Amamda and robert air pollution and ozone pptPresentation Transcript
The atmosphere is a thin layer of gases held close to Earth by gravity. The atmosphere is thinner at the poles, thicker at the equator. Two major components is N2 78% and O2 21% Atmospheric Pressure –measure of the mass per unit are of air. Pressure increases as the density of air increases. There is a higher density in the air we breathe at sea level than the air we inhale on top of the world’s largest mountain. Ozone protects us from about 95% UV radiation
Air pollution– presence of chemicals in the atmosphere where the concentration is high enough to affect climate and harm organisms. Primary pollutants – emitted directly into the troposphere in a harmful form. (carbon monoxide) Secondary pollutants – when primary pollutants react with the components of air. Majority of pollutants come from natural sources, dust particles, organic chemicals, forest fires, volcanic eruptions, and sea spray Pollutants from human activity such as burning oil, gasoline, and natural gas are the ones that cause more harm into the troposphere. Outdoor pollutants examples: carbon monoxide, nitrogen dioxide, sulfur dioxide, ozone, lead
Photochemical Smog – when nitrogen oxides and organic hydrocarbon compounds chemically react under the influence of UV radiation to produce a mixture of many primary and secondary pollutants. Factors that increase outdoor pollution:• Urban buildings, hills, mountains, high temperatures. Factors that help reduce outdoor pollution:• Rain and Snow – cleanse the air of pollutants• Salty sea spray from the oceans- wash out particles from air that flows from land onto the oceans.• Wind- sweep pollutants away, dilute them by bringing in new fresh air.
Temperature Inversion – layer of dense, cool air trapped under a layerof less dense, warm air. (traps the pollutants near the ground and itbecomes more dangerous)Acid Deposition – also known as acid rain, falling of acids andcompounds from the atmosphere into the earth’s surface. (Sulfur/nitrogen main culprits.) Acid deposition can deplete the nutrients from plants and also damage and weaken the plants. On humans, it can produce lung cancer, corrosion, haze, and also kills fish.
Indoor air pollution is a much greater threat to human health than outdoor air pollution. So dangerous due to accumulation, concentration and lack of detection Four most dangerous indoor air pollutants are: Cigarette smoke, formaldehyde, radioactive radon-222 gas, and ultra fine particles. New building are more commonly “sick” than the old ones because of reduced air exchange and chemicals released from new carpeting and furniture.
Prolonged smoking and breathing air pollutants can lead to respiratory disorders like asthma, lung cancer, and chronic bronchitis. Mechanisms that protect us from some air pollution. (hairs filter out large particles, sticky mucus captures smaller particles and dissolves some gaseous pollutants. Each year, approximately 3 million people (average 8,200 per day) die prematurely from air pollution (mostly indoor pollution in developing countries)
Clean Air Act (1970) in the U.S has reduced outdoor pollution from six major pollutants by setting emission standards. Preventions from indoor air pollution:- covering ceiling tiles and lining the AC ducts to prevent release of mineral fibers- Ban smoking or limit it to well-ventilated areas- Prevent radon infiltration- Use office machines in well-ventilated areas- Use less polluting substitutes for harmful cleaning agents, paints, and other products. Solutions for Outdoor: Improve energy efficiency to reduce fossil fuel use. - Rely more on lower-polluting natural gas. - Rely more on renewable energy (solar cells, wind)
Temperature and climate have been changingthroughout the earth’s history. Geologic records and atmospheric measurements provide a wealth of information Climate – determined about past atmospheric temperatures and mostly by its average climate temperature and average precipitation. Scientists from the U.S. National Academy of Sciences and the American Geophysical Union have also evaluated possible future climate changes.
Global Warming – temperature increases in the troposphere, which in turn can cause climate change. Global Climate Change – a broader term that refers to changes in any aspects of the earth’s climate, including temperature, precipitation, and storm intensity. The greenhouse effect warms the earth’s lower troposphere and surface. ** The two major greenhouse gases are water vapor and carbon dioxide. Humans have contributed to the increased level of carbon dioxide Albedo – reflectivity of different parts of the earth’s surface. Colored surfaces of ice and snow help cool the earth reflecting the incoming sunlight back into space.
Coupled global circulation models – global climate models that are applied to theatmosphere to project the effects of increases in greenhouse gases on averageglobal temperature. The largest burden of the harmful effects A decrease in high- of moderate global warming will fall on elevation snow packs could people and economies in poorer tropical lead to a sharp decline in and subtropical nations. agricultural productivity in heavily irrigated areas.
Disagreement on whether the world Solutions:should respond to the threat of climatechange. •Soil sequestration – plants such as switch grass are used to remove carbon•The economic costs of reducing dioxide from the air and store it in the soil.greenhouse gas emissions are higher thanthe economic benefits •Reduce the release of carbon dioxide and nitrous oxide from soil.•Developed countries, developing •Remove carbon dioxide fromcountries, or both should take responsibility smokestacks and pump it deepfor reducing greenhouse gas emissions. underground into unminable coal seams and abandoned oil fields.•Actions to reduce greenhouse gasemissions should be voluntary or requiredas a result of national laws and aninternational treaty
Kyoto Protocol – requires 39 developed countries to cut emissions ofCO2, CH4, and N2O, to an average of about 5.2% below 1990 levels by 2012. A growing number of major global companies, such as Alcoa, DuPont, IBM, Toyota, BP Amoco, and Shell, have established targets to reduce their greenhouse gas emissions by 10-65% from 1990 levels by 2010.
Chlorofluorocarbon – an organic compound that is made up of chlorine, fluorine, and carbon, produced as a volatile derivative of methane and ethane. F. Sherwood Rowland and Mario Molina proposed inc. CFC hypothesis Measurements indicate that CFCs and other ODCs are the primary culprits of ozone depletion. Widespread use of a number of useful and long lived chemicals has reduced ozone levels in the stratosphere. Polar Vortex – a huge swirling mass of very cold air that is isolated from the rest of the atmosphere
In 1987, 36 nations got together in Montreal Protocol – the goal wasMontreal, Canada to develop a to cut emissions of CFCs into thetreaty that could end with the atmosphere by about 35%CFCs emissions. between 1989 and 2000.After hearing that no changed were made in the atmosphere and that theozone was getting thinner and thinner, 93 countries got together in London andcame up with another treaty. Copenhagen Protocol – an amendment which accelerated the phasing out of key ozone-depleting chemicals.
FRQ 2007 #3
FRQ Solution A. Class of Compounds Halocarbons/Halons Fire retardant Soil fumigant/pesticide Solvent Foam Blowing Insulation CFC’s Coolants/refrigerants/AC/refrigerator Aerosol ** Needs to describe 1 class of compounds and describe 2 major uses
FRQ Solution [cont.] D. Effects of Ground Level Ozone Respitory Irritant Decreased photosynthesis due to C. Consequences Increase in UV (specifically UVB) reaching Earth’s surface. Effects: Skin Cancer Disruption of food chains B. Description CFCs are broken down by UV radiation resulting in the release of atoms– chlorine/bromine/flourine Halogens break the O3 into O+ O2