In January 2025, two large wildfires burned through large areas of greater Los Angeles damaging or destroying more than 18,000 buildings and directly causing the death of 31 people. A study by public health researchers attributed another 409 deaths to factors associated with the fires. While the fires burned, air quality in Los Angeles was terrible. Researchers from UCLA’s School of Public Health collected air samples both indoors and out during and after the fires.
In particular, the researchers tracked levels of volatile organic compounds, or VOCs. VOCs are a wide variety of chemicals associated with products found in our homes. These include compounds found in paint, adhesives, carpeting, vinyl flooring, upholstery, cleaning products, cosmetics, and more. The list is extensive. Some of them are carcinogenic or otherwise harmful to human health.
The researchers found that while outdoor VOC levels dropped after the fires were extinguished, in some cases indoor levels of some compounds actually rose. The researchers believe that homes that had been blanketed in smoke continued to release VOCs into the air after the fires were gone.
Thus, even after wildfires are extinguished, residents in the area may remain at risk of exposure to indoor VOCs. The findings emphasize the need for targeted interventions that minimize indoor exposures as areas recover from wildfires. They recommend that affected homeowners open windows, run heaters or air conditioners, and otherwise take steps to clean the air in their homes.
