ICE CORES: Nitrate (NO3-)

Nitrate is a common human pollutant that is mainly derived from NOx gases (e.g. Nitrogen dioxide) in the atmosphere. Environmental impacts of nitrate pollution include  acid rain, poor water quality, and, human respiratory health problems. Human sources of nitrate are high temperature combustion of fossil fuels, nitrate fertilizers, and biomass burning.  Natural sources of nitrate include soil exhalation, biomass burning, and lightning.  Ice core records allow a perspective of human impacts on nitrate concentrations over time.  Nitrate trends  coincide with the expansion of industry, agriculture and population during the 20th century.