Major Ions

Major ions data consist of the following key ions in precipitation: Cl-, NO3-, SO4=, NH4+, Na+, K+, Ca++, Mg++. The data sets typically also include the pH and depth of the precipitation sample. These data are collected by several provincial, national and bi-national networks. The wet-only precipitation collector samples precipitation only when it rains or snows. A snow gauge and/or a rain gauge measure the amount of precipitation that has fallen during the measurement period. Measurement periods may be 24 hours or weekly cycles depending on the operating procedures of each network. The amount of wet deposition of a pollutant is calculated by multiplying the measured amount of precipitation by the concentration of the pollutant in the precipitation.