Why Air Pollution Could Cause Lung Cancer Cases to Explode

The deleterious effects of air pollution range from the trivial (but still bad) to the very relevant (and very, very bad.) Pro athletes and chess players perform worse when exposed to high levels of air pollution, and toxic pollutants like PM 2.5 have been linked to lung inflammation, strokes, and death. Especially worrying is air pollution’s link to cancer: The European Environment Agency estimated last year that more than 10 percent of cancers on the continent are caused by exposure to pollution.

But for years, the specific way in which air pollution caused cancer was up for debate. Traditionally, researchers believed that environmental factors associated with cancer directly caused a person’s DNA to break and be repaired in an error-prone manner that could plant the seeds for a malignant tumor cell. This theory has been proven out for UV and other forms of radiation, for instance, but for fine particle air pollution known as PM 2.5, the science isn’t as clear. PM 2.5 are tiny droplets in the air—smaller than a grain of sand, a human hair, dust and pollen particles—that can be a mixture of metals, organic compounds, and hundreds of different chemicals. They form as a result of pollution emitted by vehicles, power plants, fires, and smokestacks, and people inhale unhealthy levels of them every year.

In a new study led by researchers in the U.K., the relationship between PM 2.5 and a type of lung cancer found in nonsmokers and light smokers took front and center. The team looked at nearly 33,000 instances of this lung cancer in the U.K., Canada, South Korea, and Taiwan; and gene-edited mice that developed lung cancer when exposed to PM 2.5. Based on these experiments, they were able to confirm the existence of a second pathway that causes cancer: widespread lung inflammation, resulting from air pollution. Their results were published on April 5 in Nature.

Read more at The Daily Beast.