41. Ozone | Environment Knowledge Hub Abstract The objective of the OzonAction programme is to assist developing countries and countries with economies in transition (CEITs) to achieve compliance with the Montreal http://www.ekh.unep.org/?q=taxonomy/term/11

42. Ozone - Environment, The University Of York Environment MSc Environmental Science and Management, ozone Ozone A threat to global food security? Our continued ability to feed the world’s population over the next century is http://www.york.ac.uk/environment/postgraduate/msc-dip-environmental-science-and

Skip to Content Environment Search Environment University University A to Z Departments Environment ... Outside air quality Ozone Pharmaceuticals Road salting SEI-Y Volcanic pollution ... Contact us Ozone A threat to global food security? Our continued ability to feed the world’s population over the next century is uncertain, as population increases, agricultural land decreases and degrades, and the impacts of climate change increase. But how important is air pollution globally as a threat to food security? The most important air pollutant in terms of effects on crop production is ground level ozone. Unlike many pollutants, elevated concentrations are not restricted to the vicinity of urban or industrial areas; ozone can be found at damaging levels across large areas of the countryside. It is formed in hot sunny weather by emissions from transport, energy production and industry. Ozone concentrations frequently exceed WHO air quality guidelines set to protect agricultural crops across many of the more densely inhabited parts of the planet. Evidence of the harmful effects to vegetation caused by ozone has accumulated over recent decades. In Europe, for example, visible symptoms of ozone injury are commonly seen on Mediterranean crops, especially when they are grown under irrigation. Ozone can reduce crop yield significantly even in the absence of such visible symptoms. More detailed information on the assessment of damage to crops from ozone in Europe is provided at ICP Vegetation However, ozone is not a problem that is confined to Europe and North America. Its effects in causing damage to crops have been recognised in Latin America, northern and southern Africa, South Asia and China. For example, studies in south Asia during the 1980s and 1990s have indicated that current ambient O3 levels can cause both visible injury and significant reductions in the yield of staple crops (up to 40% for rice and near 50% for wheat in one study conducted in Pakistan).

43. Smog Locations - Where Does Smog Occur? See More About smog; air quality; air pollution; ozone; environment and health http://environment.about.com/od/smogfaq/f/smog_faq_four.htm

zWASL=1;zGRH=1 zJs=10 zJs=11 zJs=12 zJs=13 zc(5,'jsc',zJs,9999999,'') zDO=0 Home Environmental Issues Environmental Issues Search Environmental Issues What's at Risk? What To Do Global Warming ... Share w(x2+zWl+'?p=1" zT="18/1[N" rel="nofollow">Print') Free Environmental Issues Newsletter! Sign Up Discuss in my Forum By Larry West , About.com Guide See More About: smog air quality air pollution ozone ... environment and health zSB(3,3) Question: Where Does Smog Occur? Answer: Severe smog and ground-level ozone problems exist in many major cities around the world, from Mexico City to Beijing. In the United States, smog affects much of California, from San Francisco to San Diego, the mid-Atlantic seaboard from Washington, DC, to southern Maine, and major cities in the South and Midwest. To varying degrees, the majority of U.S. cities with populations of 250,000 or more have experienced problems with smog and ground-level ozone. According to some studies, more than half of all U.S. residents live in areas where the smog is so bad that pollution levels routinely exceed safety standards set by the U.S. Environmental Protection Agency. Smog: Frequently Asked Questions What is Smog?

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