Air Quality Site at the Proctor Maple Research Center in Underhill, VT

The VMC Air Quality site was established in June of 1984 at the Proctor Maple Research Center (PMRCAQ) in Underhill, VT as the second of two precipitation chemistry monitoring sites in Vermont belonging to the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). NADP/NTN is a nationwide network (over 200 stations) of precipitation monitoring sites whose purpose is to collect data on precipitation chemistry for monitoring of geographical and temporal long-term trends. Precipitation at each station is collected weekly according to strict clean-handling procedures using an Aerochem wet/dry precipitation collector. Samples are sent to the Central Analytical Laboratory where they are analyzed for hydrogen (acidity as pH), sulfate, nitrate, ammonium, chloride, and base cations (such as calcium, magnesium, potassium and sodium). All NADP/NTN sites are also equipped with a Belfort (model B5-780) Weighing Rain Gage, which provides a continuous 7-day chart record of precipitation events. Precipitation chemistry and volume data from all sites in the NADP/NTN network, including PMRCAQ, are available on line at the NADP/NTN web site.

In 1988 this site became a member of The Electric Power Research Institute (EPRI) Program. As a result, environment monitoring activities were expanded to include measurement of several air quality parameters (What??) and basic meteorology including air temperature, dew point, wind speed and direction, and barometric pressure. Precipitation amount was already being collected as part of the NADP/NTN Program. By summer of 1990, EPRI research activities had ended at this site and the Vermont Monitoring Cooperative (VMC) took over responsibility for the site, including, operation of the NADP/NTN station and collection and archiving of meteorological data.

In December 1992, the VMC implemented a Hg monitoring program in cooperation with the University of Michigan Air Quality Laboratory (UMAQL). Event-based precipitation samples are collected using a MIC-B wet-only precipitation collector (MIC Co., Richmond Hill, Ontario). Ambient vapor and particulate samples are collected every sixth day for 24 hours on gold-coated bead vapor traps and glass-fiber particulate filters, respectively. Samples are shipped by overnight delivery to UMAQL for Hg analyses using cold vapor atomic fluorescence spectrometry. The PMRCAQ Hg data record, from 1992-present, represents the longest continuous concurrent monitoring of Hg in precipitation, vapor phase, and particulate form in the world.

The PMRCAQ site became part the Atmospheric Integrated Research Monitoring Network (AIRMoN) in January of 1993. AIRMoN is an array of monitoring stations designed to provide a research-based foundation for the routine operations of the nation's deposition monitoring networks -- the National Atmospheric Deposition Program (NADP) for wet deposition, and the Clean Air Status and Tends Network (CASTNet) for dry. Currently, the AIRMoN-Wet network comprises 12 sites where precipitation samples are collected daily or on an event basis. Protocols in AIRMoN-Wet differ from NADP only to the extent required to ensure temporally adequate (daily) sampling collection and enhanced sample quality. An AIRMoN-Dry monitoring site also operated at PMRC from 1993 until 2000 as one of 13 sites in the Dry Deposition Inferential Method (DDIM) Program. Data from all 12 sites in the AIRMoN-Wet network, including PMRCAQ, are available on line at the AIRMoN web site.

In October of 1996, a UVB monitoring station was added to the PMRCAQ site as part of the USDA UVB Radiation Monitoring Program. This program, operating under the US Department of Agriculture's Cooperative State Research, Education and Extension Service (CSREES), was initiated in 1992 through a grant to Colorado State University. The purpose of this project was to provide information on the geographical distribution and temporal trends of UVB (ultraviolet -B) radiation in the United States.

The UVB monitoring station at PMRCAQ uses Multifilter Rotating Shadowband Radiometers (MFRSR) (UV-MFRSR and VIS-MFRSR), supplemented with additional sensors. UVB data are downloaded daily to Colorado State University and are available online.

Today, the VMC continues to operate the PMRCAQ site as a core station in its environmental monitoring program. Day-to-day operations of the station are conducted by the station operator, Miriam Pendleton. She is responsible for collecting and shipping all samples and conducting all additional activities required by the numerous monitoring programs represented at this site. The meteorological station measuring air temperature, relative humidity, wind speed and direction, barometric pressure and precipitation continues to operate at the site. Data from this station are downloaded hourly by the NWS in Burlington for predictive purposes. Archived meteorological data from June 1988 to present are available online at the VMC web site.