Cleaning products could expose people to pollution at the same rate as cars, study finds

Cleaning products have become more ubiquitous than ever in the past two years, but a new study suggests their use may pose a health risk.

Researchers in the United States have made real-time observations under “realistic indoor conditions” that mimic the work of professional indoor cleaners.

Commercial cleaners for disinfecting indoor surfaces can deposit small polluting particles into human airways at rates equal to or greater than vehicle aerosols, they found.

The new findings may have implications for people who have worked extensively with disinfectant sprays during the Covid pandemic.

Some staff spent entire workdays frequently hosing down touchpoint surfaces in offices to prevent transmission of SARS-CoV-2.

The study was led by Colleen Rosales, an environmental scientist at the University of California, Davis and published today in Science Advances.

“One of the disturbances that humans introduce into the indoor environment is the use of household cleaning and disinfecting products, some of which have ‘natural’ scents, such as citrus or pine,” say Rosales and colleagues. in the article.

“Workplace and residential exposures leading to adverse health effects are likely to be influenced by increased chemical disinfection of indoor surfaces during the coronavirus disease 2019 pandemic.”

Scientists know that cleaning indoor surfaces with disinfectants can generate secondary indoor pollutants in the form of gases and aerosols.

But few studies have captured the formation of secondary organic aerosols under realistic indoor conditions.

A secondary organic aerosol (SOA) is a molecule produced by oxidation over several generations of a parent organic molecule.

“SOA represents a major fraction of the global atmospheric aerosol load,” said atmospheric scientist Professor Annele Virtanen at the University of Eastern Finland, who was not involved in the study.

“Understanding the formation mechanism and properties of SOA is therefore important for estimating its effects on climate, air quality and human health.”

Road transport is a source of both greenhouse gases and air pollutants, being responsible for significant contributions to emissions of carbon dioxide, nitrogen oxides and fine particles

To learn more about SOA formation indoors, the US team focused on monoterpenes, a class of volatile organic compounds (VOCs).

Monoterpenes are released from a very wide range of sources, including cooking, foodstuffs, plants, and multiple types of scented products.

In an indoor environment, monoterpenes can mix with ozone to form particles that can burrow inside the lungs.

The team used a monoterpene-based commercial household cleaner to clean surfaces inside an enclosed, mechanically ventilated test room in a research building in a wooded area for 12 to 14 minutes.

As the soil was cleaned, the researchers measured gas-phase precursors, oxidants, radicals, secondary oxidation products, and aerosols in real time.

They calculated that someone using a monoterpene-based cleaning product would first inhale about 30 to 40 micrograms of the primary volatile organic compound per minute when they begin to wash.

As secondary organic aerosols are formed when the product interacts with the air in the room, the person would then inhale about 0.1 to 0.7 micrograms of these particles per minute.

The authors suggest that keeping background ozone levels indoors below 1 part per billion before cleaning could minimize the buildup of polluting particles.

As the soil was cleaned, the researchers measured gas-phase precursors, oxidants, radicals, secondary oxidation products, and aerosols in real time. In these graphs, the gray shading corresponds to active periods of cleaning and wiping during cleaning events

The VOCs currently used in aerosols are less harmful than the ozone-depleting chlorofluorocarbons (CFCs) they replaced in the 1980s.

CFCs, which are classified as halocarbons, damage the Earth’s protective ozone layer which protects us from harmful ultraviolet rays generated by the Sun.

Recognizing the danger of CFCs, the Montreal Protocol was concluded in 1987, which led to their phasing out and, recently, to the first signs of recovery of the Antarctic ozone layer.