NASA satellite tracks ozone pollution by monitoring its key ingredients

The top row of images show each region in 2005, which had abundant NOx in urban areas where human emissions are high, leading to systems where ozone formation was controlled by VOC amounts. As pollution controls were put into place on NOx emissions, by 2015, the systems in Europe, the United States, and East Asian urban areas became limited by NOx, meaning that further controls on NOx would help reduce ozone formation. With the industrial growth of the last decade, the results in China outside the major cities show an increase in areas transitioning to being controlled by VOC amounts. Credit: NASA

Unlike its presence at high altitude where ozone acts as Earth's sunscreen from harmful ultraviolet radiation, at low altitudes, ozone is a health hazard contributing to respiratory problems like asthma and bronchitis.

It is formed through complex chemical reactions initiated by sunlight and involving two types of gases, volatile organic compounds (VOC) and nitrogen oxides (NOx). Both are represented in the study by a major gas of each type, the VOC formaldehyde and NO2, that are measureable from space by the Dutch-Finnish Ozone Monitoring Instrument aboard NASA's Aura satellite, launched in 2004.

“We're using satellite data to analyze the chemistry of ozone from space,” said lead author Xiaomeng Jin at the Lamont-Doherty Earth Observatory at Columbia University in Palisades, New York. Their research was published in Journal of Geophysical Research: Atmospheres, a publication of the American Geophysical Union.

With a combination of computer models and space-based observations, she and her colleagues used the concentrations of ozone's precursor molecules to infer whether ozone production increases more in the presence of NOx, VOCs, or a mix of the two, for a given location. Their study regions focused on North America, Europe and East Asia during the summer months, when abundant sunlight triggers the highest rates of ozone formation.

To understand their impact on ozone formation, Jin and her team investigated whether VOC or NOx was the ingredient that most limited ozone formation. If emissions of that molecule are reduced, then ozone formation will be reduced — critical information for air quality managers.

“We are asking, 'If I could reduce either VOCs or NOx, which one is going to get me the biggest bang for my buck in terms of the amount of ozone that we can prevent from being formed in the lower atmosphere?'” said co-author and atmospheric chemist Arlene Fiore at Lamont-Doherty, who is also a member of NASA's Health and Air Quality Applied Sciences Team that partially funded this work and fosters collaboration between scientists and air quality managers.

The findings show that cities in North America, Europe and East Asia, are more often VOC-limited or in a transitional state between VOC and NOx-limited. In addition, the 12-year data record of satellite observations show that a location's circumstances can change. For instance, in 2005 New York City's ozone production during the warm season was limited by VOCs, but by 2015 it had transitioned to a NOx-limited system due to reduced NOx emissions resulting from controls put into place at both regional and national levels. This transition means that future NOx reductions will likely further decrease ozone production, said Jin.

Volatile organic compounds occur in high volume naturally, given off by some plants, including certain tree species. They can also arise from paint fumes, cleaning products, and pesticides, and are a by-product of burning fossil fuels in factories and automobiles. Nitrogen oxides are a byproduct of burning fossil fuels and are abundant in cities, produced by power plants, factories, and cars. Because VOCs have a large natural source during summer over the eastern United States, for example, emission reduction plans over the last two decades in this region have focused on NOx, which is overwhelmingly produced by human activities.

Space-based methods for monitoring ozone chemistry complement surface-based measurements made by air quality management agencies. The view from space offers consistent coverage of broad areas, and provides data for regions that may not have ground stations.

###

To read the paper, visit: http://onlinelibrary.wiley.com/doi/10.1002/2017JD026720/abstract

This work was a collaboration of researchers at Lamont-Doherty with those at University of Rochester in New York; the Royal Netherlands Meteorological Institute in De Bilt, Netherlands; Wageningen University in Wageningen, Netherlands; Belgian Institute for Space Aeronomy in Brussels, Belgium; Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts; the U.S. Environmental Protection Agency Office of Research and Development in Research Triangle Park in North Carolina and its Region 8 Office in Denver Colorado; and NASA's Goddard Space Flight Center in Greenbelt, Maryland.

NASA uses the vantage point of space to increase our understanding of our home planet, improve lives, and safeguard our future. NASA develops new ways to observe and study Earth's interconnected natural systems with long-term data records. The agency freely shares this unique knowledge and works with institutions around the world to gain new insights into how our planet is changing.

Media Contact

Rob Gutro EurekAlert!

All latest news from the category: Earth Sciences

Earth Sciences (also referred to as Geosciences), which deals with basic issues surrounding our planet, plays a vital role in the area of energy and raw materials supply.

Earth Sciences comprises subjects such as geology, geography, geological informatics, paleontology, mineralogy, petrography, crystallography, geophysics, geodesy, glaciology, cartography, photogrammetry, meteorology and seismology, early-warning systems, earthquake research and polar research.

Back to home

Comments (0)

Write a comment

Newest articles

First-of-its-kind study uses remote sensing to monitor plastic debris in rivers and lakes

Remote sensing creates a cost-effective solution to monitoring plastic pollution. A first-of-its-kind study from researchers at the University of Minnesota Twin Cities shows how remote sensing can help monitor and…

Laser-based artificial neuron mimics nerve cell functions at lightning speed

With a processing speed a billion times faster than nature, chip-based laser neuron could help advance AI tasks such as pattern recognition and sequence prediction. Researchers have developed a laser-based…

Optimising the processing of plastic waste

Just one look in the yellow bin reveals a colourful jumble of different types of plastic. However, the purer and more uniform plastic waste is, the easier it is to…