An advisory for likely pollution from New Year's Eve fireworks went into effect Thursday in a large portion of Southern California.
The South Coast Air Quality Management District said the advisory for high levels of particulate matter and metal air pollutants would be in effect through Friday morning.
The air quality index could reach the category of unhealthy for sensitive groups, or even higher, the district said.
Widespread personal use of fireworks has become a problem in the region, even though it is largely banned. Fireworks emissions and a stagnant weather pattern combined to create terrible air quality last Fourth of July.
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People in direct proximity to personal fireworks may be exposed to fine particulate matter concentrations far in excess of the regional measurements, according to the district, which encompasses major portions of Los Angeles, San Bernardino and Riverside counties as well as all of Orange County.
Fireworks also raise the potential for wildfires.
NBC4 Meteorologist Anthony Yanez said the region will be mostly clear and cool.
Santa Ana Winds arrive as we start the new year Friday.
Yanez said California's first snow survey of the season was Thursday, and while the Phillips Station near South Lake Tahoe was 93% of average, the state is 52%.
"We will be tracking several storm systems in the next seven days that will bring more Sierra snow and more precipitation for Southern California next week," he said.