Sea Salts Could Be Causing Air Pollution in the Arctic

While the Arctic seems to be as pristine as it appears in photographs, scientists discover that it is actually changing fast. For instance, a team of researchers has found that sea salt may be contributing to air pollution in the Arctic.

During winter this year, the Arctic's ice levels hit record low and the air in the region is warming. Earlier studies showed that pollutants, which include gaseous nitrogen oxides and ozone, sometimes reach levels similar to those that could be seen in more populated areas. In sunlight, nitrogen oxides lead to the formation of ozone and are often found in smog, which is harmful to the atmosphere and is abundant in most cities in the world.

These gases are released into the atmosphere and are deposited on Earth as nitrates, which could then be trapped in the snow. In sunlight, snow could become a reactor, transforming nitrates back into nitrogen oxide gases.

In the Arctic, sea ice and snow may contain salt and other impurities that could cause changes in chemistry in the region. In a report published in the American Chemical Society's (ACS) Journal of Physical Chemistry, a team of researchers led by James Donaldson and Karen Morenz observed how salt and nitrate content in snow could affect the levels of nitrogen oxides in the air in sunlight.

According to a news release by ACS, the researchers tested a lab-made snow containing nitrate alone or nitrate and salt. The researchers simulated sunlight and found that about 40 to 90 percent more nitrogen dioxide (NO2) was reformed from the snow that had low levels of salt at environmentally relevant concentrations than the snow with no salt. The researchers used realistic sea salt in the experiment and observed a greater effect.

In this new study, sea ice and salty snow are found to have an effect on the balance of ozone-forming chemicals in the atmosphere, which has not been previously considered. The researchers suggest to consider these factors and to include them in future study models.