Forum für Wissenschaft, Industrie und Wirtschaft

Hauptsponsoren:     3M 
Datenbankrecherche:

 

Tracking Pollution from Outer Space

27.11.2012
TAU team uses NASA satellites to measure pollution hovering over world's megacities

The thickest layers of global smog — caused by traffic, industry, and natural minerals, among other factors — are found over the world's megacities. But getting an accurate measurement of pollution is no easy task.



On-the-ground monitoring stations do not always provide the most accurate picture — monitoring stations depend heavily on local positioning and some cities put stations in urban centers, while others build on the edge of a city.

Now Prof. Pinhas Alpert of Tel Aviv University's Department of Geophysics and Planetary Sciences and head of the Porter School of Environmental Studies, with graduate student Olga Shvainshteinand and Dr. Pavel Kishcha, is turning to three of NASA's high-tech satellites for a comprehensive view of pollutants in the atmosphere. Using eight years' worth of data collected by the satellites, the researchers tracked pollution trends for 189 megacities — metropolitan hotspots where the population exceeds 2 million. 58 of these megacities, including New York City, Tokyo, and Mumbai, have populations that exceed 5 million.

Their method, published in the American Journal of Climate Change, is the first to provide standardized global testing of pollution levels. Beyond uncovering reliable data about pollution trends, Prof. Alpert believes that this monitoring method will also hold countries accountable for their emissions and encourage more environmentally friendly practices.

A "three judge" panel

The smog which often covers megacities is actually a thick atmospheric layer several hundred meters above the Earth's surface, comprised of particles of pollutants. It's an environmental hazard and a severe health risk for those living below, who breathe in the particulates.

To accurately analyze the level of pollution over each megacity, the researchers used data gathered by three aerosol-monitoring satellites, called MODIS-Terra, MODIS-Aqua, and MISR, which NASA launched from 2000 through 2002. The combined data these satellites provide constitute an accurate survey of aerosol concentrations a few hundred meters above Earth.

Prof. Alpert likens the use of three satellites to the traditional Jewish idea of the three-judge panel. "In the Jewish tradition, individual judges don't decide cases. There must be a minimum of three. You need a majority opinion," he says. "By merging the data from three imperfect sensors, their flaws are mostly counterbalanced. In cases where the three sensors show differing signs of pollution levels, more research is required."

Winners and losers

Northeast China, India, the Middle East, and Central Africa are currently leading in pollution increase, including Bangalore, India, with a 34 percent average increase in aerosol concentration between 2002 and 2010. Ibdan, Nigeria, was also part of that group. Europe and Northeast and Central North America are seeing the largest decreases in aerosol concentrations overall. Among the cleanest cities were Houston, with a 31 percent decrease over the time period; Curitiba, Brazil, with a 26 percent decrease; and Stockholm, Sweden, with a 23 percent decrease.

Some American cities were on the list of increased pollution levels, including Portland with a 53 percent average increase and Seattle with a 32 percent average increase, but Prof. Alpert believes these numbers reflect the multiple wildfires that have been happening in the region in the second half of the period examined. In the future, he hopes to develop a method for separating such natural causes of pollution from man-made pollutants for more accurate data.

An honest view of emissions

A standardized approach to smog analysis is made difficult by often unreliable data from monitoring stations, the reluctance of politicians or government ministries to offer accurate numbers on pollution, and even a complete lack of monitoring in major parts of the world, says Prof. Alpert. When it comes to international treaties aimed at reducing pollution, this measurement method could help to keep all countries accountable for their promises by tracking compliance in an equitable way. Cities that successfully decrease pollution could be applauded for their efforts and stand as a positive example to follow, he suggests.

George Hunka | EurekAlert!
Further information:
http://www.aftau.org
http://www.aftau.org/site/News2?page=NewsArticle&id=17597

More articles from Ecology, The Environment and Conservation:

nachricht Dispersal of Fish Eggs by Water Birds – Just a Myth?
19.02.2018 | Universität Basel

nachricht Removing fossil fuel subsidies will not reduce CO2 emissions as much as hoped
08.02.2018 | International Institute for Applied Systems Analysis (IIASA)

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Vorstoß ins Innere der Atome

Mit Hilfe einer neuen Lasertechnologie haben es Physiker vom Labor für Attosekundenphysik der LMU und des MPQ geschafft, Attosekunden-Lichtblitze mit hoher Intensität und Photonenenergie zu produzieren. Damit konnten sie erstmals die Interaktion mehrere Photonen in einem Attosekundenpuls mit Elektronen aus einer inneren atomaren Schale beobachten konnten.

Wer die ultraschnelle Bewegung von Elektronen in inneren atomaren Schalen beobachten möchte, der benötigt ultrakurze und intensive Lichtblitze bei genügend...

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

Eine Gruppe von Forschern um Andrea Cavalleri am Max-Planck-Institut für Struktur und Dynamik der Materie (MPSD) in Hamburg hat eine Methode demonstriert, die es erlaubt die interatomaren Kräfte eines Festkörpers detailliert auszumessen. Ihr Artikel Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, nun online in Nature veröffentlich, erläutert, wie Terahertz-Laserpulse die Atome eines Festkörpers zu extrem hohen Auslenkungen treiben können.

Die zeitaufgelöste Messung der sehr unkonventionellen atomaren Bewegungen, die einer Anregung mit extrem starken Lichtpulsen folgen, ermöglichte es der...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Verlässliche Quantencomputer entwickeln

Internationalem Forschungsteam gelingt wichtiger Schritt auf dem Weg zur Lösung von Zertifizierungsproblemen

Quantencomputer sollen künftig algorithmische Probleme lösen, die selbst die größten klassischen Superrechner überfordern. Doch wie lässt sich prüfen, dass der...

Alle Focus-News des Innovations-reports >>>

Anzeige

Anzeige

VideoLinks
Industrie & Wirtschaft
Veranstaltungen

Von festen Körpern und Philosophen

23.02.2018 | Veranstaltungen

Spannungsfeld Elektromobilität

23.02.2018 | Veranstaltungen

DFG unterstützt Kongresse und Tagungen - April 2018

21.02.2018 | Veranstaltungen

VideoLinks
Wissenschaft & Forschung
Weitere VideoLinks im Überblick >>>
 
Aktuelle Beiträge

Vorstoß ins Innere der Atome

23.02.2018 | Physik Astronomie

Wirt oder Gast? Proteomik gibt neue Aufschlüsse über Reaktion von Rifforganismen auf Umweltstress

23.02.2018 | Biowissenschaften Chemie

Wie Zellen unterschiedlich auf Stress reagieren

23.02.2018 | Biowissenschaften Chemie

Weitere B2B-VideoLinks
IHR
JOB & KARRIERE
SERVICE
im innovations-report
in Kooperation mit academics