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When you cook or clean inside your home, what chemicals are you breathing in and are they potentially harmful? Chemists at Colorado State University have given us a head start on the answer.

A large collaborative research experiment to map the airborne chemistry of a typical home took place in 2018 and was co-led by Delphine Farmer, associate professor in the Department of Chemistry at CSU. The experiment, called HOMEChem, brought together 60 scientists from 13 universities in a test house at the University of Texas at Austin to perform typical household activities like cooking and cleaning and to use sophisticated instruments to document the chemistry which resulted. The effort, called HOMEChem, was supported by the Sloan Foundation.

In a new article from Environmental science and technology, Farmer’s team at CSU took the massive amounts of data collected during HOMEChem and sorted it by health effects. They identified the number of compounds they observed that are either known human toxins or, based on more recent Environmental Protection Agency models, predicted to be likely human toxins. Most of these compounds are emitted in small quantities and can be removed with adequate ventilation. But the health effects of the individual compounds and their complex mixtures within are not well understood by scientists.

The bottom line? “Indoor air is not going to kill you, but we find that indoor air contains significantly more – and often at higher levels – of known and potential airborne toxicants than outdoors, especially when cooking” said Farmer, an atmospheric chemist who, prior to this experiment, had spent most of his career measuring more “traditional” outdoor air toxicants.

Data management

The data management feat to meaningfully connect HOMEChem data to toxin databases was led by co-author Anna Hodshire, a former CSU postdoctoral researcher with skills in the analysis of atmospheric instrumentation data.

“I think it’s very interesting that there are so many compounds emitted from common household activities and that the majority of these compounds have not been studied from a toxicity perspective,” Hodshire said. “This does not automatically mean that all of these compounds are toxic, but it does indicate that much more work needs to be done to assess some of the compounds that are frequently emitted in high concentrations from household activities.”

From the wide range of compounds measured during HOMEChem, the usual suspects emerged, such as benzene and formaldehyde, in varying amounts. The lesser-known acrolein, which is a lung toxicant emitted from wood and burning fat, has emerged as an interesting potential compound for further investigation, Farmer said. Another compound that emerged from Hodshire’s analysis was isocyanic acid, which is not well studied and is known to react with proteins in the human body.

The researchers found that cooking activities produced greater amounts of potentially toxic compounds, similar to those seen in smoke from wildfires – which made sense to Farmer, when considering a wildfire as an “extreme form of the kitchen “.

Gaps in Understanding Everyday Toxins

Contributing to the body of knowledge about indoor air chemistry through the HOMEChem experiment has given Farmer and his team a new appreciation for just what is missing in our understanding of our daily exposures to potential toxins.

“We’ve done our part now, and hopefully there’s enough information for others to pick up the slack and see which compounds are important to study,” Farmer said.

Farmer and collaborator Marina Vance of the University of Colorado Boulder led a follow-up experiment to HOMEChem in 2022 called CASA, which delved into how chemicals emitted indoors react with surfaces such as floors , walls and furniture. The results of this experiment are forthcoming.

Source of the story:

Material provided by Colorado State University. Original written by Anne Manning. Note: Content may be edited for style and length.