Description: In-park, representative and general visibility monitoring sites are from the Interagency Monitoring of Protected Visual Environments (IMPROVE) network. Representative IMPROVE monitoring sites were selected based the following criteria: within +/- 100 feet or 10% of maximum and minimum elevation of the park and at a distance of no more than 150 kilometers from park boundaries. IMPROVE representative monitors are not assigned to parks with an urban land-use category unless the monitor is also within the urban land-use category (e.g. Puget Sound monitoring site [PUSO1] is representative of Klondike Gold Rush – Seattle Unit). Land-use categories were derived from the National Land Cover Database 2011 edition. There are monitoring sites that are classified as in-park but are slightly outside of park boundaries (i.e. within 1 km boundaries).
Description: <p style="box-sizing:inherit; margin-top:0px; margin-bottom:15px; padding:0px; border:0px; background-image:initial; background-position:initial; background-size:initial; background-repeat:initial; background-attachment:initial; background-origin:initial; background-clip:initial; line-height:18px;"><font color="#333333" face="arial, helvetica, sans-serif"><span style="font-size:12px;">Webcams are part of the NPS air quality web camera network ran by NPS Air Resources Division. The webcam network provides current digital images and air quality information from national parks. Images are updated every 15 minutes. Air quality data—including ozone, particulate matter, visual range, & weather conditions—are updated hourly. </span></font></p><div><br /></div>
Description: <span style="font-family:"Avenir Next W01", "Avenir Next W00", "Avenir Next", Avenir, "Helvetica Neue", sans-serif; font-size:16px;">In-park, representative and general o</span>zone monitoring sites report data to the Environmental Protection Agency and stored in AQS (the Air Quality System data mart). Representative ozone monitoring sites are within 10 km of park boundaries. There are a handful of representative monitors that are no longer the closest monitor within a 10 km radius but are retained as the representative monitor to maintain consistent historic trend records.
Description: <div>In-park, representative and general wet deposition nitrogen and sulfur monitoring sites are part of the National Atmospheric Deposition Program (NADP) National Trends Network (NTN). Nitrogen and sulfur in air are monitored by the Clean Air Status and Trends Network (CASTNET). </div><div>Representative NADP/NTN or NADP/MDN wet deposition monitors are within 16 km of park boundaries. Note that for end years 2009 to 2015, the Gates of the Arctic NP & PRES representative monitor (NADP/NTN ID: AK06) was an exception to the distance criteria because it was located 26 km outside of park boundaries for accessibility reasons. All CASTNET sites are in-park. </div>
Description: Mercury deposited through precipitation is monitored by the National Atmospheric Deposition Program (NADP) Mercury Deposition Network (MDN). NADP/MDN wet deposition representative monitoring sites are within 16 km of park boundaries.
Description: Ammonia, a gaseous nitrogen compound, is monitored through the National Atmospheric Deposition Program (NADP) Ammonia Monitoring Network (AMoN). All park monitoring sites are in-park. There are no representative monitoring sites.
Description: Particulate Matter (PM) pollution data are reported to the Environmental Protection Agency and stored in AQS (the Air Quality System data mart). Representative particulate matter monitors are within 10 km of park boundaries. In-park or nearby representative monitoring sites can measure both PM2.5 and PM10 but there are sites that only measure PM2.5 or PM10. In those cases where both PM2.5 and PM10 are not available from one site, parks may have two representative particulate matter monitors where one represents PM2.5 and the other PM10. Note that sometimes supplementary representative monitoring sites monitors both PM2.5 and PM10 but only the missing PM is used from that monitor. If there is not a nearby representative site that could supplement the missing data, the park will only have PM2.5 or PM10. FRM or FEM monitors take precedence over in-park or nearby representative IMPROVE monitors. This is because IMPROVE data are collected only every 3 days resulting in less data for condition assessments. There are a handful of representative monitors that are no longer the closest monitor within a 10 km radius but are retained as the representative monitor to maintain consistent historic trend records.