Worst air pollution Union City, today and tomorrow
Today (15 July): Air quality in Union City is fair. AQI and O3 are fair; PM2.5, PM10, NO2, SO2, CO, HCHO, and PM1 are good. Pollution peaks around 8:00 AM (O3: 39.4/100).
Tomorrow (16 July 2026): Air quality in Union City is fair. AQI improves to medium; PM2.5 increases to fair; O3 decreases to medium; all other pollutants stay as today. Pollution peaks around 10:00 AM (O3: 41.0/100). Airmine updates local air quality forecasts four times daily.
For long term forecasts and maps, see the Airmine app
Developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team
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Union City's air quality reflects the East Bay Fremont plain position, with vehicle emissions from I-880 and the surrounding industrial and residential character generating elevated NOₓ alongside the dense suburban character of this Alameda County community. The Bay Delta breeze provides afternoon ventilation, while the Diablo Range to the east creates topographic enclosure and the Port of Oakland's freight diesel influence extends southward along the I-880 corridor throughout the year.
Today - 15 July | Pollution peaks at 08:00
AQI:
Fair
39.4/100
PM2.5 (fine particles):
Good
15.5/100
PM10 (coarse particles):
Good
9.5/100
NO2 (nitrogen dioxide):
Good
8.1/100
O3 (ozone):
Fair
39.4/100
SO2 (sulfur dioxide):
Good
3.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
2.2/100
PM1 (ultrafine particles):
Good
8.5/100
Levels show the poorest local air quality during the day
Tomorrow - 16 July | Pollution peaks at 10:00
AQI:
Medium
41.0/100
PM2.5 (fine particles):
Fair
21.3/100
PM10 (coarse particles):
Good
10.5/100
NO2 (nitrogen dioxide):
Good
17.3/100
O3 (ozone):
Medium
41.0/100
SO2 (sulfur dioxide):
Good
3.5/100
CO (carbon monoxide):
Good
0.0/100
HCHO (formaldehyde):
Good
1.9/100
PM1 (ultrafine particles):
Good
14.2/100
Pollen forecast in Union City
View pollen forecastFrequently Asked Questions
Is air quality bad in Union City right now?
On 15 July 2026, overall air quality in Union City is fair. AQI is the main air quality indicator at 39.4/100. Pollution peaks around 8:00 AM (O3: 39.4/100).
Will air quality be worse tomorrow in Union City?
On 16 July 2026, air quality conditions in Union City will be similar to today, with PM2.5 forecast at fair at 21.3/100. Pollution peaks around 10:00 AM (O3: 41.0/100).
When is air pollution at its worst in Union City?
Air quality in Union City shifts across the year. In short, the cleanest air usually comes in winter, when storms periodically flush pollution out of the basin, whereas summer and early autumn bring the highest ozone levels, and wildfire smoke can spike particulate readings sharply from August through October. The mountains ringing the basin can trap pollution close to the ground for days when winds are calm.
Are air quality levels in Union City based on measurements or forecasts?
It is forecasts derived by downscaling forecasts provided by EU’s Copernicus Atmosphere Monitoring Service (CAMS) by taking into account local conditions such as traffic patterns. CAMS bases its forecast on satellite measurements of particles and chemical compounds in the atmosphere. Airmine’s services were developed with support from the European Space Agency (ESA)’s Business Applications and Space Solutions (BASS) team.
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Data provided by Airmine — Last update: 16 July 2026 at 10:33 CEST (Data is updated four times daily.)
This forecast is produced independently using Airmine's own atmospheric data and models.
Unless explicitly made clear, the content on this site has not been paid for by external organisations and is Airmine's sole responsibility.
For long term forecasts and maps, see the Airmine app