California’s Air Monitor Finds Toxic Lead in Wildfire Smoke

The black smoke that blanketed Northern California as a result of 2018’s Camp Fire contained extreme levels of lead and other toxic metals, according to a new study by the state’s air regulator. As summertime wildfires hammer the drought-stricken Western U.S., the new findings raise alarms about the risk of previously unforeseen health impacts such as cancer and learning deficits.

Some parts of California such as the city of Chico saw lead concentrations briefly spike to 50 times the average level, the study by the California Air Resources Board found. “This report makes it clear that wildfire smoke poses a real health threat not only to people living and working near these fires, but to anyone affected by the smoke as it travels across California and beyond,” said Richard Corey, executive officer of the agency, in a press release.

CARB’s report is based on air-quality samples taken during a November 2018 wildfire sparked when a PG&E Corp. power line broke loose from a transmission tower. The Camp Fire was especially destructive, killing 85 people and leveling the entire town of Paradise, including some 19,000 buildings. When structures burn, toxic substances can enter the air.

California’s Air Monitor Finds Toxic Lead in Wildfire Smoke

In addition to lead, researches founded elevated levels of zinc, calcium and iron. Smoke containing these metals reached San Jose, far from the burn site. Researchers pinpointed the most concerning spike to a 24-hour period on Nov. 10, 2018.

The findings come as the Western U.S. faces unusually elevated risk of wildfire. Already, the Bootleg Fire in Southern Oregon has charred 150,000 acres and has taken down key power lines that connect to California.

Man-made climate change has been definitively linked by scientists to the intensified heat and drying events that are plaguing the West and driving these fires. Late June and early July saw the region break  heat records at a stunning pace. California’s Death Valley region reached 130° Fahrenheit (54.4° Celsius) over the weekend; Las Vegas passed 117°F.

Academic studies have linked global warming to a five-fold increase in annual burned area in California from 1972 to 2018, putting more infrastructure built with metals at risk. In recent years, scientists have also advanced the knowledge of the ill effects caused by the particulate matter carried by wildfire. Because such particles can be very fine they can be inhaled deeply in the lungs.

Short-term wildfire smoke exposure has been linked with upticks in asthma and other respiratory illnesses as well as pulmonary disease and is correlated with an uptick in emergency room visits.

Vijay Limaye, an environmental epidemiologist with the Natural Resources Defense Council who specializes in air emissions, said the findings of the study  were worrying and required further study.  While there’s extensive data on devastating impact of long-term exposure to lead and other chemicals, particularly for children under 6, there’s less knowledge about effects from wildfire smoke exposure that is short but intense, like the spike seen in 2018.

“These toxics represent new territory in terms of acute exposure,” Limaye said. 

Heath data from the U.S. Environmental Protection Agency doesn’t yet capture lead exposure from wildfire smoke, he added, suggesting that that should soon change. “Because more and more this is going to be an area of concern,” Limaye said. “Not just people exposed to the flames but also that smoke is potentially traveling hundreds of miles downwind.”

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