New Study Offers Detailed Look at How Wildfire Smoke Impacts Reno's Air Quality

A new study by Nevada's Desert Research Institute (DRI) gives a detailed look at the toxic chemicals in the wildfire smoke that blankets Reno each summer. Published Aug. 8 in the journal Atmospheric Pollution Research, the study compared air quality on smoke-free days in August-October 2019 with smoke-affected days in 2020, when California wildfire smoke drifted into northern Nevada.

The researchers measured fine particulate matter known as PM2.5 -- particles 2.5 micrometers or smaller that can lodge deep in the lungs -- along with organic carbon, elemental carbon, ozone, and more than 100 polycyclic aromatic hydrocarbons (PAHs), toxic compounds formed when fuel burns incompletely. PM2.5 exceeded U.S. Environmental Protection Agency (EPA) standards on 18 of the 50 smoke-affected days studied, which the researchers said showed substantial exposure relevant to public health.

Ground-level ozone, which forms when smoke's chemical compounds react with sunlight and other pollutants, rose by about 12% on smoky days. The increase was smaller than expected, since some smoky days actually recorded below-average ozone -- suggesting vehicle exhaust and other local pollution remain the main ozone source in the Reno area. PAH levels ranged from 6.3 to 47 times higher on smoke-affected days than on clean days, with methyl- and dimethylnaphthalenes the most abundant compounds found. Naphthalene, one of the gas-phase PAHs detected, is listed as a hazardous air pollutant by the EPA.

"The smoky summers are difficult for everyone in Reno, but they are challenging for sensitive groups, including children, older adults, people with preexisting health conditions, athletes and outdoor workers," said Vera Samburova, an atmospheric scientist at DRI and one of the study's lead authors. She said the findings can help identify which air pollutants most need close monitoring.

Study author Andrey Khlystov, a DRI research professor of chemistry, said the results show that further health studies and regular monitoring for a range of PAHs are needed in regions frequently hit by wildfire smoke.