Cleaning and disinfecting have taken on new levels of seriousness in the wake of the global COVID-19 pandemic. But new research from Indiana University suggests that increased use of chemicals to help thwart the spread of the virus may pose health risks of their own.

"Increased Indoor Exposure to Commonly Used Disinfectants During the COVID-19 Pandemic," co-authored by O'Neill School of Public and Environmental Affairs Associate Research Scientist Amina Salamova, Visiting Research Associate Guomao Zheng, and IUPUI Professor Gabriel Filippelli, appears in a forthcoming edition of Environmental Science and Technology Letters.

The researchers examined dust samples taken from vacuum containers and bags from residential homes across Indiana in June 2020, and compared them with previously collected samples in 2018 and 2019, before the COVID-19 outbreak. They discovered a significantly higher concentration of quaternary ammonium compounds (QACs), a major class of chemicals widely used as disinfectants in household cleaning products, in the samples collected after the COVID-19 outbreak.

"Some of those compounds are included on the Environmental Protection Agency's -N List of substances effective for elimination of the novel Coronavirus, and are widely used in homes, care and food facilities, schools, and stores," Salamova said.

While the good news is that people seem to be disinfecting and cleaning residential areas more than they had been previously, the chemicals they are using can cause health problems on their own if used in high enough concentrations.

"Elevated exposure to these compounds is concerning because it has been linked with increased risks of asthma, skin irritation, and reproductive effects," Salamova said.

The study is believed to be the first of its kind to investigate the occurrence of and exposure to QACs in residential dust samples collected before and after the COVID-19 outbreak. Other notable findings included:

• The levels of QACs in homes that have increased disinfecting routines due to the pandemic were higher than in homes that didn’t change their cleaning habits
• The levels in homes that disinfected more frequently during the pandemic (between one and five times a week) were significantly higher than in homes that disinfected less (less than once a week)
• The make-up of QACs found in products and in dust were similar, suggesting that cleaning products are a significant source of QACs in residential homes
• Scientists also found that homes that used alcohol or products that did not contain QACs also had lower levels, which could be a potential option for people to decrease QAC exposures in their homes

"Household dust has long been recognized as a reservoir and major human exposure pathway for many environmental contaminants, especially for children," Filippelli said. "Due to their low volatility, QACs are easily adsorbed into airborne particles and dust, which leads to long-term contamination of an indoor environment that is likely to last long after the pandemic."

Cleaning and disinfecting is essential during the pandemic and the safety of people in their homes and in public needs to be prioritized, and as part of the response to the pandemic the use of QACs will increase. However, we must pay attention to their levels in our environment and potential effects on our health and develop strategies to reduce our exposure.