Ozone

  • Revised ozone standard angers environmentalists

    The US Environmental Protection Agency (EPA) is once again under fire for ignoring its science advisers

  • Check aviation generated pollution

    Some of the major airlines of the world seem to be lately realizing the adverse role of their big passenger jets on climate changes resulting in emissions of carbon dioxide and other greenhouse gases from the engine-exhausts into the earth's atmosphere. In this context Virgin Atlantic's first flight of a commercial aircraft powered with biofuel from London to Amsterdam on February 24, 2008 to show it can produce less carbon dioxide than normal jet fuels was an appreciable endeavour. This particular flight was partially fueled with a biofuel mixture of coconut and babassu oil in one of its four main fuel tanks and is expected to produce much less CO2 than regular jet fuel. Since aircraft engines emit gases and particulates that reduce air quality, spearheading the test flight was indeed a potentially useful experiment aimed at cutting down emission of greenhouse gases. A few weeks prior to this, an airbus A 380 too had taken off on a similar test sortie, powered on a blend of regular fuel and liquid fuel processed from natural gas with the hope that the super jumbo will become a centerpiece of efforts to develop the next generation of cleaner fuel. Besides, Air France-KLM is reported to invest almost US$3 billion a year until 2020 to modernize its fleet with the aim of cutting pollution. Several other airlines have also pledged to clean up their fleets as fears about global warming and fuel costs have mounted. Usually, people form their opinion on the adverse impact of air pollution by observing petrol and diesel-driven vehicles leave harmful trails of smoke on the roads. However, the great damage being done by thousands of air turbine fuel (ATF) guzzling aeroplanes that release tonnes hazardous fumes into our biosphere daily goes unnoticed. The increasing size of aircraft, the emission of black smoke during take-off, and the density of air traffic at major airports, have drawn environmentalists' attention to pollution by aircraft. A loaded jumbo 747, for instance, uses tens of thousands of litres of fuel on merely take-off. Further pollution by aircraft arises from the jettisoning of spare fuel after being airborne. Under such circumstances, it must be released at a height sufficient to allow it to vaporize so that it does not reach the ground in liquid form. Commercial jet planes make a significant contribution to the problem of global warming. According to a UN report, aviation is responsible for over half of the pollution caused by transportation on the surface. Scientists estimate that the effect of aviation emissions on the climate is up to five times the impact of emissions occurring on the ground. The primary gas emitted by jet aircraft engines is carbon dioxide, which, scientists believe, can survive in the atmosphere up to 100 years. It means denying the coming generations from living in a world where they can breathe clean air, enjoy diverse ecosystems and eat healthy food. In India the number of passenger and freight aircraft flown by private airlines is fast multiplying. Similarly, the Indian Air Force, currently in aircraft acquisition mode, is likely to increase its flying operations in the coming years. Its increasing use of supersonic combat aircraft flying at high altitudes may lead to increasing pollution of the upper air, where pollutants may accumulate since natural dispersion at such heights is not very effective. This development is going to be a major contributory factor in the destruction of ozone and the accumulation of green house gases in the upper layers of the atmosphere. It is estimated that one multi-engine passenger aircraft is being added every fortnight to the fleets of India's domestic carriers that are engaged in cutthroat competition to fly to the remotest corners of the country. As a result, the number of aircraft flying the Indian skies has gone up considerably. Here, one must not forget the domain of military aviation, Air Force, Army, Navy and the coast guard, where more than 1,000 fighter jets, transport planes and helicopters are kept aloft in routinely scheduled day and night flying. As per the estimates, the movement of aircraft in Indian airspace is growing at an annual rate of 15 per cent. Incidentally, kerosene happens to be the principal component of ATF. It is used as a propellant in modern commercial as well as military aircraft. Like other fossil fuels, kerosene produces carbon dioxide and water vapour on combustion. As the combustion process can not be said to be entirely efficient, carbon monoxide and oxygenated organic compounds, that are the products of partial oxidation, are emitted into the upper layers of the atmosphere. Hence, the extremely harmful environmental impact of pollutants left behind by aircraft engine exhaust fumes should be a great cause of concern for enlightened citizens. Though the International Civil Aviation Organisation (IACO), a UN body is reportedly supposed to regulate aircraft engine emissions by setting emission certification standards for all aircraft but it more or less appears to be an exercise on paper. In December 2007, the UN Climate Conference in Bali, Indonesia negotiated a new climate policy to chart out long term goal for global green house gas emissions. The world will not be able to realise these objectives unless technological breakthroughs are achieved in drastically reducing exhaust emissions from commercial as well as military aircraft gas turbine engines. This will necessitate a global effort in finding alternative jet fuels and developing engines that burn existing fuels more slowly.

  • The Effect of ambient air pollution during early pregnancy on fetal ultrasonic measurements during mid-pregnancy

    Over the past decade there has been mounting evidence that ambient air pollution during pregnancy influences fetal growth. This study was designed to examine possible associations between fetal ultrasonic measurements collected from 15,623 scans (13

  • Air quality in Europe may be deteriorating

    Air quality in Europe has declined in recent years, according to a report from the European Topic Centre on Air and Climate Change (ETC/ACC), which also cautions that the short time period involved makes it difficult to draw reliable conclusions. March 2008

  • Carbon dioxide rise linked to pollution deaths

    Increased carbon dioxide in the Earth's atmosphere also could worsen air pollution worldwide and lead to the deaths of up to 22,000 people a year, a new study shows. Rising carbon dioxide (CO2) levels from burning fossil fuels have been linked to sea-level changes, snowmelt, disease, heat stress, severe weather, and ocean acidification, but this is the first study to link CO2 rise to pollution. Because carbon dioxide doesn't directly affect respiration, it hasn't been classified as an air pollutant. But the study, led by Mark Jacobson of Stanford University, predicts that as temperatures and water vapor rise because of extra atmospheric CO2, ozone pollution levels also will rise. Using a high-resolution model that correlates pollution levels to human health, Jacobson found that each 1.8-degree rise in temperature could increase yearly air pollution deaths in the USA by about 1,000, which he extrapolated to 22,000 worldwide. Jacobson notes that many of these deaths would likely occur in smoggy urban areas.

  • Greasy hair 'cleans' the air you breathe

    Greasy hair may not help you to attract the object of your affection, but it might reduce the amount of ozone you breathe in. Lakshmi Pandrangi and Glenn Morrison from the University of Missouri in Rolla exposed eight washed and eight unwashed hair samples to ozone for 24 hours. They found that, on average, unwashed hair. absorbs around seven times as much ozone as freshly washed hair

  • State of the air 2008

    Air pollution continued to challenge the nation in 2004, 2005, and 2006. Some cities

  • Assessment of yield losses in tropical wheat using open top chambers

    The present study deals with the evaluation of effects of ambient gaseous air pollution on wheat (Triticum aestivum L. var. HUW-234) growing in a suburban area situated in eastern Gangetic plain of India, using open top chambers. Eight hourly air monitoring was conducted for ambient concentrations of SO2, NO2 and O3 in filtered chambers (FCs), non-filtered chambers (NFCs) and open plots (OPs).

  • US to revise air quality standards for ozone

    the us Environmental Protection Agency (epa) has proposed to revise the national ambient air quality standards for ozone for the first time since 1997. The proposal recommends an ozone standard

  • Urban ambient air quality in Chennai city based on exceedence factor criteria during 1999-2003

    Five years air monitoring study was carried out to assess the primary air pollutants present in the ambient air in Chennai city during 1999-2003 at two different sampling stations.

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