EESA10H3 Lecture 2: EESA10 WEEK 2

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Environmental Science
Silvija Stefanovic

Week 2: Lecture 2 Air ● london smog(1952) ○ smoke and sulphur dioxide pollution killed many ● airborne hazards (outdoor and indoor) ● sources (outdoor) air pollution: ○ human sources ■ stationary (factories) ■ mobile (cars) ○ natural sources ■ volcano eruption ○ burning fossil fuels ■ for electricity ■ releases CO2 into the air and many other pollutants ● health effects (outdoor) air pollution ○ asthma ■ particles (SO2) irritate bronchial passages leading to severe difficulty in breathing ○ chronic bronchitis ■ excessive mucus produced in cough causing lasting cough ■ from SO2 and smog ○ Pulmonary emphysema: weakening of alveoli wall ■ shortness of breath (NO2 involved) ○ can also cause lung cancer and heart disease ● Common air pollutants: ○ particulate matter, CO, Nitrogen Oxide, Sulphur dioxide, volatile organic compounds (VOC), lead, ground level ozone ● Particulate matter ○ particles found in air (dust, smoke) ○ from vehicles and factories ○ serious health effects ● CO (carbon monoxide) ○ incomplete burning of fuels containing carbon ■ ex: heaters, stoves, fireplace ○ mainly a problem for indoor air pollution ○ health impacts: ■ interferes with oxygen delivery ■ fatigue headache nausea ● Nitrogen Oxide ○ forms in any time of combustion process ○ formation of ground level ozone ○ acid rain formation ● Sulphur Oxide ○ burning of coal and oil ○ dissolves into water and makes it acidic ○ causes respiratory illness—> increases chance of heart and lung disease ● VOC ○ made of many organic compounds ○ hydrocarbons: methane, butane and propane ○ photochemical smog ● Lead ○ vehicles and industrial sources ○ deposit in soil and water ○ affects mainly young children (dirt etc) ○ neurotoxicant ■ lowers IQ and neurological performance ■ cardiovascular mortality ○ Ozone ■ VOC +NOx + heat + sunlight = ozone ■ good in stratosphere but bad in ground level ■ causes lung damage (shortness of breath) ○ Indoor air pollution ■ 5X more concentrated than pollutants in the other air ■ buildings are airtight with less ventilation ○ Sources: ■ building materials, furniture ■ cleaning products ■ pesticides, cooking ■ “Sick building syndrome”: ■ same symptoms experienced by occupants of a buildings ○ health effects (indoor air pollution) ■ takes years to develop ■ asthma, cancer ■ headaches ● Asbestosis ○ fibrous minerals used in buildings, car breaks, and heat resistant fabrics ○ doesn't evaporate into air or dissolve in water ○ cant move through soil ○ doesn't break down ● Health ○ impacts lungs and membrane that surrounds the lungs ○ asbestosis—> scar like tissue(causes difficulty in breathing) ○ plaques in neural membranes ○ lung cancer, mesothelioma ○ increased risk of other cancers ● Formaldehyde ○ VOC, naturally occurring gases ○ gas at normal room temperature ○ released by burning wood, cars, glue in pressed wood or paints ○ allergic reactions ■ skin rash, burning eyes, throat ○ nausea, cancer, coughing ● Mold and moisture ○ needs moisture to form, not standing water ■ bathroom, kitchen, gym area, locker room, damp basement ○ triggers asthma by toxins and irritants, indoor allergens ○ control moisture to stop this ○ can produce tiny spores, odour, discolouration ● Second hand smoke ○ non smoker exposed has 25% more chance of lung cancer ■ many die from exposure ○ adults can get heart disease/attack, lung cancer ○ children usually get asthma and pneumonia ○ Lec. 2- Chapter 4 (pg. 128-136) ENVIRONMENTAL IMPACTS OF BURNING FOSSIL FUELS (PG. 128 -136) - Most combustion products from burning fossil fuels are released into the atmosphere becoming air pollution, a term that has traditionally referred to pollution of the troposphere. About Combustion: - Basic definition: combustion is a chemical reaction that requires a hydrocarbon fuel, the presence of oxygen, and an initial source of heat. - Heating causes the hydrocarbon fuel to break down & recombine with the oxygen, forming water and carbon dioxide. This oxidation reaction also releases heat energy, causing combustion to continue as long as fuel remains. - The extra heat energy, beyond that needed to maintain the combustion, can be put to use for human purposes. When not enough oxygen is immediately present for a hydrocarbon fuel to burn completely, carbon monoxide is formed instead of carbon dioxide. - Combustion under real-world conditions is often incomplete, and fossil fuels are more than just hydrocarbons. Further, some air pollutants from the burning of fossil fuels set in motion complex secondary impacts. - Most of the water used in power production is not consumed, but is returned to the body of water from which it was originally taken - Even after cooling, this water is still warmer than the receiving body of water, an effect referred to as thermal pollution Basic Products of Combustion: Oxides and Particulates - We burn fossil fuels to power vehicles of all types, to generate electricity, and to heat commercial and residential buildings - Some heavy manufacturing facilities, including petroleum refineries, metal smelters, and pulp and paper mills, are powered directly by burning fossil fuels - Because combustion is oxidation, the combustion of fossil fuels produces several oxides - Carbon dioxide (CO2), a natural constituent of the atmosphere, is released anytime fossil fuels are burned - Carbon monoxide (CO) is mainly a product of inefficient burning when vehicles idle - Nitrogen is plentiful in the atmosphere, and thus oxides of nitrogen—the gases nitrous oxide (N2O), nitrogen dioxide (NO2), and, if combustion is incomplete, nitric oxide (NO)—are produced by burning - Cars and power plants are the major sources of these pollutants - Nitrogen dioxide is a brownish gas that is a visible marker of air pollution - In the field of air pollution, NO2 and NO are together referred to as NOx, pronounced “nox” - Sulfur is present in most cool and crude oil - Sulfur dioxide (SO2) gas is produced mainly when coal or sulfur containing oil fuel is burned - Sulfur Oxide (SO) may also formed, but does not persist as a stable compound - SO and SO2 are together known as Sox - Because sulfur is refined out of gasoline and heating fuels, cars and furnaces did not produce Sox - Because sulfur is refined out of gasoline and heating fuels, cars and furnaces did not produce Sox In the atmosphere, some sulfur dioxide is converted to tiny water soluble particles known as sulfates The burning of fossil fuels adds to the burden of particles in the air - Particulate Matter (PM)/ Particulates: the complex mixture that may consist of both small solid particles and fine liquid droplets, and may include solid particles (dust), sulfate, metals, and organic chemicals; long, narrow fibers, such as asbestos fibers, are considered elongated mineral particles - A common organic component of particulates is a group of compounds known as polycyclic aromatic hydrocarbons (PAHs) - Polycyclic aromatic hydrocarbons (PAHs) A group of related organic compounds that are products of incomplete combustion and are ubiquitous in the environment Other Pollutants Liberated by Combustion: Mercury, Lead, VOCs - The burning of fossil fuels releases other substances as well o Mercury: A neurotoxic heavy metal that is liquid at room temperature § Elemental mercury vapor rises and moves into the atmosphere § The quantity released for ton of coal burned is small, but we burn many tons of coal, and mercury is strongly neurotoxic - In the atmosphere, elemental mercury can be carried with air currents for some time, but eventually it settles out or is deposited with rain or snow - Certain species of bacteria convert the mercury from its elemental form to a different form called methylmercury o Methylmercury becomes concentrated in the muscle of fish - Like mercury, lead has long been known to be neurotoxic at high doses - Lead: A neurotoxic heavy metal o Lead was deliberately added
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