The role of cancer-causing airborne particulate matter
But even if measures are perfectly implemented, Joan Schiller, MD, will not breathe easy. An adjunct professor of oncology at the University of Virginia in Charlottesville, Dr. Schiller has researched the role of airborne particulate matter in causing cancer, a correlation barely mentioned in the ProPublica analysis, she pointed out.
Particulate matter contains a wide range of toxic substances, she said. Researchers have focused on particles 2.5 microns in diameter, or PM 2.5. Some studies have indicated that it’s responsible for one in seven deaths from lung cancer, Dr. Schiller said. “Air pollution also causes lung cancer in never smokers, people who’ve never smoked, not just in smokers.”
Power plants and automobile traffic may be more significant sources of PM 2.5 than industry, and wildfires have recently emerged as increasingly important source, a result of climate change and poor forest management, she said.
PM 2.5 doesn’t affect just lung cancer, said Alexandra White, PhD, an investigator at the National Institute of Environmental Health Sciences in Research Triangle Park, N.C. “My work, as well as work of others, is increasingly suggesting that air pollution is also related to breast cancer risk, in particular, air pollution that is arising from traffic related forces.” And more research is needed on other cancers, she said. “I think that the lack of findings of other cancer sites reflects a lack of study.”
Other pollutants not analyzed in the ProPublica report are also correlated to cancer risk. In a recent meta-analysis, researcher Stephan Gabet, PhD, PharmD, and colleagues at the University of Grenoble, France, estimated that 3.15% of new breast cancer cases in that country could be attributed to nitrogen dioxide and 2.15% to PM 10.
Sources of nitrogen dioxide, PM 2.5, and PM 10 in France include automobile traffic, inefficient wood-burning stoves, and coal-burning power plants in neighboring countries, Dr. Gabet said.
A good approach to reducing pollution from road traffic is the implementation of low-emission zones that prohibit the most polluting vehicles, he said. But a 2019 United Kingdom government study found that brake wear, tire wear, and road surface wear account for 72% of the PM 10 and 60% of the PM 2.5 pollution from road traffic, suggesting that a transition to electric vehicles won’t fix the problem. Better yet, is “the promotion of active modes like walking, cycling, etc., because like this, you can bring additional health gains due to the increase in physical activity,” he said.
Oncologists can help their patients reduce their exposure to air pollution, Dr. Schiller said. “If you have lung cancer, air pollution will hasten your demise. It makes you sicker. Oncologists should be telling their patients about this and advising them to move away from air pollution if possible, and also making sure they know to monitor the health of the air.”
On days when air pollution is high, patients may want to avoid exercising outdoors, or stay indoors altogether, Dr. Berg said. Air purifiers and N95 masks may also help.
And physicians can make a difference by speaking out in their communities, Dr. Schiller said. She is inviting oncologists to join a new group, Oncologists Understanding for Climate and Health. Through this group or on their own, oncologists can speak to their local legislatures or city councils in support of measures to reduce pollution, she said. “Doctors are trusted messengers.”
Dr. Berg disclosed affiliations with Grail, Mercy BioAnalytics and Lucid Diagnostics.
