What is the most effective Air Filtration Technology?
Comparing Air Purification technologies
We have all wondered, from time to time, what is the best way to protect us from harm, be it through the food we eat, the water we drink, or the air that we breathe.
During these troubled times, what we breathe has become of utmost importance - how can we stay safe, while not endangering others?
This issue now concerns everybody, from the smallest household to the largest company, regarding personal safety and staying clear of liabilities.
In this post, I will try to demonstrate to you the most common air filtering technologies and summarise their performances.
What is a filter in the first place?
A filter may be considered any substance or device through which liquid or gas is passed to remove impurities or to trap solids.
It is only natural that different substances and different devices have different filtration qualities, based on their chemical or mechanical properties; as an example, pure water itself has a small filtering capacity, deriving from the weak polarity of its molecules (water molecules work like tiny magnets for particles in the air).
Given this introduction, let’s take a look at the different types of technologies that can surely be found in the air purifiers in your home or your office.
Membrane filters are the most common filtration technique, the air is led through the layered cloth inside the device, which physically stops and contains pollutants.
The simplicity of this technology is also its weak spot: all the tiny empty portions in the textile that allow the air to flow can also allow the smallest particles to flow through the filter untouched. A denser cloth would simply stop the airflow entirely, which would defy its purpose.
Blocked pollutants also cause issues, since they are trapped in the tangle of the membrane, they are bound to stay there and, with time, saturate the filter which will eventually need to be replaced.
Even the highest performing, the HEPA (High-Efficiency Particulate Air filter) and ULPA (Ultra Low Penetration Air) suffer from the same limitations that this kind of technology poses.
Carbon Active Filters
Carbon Active Filters work similarly to membrane filters as they are composed of carbon grains, that purify the airflow.
The grains of carbon are exposed to extremely high temperatures to create cracks, nooks, and crannies in them so that the polluting particles can be easily captured.
Carbon’s structure allows it to adsorb those particles by integrating them in its molecular reticule, preventing even tiny pollutants from flying past the filter.
As a common membrane filter though, carbon active filters reach saturation after a certain amount of time (depending on their size and thickness) and must be replaced.
PECO technology (Photo ElectroChemical Oxidation) is usually used in combination with a membrane filter, that cleans the airflow before it reaches the PECO chamber, hence introducing all the issues that this kind of filter brings along with it.
Once the air flows through the membrane, it enters the PECO filter, where the remaining pollutants are oxidized and destroyed by UV lights.
RNA/DNA virus, fumes, and volatile compounds typical of a household can be completely wiped out. Thicker particles (smoke, dust, pollen), however, are just blocked by the membrane filter and not captured.
Depending on the kind of UV, a PECO filter may release, due to oxidation, traces of ozone.
Furthermore, the PECO filter must be entirely replaced once every 3 months to ensure your full protection.
Scrubbers are a large family of filters, used mostly in industrial environments to remove waste products.
The most used are:
● Burners, when enough oxygen is present.
● Wet scrubbers, requiring contact between the pollutants and the scrubbing solution (pure water or solutions of reagents).
Both methods present further complications concerning the disposal of the burn products or the polluted liquid.
U-Earth technology is very simple: a population of bacteria lives on the inside walls of the filter and kept moisturized by a constant water flow, that feeds them the pollutants in the air, attracted by a difference of potential created by the bacterial colony itself.
This technology allows a flow of clean air since all the particles in contact with the colony have either been digested or washed away by the water flow.
Wastewater can then be easily disposed of, while periodically new bacteria need to be inserted into the filter (roughly once a month), granting an ever-thriving colony.
Independent, validated tests show a significant reduction in pollutants in the environment in which the filter is installed.
As you can see, all most used filters have a lifespan, during which their performances tend to decrease, so the right step is to choose one that grants you full safety even when not operating at its maximum capacity.
While we can see a drop in the membrane filter performance in time, we see a minor slope in the PECO filter and a steady purification rate in U-Earth bio-filters; taking into account the general maintainability of the devices instead, U-Earth biofilter is the only one that needs no part periodical replacement, just a refill of the bacteria and a water change, things that can be easily be performed by everyone.
U-Earth technology is also significantly more appealing to corporate and industrial customers since it can easily be scaled to solve specific problems and meet different needs.