If you live in a city or in a wildfire-prone region, you just need to look out your window to see why an air purifier is necessary. Smog, smoke, and hazy skies are clear indicators that the air quality is low. But, what about if you live in the countryside or in a lush suburb? If the air quality outside is good, shouldn’t the air indoors be clean as well?
No matter how clean your outdoor air is, your indoor air quality can still be poor. In fact, the Environmental Protection Agency has shown that indoor air is generally 2 to 5 times more polluted than outdoor air.
Why is indoor air quality so poor?
Human activity is the main reason indoor air quality is so poor. Every time you cook, burn wood, candles, or incense, you are releasing large amounts of particulate matter into the air. Particles also can form indoors from complex reactions of gases emitted from things like household cleaning products and air fresheners.
Human activity and products, combined with the lack of ventilation, produces and retains large concentrations of particulate matter.
But particular matter is not just generated indoors. No matter how tightly sealed your home is, particles can still enter indoor spaces through doors, windows, and “leakiness” in building structures.
What’s so dangerous about Particulate Matter?
Because PM2.5 and ultrafine particle matter are so small, they are easily inhaled and are able to penetrate deep into your respiratory system.
Short-term issues from PM exposure include eye, nose, and throat irritation, coughing, sneezing, and shortness of breath. Long-term exposure to PM2.5 can cause permanent respiratory problems such as asthma, chronic bronchitis, and heart disease. PM2.5 particles also elevate the likelihood of premature birth and infant mortality.
What makes the danger of particulate matter even more difficult to assess is that it’s rarely the direct cause of death. Rather, air pollution is the world’s 4th leading contributing cause of early death, accounting for:
- 29% of all deaths and disease from lung cancer
- 17% of all deaths and disease from acute lower respiratory infection
- 24% of all deaths from stroke
- 25% of all deaths and disease from coronary heart disease
- 43% of all deaths and disease from chronic obstructive pulmonary disease
Overall, 4.2 million people die every year from breathing in large amounts of fine and ultrafine particulate matter.
Even areas with seemingly clean air can still have pollutants
It isn’t only exhaust from cars and factory emissions that lower air quality. Pollen, mold, and wildfire smoke are common even in suburban or rural areas.
Wildfire smoke is particularly concerning because it’s made of gases and microscopic particles from vegetation, metals, and other building materials that have been burnt. The smaller the size of the particle, the more dangerous it is.
Because of their tiny size, these particles can also travel far, potentially damaging the health of people across states. In fact, California wildfire smoke has been detected 3,000 miles away in New York City.
How can a purifier with a HEPA filter help?
Although the standard for HEPA filters is that they need to be able to filter out 99.95% or more of all particles which are 0.3 microns in diameter, they are actually capable of filtering out particles of almost any size. A True HEPA filter can trap dust, smoke, pet allergens, and, most importantly, PM2.5.
HEPA filters trap particles in different ways depending on their size.
Particles larger than 1 microns: As air flows through the filter, the larger particles are heavy enough that the airflow from the filter propels them forward into the fibers of the filter where they get stuck.
Particles that are .3 to 1 micron: Particles this size can fit between the gaps in the filter. But, they are too heavy and slow to follow the air flow around the HEPA filter and end up getting stuck in the fibers.
Particles smaller than .3 microns: While HEPA filters only need to filter particles of .3 microns, the truth is that they are also very effective at filtering out smaller ones. Because of a phenomena known as Brownian Motion, tiny particles bounce wildly off of other larger particles in the air in random patterns that send them careening off into different directions. It’s these zigzag patterns that cause them to hit the fibers of the HEPA filter and get stuck.
Because of the demand for high quality air purifiers, many companies are using the term “HEPA” to describe their filters. However, a True HEPA filter must meet the United States Department of Energy’s standard of removing 99.95% or more of all particles which are 0.3 microns in diameter.
For the cleanest air, no matter where you live, look for a high-quality air purifier with a combination of True HEPA filter and activated carbon filter.