CU Boulder Study Reveals Pollutants in Smoke-Infected Homes for Weeks

BOULDER, Colo. – Nearly three years after the devastating Marshall Fire destroyed over a thousand homes in Colorado, a research study conducted by a team from the University of Colorado Boulder is trying to answer some of the questions raised by the disaster.

In the days following the fire, concerns arose among residents who still had houses standing about the effects of the smoke on their health and homes. Those concerns led CU Boulder to assemble a team of engineers, chemists, geographers and other scientists to begin analyzing the data as soon as possible.

University of Colorado Boulder

Joost de Goux, a CU Boulder chemistry professor and one of the lead researchers, helped set up measuring equipment inside a Superior home within ten days of the fire. “The unique thing about the Marshall fire is that it happened right next to Boulder, Colorado,” de Goux noted. “We had all these scientists with all their equipment that could start making these measurements.”

The homes acted like mushrooms, absorbing smoke from the fire and slowly releasing it again. “We expected these things to be gone within hours from these homes, but in fact it took days to weeks,” explained de Goux. “It was a surprise and something that we still don’t fully understand.”

University of Colorado Boulder

The figures showed that the concentration of several pollutants was much higher than normal at the start of the study. The pollution inside the homes was comparable to the city air of Los Angeles in the 1990s, but the pollution rate dropped to 20% of the original value in about five weeks.

The pollutants they analyzed are called volatile organic compounds (VOCs), which can be toxic. Before the air returned to normal, the team explored practical ways to mitigate VOCs. “We open windows and it makes the air inside cleaner,” de Goux said. “We also built these do-it-yourself activated carbon air purifiers, and they were also very effective at making the air cleaner.”

The air cleaners cost about $80 to make with parts from local hardware stores. They are constructed of a box fan and pour pleated air filters with activated carbon. While the cleaners only ran for an hour, they measured a drop of more than 50% in VOC. Unfortunately, the pollution level would quickly rise when the purifiers were turned off again.

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Professor de Goux is relieved to finally release their research after almost three years. “It takes time and it can be frustrating for the public,” de Goux said. “It’s frustrating for us, frankly. We know quite a lot very quickly, and we want to share that, but it’s better to get the most out of that data so you’re completely confident in your results.”

If you want to read about the results of the survey yourself, you can check it out per by following this link:

You can also look at CU Boulder’s companion study analyzing the long-term health effects of living near the fire area, at by following this second link: