Updated July 31, 12:31 p.m.
Dense smoke from a series of wildfires burning in California has triggered air quality alerts across more than a 400-mile stretch of Nevada from Reno to Las Vegas.
The Clark County Department of Air Quality in Las Vegas has issued a smoke, ozone advisory through Wednesday in anticipation of air quality levels moving into the unhealthy range for the most vulnerable populations, including young children, senior citizens and those with respiratory issues.
The smoke is heavier in Reno and Carson City where the air pollution reached some of the worst ozone levels ever recorded in those cities on Monday because of big fires to the south near Yosemite National Park and to the north near Redding, California.
Air quality warnings that were in effect for all residents in Reno, Sparks and Carson City on Monday were dialed back to apply only to sensitive groups Tuesday morning but health officials say conditions may worsen as the day goes on.