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Air quality expert recommends fourth 'W' to limit virus exposure: Open windows

Posted January 7

— Despite pleas from health officials to limit indoor gatherings, family and friend get-togethers continue pushing the state’s daily coronavirus case totals to record highs.

In addition to the oft-repeated guidance to wear masks, keep at least 6 feet away from others and routinely wash your hands, one expert says keeping your indoor air fresh also will help lower the exposure to the virus.

"COVID actually helped us a lot for people to understand [that], if something is invisible, it doesn’t mean it’s not dangerous," said Ellie Amirnasr, chief executive of Raleigh-based qlair, which specializes in analyzing and improving indoor air quality in businesses and homes.

Business has picked up because of the virus, and customers are usually pleased to know a lot of the fixes are simple and fairly inexpensive, Amirnasr said.

"The best thing at this point that we recommend for our customers is improve your filtration system," she said.

With the market flooded with devices that claim to fight the virus, she cautioned people against dropping a lot of money on things like bipolar ionization systems. She agrees with a top indoor air quality group that there’s not enough evidence those systems work.

"The tests have been done and show the effectiveness in the lab, not in real life," she said.

Ultraviolet systems are also being advertised to the kill coronavirus. While that’s a proven method for years, actually killing virus in your home’s air is tricky, Amirnasr said.

"UV originally was used for surface treatment, and for air treatment, if you want to do that, you have to slow the air flow, and you have to give it enough time," she said.

Adding a UV system to your air handler may not do the trick, she added: "With one pass through, nothing will happen."

Top-of-the-line air intake filters for your HVAC system can capture virus, but if you're determined to buy a device, Amirnasr recommended getting an air purification system. While they’re hard to find at times in stores, she said to make sure you get one with HEPA filters.

"HEPA filtration units are very useful for capturing very small particles, especially viruses," she said.

Qlair is working with North Carolina State University and two other schools in the University of North Carolina system to prepare for in-person instruction in the spring.

The company installed sensors in labs and classrooms that constantly measure air quality. Using a simple red, yellow and green display, the sensor shows when it’s time to refresh the air. One of the key detection methods is the amount of carbon dioxide in the air, which is what people exhale. Once that level gets high, there’s an increased risk of viral spread if someone in the room is infected.

There’s no one device that’s been proven to stop the virus, and Amirnasr said part of the challenge is getting reliable test results,

"Virus measurement is almost impossible because it requires air sampling [and] lab testing," she said. "It’s super-difficult. It’s very expensive."

But, she said, one of the best ways to fight the virus is free. Simply open doors and windows on opposite sides of the house, especially if you have guests over.

"That will help to have clean air inside the building," she said. "So, you have the old air out [and] the clean air inside the building. You have fresh air, and you reduce the chance of any virus sitting around."

Amirnasr recommended that people recycle residential indoor air two to three times an hour. Businesses should recycle four times an hour and schools six times an hour just by opening a classroom window, if possible.

Ceiling fans or standalone fans can help move air around, which helps. But Amirnasr said that’s not effective by itself.

"When you are actually turning on the ceiling fan," she said, "if there’s no fresh air coming in, you’re only recirculating the air inside the building.

"If you are turning on the ceiling fan, you better only do it in combination with opening the window," she added.