A - C
The Canadian Air and Precipitation Monitoring Network is a non-urban air quality monitoring network with siting criteria designed to ensure that the measurement locations are regionally representative (not affected by local sources of air pollution). Scientists involved with the measurement of atmospheric pollution in urban centres would consider most CAPMoN sites to be remote and pristine. There are currently 28 measurement sites in Canada and 1 in the U.S.A. http://www.msc.ec.gc.ca/capmon/index_e.cfm
CAPMON