Why should we buy an air purifier? How to choose a one?

 While outdoor air pollution has been talked about for decades, indoor air quality has more recently become a public health issue. Between home, office, and transport, we spend more than 80% of our time in enclosed spaces. And indoor air is even more polluted than outdoors. People show much interest in air purifiers. We will talk about this in this article.

Spring is a time conducive to allergies due to the proliferation of pollen. So you might think that this is the ideal season to use an air purifier. However, these devices are useful all year round. Because indoor air is even more polluted than the air we breathe outside. And indoor pollution is not only made up of pollen. The particles that pollute the air in our interiors do not only come from outside, on the contrary: they emanate from our homes and therefore rage all year round.  

What kind of people need an air purifier?  

People with allergies, asthma, or respiratory diseases are of course the main audience for air purifiers. In an indoor polluted area, these sensitive people may feel difficulty breathing, sneeze, and experience redness or itching in the eyes…. However, air purifiers are not useless for less fragile people, even if the feeling of "well-being" is less immediate. Because that is the difficulty of air pollution issues: the finest and most harmful polluting particles are invisible to the naked eye. It is therefore difficult to assess the state of the air we breathe. However, all interiors are “polluted”, whatever the place and the season. It is for this reason that it is recommended to open your windows 10 to 15 minutes a day, in summer and winter. While people with allergies or respiratory conditions can experience a direct benefit, purifying indoor air is useful for everyone, all year round.

What does an air purifier used for?

We hear a lot about air pollution and fine particles, but indoor pollution is different. If some particles are visible (such as dust in suspension), it is especially the finer ones that must be eliminated, so as not to inhale them. According to the WHO, all particles smaller than 10 microns (PM10) are dangerous to health – among these, we find in particular the famous PM2.5 (which measures 2.5 microns or less).

The air purifier, therefore, promises to filter the air of the house to rid it of a large part of these particles harmful to health.

How does an air purifier work?

The air purifier absorbs the air from the room, then rejects it purified, freed from a large part of the polluting particles, also irritants and allergens. The air passes through several filters. First, a prefilter that retains the thickest particles, often visible to the naked eye: dust, hair, animal hair... Then the air passes through an activated carbon filter, which retains gases, odors, fumes, and certain volatile organic compounds. Finally, a HEPA (High-Efficiency Particulate Air) filter, like those in vacuum cleaners, retains the finest particles, invisible to the naked eye.

You should know that some manufacturers have merged the filters so that their purifiers only have one, which is easier to maintain. They do not ignore the capture of fine particles or gases: these filters are simply composed of several layers and thus combine several functions

Note that more rarely, some purifiers use photocatalysis or ionization. Photocatalysis consists of destroying particles by producing a chemical reaction. It is decried because it could generate harmful particles. The ionization process, it consists of eliminating particles suspended in the air by pressing them to the ground (the device produces negative ions which attach to the polluting particles and make them heavier). Some organizations (UFC Que Choisir, Anses) have reservations about the use of ionization processes and more specifically photocatalysis, the safety of which is not guaranteed.