Air Qualityi
TRI Facilitiesi
Active NPDESi
Air Quality — San Mateo County (2024)i
AQSThe Air Quality Index measures how clean or polluted the air is on a given day. AQI is reported at the county level. A score of 0–50 is considered good; 51–100 is moderate; above 100 may be unhealthy for sensitive groups.
Median AQI
PM2.5 Daysi
258Ozone Daysi
48Toxic Release Inventory (TRI)i
TRIFactories, refineries, and other industrial facilities that use or store hazardous chemicals are required to report their releases annually to the EPA. Being listed here does not mean a violation occurred — it means the facility is transparently tracking its chemical usage.
Reporting Facilitiesi
16With Chemical Datai
9Total Reported Releasesi
506 lbsWastewater & Stormwater Permits (NPDES)i
NPDESUnder the Clean Water Act, any facility that discharges wastewater or stormwater into rivers, lakes, or streams must hold an NPDES permit. "Effective" means the permit is currently active and the facility is authorized to discharge under its permit conditions.
Active Permitsi
3Expired / Terminatedi
27Cleanup Sites (Brownfields)i
EPA BrownfieldsFormer industrial or commercial properties where contamination has been found. "Remedy Complete" means cleanup is finished. "Construction Complete" means cleanup infrastructure is built but monitoring continues. "In Progress" means the site is still being investigated or cleaned up.
EV Charging & Alternative Fuel Stationsi
AFDCPublicly listed alternative fuel and EV charging stations within the municipality. Data from the U.S. Department of Energy. "Open" stations are currently available for use; "Planned" stations are approved but not yet operational.
Total Stationsi
26EV Stationsi
24Level 2 Portsi
40DC Fast Portsi
37