Data collected from the Tropospheric Monitoring Instrument (TROPOMI) on the European Space Agency's Sentinel-5 Precursor satellite provide unparalleled views of dozens of trace gases that influence air quality around the world.
By analyzing the satellite observations during the first months of 2018, scientists at NASA's Goddard Space Flight Center in Greenbelt, Maryland, created global maps of pollutants such as nitrogen dioxide (NO2), carbon monoxide (CO), formaldehyde (HCHO), and aerosols—tiny particles suspended in the atmosphere.
The maps illustrate how human activities such as burning fossil fuels and agricultural practices affect the amount and distribution of these pollutants.
Nitrogen dioxide, a reddish-brown gas, is primarily produced by the burning of fossil fuels, particularly in vehicles, power plants, and industrial facilities. Long-term exposure to NO2 can cause a number of health problems, including asthma, bronchitis, and emphysema.
The TROPOMI data show elevated levels of nitrogen dioxide over highly polluted areas such as the eastern United States, Europe, China, and India. The satellite observations also reveal the impacts of pollution from ships in major shipping lanes, such as the North Atlantic Ocean.
Carbon monoxide, a colorless, odorless gas, is also emitted from burning fossil fuels. It can cause headaches, dizziness, and fatigue, and can be fatal in high concentrations. The TROPOMI data show elevated levels of carbon monoxide in industrialized regions and over megacities, especially during the cold season.
Formaldehyde, a colorless, flammable gas with a strong odor, is emitted from a variety of sources, including burning wood, tobacco, and certain household products. It can cause eye, nose, and throat irritation, and is a known carcinogen. The TROPOMI data show higher levels of formaldehyde in forested regions, particularly in areas affected by wildfires.
Aerosols are tiny particles of solid or liquid matter that are suspended in the atmosphere. They can come from natural sources such as dust storms, sea salt, and volcanic ash, or from human activities such as burning fossil fuels and biomass, industrial emissions, and agricultural practices. Aerosols can affect climate by reflecting sunlight back into space, and can also have adverse effects on human health.
The TROPOMI data show elevated levels of aerosols over desert regions, polluted areas, and regions downwind of agricultural areas.
"The TROPOMI data are providing us with a wealth of new information about air quality around the world," said Bryan Duncan, a scientist at Goddard who worked on the data analysis. "These data are helping us to understand the impacts of human activities on air quality, and to identify areas where we can improve air quality for people around the world."
The TROPOMI data are also being used to validate and improve air quality models. These models are used to predict air quality and to develop policies to reduce air pollution.
"The TROPOMI data are a major leap forward for our ability to monitor air quality from space," said Paul Newman, a scientist at Goddard who works on air quality models. "These data are helping us to improve our understanding of how air pollution impacts human health and climate change, and to develop policies to reduce air pollution."
The TROPOMI instrument was developed by the Royal Netherlands Meteorological Institute (KNMI) and the Netherlands Space Office (NSO), in partnership with the European Space Agency (ESA). The instrument was launched into orbit on October 13, 2017, and began collecting data in February 2018.
