Why we see unhealthy air over the holidays

Holidays and the winter weather could be partly to blame for Southern California’s less than ideal air quality lately.

Burning wood is a large source of fine particle pollution that really drives air quality concerns in the region during the cooler months.

Scott Epstein, who oversees air quality assessments with the South Coast Air Quality Management District (AQMD), told LAist that people usually light up their fireplaces and fire pits a lot more during the holidays.

“So, we tend to see some pretty high concentrations [of fine particle pollution] during the week between Christmas and New Year's,” he said.

The worst days tend to happen when we have stagnant air masses in the region with cooler nights, higher humidity, and less wind.

This week, the air quality has been moderate to unhealthy for sensitive groups, but that’s still better than during wildfires and around the July 4th fireworks.

“It's much, much cleaner than 4th of July,” Epstein said. “So 4th of July and 5th of July, we tend to reach very unhealthy or even hazardous levels on the [Air Quality Index] scale.”

The AQMD issues an air quality forecast each day based on the levels of fine particle pollution, ozone, nitrogen dioxide, and carbon monoxide for 45 different regions in Southern California. Those forecasts can have implications, including wood burning bans.

Five have been issued so far this season, but we’ve seen anywhere from eight to 35.

When in doubt, you can check the air quality in your neighborhood with the AQMD air quality map.