Sulfate and nitrate concentrations in Greenland ice cores reflect the historical trend in fossil fuel burning, with concentrations increasing near the turn of the last century due to emissions of SO₂ and NO_x.  The figure on the right reflects this trend, showing measurements from the Site A (solid circles) [Alexander et al., 2004] and GISP2 B (triangles) [Mayewski et al., 1997] ice cores.

The figure to the left shows D¹⁷O measurement of sulfate and nitrate [Alexander et al., 2004] from the Site A core, along with fire index data from summit, central Greenland [Savarino and Legrand 1998].  The D¹⁷O values show a peak just prior to the Industrial Revolution that correlates (R² = 0.5) with indicators of biomass burning.  This biomass burning "event" resulted from the burning of land in North America for agricultural purposes as the population was expanding westward. 

Biomass burning can increase D¹⁷O values of sulfate and nitrate by increasing O₃ concentrations and the degree of heterogeneous processing of these aerosols.  Reaction in bold in the cartoon to the right demonstrate reactions that will contribute to the large D¹⁷O values measured in the Site A core.  This data set demonstrates a significant effect of biomass burning on atmospheric chemistry in the preindustrial atmosphere.

Andreae, M.O., Fire and Ice, Nature, 429, 713 (2004).

Mayewski, P.A., L.D. Meeker, M.S. Twickler, W. Whitlow, Q. Yang, W.B. Lyons, and M. Prentice, Major features and forcing of high-latitude northern hemisphere atmospheric circulation using a 110,000-year-log glaciochemical series, J. Geophys. Res., 102(C12), 26,345-26,366 (1997).

Savarino, J., and M. Legrand, High northern latitude forest fires and vegetation emissions over the last millennium inferred from the chemistry of a central Greenland ice core, J. Geophys. Res., 103(D7), 8367 (1998).