Air quality monitoring: precipitation chemistry

Nipher Shielded
Snow Gauge

The wet-only precipitation collector samples precipitation only when it rains or snows. During precipitation events sensors located on the collector automatically signal the roof to uncover the bucket. The bucket holds a specially designed plastic bag (Mylar outer laminate and Polyethylene inner laminate). The bags are replaced every day between 0800 and 0900 LST and all exposed bags (containing 24 hour integrated samples) are immediately sealed and refrigerated at 4^oC until chemical analyses has been completed.

The Nipher Shielded Snow Gauge and the type B Rain Gauge measure the amount of precipitation that fell in the last 24 hours in mm of water. 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.