San Mateo, CA
Environmental data for San Mateo in California
San Mateo, CA is tracked across three EPA datasets covering 14 Toxics Release Inventory (TRI) facilityies, 0 Safe Drinking Water Act systems, and 0 Superfund National Priorities List sites. Together these generate an environmental burden score of 24/100 (Low Risk), calibrated against national distributions for facility density, chemical release volume, Superfund concentration, and water-system health violations.
Industrial disclosures inside the county total 258.0K lbs of reported toxic releases under EPCRA Section 313, while 0 water systems carry an active health-based violation in the SDWIS record. EPA Air Quality System monitors logged a median AQI of 27 and a peak AQI of 73 in 2024, with 88% of observed days rated "Good" (0–50).
All figures below draw directly from federal EPA records, TRI self-reported emissions, SDWIS compliance history, NPL Hazard Ranking System scores, and AQS daily AQI summaries, and are not adjusted, weighted, or forecast. A past violation or elevated score does not itself indicate current unsafe conditions; it documents the regulatory and disclosure history publicly filed with the U.S. Environmental Protection Agency through the most recent reporting cycle.
Air Quality History (2020–2024)
EPA Air Quality Index (AQI) data showing how many days per year fall into each air quality category.
| Year | Good | Moderate | Unhealthy (SG) | Max AQI |
|---|---|---|---|---|
| 2024 | 281 (88%) | 38 | 0 | 73 |
| 2023 | 355 (98%) | 8 | 0 | 71 |
| 2022 | 267 (73%) | 98 | 0 | 85 |
| 2021 | 290 (79%) | 75 | 0 | 90 |
| 2020 | 257 (70%) | 99 | 5 | 199 |
Source: EPA Air Quality System (AQS) Annual AQI by County EPA Air Quality System (AQS) Annual AQI by County AQI categories: Good (0-50), Moderate (51-100), Unhealthy for Sensitive Groups (101-150), Unhealthy (151-200), Very Unhealthy (201-300), Hazardous (301+)
For detailed air quality monitoring data, pollutant breakdowns, and metro-level AQI trends, see Air Quality in California on PlainAirData.
TRI Facilities (14)
| # | Facility | Total Releases |
|---|---|---|
| 1 | Csbio | 230.1K lbs |
| 2 | Nxedge San Carlos | 20.7K lbs |
| 3 | US Doe Slac National Accelerator Laboratory | 4.7K lbs |
| 4 | Chemelex LLC | 2.4K lbs |
| 5 | Central Concrete Supply Co. Inc. - South San Francisco | 80 lbs |
| 6 | Central Concrete Supply Co Inc - Redwood City | 40 lbs |
| 7 | Granite Rock Co Redwood City | 15 lbs |
| 8 | Univar Solutions USA | 12 lbs |
| 9 | Harbor Ready Mix | 4 lbs |
| 10 | Harbor Ready Mix - Redwood City | 1 lbs |
| 11 | Te Connectivy Inc. | 0 lbs |
| 12 | Cemex San Carlos | 0 lbs |
| 13 | Vivion Inc | 0 lbs |
| 14 | Garratt-Callahan Co Burlingame | 0 lbs |
Cities in San Mateo (5)
Frequently Asked Questions
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What does this county environmental profile show?
This county environmental profile rolls up EPA Toxics Release Inventory facility reports, Safe Drinking Water Information System public-water-system filings, and Superfund National Priorities List sites for the county boundary defined by the U.S. Census Bureau. Facility counts reflect facilities with a reporting address inside the county, not where downstream environmental effects may be observed. Population figures are from the most recent Census ACS 5-year estimate. The county detail page is updated whenever the upstream EPA programs publish revised data; see the methodology page for the documented ingest cadence and the editorial choices governing how aggregations are computed.
Read our methodology — how this data is sourced, computed, and verified.