As notorious as the most commonly known airborne irritants are, they are not the most damaging threat to your health. Neither pollen, dust mites, nor pet dander pose the same risk as ultra-fine lung penetrating particles.
Most of the irritants and allergens you may be familiar fall into the category of coarse airborne particulates. That is , they are in the 2.5 to 10 micron size range.
Coarse particulates usually become trapped in the nose and throat causing sinus irritation and allergies. That’s certainly reason enough to want rid of them and many an air purifier can serve that purpose.
But more than 90% of all particulates are 0.3 micron or smaller in size. These can enter deep into the lungs, depositing in the alveoli. Particles smaller than 0.1 micron can traverse the lung membranes and enter the bloodstream. These are the most toxic of all and not every air purifier will combat them effectively.
What are the health risks of lung penetrating particles?
Lung penetrating, ultra-fine particle pollution diminishes lung function, causes greater use of asthma medications, emergency room visits and hospital admissions.
The latest studies link them to health effects like:
- Death from respiratory and cardiovascular causes, including strokes
- Increased heart attacks
- Inflammation of lung tissue
- Increased hospitalization for cardiovascular disease
- Increased emergency room visits
- Increased hospitalization for asthma attacks
- Increased severity of asthma attacks
- Premature births
- Slowed lung function growth in children and teenagers
- Significant damage to the small airways of the lungs
- Increased risk of lung cancer
Considering the serious nature of these health effects it is very important when buying an air purifier to make sure it will filter ultra-fine particulates smaller than 0.3 micron in size. This is why the HEPA filters have become so important.
Which type of air purifier really works best?
There are four basic types of air purifier dominating today’s market; HEPA filters, electrostatic precipitators commonly called ionic air purifiers, negative ion generators and ozone air purifiers. How does each one rate against ultra-fine particulates?
First, let’s reject ozone generators entirely. Studies have shown reactions with pollutants in the air actually produces even more ultra-fine particulates. Add the widely recognized respiratory irritation and lung damage ozone can cause and you have every reason to reject them.
Negative ion air purifiers also pose risks. Both the EPA and the American Lung Association believes particulates that have been ionized have an increased chance sticking to your respiratory system. This makes matters worse.
Ionic air purifiers produce ozone, bringing up the problems mentioned earlier with ozone generators. They can remove ultra-fine particles and are often advertised as effective on particles as small as 0.1 micron. This results in marketing claims of “better than HEPA.” Unfortunately, they are only about 80% efficient at best, have dismal air flow rates and can lose more than 80% of their cleaning capacity in as few as three days due to buildup on their collector plates. They are not your best choice.
That leaves HEPA filter air purifiers. As you’re likely aware, they are prominently advertised as 99.97% effective on particles as small as 0.3 micron. But we need something effective on even smaller particles. Is this a problem?
A misunderstood point about HEPA is it is not limited to 0.3 micron particles. The 99.97% efficiency rating at that size is intended to indicate HEPA’s worst case performance, not it’s best performance. It just so happens that 0.3 micron particles are small enough and yet still of sufficient mass to negotiate their way through the filter’s mat of fibers. All other particles, even down to 0.01 micron are trapped at even higher efficiency rates.
Therefore, our need to filter out particulates in the 0.01 to 0.3 micron size leaves us with HEPA as our only real choice.