Giant pollution cloud found over Indian state

<body leftmargin="0" bgcolor="#000060" text="#FFFFFF" link="#FFFF00" vlink="#FF9900"> <b> <p class="MsoNormal"><font face="Arial" size="4">Giant pollution cloud found over Indian state</font></p> </b> <p class="MsoNormal"><font face="Arial" size="1">Posted Jan. 31, 2005<br> Courtesy the University of Illinois at Urbana-Champaign <br> and World Science staff</font> <font size="2" face="Arial"> <b> <br> </b> </font><b><font size="2" face="Arial"><br> Scientists studying satellite data have discovered an immense wintertime pool of pollution over the northern Indian state of Bihar. Blanketing around 100 million people, primarily in the Ganges Valley, the pollution levels are about five times larger than those typically found over Los Angeles, California, the scientists found.<br> <br> The discovery was made by researchers analyzing four years of data collected by a NASA satellite called Terra. <br> <br> “This study is the most comprehensive and detailed examination of industrial, smoke and other air pollution particles over the Indian subcontinent to date, and reveals how topography, meteorology and human activity help determine where these particles are concentrated,” said Larry Di Girolamo, a professor of atmospheric sciences at the University of Illinois at Urbana-Champaign and a co-investigator on the mission.<br> <br> “By measuring reflected sunlight at nine angles, we can accurately determine the amount of particulate matter, including that generated from man-made pollution, in the atmosphere,” Di Girolamo said.<br> <br> While high pollution levels were found over much of India, a concentrated pool of particles was discovered over Bihar, a largely rural area with a dense population. A large source contributing to the Bihar pollution pool is the inefficient burning of a variety of biofuels during cooking and other domestic use, Di Girolamo said. Particles in the smoke remain close to the ground, trapped by valley walls, and unable to mix upward because of a high-pressure system that dominates the region during winter.<br> <br> “The result is a pollution episode that can affect both human health and local climate,” he said. “The airborne particles can damage delicate lung tissue, and by altering the radiative heating profile of the atmosphere, the particles may change temperature and precipitation patterns.”<br> <br> Prior to the study, atmospheric models had predicted a tongue of pollution extending across the middle of India. The new observations, however, show the pollution lies much farther north.<br> <br> “These models are very important to us, as they are used to forecast pollution episodes and climate change,” Di Girolamo said. The fact that model results don’t match the new observations “suggests there are problems in the models or the model inputs that need to be fixed.” The role of airborne particles remains one of the largest uncertainties in atmospheric modeling. In addition to modifying local climate, the particles can interact with clouds and change the cloud properties. This is particularly important, since clouds have the greatest radiative forcing on the climate system.<br> <br> “The Bihar pollution pool must be having a tremendous impact on the local climate and the health of the approximately 100 million people that reside within this pool.” Di Girolamo said. “Our long-term goal is to better predict the occurrence of these pollution episodes and their impact on public health and local climate.”<br> <br> The pollution doesn’t originate solely from Bihar, “but also from the surrounding regions, including the western portions of the Ganges Valley,” he added in an email. “During the winter the winds typically blow gently from west to east through the Ganges Valley So, pollution from New Delhi and Kanpur are also contributing to the observed Bihar pollution pool. In addition, the meteorology and topography surrounding Bihar favor a trapping of pollution during the winter.<br> <br> “Based on other studies, we believe that the sources of pollution observed in Bihar during winter are largely from the burning of biofuels (largely fuelwood, dung-cake, and crop waste) used during cooking and other domestic use, the use of coal for utilities and industries, and the use of diesel oil for transportation.”</font> </b> </p> <p class="MsoNormal"><a href="http://groups.yahoo.com/group/world-science"><font face="Arial" size="2">http://groups.yahoo.com/group/world-science</font></a> </p> </body>