Daily air tracker
Chula Vista air quality
South Bay air can swing fast with border traffic, marine layer and inland heat. Here's today's reading and what to do about it.
Updated daily
Chula Vista air quality & pollen
Live U.S. AQI for the South Bay with particulate readings, the next 24-hour peak, and what it means for your day.
Why the South Bay differs
Idling traffic at San Ysidro and Otay Mesa plus the I-5/I-805 corridors push particulate levels above the county average on still days.
Best air of the day
Mornings before 9 AM usually have the lowest ozone — the sweet spot for running the Bayshore Bikeway.
Wildfire season
During Santa Ana events, AQI can jump 100+ points in hours. Check before outdoor sports practice.