Today in the city

Air quality in National City

We sit next to a working port, two freeways and rail lines. Air quality here matters more than the county average suggests — so here's where to check it and what to do.

Live AQI for 91950

AirNow's official reading for our ZIP code, from the EPA and the San Diego County Air Pollution Control District.

Check AirNow

Neighborhood-level sensors

PurpleAir shows block-by-block readings, which can differ a lot between the bayfront and the east side.

Open the sensor map

What the numbers mean

Air quality index ranges and what to do
AQI	Level	What to do
0–50	Good	Normal day. Go to the park.
51–100	Moderate	Fine for most people; sensitive groups take it easy outdoors.
101–150	Unhealthy for sensitive groups	Kids, seniors and anyone with asthma should limit long outdoor exertion.
151–200	Unhealthy	Move workouts indoors, close windows, run a filter if you have one.
201+	Very unhealthy	Stay inside, keep windows shut, and check on elderly neighbors.

Why it's different here

Port operations and ship traffic sit right at the west edge of the city.
I-5 and SR-54 push diesel exhaust through the neighborhoods that border them.
Onshore afternoon breezes usually clear the bayfront first; the east side clears last.
Wildfire smoke from inland San Diego County can spike the AQI with no local cause.