Karteikarten
Chapter 15: Air Pollution and Stratoshpheric Ozone Depletion
Karten in diesem Stapel (45)
- 1air pollution-introduction of chemicals, particulate matter, or microorganisms into the atmosphere at concentrations high enough to harm plants, animals, and materials such as buildings, of to alter ecosystems
-refers to pollution in troposphere (ground level pollution) - 2What are the six criteria air pollutants?sulfur dioxide
nitrogen oxides
carbon monoxide
particulate matter
tropospheric ozone
lead - 3Sulfur dioxide SO2-corrosive gas
-product of fossil fuel combustion (coal, oil), volcanic eruptions, forest fires
-respiratory irritant, affects plant tissue
-when fossil fuels are combusted, sulfur combines with oxygen to form sulfur dioxide - 4Nitrogen Oxides NOx-nitrogen oxide NO = colorless, odorless gas
-NO2=pungent, reddish brown gas
-product of motor vehicles and stationary fossil fuel combustion, forest fires, lightning, microbial action in souls
-atmospheric nitrogen forms photochemical smog - 5Carbon Oxides CO and CO2-carbon monoxide CO = colorless, odorless gas formed during incomplete combustion of most matter (vehicle exhaust)
-carbon dioxide CO2-colorless, odorless gas formed during complete combustion of most matter (fossil fuels, biomass), absorbed by plants in photosynthesis and released in respiration - 6particulate matter PM-solid or liquid particles suspended in air
-product of road dust, rock crushing operations, volcanoes, forest fires, dust storms, combustion of wood, animal manure and other biofuels, coal, oil, and gasoline
-diesel vehicles emit more PM
-PM 10 deposited deep within respiratory tract
-PM 2.5 more toxic substances, deposited deeper in tract
-scatter and absorb sunlight (haze) - 7photochemical oxidantsclass of air pollutants formed as a result of sunlight acting on compounds such as NOx and SO2
-harm plant tissue, human respiratory tissue, and construction materials - 8tropospheric ozone-harmful to plants and animals, causes respiratory inflammations
-reacts with NOx and VOCs to form harmful oxidants
-reacts with sulfur and NOx to form PM - 9smog-resulting mixture of oxidants and particulate matter
- 10photochemical smog-dominated by oxidants such as ozone
-LA type smog
-brown smog - 11sulfurous smog-dominated by sulfur dioxide and sulfate compounds
-London type smog
-grey smog - 12Lead-product of leaded gasoline, old paint
-affects learning and intelligence
-levels in US decreased significantly due to unleaded gasoline - 13mercury-combustion of fossil fuels, especially coal
-affects central nervous system, bioaccumulation
-concentrations increased dramatically - 14volatile organic compounds VOCs-organic compounds that become vapors at typical atmospheric temperatures
-hydrocarbons such as gasoline, lighter fluids, dry cleaning fluids, oil based paints, perfumes
-formation of photochemical oxidants - 15primary pollutants-compounds that come directly out of the smokestack, exhaust pipe, or natural emission source
-CO, CO2, SO2, NOx, PM, many VOCs - 16secondary pollutants-primary pollutants that have undergone transformations in the presence of sunlight, water, oxygen, or other compounds
-occurs rapidly in day due to sunlight and water
-ozone is the result of emissions of NOx and VOCs - 17natural emissions-volcanoes release SO2, PM, CO, NOx
-lightning strikes release NOx
-forest fires release PM, NOx, CO
-living plants release VOCs - 18welfarevisibility, status of crops, natural vegetation, animals, ecosystems, buildings
- 19National Ambient Air Quality StandardsEPA periodically specifies concentration limits for each air pollutant
-concentration should not be exceeded over a specified time period - 20production of photochemical smog1. during the day, nitrogen oxides in the atmosphere form O3
2. when sunlight intensity decreases, nitrogen oxide combines with O3 to produce O2 + NO2
3. VOCs combine with nitrogen oxides
4. Nitrogen oxide can't break down ozone
5. ozone accumulares to produce photochemical oxidants - 21How does atmospheric temperature influence the formation of smog?-emissions and evaporation of VOCs increase as the temperature increases
-air conditioning increases NOx emissions
-faster reactions
-thermal inversion - 22What is acid deposition?deposition with a pH lower than 5.6
- 23How does acid deposition form?1. Nitrogen oxides and sulfur dioxide are released into the atmosphere
2. react with atmospheric oxygen and water to form nitric acid and sulfuric acid
3. break down further to produce nitrate, sulfate, and hydrogen ions - 24What are the major effects of acid deposition?-lower pH of aquatic ecosystems, decreases species diversity of aquatic organisms
-mobilization of metals from soil into surface water causes species loss and affecting food sources
-hydrogen ions react with limestone or marble, erodes structures and painted surfaces - 25fluidized bed combustion-removes sulfur dioxide from coal exhaust combustion
1. granulated coal is burned in close proximity to calcium carbonate
2. heated calcium absorbs sulfur dioxide and produces calcium sulfate, used for gypsum wallboard - 26How can nitrogen oxide emissions be reduced?-reduce burn temperatures and control amount of oxygen, although this decreases efficiency and increases PM and CO concentrations
-catalytic converters in vehicles and other improvements in combustion technologies - 27What are some methods of reducing particulate matter?-gravitational settling (gravity removes particles and is disposed in a landfill)
-baghouse filter
-electrostatic precipitator
-scrubber - 28baghouse filter1. dirty air enters housing
2. combustion exhaust steam moves through, particles trapped in filter bags
3. filtered air leaves unit
4. shaker mechanism dislodges particles - 29electrostatic precipitator1. dirty air enters the unit
2. particles in combustion exhaust stream pass by negatively charged plates, which gives them a negative charge
3. negatively charged particles are attracted to positively charged collection plates
4. clean air moves out of the unit
5. positively charged collection plates are discharged so particles can be removed - 30scrubber1. dirty air enters scrubber
2. combustion exhaust steam moves upward in shower of water mist
3. mist collects particles and brings them to bottom of unit
4. dirty water moves to a sludge removal system
5. sludge is separated from water and disposed, excess mist collects on screen
6. clean air exits through stack - 31What are some smog reduction methods?-reduce VOC emissions so there will be fewer compounds to interact with NOx and more nitrogen oxide will be able to recombine with ozone
-reduce nitrogen oxide emissions (more effective method) - 32examples of innovative pollution control-reduction in use of wood burning stoves to reduce nitrogen oxide, PM, VOCs, and CO emissions
-automobile restrictions
-carpool lanes
-improvement of public transportation
-Acid Rain Program of the Clean Air Act reduced sulfur emissions from power plants
-sulfur allowances - 33sulfur allowance-authorizes a power plant or industrial source to emit one ton of SO2 during a given year
-must possess number of allowances at least equal to its annual emissions
-can be bought or sold on open market - 34What are the beneficial properties of ozone?-absorbs UV-A (initiates and contributes to skin cancer), and UV-B and UV-C (cause potentially significant damage to tissues and DNA)
-absorbs over 99% of UV-B and UV-C radiation - 35How does stratospheric ozone break down and form?1. UV-C breaks the bonds holding the oxygen molecule together, leaving two free oxygen atoms
O2 + UV-C = 2O
2.O2 reacts with free oxygen atoms and forms ozone
O2 + O = O3
3. ozone is broken down into O2 and free oxygen atoms when it absorbs UV-C and UV-B radiation
O3 + UV-B or UV-C = O2 + O
ozone is continuously formed and broken down in the presence of sunlight - 36What are chlorofluorocarbons CFCs?-family of organic compounds whose properties make them ideal for use in refrigeration, air conditioning, propellants, and insulation.
-stable, inert, nontoxic, nonflammable
-major source of chlorine in stratosphere, extremely persistent - 37What time of year does ozone depletion occur over the antarctic?-roughly August through November
- 38How does ozone break down over the poles?-ice crystals mixed with nitrogen oxide cause the perfect surface for the formation of Cl2
-atmospheric chlorine interacts with ice crystals
-in spring, UV radiation breaks down Cl2 to Cl, which destroys ozone
-no ozone forms during dark winter, leading to "hole" - 39How does the ozone hole lead to harm in organisms?-increased UV-B radiation
-harmful to cells
-reduce photosynthesis
-increased risk of skin cancer, cataracts, suppressed immune system - 40What steps are being taken to reduce ozone depletion?-1987 Montreal Protocol on Substances that Deplete the Ozone layer
-amendments requiring the elimination of CFC production and use in developed world - 41What causes indoor air pollution in developing countries?-incomplete combustion of biomass and coal in open pit fires, no exhaust system leads to build up of CO and PM
- 42What causes indoor air pollution in developed countries?-people spend more time indoors
-homes are more tightly insulated
-more toxic materials (old paint, floor and ceiling tiles, leaky gas from stoves and furnaces, fireplaces, household products) - 43asbestoslong, thin, fibrous silicate mineral with insulating properties
-fibers become airborne when insulating materials become old, damaged, or disrupted - 44What is the source and health problems of indoor CO?-result of malfunctioning exhaust system in household heaters, mostly natural gas heaters
-combines with hemoglobin and interferes with oxygen transport in blood - 45What are the sources and health effects of indoor radon pollution?-seeps into a home through cracks in the foundation or soil
-drinking water from underlying rock, soil, or groundwater
-radon 222 or polonium 210 attach to dust particles and are inhaled
-lung cancer
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