05/31/2026
When fire tore through Los Angeles County in January 2025, westerly winds blew most of the smoke and ash over the Pacific, keeping the main measure of air quality, total mass of particles smaller than 2.5 microns, at or near normal levels.
But a study published in the Journal of Hazardous Materials found the particles floating while the fires burned differed sharply from ordinary urban pollution and from smoke generated mainly by burning vegetation. The samples contained enriched levels of chemicals in manufactured products: toxic metals, polycyclic aromatic compounds, volatile organic compounds and polyfluoroalkyl substances – also known as PFAS or “forever chemicals” – in the ash.
The findings suggest that mass-based smoke readings can understate the potential hazard of fires that burn through densely built communities. “I do not want the message to be simply scary,” said the lead study author and RCEI affiliate José Guillermo Cedeño Laurent, an assistant professor at Rutgers School of Public Health. “The point is that if we want to understand the risks, we need to know the composition of the particles, not just the amount.”
Read and learn more at https://rcei.rutgers.edu/when-neighborhoods-burn-the-smoke-carries-more-than-soot/