Typically, both sites have lower volume-weighted pH means in the summer than in the winter. Mt. Mansfield, Underhill and a site located in Morrisville were examined for elevational and spatial variations. In addition, a lower pH can be expected on the west side of the Green Mountains due to storm fronts moving west to east. Description Measurement of bulk pH and amount to determine spatial and temporal trends within Vermont, and specifically at the VMC site. The program was initiated in 1980 to assess the impact of the 1970 Clean Air Act, which mandated the improvement of air quality in the vicinity of midwestern and southeastern fossil fuel burning plants.
Bulk precipitation is collected and measured on an event basis.
Precipitation amount and pH are measured for each event. The pH is measured with a Cole Parmer digital pH meter model 5987 and a Cole Parmer combination electrode with a calomel reference. The entire apparatus is housed in a wooden box, one foot in width and four feet in height. Snow is collected in a five gallon polyethylene bucket and brought indoors to completely melt before the pH is measured. All monitors are trained by the DEC and the monitor's techniques are observed bi-annually.