The Mid-Atlantic Vital Signs Network (MIDN) consists of ten NPS units in Pennsylvania and Virginia. The parks include cultural, historical and natural areas, many of which were established to preserve important sites associated with the Civil War. Shenandoah National Park (NP) is designated a Class I air quality area; the other nine units are Class II areas.
With the exception of Shenandoah NP and Valley Forge National Historical Park, the Network parks have no on-site ambient air quality monitoring; however, in most cases, there are nearby monitors. The air pollutants of significant interest for the MIDN are ozone and toxic pollutants. At Shenandoah NP, visibility impairment and atmospheric deposition are also of concern. Seven of the Network parks are in proposed 8-hour ozone non-attainment areas. An ozone injury risk assessment indicates the risk of injury is moderate to high in MIDN parks. Fish consumption advisories for mercury, PCBs, and chlordane have been issued in Pennsylvania and Virginia. Whether the major pathway for toxic pollutants in these states is airborne or waterborne is unknown.
The Network map below provides information on air quality monitoring. Ozone, sulfur dioxide, dry deposition, and meteorology are collected by the Clean Air Status and Trends (CASTNet) and Gaseous Pollutant Monitoring (GPMN) networks. Ozone is also monitored with passive samplers and portable continuous analyzers. Wet Deposition is monitored through cooperation with National Atmospheric Deposition Program/National Trends Network (NADP/NTN). The Mercury Deposition Network (MDN), part of NADP, collects precipitation samples that are analyzed for mercury. Visibility is monitored as part of the Interagency Monitoring of Protected Visual Environments (IMPROVE). Additional details on these parameters are described in Air Quality Monitoring.
Air quality monitoring in or near the network is indicated on the map by symbols, with the blue line showing the approximate borders of the network. The legend shows the symbols for the type of monitoring present, with NPS park units in green. The Class I area has linkable access to ARIS information.