Smoke from two major wildfires burning in British Columbia’s Fraser Canyon is leading to air quality warnings across parts of the province, with an emergency physician warning the health effects extend far beyond watery eyes and a scratchy throat. “It is considered to be one of the biggest public health threats that we face,” said Dr. Courtney Howard, who is also the president-elect of the Canadian Medical Association. … “The particulate matter in smoke that’s less than 2.5 microns can go all the way down into our lungs, and the ultrafine particles can actually cross over into our bloodstream,” she said. …Howard said scientists are only beginning to understand the long-term health effects of repeated wildfire smoke exposure because the research is still limited. “We don’t have good evidence on the long-term outcomes yet,” she said. But a small number of studies, according to Howard, have suggested possible links with high rates of brain cancer and lung cancer.