shown to be effective in reducing volatile organic compounds (VOCs). That said, according to this 2021 MIT study, models vary in effectiveness and some were even found to be a source of VOCs.
The short version, then, is that air purifiers generally work… but how do they Well How they work depends on several factors. These include the specific product in question, the type of purifier, the size of the room, the specific air quality problems in a particular building, the level of ventilation in your home, the size of the space, the consistency with which use the air purifier. and how often you change the filters.
Even at the best of times, air purifiers are No a panacea for indoor air quality problems. First, they cannot remove all contaminants, especially those that have settled on surfaces. And secondly, they are most effective when used in conjunction with other measures to improve air quality, such as regular cleaning and proper ventilation.
The University of Massachusetts puts it clearly in this report: “Using a portable air purifier is the least effective way to clean the air, but it can be a good complement to ventilation.” In other words, if you use an air purifier but rarely open your windows or clean your house, don't be surprised if you still get sick.
How to choose an air purifier
When purchasing an air purifier, there are several key factors to consider:
The first is CADR (Clean air delivery rate). This is a measure of how quickly the purifier can clean the air in a given room size. Look for a CADR that represents at least two-thirds of the room's area in square feet. For example, for a 300 square foot room, you'll want a CADR of at least 200.
Second, think about your room size. Manufacturers usually indicate the maximum room size for which an air purifier is effective, so be sure to check this before purchasing.
Third, pay attention to filter type. As we mentioned above, HEPA filters are the gold standard for particulate removal. Look for 'True HEPA' filters, which meet U.S. Department of Energy standards. Some models also include additional filters, such as activated carbon filters (to remove odors and some gases) or UV-C light filters, which They can kill some bacteria and viruses, although they do not eliminate particles.
Fourth, consider how much you value peace and quiet, as air purifiers can produce noise, especially at higher fan speeds. If this concerns you, check the decibel rating before purchasing.
Finally, consider whether you need added features. Some air purifiers come with nice extras such as air quality sensors, auto mode and smartphone connectivity, although these will usually be reflected in a higher overall price.