New tool differentiates between man-made and natural nitrogen-oxide pollution

March 26th, 2009 - 3:13 pm ICT by ANI  

Washington, March 26 (ANI): Scientists have used a new tool to differentiate between man-made and natural nitrogen oxide emissions.

Nitrogen oxides in the atmosphere, which are produced by lightning, biomass burning, and soil outgassing, are converted into atmospheric nitrate through oxidation reactions.

Nitrogen oxide, itself a pollutant, controls the production of ozone, which in turn is a greenhouse gas and a pollutant at ground levels.

Atmospheric nitrate contributes to the load of atmospheric particulate matter and, along with sulfate, to acid rain.

Despite efforts to regulate and monitor emissions, nitrogen oxide and atmospheric nitrate burdens in the atmosphere are increasing in many regions.

To learn more, S. Morin and his team from Institut National des Sciences de l’Univers, CNRS, Grenoble, France, studied the stable isotopic composition of nitrate within aerosol samples.

These samples were collected along a shipborne transect, in the lower atmosphere over the Atlantic Ocean from 65 degrees South to 79 degrees North.

The researchers found that in nonpolar regions, nitrate derived from anthropogenically emitted nitrogen oxide had isotopic properties distinct from locations influenced by natural nitrogen oxide sources.

Further, air masses exposed to snow-covered areas have low nitrogen isotopic ratios, showing that snowpack emissions of nitrogen oxide from upwind regions can have a significant effect on the local surface budget of reactive nitrogen. (ANI)

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