Troposphere ozone pollution highest near the equator

A new research, conducted by the University of North Carolina (UNC), shows the pollution emissions are increasing in the area close to the equator where they produce a much greater impact on the ozone formation.

The air pollution across the globe has increased since the 1980s, and at a much faster pace near the equator. The new study reveals that the changing global emissions map is creating more total ozone worldwide when compared to the emitted pollution, suggesting the effect will need strategic planning to get it under control.

“Emissions are growing in places where there is a much greater effect on the formation of ozone. A ton of emissions in a region close to the equator, where there is a lot of sunlight and intense heat, produces more ozone than a ton of emissions in a region farther from it,” said Jason West, a leader of the research at UNC-Chapel Hill.

When ozone-forming pollutants are present in the lower atmosphere, they are capable of causing respiratory and heart-related problems.The research shows which areas of the globe will require the strategical approach to emissions of ozone-forming pollutants.

Ozone forms when ultraviolet light collides with the nitrogen oxide, a component of car exhaustion and other similar sources. When the pollutants interact with intense sunlight and higher temperatures, the chemical reactions responsible for ozone formation speed up. The equator is exposed to higher temperatures which also increase the vertical air mass transport. In this way, the chemicals get transferred into higher layers of the troposphere, where they can live longer, consequently forming more ozone.

In the period between 1980 and 2010, China's emissions have increased more the Southeast Asia's and India's. However, despite that, because of its proximity to the equator, it appears that Southeast Asia and India have made a bigger contribution to the total global increase in ozone.

“The findings were surprising. We thought that location was going to be important, but we didn’t suspect it would be the most important factor contributing to total ozone levels worldwide. Our findings suggest that where the world emits is more important than how much it emits," explained West.

In cooperation with scientists from the University of Colorado Boulder and NOAA's Earth System Research Laboratory, a computer model was used to simulate a total amount of ozone present in parts of the troposphere where it can harm humans and agriculture in the period between 1980 and 2010. The emission was shifted to the south in this period, and the scientists wanted to find out what had contributed to the increased ozone production.

Results showed the location was the most significant contribution factor and it suggests regions in the equator proximity should decrease ozone emissions and develop the necessary strategies.

“A more challenging scenario is that even if there is a net reduction in global emissions, ozone levels may not decrease if emissions continue to shift toward the equator. But continuing aircraft and satellite observations of ozone across the tropics can monitor the situation and model forecasts can guide decision making for controlling global ozone pollution,” said Owen Cooper from the University of Colorado Boulder, who participated in the research.

Featured image credit: OrganicXO (Flickr-CC)