St. Maries Air Monitoring Station | Benewah County, Idaho | US EPA AQS Network

St. Maries is an air monitoring station located at the USFS facility at 9th and Center in St. Maries, Idaho, within Benewah County. The station is operational and reports to the Idaho Department of Health and Welfare-Environment Division, contributing to the US EPA's Air Quality System (AQS) network. As a rural monitoring site, it plays a role in assessing regional air quality in the Pacific Northwest. The station operates under the regulatory framework of the US Clean Air Act, which mandates monitoring of criteria pollutants such as ozone, particulate matter, and nitrogen dioxide. While specific parameters measured are not detailed, typical rural stations in Idaho monitor ozone and PM2.5 to support compliance with National Ambient Air Quality Standards (NAAQS). The station's last reported sample date is June 30, 2025, indicating ongoing data collection. Environmental monitoring in this region is important due to influences from wildfire smoke, agricultural activities, and industrial sources in the broader inland Northwest. Data from St. Maries helps track long-term air quality trends and supports public health advisories. The station's siting at a USFS location ensures representativeness of background conditions, contributing to a comprehensive understanding of regional air quality.

The St. Maries air monitoring station is situated in a rural area of northern Idaho, where air quality can be affected by seasonal wildfires, agricultural burning, and occasional industrial emissions from nearby timber and mining operations. Monitoring in this region focuses on criteria pollutants like ozone and particulate matter to assess compliance with NAAQS. The station's location within a USFS facility provides a representative background site, helping to differentiate local sources from regional transport. Continuous reporting to the Idaho Department of Health and Welfare supports state and federal air quality management programs.