Acidity in the atmosphere is back to the lowest point since humans started the industrial revolution

Breakthrough research at the Greenland ice sheet are telling us that environmental acidity has dipped below the level it was at in the 1930's, when we first started spewing the stuff into the atmosphere en masse.

The findings, published in the scientific journal, Environmental Science and Technology, highlight that last 100 years of environmental acidity.  It's easy to measure earlier times, because the ice sheet is compacted.  Near the surface, where the new data was gathered, the process was more complicated, until recently.

“We have therefore developed a new method that can directly measure the acidity of the ice using a spectrometer. We have an ice rod that is cut along the length of the ice core. This ice core rod is slowly melted and the meltwater runs into a laboratory where they take a lot of chemical measurements. With our new method you can also measure the acidity, that is to say, we measure the pH value and this is seen when the water changes colour after the addition of a pH dye. We can directly see the fluctuations from year to year,” explains Helle Astrid Kjær, postdoc in the Centre for Ice and Climate at the Niels Bohr Institute, University of Copenhagen.

The new method has measured data that was surprising.

The new method can also measure whether the emissions come from volcanic eruptions, large forest fires or industry. They can, then, decided whether the pollution came from volcanoes and forest fires and locate the man-made pollutants.

“We can see that the acid pollution in the atmosphere from industry has fallen dramatically since manmade acid pollution took off in the 1930s and peaked in the 1960s and 70s. In the 1970s, both Europe and the United States adopted the ‘The clean air act amendments’, which required filters in factories, thus reducing acid emissions and this is what we can now see the results of. The pollution of acid in the atmosphere is now almost down to the level it was before the pollution really took off in the 1930s," explains Helle Astrid Kjær.