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Lecture 9

LECTURE 9- Arctic Haze.docx

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University of Toronto Scarborough
Environmental Science
Tanzina Mohsin

LECTURE 9 - LONG RANGE TRANSPORT OF POLLUTANTS IN THE ARCTIC o The two types of ARTIC pollutants are , Arctic Haze and Persistent Organic Pollutants (POP’s) ARCTIC HAZE What is it? - When was arctic Haze first discovered? Itw as first discovered in the 1950s by aircraft pilots, and since the arctic was considered to be a pristine environment the discovery was quite surprising - When did the haze occur most frequently (SEASON) ? it tended to occur most commonly in the spring - What appeared to occur with the pollutants? Pooling of the pollutants appeared to occur - Glen shaw stated that? Long range transport was responsible for the appearance of pollutants in the Arctic - How is the haze removed? Removal of the haze occurred via the arctic ocean or surrounding waters - What is the arctic haze mostly composed of ? the arctic haze is mostly composed of sulfate (90%) and the remainder is soot (carbon) and dust o Coal burning the major culprit o How are aerosols formed? Sulfates , which mix with uncombusted carbon o Sulfates mix with uncombusted carbon to form aerosols which block light and appear grayish or brownish in colour o – trace metals (vanadium, manganese) indicate sources o What will adhere to aerosols? Trace constituents such as metals and persistent organic pollutants (POPs) can adhere to the aerosols and pool in the Arctic What did Glen Shaw state? He stated that long range transport is a likely mechanism for the source of Arctic haze to occur. This is accomplished through global circulation, as it CARRIES POLLUTANTS FROM industrialized parts of the globe. WHY DO POLLUTANTS POOL IN THE ARCTIC? There is a STABLE ATMOSPHERE In the arctic and a persistent temperature inversion in the winter. - What does persistent temperature inversion (winter) mean? This means that the ground in the winter near the poles is very cold since there is very little sunlight, so temperatures do not decrease with height as sharply as they would in other regions. - Often what tends to happen with the temperature? The temperature tends to increase with height (does the opposite) - What is TEMPERATURE INVERSION? The temperature INCREASES WITH HEIGHT instead of decreases - What is circumpolar circulation? CLOSED CIRCULATION , that is located around the polar regions - Where is the major source and WHY ? Eurasia due to the coal burning plants located north in North America and China - Arctic haze has a pronounced seasonal cycle, WHEN DOES THE ARCTIC HAZE PEAK? The haze peaks in the SPRING. b - Why does the arctic haze peak in the Spring? It peaks in the Spring due to atmospheric stability - When do the pollutants tend to pool? Pollutants pool in the winter and spring during the seasonal temperature inversion , but the solar radiation in the spring destroys temperature inversion and the pollutants will mix vertically and dissipate - WHAT are the negative impacts of Arctic haze? Reduced visibility , during the spring - Contamination of snow, ice and Arctic waters - What can contamination cause? Bioaccumulation of pollutants WHAT ARE SOLUTIONS (Remediation) ? reduce the emissions of sulfates from COAL BURNING PLANTS. This is very difficult to implement. - Where should coal emissions be reduced ? coal emissions should be reduced FROM EURASIA, since it has the highest level , US is not the major culprit What are persistent organic pollutants? Persistent organic pollutants or POPs are toxic organic compounds - What kind of life span do they have and how does it affect things? They tend to have LONG lifespans, and because of this they become CONCENTRATED as they move up through the food chain - What are the characteristics of Persistent organic pollutants? o Hydrophobic- don’t dissolve easily in water o Lipophobic- don’t attach to fats o Bioaccumulate- accumulate in living things o Biomagnify- concentration of POP gets higher as you move up the food chain - EXAMPLES of POPs? PCB’s , DDT, Chlorodane, Heptachlor - What are PCB’s? they are polychlorinated biphenyls - What are PCB’s used for? They are used for coolants and lubricants in electronic equipment - What happened in 1971? Production and import of PCB’s stopped but they are still in use - What are PCB’s linked to ? liver damage and skin conditions - PCB’s in the environment - Hydrophobic means that ? the PCB’s do not bond with water - IF PCB’s are released into the great lakes what will happen? o Go into sediment o Bioaccumulate in the biota o Volatize readily into the atmosphere o Great lakes bioaccumulates PCB’s to a high level and there are many risks o What kinds of risks occur? There are concerns for fish consumption due to the bioaccumulation by pregnant women especially in the first nations - What is DDT? Dichlorodiphenyltrichloroethane - What was DDT first introduced as? It was first introduced as INSECTICIDE in WWII , to combat malaria and typhus - When was it banned? 1972 in the US - How many tons of DDT were applied? 675,000 tons were applied in the US alone - Because its extremely hydrophobic and lipophobic how does DDT affect birds? Biomagnifications affects predatory animals - Its also toxic to aquatic life especially fish -DDT is a probable carcinogen, but studies of the extent that it is toxic or carcinogenic in humans is inconclusive. What is cholorodane?Chlordane is C10H6Cl8 (Octachlorodihydrodicyclopentadiene). What is chlorodane used for? Chlorodane is used as an INSECTICIDE from 1948 to 1983 When was it banned in Canada? 1995 When was in banned in the US? It was banned in the US in 1988 except for fire ant control in power transformers. What kind of disorders is it linked to? Nervous system and digestive system What is Heptachlor? C10H5Cl7 Heptachlorodicyclopentadiene, it’s an insecticide What does Heptachlor look like? It’s a white powder, that smells like moth balls IN Canada banned in 1985 and in US it was banned in 1988 except for the use on fire ants and power transformers What are the negative impacts ? damage to the nervous system POP transport (WANIA AND Mackay) Who? Frank Wania and Donald Mackay from The Wania Research Group Why? To track the fate of POPs in the environment, especially the Arctic, since POP’s are ubiquitous in the 2\ environment , even though they are banned there hasn’t been a reduction in levels Where? Arctic • How? • 1. Examination of pollutant concentration data in air, snow, fish, seals • 2. Creation of a chemical fate model to explain high concentrations WHAT? Transfer of POP’s in the environment POP’s are ubiquitous despite of? no local sources of POP’s and banning that has occurred - There hasn’t been a reduction of POP’s despite these reforms but WHY ? global distillation , cold condensation - What do lower temperatures do ? lower temperatures lead to deposition and absorption on particulate matter POP TRANSPORT 1. POP’s are released into the atmosphere (volatized) in gas form 2. As it travels poleward , fractionation and condensation occurs, due to cooler temperatures 3. As the POP travels via air currents poleward, cooling occurs and the POPs (depending on
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