RELEASE NO: 98-207

NASA MONITORS SMOG POLLUTION FROM TROPICAL FIRES

For the first time, real-time maps of tropospheric ozone levels in the tropics are available to the world.

NASA researcher Dr. Anne Thompson and her colleague, Dr. Robert Hudson, University of Maryland, and their graduate student, Hua Guo have developed a new technique for retrieving near ground levels of ozone.

Using NASA’s Total Ozone Mapping Spectrometer (TOMS), tropical ozone pollution from large fires now can be tracked at the same time as smoke, dust and UV exposure. "Using a single sensor for multiple products instead of piecing together data from multiple sensors is more accurate," said Thompson, an atmospheric scientist at NASA’s Goddard Space Flight Center, Greenbelt, MD. "TOMS already obtains images of the amount of smoke present in the atmosphere anywhere in the world. We’re just adding another element by applying a new algorithm."

Scientists have a special interest in smoke aerosols caused by fires because smoke contributes to the overall global air-pollution levels than can impact the quality of air that humans breathe. They also want to monitor smoke from large fires which could contribute to global climate change.

The public and government now can follow what policy makers call "trans-boundary pollution" in which pollution sources-urban and fire-over one country create ozone pollution over their neighbors or even far away. Indonesia fires sent smoke and ozone pollution to highly populated areas in Malaysia.

Ozone from African savanna fires ends up over the Atlantic, the Pacific and even Brazil. Brazilian fires lead to ozone over the Atlantic and Pacific.

Since the beginning of the Mexican fires in March and April of 1998, NASA atmospheric researchers closely monitored the smoke aerosols emitted from the fires with NASA’s TOMS. The smoke was thick enough that it was easily visible on the ground and resembled a light haze to medium fog in parts of Texas, Georgia, and Florida. On April 16 the smoke plume extended across the Eastern U.S., passing through Ohio, and into southern Canada.

"The ability to have multiple products, UV, smoke, and tropospheric ozone from a single sensor, is very attractive," said P. K. Bhartia, TOMS Project Scientist at Goddard Space Flight Center. "This now truly puts us on the threshold of the EOS (Earth Observing System) era where we’ll have integrated spacecraft doing many things."

By 2000, the EOS AM-1 spacecraft will add carbon monoxide, a key ingredient in tropospheric ozone formation and a major product of large fires, to the list of chemicals that can be followed from space.

The small particles that comprise smoke, called aerosols, can affect the amount of energy reaching the Earth’s surface by reflecting and/or absorbing sunlight. Smoke aerosols also can affect clouds by acting as small particles (condensation nuclei) upon which clouds can form. Clouds containing smoke aerosols are believed to reflect and absorb energy in different ways than clouds formed from other particles such as dust or sea salt.

The impact of the 1997-1998 tropical fires from El Niño shows that a record high of tropospheric ozone (the "bad ozone" or "smog" of pollution) was a product of the fires that followed the drought of the 1997 El Nino. The normal progression of ozone from biomass burning - both seasonal agricultural burning over Africa that happens each year, followed by South American savanna and slash-and-burn/deforestation - was dramatically altered as Indonesian fires built up in late August and peak in September and October 1997.

The NASA-developed TOMS instrument, which measures ozone indirectly by monitoring ultraviolet light scattered by the atmosphere, also produces daily maps of the global distribution of ozone in Earth’s atmosphere and of the surface UV. TOMS is part of NASA’s Earth Science Enterprise, a long-term research program designed to study the Earth’s land, oceans, air, ice and life as a total system. The TOMS program is managed by Goddard for NASA’s Office of Earth Science, Washington, DC.

See images at: http://svs.gsfc.nasa.gov:2001/imagewall/UARS/trop_ozone.html