Guideline on Regular COVID-19 Prevention and Control

As confirmed cases of COVID-19 continue to increase, community containment, home isolation, and remote working force industries once again to face a slowdown and stagnation.

For the past nearly three years, local confirmations, asymptomatic infections, epidemiological investigation, and nucleic acid screenings have invaded our lives. People may be anxious, terrified, angry, and numb. Some are eager to get back to normal and work offline to support their families, and others assume that lockdown may better control the spread for the fear of cross-contamination. We will NOT discuss which approach is the best, or judge the release and implementation of policies.

As a part of the struggling, I suggest that we face the plight rationally and calmly, and learn about scientific, effective and safe prevention while fighting for our democratic rights.

—–Know the enemy, and you will not be afraid of it.

Remote working, home isolation, full liberalization, how to reduce the risk of indoor virus transmission to secure indoor breath safety? We have selected the most asked questions:

1. Is it true that air purifiers can filter viruses?

Absolutely yessss!

HEPA air purifiers are very effective tools for removing airborne viruses and reducing your risk of catching a virusA CDC study shows HEPA filters reduced COVID-19 spread in schools by 41%.

Learn more:

2. Do UV light air purifiers help kill viruses?


Scientists have shown a dose of 75mJ/cm2 is needed to kill >99.9% of the COVID-19 virus. However, typical UV light air purifiers on the market can’t meet the requirement of dose or duration time. What’s more, UV light can also damage HEPA filters and reduce the filtering efficiency. It’s HEPA filters that are great at capturing viruses.

As for why so many businesses are touting that UV light purifiers can kill viruses, the answer is straightforward, money.

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3. What about ionizers?


Ionizers work by adsorbing airborne particulate matters, while scientific tests found that most air ionizers have no noticeable effect, and rather create ultra-fine particles (such as PM2.5). Besides, Ionizer air purifiers produce ozone. On its own, ozone is a harmful lung irritant and highly reactive. Ozone often reacts with other substances in the air and creates new byproducts, including formaldehyde and other VOCs.

Then why do many brands boast that “ionizers can purify the air” and “can destroy the barrier of viral charges”? This is the same as the gimmicks of UV lights.

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4. Air purifiers of big brands with fancy technology are better at filtering the virus?


In fact, air purifiers that contain HEPA filters are all good at capturing the virus! A study at the University of Minnesota showed that HEPA filters captured 99.99% of particles smaller than 5nm. The COVID-19 coronavirus measures 0.06–0.14μm in diameter, which can be captured by HEPA filters. (?FYI: 1nm=0.001μm)

In the past three years affected by the epidemic, many purifier brands have exaggerated or falsely marketed and advertised that only their “high-tech products” are “effective” to “eliminate the virus”. This is why Smart Air has been devoting to uncovering the truth of air purifiers through open data and research!

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5. What is the recommended air change rate?

Be aware that opening windows for ventilation may reduce viral infections or CO2, but it could also bring more PM2.5 in if the outdoor air is terrible!

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6. How to limit COVID-19 spread in the office or classroom?

Schools and companies are advised to purchase suitable air purifiers in classrooms and offices to remove airborne particulate pollution (including outdoor haze, viruses, bacteria, pollen, allergens, etc.).

To choose a purifier suitable for a classroom/office, you will need:

  1. Measure the area/dimension, calculate the CADR and find an appropriate air purifier;
  2. Avoid extra add-ons such as UV-lights and ionizers. These add-ons increase cost and may pose an additional health risk for office workers;
  3. Consider cost/lifespan of replacement filter! Take note that many air purifier companies are not transparent with HEPA filter replacement recommendations;
  4. Consider noise level: At Smart Air, we recommend air purifiers with a top sound of close to 50 dB. Anything above 60 dB is likely to be a disturbance in the office.

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7. How about buying kids a wearable air purifier?


Study has proven that wearable air purifiers are ineffective at purifying the air. What’s worse, wearable air purifiers can create ozone due to the use of an ionizer instead of a HEPA filter. Kid’s clothes and skin may also act as the magnet for the pollution to stick to, resulting in greater breathing risk.

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8. N95 masks vs. Surgical masks: Which is better for COVID-19?

Qualified N95 and surgical masks BOTH work.

N95 masks offer better protection, filtering at least 94% of airborne particulate matters, but medical masks also block 80% of virus-sized particles. Well done!

Note: masks are becoming fancier, but we need to pay attention to the quality, otherwise wearing masks will be ineffective.

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9. How to disinfect masks when coming back home?

Washing N95/KN95 masks with water reduces their filtration effectiveness by 21%, and dipping N95 masks in rubbing alcohol reduced particle capture by 37%. Leaving masks out to dry should disinfect them from COVID-19, SARS, and influenza A in under 48 hours. 72 hours would be even more conservative.

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10. What if I see a bunch of anxious and annoying information on social media?

We suggest you to read more scientific information released by Smart Air for in-depth knowledge of virus, haze and air pollution prevention tips.

Feel free to contact us if you are curious about something and the researchers are in place ? (@Thomas, Paddy and Tyler).

Having published more than 28 articles and 16 videos on COVID-19 since 2020, Smart Air strives to help dispel common misconceptions and provide effective ways to prevent the virus. Smart Air has been providing transparent and reliable sources of scientific support and information during the epidemic.

In addition, Smart Air has provided effective air purifiers (over $70,000) to schools and hospitals around the world, to protect vulnerable groups of society.

Last but not the least——Know the enemy, and you will not be afraid of it.

May we all be able to protect ourselves and loved ones with science! Breathe safe!

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Smart Air is a social enterprise and certified B-Corp that offers simple, no-nonsense air purifiers and provides free education to protect people from the harms of air pollution. We are proud to be the only certified B-Corp dedicated to fighting air pollution.

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