Air Purification

Common Misconceptions about Air Quality

Indoor air quality is widely recognized as a key strategy for mitigating airborne viruses, but in the rush to learn about air purification there have been instances of disinformation or misleading claims about what works and what doesn’t. Aeroex has been in the business for over 20 years but we are seeing newcomers jump on the COVID opportunity, misleading their customers. We want to arm you with the facts so you can restore confidence in the promises of air purification. 

What is Air Purification?

Air purification is the process of filtering and removing suspended particles. So, air purification relies on ways of removing these particles, most commonly through filtration. While this seems simple, the range of pollutant types and particle sizes means air purification quickly gets challenging without the right tools.

So If Some Bad Particles Are Small, All You Need Is A Small Enough Filter Right?

Wrong! Understanding particle science is the first step but it misses something. Having a very fine filter is good, but if it can’t filter particles faster than they are spreading you’re not sufficiently purifying the space. This is why air exchanges are important, the frequency that a volume of filtered air is replaced – it must be higher than the source in order to maintain air purification (depicted below). Often, many times that frequency. Not to mention factors like the volume of the facility/room. Before doing a detailed analysis of airflow, it’s good to start with a simple calculation of air volume in a room.


Source: Hong Kong Training Portal on Infectious Control


Know Your Filters

Companies may try to confuse you with proprietary naming, but knowing the international standards for filtration will help you navigate their claims. The two main types you should know are MERV and HEPA. MERV is a standard certified by the EPA for 95% particles from 10 to 0.3 microns – for some applications, this is effective enough. HEPA goes further, capturing 99.97% of 0.3 micron particles. Start by learning the particle size of your contaminants and reference this against the filter rating. Consider this in the context of other filter characteristics like filtration type (pleated membrane vs depth filter, another Aeroex passion!) and air handling capacity (commonly measured in cubic feet per minute).

Don’t Be Fooled

Air exchanges are a critical factor many vendors conveniently ignore – you can have the best filter for small contaminant particles in the world and if it doesn’t have air exchange capacity your room could be full of impurities. And, this is before even considering how to handle a ranging mixture of particle sizes! At best this leads to the wrong purchase, but at worst many people are making decisions with false promises that risk health and safety. Make sure to consider both filter size and exchange rate, plus the many other tips Aeroex has. Stay tuned for more!