Great Falls, Montana
Environmental Quality Report Card
Great Falls reports good air quality, with AQI levels worse than the national average. Water tests indicate safe conditions across key measures. Facility compliance with environmental standards is above the national average.
Air Quality (Annual Overview)
Grade BYearly average AQI (2024): 41.5. National average: 41.4. 93 moderate days, 2 unhealthy days recorded.
Water Quality (Key Indicators)
Grade ALatest pH level (2024): 8.38. Ideal range: 6.5–8.5.
Facility Violations
Grade BFacilities like factories and treatment plants had 8 significant and 452 total violations reported in 2024.
Water Quality (with EPA Standards)
Water quality measurements are provided by the Water Quality Portal , a collaboration between the USGS, EPA, and other agencies.
| Characteristic | Local Value | Safe Range | Grade | Last Measured |
|---|---|---|---|---|
| Copper | 0.00 mg/L | <1.3 | A | 3/18/2025 |
| pH | 8.38 | 6.5 - 8.5 | A | 10/15/2024 |
| Arsenic | 0.02 mg/L | <0.01 | F | 8/19/2024 |
| Zinc | 0.00 mg/L | <5 | A | 8/19/2024 |
| Lead | 0.00 mg/L | <0.015 | A | 8/19/2024 |
Water Quality (No EPA Standard)
These measurements do not have formal EPA standards but are still important indicators of local water quality.
| Characteristic | Local Value | Unit | Last Measured |
|---|---|---|---|
| Calcium | 44.00 | mg/L | 3/18/2025 |
| Bicarbonate | 180.00 | mg/L | 3/18/2025 |
| Sulfate | 39.40 | mg/L | 3/18/2025 |
| Total suspended solids | 5.00 | mg/L | 3/18/2025 |
| Aluminum | 0.10 | mg/L | 3/18/2025 |
| Chloride | 11.30 | mg/L | 3/18/2025 |
| Sodium | 20.00 | mg/L | 3/18/2025 |
| Temperature, water | 13.60 | deg C | 10/15/2024 |
| Organic carbon | 2.20 | mg/L | 3/18/2025 |
| Nitrate + Nitrite | 0.73 | mg/L | 10/22/2024 |
| Potassium | 4.00 | mg/L | 3/18/2025 |
| Magnesium | 13.00 | mg/L | 3/18/2025 |
| Hardness, Ca, Mg | 161.00 | mg/L | 3/18/2025 |
| Total Nitrogen, mixed forms | 0.89 | mg/L | 10/22/2024 |
| Total Phosphorus, mixed forms | 0.01 | mg/L | 10/22/2024 |
| Alkalinity, total | 150.00 | mg/L | 3/18/2025 |
| Specific conductance | 400.10 | uS/cm | 10/15/2024 |
| Total dissolved solids | 228.00 | mg/L | 8/19/2024 |
| Cadmium | 0.00 | mg/L | 8/19/2024 |
| Iron | 0.17 | mg/L | 8/19/2024 |
| Nitrogen | 0.02 | mg/L | 8/19/2024 |
| Dissolved oxygen (DO) | 8.34 | mg/L | 9/3/2024 |
| Orthophosphate | 0.00 | mg/L | 9/3/2024 |
| Manganese | 0.02 | mg/L | 8/19/2024 |
| Phosphorus | 0.02 | mg/L | 8/19/2024 |
| Temperature, sample | 16.20 | deg C | 8/19/2024 |
| Carbonate | 11.10 | mg/L | 10/15/2024 |
| Selenium | 0.00 | mg/L | 3/18/2025 |
Air Quality Details (2024–2025)
The Air Quality Index (AQI) measures how clean or polluted the air is. A lower AQI means cleaner air. Main pollutants include particulate matter like PM2.5, ozone, and others regulated by EPA standards.
Air quality data sourced from OpenAQ, aggregating official monitoring stations.
| Yearly Average AQI | National Average AQI | Good Days | Moderate Days | Unhealthy Days | Worst Day AQI | Top Pollutant |
|---|---|---|---|---|---|---|
| 41.5 | 41.4 | 266 | 93 | 2 | 140 (on 7/21/2024) | PM2.5 |
Monthly AQI Trend
Monthly average AQI values over the past year. Lower values are better. Peaks may indicate pollution events.
Facility Compliance
Facility compliance and violation data come from the EPA's ECHO database.
2,042 monitored facilities
Total Violations: 452
Significant Violations: 8
Total Penalties: $5,740,709
Despite 8 significant violations, Great Falls reported 452 total violations across monitored facilities in 2024. This results in a compliance grade of B, reflecting strong adherence to environmental standards compared to national benchmarks.
About the Data
This report uses the latest publicly available environmental data:
- Air Quality: Data sourced from the OpenAQ Platform, aggregating official air quality monitoring stations near Great Falls.
- Water Quality: Measurements from the Water Quality Portal, a collaboration between the USGS, EPA, and other agencies.
- Facility Compliance: Sourced from the EPA's ECHO Database, detailing facility violations, penalties, and compliance rates.
All data is refreshed regularly and reflects the latest available figures for 2024.