New study from Hokkaido University details processes that keep pollutants aloft despite a drop in emissions.
New study from Hokkaido University details processes that keep pollutants aloft despite a drop in emissions.
Nitrates in the atmosphere reduce air quality and play an important role in climate change. An international team led by Hokkaido University researchers has revealed how chemical processes in the atmosphere have led to persistently high nitrate levels despite a reduction in emissions over the past few decades. These findings, published in Nature Communications, will help improve climate modelling by refining our ability to assess and predict atmospheric nitrate levels.
Atmospheric nitrate levels peaked between 1970 and 2000. The levels decreased somewhat with the decrease in the emission of nitrate precursors since the 1990s, but the drop in nitrate levels is smaller than the drop in the emission of precursors—something is keeping nitrates in the atmosphere.
Nitrates can exist in either a gaseous or particulate form in the atmosphere. Gaseous nitrate is more easily deposited out of the atmosphere, while the particulate form—particularly finer particles—can be transported over long distances. Understanding the balance between gaseous and particulate nitrates is therefore important in getting a picture of the atmospheric dynamics and persistence of nitrates.
Read more at Hokkaido University
Image: The ice core used in the study (Photo: Mai Matsumoto) (Credit: Photo: Mai Matsumoto)
