ChemistryProf-Bucknell
Professor Douglas Collins, chemistry, conducts research in Bucknell's Mass Spectrometry Laboratory with Chris Azzam '23, a chemistry and teaching/research assistant.
Lewisburg, Pa. -- As workers return to offices and students to classrooms amid a COVID-19 resurgence from the delta variant, many are again asking how to ensure the air indoors stays safe.
 
For Bucknell University Professor Douglas Collinschemistry, there’s no debate. In a new paper, Collins uses existing indoor air quality management research to make the case for masks, high efficiency particulate air (HEPA) filters and ventilation as the most effective ways to mitigate the indoor spread of the virus. The paper also warns against dispersion of chemical cleaning agents using foggers, which can actually degrade air quality.

Collins teamed with Delphine Farmer, an associate professor of atmospheric chemistry at Colorado State University, on the perspective piece “Unintended Consequences of Air Cleaning Chemistry,” which was published late last week in Environmental Science & Technology, a journal of the American Chemical Society.

The authors write that the optimal way to maintain air quality is to limit pollutant sources in the first place, which is why Collins urges mask-wearing indoors.

“The best way to keep air quality healthy indoors is to eliminate or reduce the sources of pollutants that get into the building,” says Collins, who conducts indoor air chemistry research. “Most of the time, we bring contaminants or pollutant sources in, and some even originate from our own bodies. This is one reason we wear masks indoors — to reduce the emission of virus particles into the air if someone is shedding virus at the time.”

Once contaminants are introduced into the air inside a building, the authors report that proper ventilation and filtration of air are well-documented, effective strategies for mitigation. They endorse the use of HEPA filters to reduce indoor pollutants, and Collins expanded that to MERV 13 filters too.

“During the pandemic, and really any time, the safest, most effective way to eliminate contaminants is to use high-quality filtration — portable HEPA filter units or MERV 13 filters in HVAC systems — and also to bring in outdoor air when it’s safe to do so,” he says. “Both of those things are known to reduce the load of bioaerosol — air potentially containing pathogens  — and also to improve overall air quality in the building. That’s been well-tested and shown thoroughly in the literature, including in a number of recent studies.”

In his own classroom, Collins uses a simple filtration device consisting of a MERV 13 filter and box fan, a do-it-yourself remedy that’s cheap and easy to build. The filters are safe, inexpensive and readily available at hardware stores, retailers and online.

“There are a lot of different ways to filter the air that don’t involve an expensive retrofit,” he says. “You can upgrade the filters in your HVAC system, but it’s not always simple to switch out filters in a commercial building. A great way forward is to put portable air filters in the room and run them all of the time.”

Filters and outdoor ventilation have been proven to be safer and more effective than foggers, which disperse chemical cleaning agents designed to kill the virus on surfaces. Introducing cleaning chemicals into the air may have a detrimental impact on respiratory health, according to the authors.

“Introducing even more reactive chemical material into the air could potentially cause long-term effects on our health,” Collins says. “For example, cleaning professionals who use bleach on a regular basis have been shown to have a higher incidence of respiratory issues than people who don’t.”

The authors wrote that there is an urgent need to apply existing knowledge and perform specific chemistry studies associated with air cleaning technologies in realistic indoor settings. Collins plans to continue his own indoor air chemistry research.

Collins and Farmer conclude that prolific use of chemical disinfectants and reactive processes for air cleaning warrants extreme caution.


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