Most holiday seasons, questions about air filtration were about cooking odors or smelly holiday guests. This year, it’s all about viruses.
Let’s look at the options. (TL:DR – here’s our choice)
The goal in ventilation is to replace potentially virus-laden air indoors with virus-free air. One way to do this is to bring more outdoor air inside. But this isn’t always doable. You can’t easily open windows for ventilation when there’s a lot of hazardous pollution outside ( like wildfire smoke ). So, the other way is to filter the indoor air itself.
It starts with getting a good air filter. For this, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers suggests using filters with a MERV-13 designation or higher. Or use a portable HEPA filter (there are some DIY versions you can try on the cheap MERVs are based on a filter’s performance in filtering out particles between 0.3 and 10 microns. SARS-CoV-2 could very well be found in respiratory droplets in this size range; the higher the MERV number, the higher the probability that the filter will remove these droplets.
HEPA filters, more common in portable air filters, are slightly different. The “HEPA” designation means they filter out at least 99.97 percent of particles that are 0.3 microns. Which is to say, they filter out practically everything. (A quirk of the physics of filtration is the very smallest particles are actually easier to filter out than the 0.3 micron ones. The smallest particles get pushed toward filter fibers because of their collisions with gas molecules in the air, Siegel explains.) But installing higher-quality filters isn’t enough.
“I can’t just tell you in good conscience, ‘This is the filter you should use to protect against Covid-19 transmission,’ because it really depends how you use that filter,” Siegel says. “We much more often have an implementation problem than a lack of technology problem.” Often, he says, in buildings, a filter will be improperly sealed so that some unfiltered air sneaks past it and recirculates in the building; this downgrades its filtering ability. Also, not all systems can run these higher-efficiency filters, which can be quite dense. They often require more powerful fans to push air through. (vox.com)
You’ve likely seen this designation on air purifiers and other products before. HEPA stands for “high efficiency particulate air.” HEPA filters are physical filters designed to clear out at least 99.7 percent of particulates that are 0.3 microns or larger in size. For reference, a micron, or micrometer, is about one twenty-five thousandth of an inch and designated with an μm. (nbcnews. com)
Any air cleaner that has a HEPA filter has been tested and approved by the nonprofit Institute of Environmental Sciences and Technology . This means they are true HEPA. Some filters will label themselves as “HEPA-type” or “HEPA-like,” but these filters are not verified HEPA so may not be as effective. True HEPA filters draw particles in via a fan and trap them in a web of fibers. They perform better than standard filters and have become increasingly popular, says Varghese.
How do HEPA filters and UV light air purifiers work?
HEPA stands for “high-efficiency particulate arresting.” As the name suggests, these filters are really good at pulling things out of the air and holding onto them so that they can’t be recirculated. The fibers in a HEPA filter are designed to trap particles as small as .01 micron in diameter just a tiny fraction of the width of a human hair.
UV light devices, on the other hand, don’t remove anything. Instead, they’re designed to kill any viruses, bacteria or mold spores floating around by exposing them to ultraviolet light.
https://newsbreak.com/topics/guerin-green https://www.talgov.com/Main/exit.aspx?url=https://thecherrycreeknews.com
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