Featured Research

from universities, journals, and other organizations

Tracking pollution from outer space: Team uses NASA satellites to measure pollution hovering over world's megacities

Date:
November 27, 2012
Source:
American Friends of Tel Aviv University
Summary:
A researcher in Israel 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, he tracked pollution trends for 189 megacities -- metropolitan hotspots where the population exceeds 2 million.

Smoggy Los Angeles.
Credit: iStockphoto/Lee Pettet

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.

Related Articles


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 Earth's surface, composed 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 human-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.


Story Source:

The above story is based on materials provided by American Friends of Tel Aviv University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Pinhas Alpert, Olga Shvainshtein, Pavel Kishcha. AOD Trends over Megacities Based on Space Monitoring Using MODIS and MISR. American Journal of Climate Change, 2012; 01 (03): 117 DOI: 10.4236/ajcc.2012.13010

Cite This Page:

American Friends of Tel Aviv University. "Tracking pollution from outer space: Team uses NASA satellites to measure pollution hovering over world's megacities." ScienceDaily. ScienceDaily, 27 November 2012. <www.sciencedaily.com/releases/2012/11/121127130248.htm>.
American Friends of Tel Aviv University. (2012, November 27). Tracking pollution from outer space: Team uses NASA satellites to measure pollution hovering over world's megacities. ScienceDaily. Retrieved October 25, 2014 from www.sciencedaily.com/releases/2012/11/121127130248.htm
American Friends of Tel Aviv University. "Tracking pollution from outer space: Team uses NASA satellites to measure pollution hovering over world's megacities." ScienceDaily. www.sciencedaily.com/releases/2012/11/121127130248.htm (accessed October 25, 2014).

Share This



More Earth & Climate News

Saturday, October 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

EU Gets Climate Deal, UK PM Gets Knock

EU Gets Climate Deal, UK PM Gets Knock

Reuters - Business Video Online (Oct. 24, 2014) EU leaders achieve a show of unity by striking a compromise deal on carbon emissions. But David Cameron's bid to push back EU budget contributions gets a slap in the face as the European Commission demands an extra 2bn euros. David Pollard reports. Video provided by Reuters
Powered by NewsLook.com
Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Deep Sea 'mushroom' Could Be Early Branch on Tree of Life

Reuters - Innovations Video Online (Oct. 24, 2014) Miniature deep sea animals discovered off the Australian coast almost three decades ago are puzzling scientists, who say the organisms have proved impossible to categorise. Academics at the Natural History of Denmark have appealed to the world scientific community for help, saying that further information on Dendrogramma enigmatica and Dendrogramma discoides could answer key evolutionary questions. Jim Drury has more. Video provided by Reuters
Powered by NewsLook.com
Raw: Tornado Rips Roofs in Washington State

Raw: Tornado Rips Roofs in Washington State

AP (Oct. 24, 2014) A rare tornado ripped roofs off buildings, uprooted trees and shattered windows Thursday afternoon in the southwest Washington city of Longview, but there were no reports of injuries. (Oct. 24) Video provided by AP
Powered by NewsLook.com
Fast-Moving Lava Headed For Town On Hawaii's Big Island

Fast-Moving Lava Headed For Town On Hawaii's Big Island

Newsy (Oct. 24, 2014) Lava from the Kilauea volcano on Hawaii's Big Island has accelerated as it travels toward a town called Pahoa. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:

Strange & Offbeat Stories


Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins