Ozone 8-hour 4th-highest daily max
Ozone 8-hour 4th-highest daily max in Tuolumne County reached 0.071 ppm in 2024, 1% above the EPA NAAQS of 0.07 ppm.
County · TRI 2024
Tuolumne County, California Pollution
1 top TRI facilities tracked here. Ozone 8-hour 4th-highest daily max (NAAQS 0.070 ppm (8-hour)) rose modestly year over year (+6%). Ozone 8-hour 4th-highest daily max (NAAQS 0.070 ppm (8-hour)) concentrations have fallen 21% since 2010.
FIPS 06109 · population 54,993
Anomaly engine
Notable Signals
Top facilities mapped
Where Chemicals Are Released In Tuolumne County
Each red dot is one of the top TRI facilities. Size reflects 2024 total releases. County boundary outlined in blue.
Pollutant pathways
Tuolumne County Pollutant Multi-Year Trends
Ozone 8-hour 4th-highest daily max (NAAQS 0.070 ppm (8-hour))Health riskGround-level ozone (smog) forms when vehicle and industrial emissions react in sunlight. Inflames the airways, triggers asthma attacks, and worsens heart and lung disease.
Ozone 8-hour 4th-highest daily max (NAAQS 0.070 ppm (8-hour)) concentrations have fallen 21% since 2010.
Lifetime cancer risk all pollutants (100 in a million (EPA elevated threshold))Health riskEPA-modeled added cancer cases per million residents from a lifetime of breathing local air toxics. EPA flags 100-in-a-million as elevated.
Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.
Formaldehyde ambient mean (0.077 µg/m³ (1-in-a-million URE))Health riskAn air toxic emitted by refineries, wood products, and combustion. EPA classifies it as a known human carcinogen — long-term inhalation raises cancer risk.
Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.
Benzene ambient mean (0.13 µg/m³ (1-in-a-million URE))Health riskAn air toxic from gasoline, refineries, and tobacco smoke. A known human carcinogen — chronic exposure is linked to leukemia and other blood cancers.
Single-vintage exposure modeling — EPA cadence is multi-year, so no trend line yet.
TRI air releases (5.1 fugitive + 5.2 stack)Health riskToxic chemicals reported by industrial facilities as released into the air — fugitive leaks plus smokestack emissions. Higher pounds means more inhaled exposure for nearby residents.
TRI air releases (5.1 fugitive + 5.2 stack) volumes here are too small to anchor a multi-year trend; YoY movement is still shown above.
TRI water releases (5.3)Health riskToxic chemicals reported by industrial facilities as discharged to surface waters (rivers, lakes, the ocean). Affects fishing, recreation, and downstream drinking-water intakes.
TRI water releases (5.3) volumes here are too small to anchor a multi-year trend; YoY movement is still shown above.
TRI land + off-site releasesHealth riskToxic chemicals released to land on-site or transferred off-site for disposal — landfills, deep-well injection, and similar. Risks groundwater contamination over time.
TRI land + off-site releases volumes here are too small to anchor a multi-year trend; YoY movement is still shown above.
Top facilities · 2024
Where The Chemical Releases Are Concentrated
| Facility | City | Top chemical | Total releases | YoY |
|---|---|---|---|---|
| Spi Sonora DivSierra Pacific Industries | Sonora | Dioxin and dioxin-like compounds | 0 lb | -25% |
Equity context · ACS 2018-2022 · USEPA-clone EJ disparity
Who Lives In Tuolumne County
All block groups in Tuolumne County County, CA: 54,993 residents. County disparity score for pm2.5 (fine particulate) sits below the reference (88). Why we surface this →
11.4%
Low-income
20.8%
People of color
5.2%
Under age 5
27.3%
Over age 64
- PM2.5 (fine particulate)Health riskFine inhalable particles 2.5 micrometers or smaller. They travel deep into the lungs and into the bloodstream — linked to asthma, heart disease, stroke, and premature death.95in the highest 5% nationally
- OzoneHealth riskGround-level ozone (smog) inflames the airways. Even short exposures trigger asthma attacks and worsen chronic lung and heart disease.93in the highest 10% nationally
- Nitrogen dioxide (NO₂)Health riskA tailpipe and combustion gas. Concentrates near busy roads and industrial sites; raises risk of airway inflammation, asthma, and lower respiratory infections in children.25below the national median
- Diesel particulateHealth riskSoot from diesel engines (trucks, trains, ports, construction). EPA classifies it as a likely human carcinogen and a major driver of childhood asthma near freight corridors.5below the national median
- Toxic releases (RSEI)Health riskEPA's Risk-Screening Environmental Indicators score — weights TRI chemical releases by toxicity, where they go, and how many people are nearby. Higher means greater modeled cancer and chronic-health risk.6below the national median
- Traffic proximityHealth riskPopulation-weighted distance to high-volume roads. Living close to heavy traffic raises exposure to PM2.5, NO₂, and diesel exhaust — and the cardiovascular and asthma risks that follow.21below the national median
- Lead-paint risk (pre-1960 housing)Health riskShare of housing built before 1960, when lead-based paint was common. Dust from deteriorating paint is the leading cause of childhood lead poisoning, which permanently impairs cognitive development.49near the national median
- Superfund site proximityHealth riskPopulation-weighted distance to NPL Superfund sites — the most contaminated waste sites in the country. Nearby groundwater, soil, and air can carry industrial solvents, metals, and other long-lived contaminants.56near the national median
- RMP-facility proximityHealth riskDistance to facilities holding chemicals at quantities large enough to require an EPA Risk Management Plan (refineries, fertilizer plants, etc.). These pose acute exposure risk during accidental releases.28below the national median
- Hazardous-waste site proximityHealth riskDistance to RCRA hazardous-waste handlers (treatment, storage, disposal facilities). Indicates potential exposure to industrial chemicals in air, soil, and groundwater.39below the national median
- Underground storage tanksHealth riskDensity of underground tanks (gasoline, heating oil, industrial fluids). Leaking tanks are a leading source of benzene and other volatile organic compounds in groundwater drinking-water supplies.28below the national median
- NPDES wastewater proximityHealth riskDistance to permitted industrial wastewater dischargers. Closer proximity raises exposure to pollutants released into surface waters used for fishing, recreation, and downstream drinking-water intakes.58near the national median
- Drinking-water non-complianceHealth riskEPA score for public water systems with health-based Safe Drinking Water Act violations. Higher means more residents on systems that recently exceeded safe limits for contaminants like lead, arsenic, or nitrate.76above the national median
| Indicator | Disparity score | Reading |
|---|---|---|
| PM2.5 (fine particulate) | 88 | below the reference |
| Ozone | 85 | below the reference |
| Nitrogen dioxide (NO₂) | 25 | well below the reference |
| Diesel particulate | 6 | well below the reference |
| Toxic releases (RSEI) | 2 | well below the reference |
| Traffic proximity | 20 | well below the reference |
| Lead-paint risk (pre-1960 housing) | 34 | well below the reference |
| Superfund site proximity | 0 | well below the reference |
| RMP-facility proximity | 8 | well below the reference |
| Hazardous-waste site proximity | 29 | well below the reference |
| Underground storage tanks | 0 | well below the reference |
| NPDES wastewater proximity | 12 | well below the reference |
| Drinking-water non-compliance | 6 | well below the reference |
Source: Census ACS 2018-2022 (5-year) + USEPA-clone EJ blockgroup stats (raw indicators + EJ disparity mirror).
Health context
Co-Located Health Indicators
Modeled adult-prevalence estimates published by CDC PLACES, paired with this county's pollution and demographic context. Comparisons are ecological, not causal — pollution and disease prevalence covary at the area level, but the data does not attribute any individual's diagnosis to local exposure. How this section works →
Adult asthma (current)
10.3%
CDC PLACES · 2025 release · BRFSS 2022-2023
COPD prevalence
7.6%
CDC PLACES · 2025 release · BRFSS 2022-2023
Coronary heart disease
8.0%
CDC PLACES · 2025 release · BRFSS 2022-2023
Diabetes (diagnosed)
12.1%
CDC PLACES · 2025 release · BRFSS 2022-2023
Frequent mental distress
16.8%
CDC PLACES · 2025 release · BRFSS 2022-2023
PLACES uses BRFSS-modeled small-area estimates, not individual records. Crude prevalence shown above is the local rate as published; comparators are age-adjusted vs the California mean and the US mean — both population-weighted across counties — so geographies with different age structures stay apples-to-apples. Sources: CDC PLACES · 2025 release · BRFSS 2022-2023.
Browse
All 10 Tuolumne County Cities With TRI Data
Pollution trends and TRI 2024 pages for every tracked city in this county. Alphabetical.
- Cold Springs pollution· 0 facilities
- Columbia pollution· 0 facilities
- Groveland pollution· 0 facilities
- Jamestown pollution· 0 facilities
- La Grange pollution· 0 facilities
- Long Barn pollution· 0 facilities
- Mi-Wuk Village pollution· 0 facilities
- Sonora pollution· 0 facilities
- Soulsbyville pollution· 0 facilities
- Twain Harte pollution· 0 facilities
Sources.
- EPA Toxics Release Inventory · retrieved 2026-05-07.
All sources are federal public-domain datasets under 17 USC §105. We aggregate but do not relabel; the underlying observations remain attributable to EPA.