air quality deterioration caused by fire in USA and Canada

on October 15, 2017 local time, San Francisco issued a red air quality warning due to the spread of smoke and dust pollutants in the bay area caused by a continuous mountain fire in Northern California, Santa Rosa, California. Masks sold out on the market, and a mask was up to $10.99. Tom Flannigan, a spokesman for the air quality administration, said that wildfires caused a large amount of carbonized ash in the air, which was blown around by strong winds, and the smoke carbon index in the air of nearby cities and counties had reached the level of “very unhealthy” or “harmful”