APES ch. 17
History of air pollution in London
- 13th century, pollution from coal burning, King edward threatened death for burning certein coal - industrial revolution in18th and 19th century expanded use if coal -1952, killer smog (pollution trapped by weather conditions) killed 4,000 - today, londonders have cleaner air, but smog from urban traffic is the problem (250,000 cars bring CO2, CO, nitrogen oxides, particulare matter) -Ken Livingatone congestion-charging program proposed to charge drivers for entering central city (relieve traffic, encoursge mass tranist, cut pollution) - traffic congestion decreased 30%, businesses and economy remained strong - part. Matter declined 15%, nitrogen oxide fell by 13%, and CO2 by 16% - most CO2 reduction due to less congestion and half cuts in part. Matter and nitrogen oxides due to less congestion and other half to Improved vehicle tech
Montreal Protocol
- 180nations agreed to cut CFC production in half. - today, production and use of ozone-depleting compounds has fallen 95%, beginning long-term recovery of ozone layer - however, nations can plead for some ozone-depleting chemicals and U.S. recently allowed to continue using methyl bromide
Toxic air pollutants
- 1990 clean air act identifies 188 of these - include substances known to cause cancer, reproductive defects, or neurological, developmental, immune system, or respiratory problems in people, as well as those that affect animals and plants -
History of composition of the atmosphere
- O2 began building in atmosphere dominated by CO2, nitrogen, CO, H2, about 2.7 bya, with evolution of autotrophic microbes that edited oxygen as by-product of photosynthesis
Temperature Inversion or Thermal Inversion
- Under most conditions, air in troposphere decreases in temp. as altitude increases - occasionally, layer of cool air occurs beneath layer of warmer air - cooler air at bottom of Inversion layer (area where temp rises with altitude) is denser than warmer air at top, so resists vertical mixing and remains stable - can occur high above ground or near surface - common type of Inversion occurs in mountain valleys where slopes block morning sunlight, keeping ground-level air within valley cool - trap pollutants near ground (killer smog in London 1952 occurred when high pressure system acted like cap to trap pollutants) -inversions regularly cause smog buildup in metropolitan areas
What are the effects of acid deposition on ecosystems?
- acids leach nutrientssuch as calcium, magnesium, and potassium from topsoil, altering soil chemistry and harming plants and soil organisms. occurs because hydrogen ions from acid precipitation take place of ions in soil compounds. - acid rain mobilizes toxic metal ions like Al, Zinc, Mercury, and copper by converting them from insoluble forms to soluble forms. Elevated soil concentrations of metals hinder water and nutrient uptake by plants - thousands of lakes have lost fish, because acid prec. leaches aluminum out of soil and rock and into waterways in a form deadly to marine life. Al damages fishes gills and disrupts their salt balance, water balance, breathing, and circulation. - damages agricultural crops, erodes stone buildings, corrodes cars, damages ancient monument. - effects can be felt long distances from source of acid precipitation. many regions of greatest acid prec. are downwind of source
Bush admin'c Clear Skies initiative
- aimed to abandon a command-and-control policy approach and establish a market=based cap-and-trade program SO2, nitrogen oxides, and mercury.
What happens to body when humidity is high
- air already holding nearly as much water vapor as it can, so sweat evaporates slowly and body can't. lol efficiently - makes it feel hotter - low humidity speeds evaporation and makes it feel coolef
Low-pressure system
- air moves toward low atmospheric pressure at center of system - air expands and cools, and clouds and precipitation result
What happened in Donora, Penn?
- air near ground cooled during night, and because of hilly terrain, not enough morning sun reached valley to warm and disperse the cold air. - thermal inversion trapped smog containing particulate matter emissions from steel and wire factory - 21 killed and nearly half town became ill
high-pressure system
- air that moves outwards from center of high pressure as it descends - beings fair weather
VOCs
- airborne carbon-containing compounds released by everything from plastics, oils, perfumes, cleaning fluids and pesticides - VOCs evaporate from furnishings, building materials, color film, carpets, and sheets of paper - photocopying machines emit VOCs each time used - 81% US office buildings had at least one type of VOC - VOC released in small amounts (0.1 parts per million indoor) yet much greater amount exists indoors than outside
Tropopause
- at to of troposphere, temp stops to decline with altitude, marking boundary between stratosphere - acts like a cap, limiting mixing between the two atmospheric layers.
Describe the emissions reductions in London
- between 1996 and 2005, London achieved a 56% reduction in CO emissions - 41% drop in NOx emissions - 28% decline in particulate matter release - 73% decrease in SO2 emissions - tropospheric ozone did show an increase
Volatile Organic Compounds (VOCs)
- carbon-containing chemicals used in and emitted by vehicle engines and a wide variety of solvents and industrial processes, as well as by many household chemicals and consumer items - one group of VOCs consists of hydrocarbons like methane, propane, butane and octaine - humans account for about half of VOC emissions in the U.S. , and remainder comes from natural sources (plants produce isoprene and terpene)
what are the reasons for the declines of emissions of six monitored pollutants?
- cleaner-burning motor vehicle engines and automotive technologies such as catalytic converters have decreased emissions of CO and others - sulfur dioxide permit-trading program and clean coal tech have reduced SO2 emissions - tech like baghouse filters, elecrtrostatic precipitators and scrubbers that chemically convert or physically removed airborne pollutants - leaded gasoline phaseout caused U.S. lead emission to plummet by 93%
Tropospheric Ozone
- colorless gas with "objectionable" odor - ozone in stratosphere shields us from UV radiation - O3 from human activity forms and accumulates low in troposphere and acts as a pollutant. In troposphere, ozone results from interaction of sunlight, heat, nitrogen oxides, and volatile carbon-containing chemicals/ - tropospheric ozone is a secondary pollutant - major component of smog - can pose health risks as a result of its instability as a molecule; triplet of oxygen atoms will release one of its threesome, leaving a molecule of oxygen gas and a free oxygen atom. the free oxygen may participate in reactions that injure living tissue and cause respiratory problems - pollutant that most frequently exceeds EPA air quality standard
Sulfur Dioxide
- colorless gas with pungent odor - vast majority of SO2 pollution results from combustion of coal for electricity and industry - during combustion, elemental sulfur in coal reacts with oxygen to form SO2. - In atmosphere, SO2 reacts to form Sulfur Trioxide (SO3) and sulfuric acid HSO4 which creates acid precipitation
Carbon Monoxide
- colorless, odorless gas produced primarily by incomplete combustion of fue; - vehicles and enginges account for 78% of CO emissions in U.S. - other sources include industrial processes, combustion of waste, and residential wood burning - Carbon Monoxide poses risks to humans and animals even in small concentration - CO can irreversibly bind to hemoglobin in red blood cells, preventing hemoglobin from binding with oxygen
Particulate matter
- composed of solid or liquid particles small enough to be suspended in atmosphere - includes primary pollutants like dust and soot and secondary pollutants such as sulfates and nitrates - damage respiratory tissues when inhaled - 60 percent of particulate matter in atmosphere is wind-blown dust; human activity accounts for much of the rest - contributed to London's killer smog in 1952
Clean Air legislation in U.S.
- congress passed Air Pollution Control Act of 1955 - Clean Air Act of 1963 funded research into pollution control and encouraged emissiobns standards for automobiles and stationary point sources - Clean Air Act of 1970: stricter standards for air quality, imposed limits on emissions from new stationary and mobile sources, provided new funds for pollution-control research, enabled citizens to sue parties violating the standards (Amended in 1977, as some standards considered too ambitious) - Clean Air Act of 1990: strengthen regulations pertaining to air quality standards, auto emissions, toxic air pollution, acidic deposition, stratospheric ozone depletion. Introduced emissions trading program for sulfur dioxide (businessess allocated permits for emitting this pollutant, and could then buy, sell, or trade allowances with one another)
What causes air quality problems in rural areas?
- drift of airborne pesticides, industrial pollutants from cities, factories, power plants - great deal of pollution comes from feedlots. waste of the animals produces dust as well as methane, hydrogen sulfide, ammonia. - ammonia contributes to nitrogen deposition across wide areas.
What is being done in many U.S. states to tackle photochemical smog?
- drivers in 34 states required to have vehicle exhaust inspected periodically at check stations
What causes the change in seasons?
- earth tilted on axis by about 23.5 - northern and Southern Hemispheres tilt toward sun for half the year - regions near equator unaffected by tilt and half 12 hour days throughout year - near poles effect is strong and seasons pronounced
What is said to be the greatest human-induced air pollution problem?
- emission of greenhouse gases that contribute to global climate change
How does temp, in earth vary at a global scale? Local scale?
- global scale: temp. varies over surface because sun rays strike area more directly than others - local scale: temp. Varies because of topography, plant cover, proximity of land to water, and other factors
Why is air more dense near surface?
- gravity pulls gas molecules towards surface
Secondary Pollutants
- harmful substances produced when primary pollutants interact or react with constituents of the atmosphere - like tropospheric ozone and sulfuric acid
What does energy from sun do?
- heats air in atmosphere - drives air movement - helps create seasons -influences weather and climate
Lead
- heavy metal that enters the atmosphere as a particulate pollutant - lead-containing compounds tetraethyl lead and tetramethyl lead, when added to gasoline, improve engine performance. eventually phased out, begining in 70s. - exhaust from combustion of leaded gasoline emits lead into atmosphere, from which it can be inhaled or deposited on land or water - lead can bioaccumulate and cause central nervous system damage. - greatest source of atmospheric lead pollution in developed nations is industrial metal smelting
what geographic occurrence worsens smog?
- hilly topography is factor in air pollution of many cities, as surrounding mountains trap air and create inversions
What did officials in Athens do to combat photochemical smog?
- incentives to replace aging vehicles - mandated that autos with odd-numbered licenses be driven only on odd-numbered days and autos with even-numbered licenses be driven on even-numbered days - smog reduced by 30%
Describe indoor air pollution in the developing world.
- indoor air pollution has the greatest effect in the developing world - millions burn wood, charcoal, animal dung or crop waste inside homes for cooling and heating.In the process, they inhale soot and CO. Concentration of particulate matter in such homes can rise 20x over WHO standards - poverty forces half of population and 90% of rural residents to heat and cook with indoor fires. -indoor air pollution from fuelwood burning kills 1.6 million a year, 5% of all deaths in some developing nations and 2.7% of entire global disease burden - many people not aware that chemicals and soot released by burning fuel can increase risks of pneumonia, bronchitis, allergies, sinus infections, cataracts, asthma, emphysema, heart disease, cancer, and premature death. Many who are aware of risks are too poor to have other alternatives.
Health effects of cigarette smoke and secondhand smoke
- irritation of eyes, nose and throat - worsened asthma and respiratory ailments - lung cancer (environmental tobacco smoke consists of over 4,000 chemical compounds)
What do the three cells (Hadley, ferrel, and polar) account for?
- latitudinal distribution of moisture across surface - wet climates near equator - arid climates near 30 degrees latitude - moist regions near 60 latitude - dry conditions near poles Help explain why biomes tend to be arrayed in latitudinal bands
National ambient air quality standards
- maximum allowable concentrations of the 6 criteria pollutants in ambient outdoor air - created by EPA
Is acid precipitation declining?
- new tech like scrubbers implemented - declining emissions of SO2 has led to decrease in average sulfate prec. - increasing NOx emissions cause average nitrate precipitation to increase by 3% between 1996-2000 - report from Hubbard Brook research forest said effects of acid prec. are worse than predictedand mandates of 1990 Clean Air Act are not adequate. Additional 80% reduction in sulfur emissions needed to allow New Hampshire steams to recover in 20-25 years
How much solar energy hits upper atmosphere? How much absorbed by atmosphere and surface?
- over 1,000 watts/m^2 - 70% absorbed by atm. And surface and rest reflected back
How does burning vegetation pollute the atmosphere? How do humans worsen fires?
- over 60 million ha of forest and grassland burn in a typical year...these burn naturally but many are worsened by humans - fuel buildup from decades of fire suppression has caused damaging forest fires - in tropics, many fires result as farmers clear forest for farming and grazing using slash and burn approach - fires release carbon monoxide
What accounts for Nitrogen oxide NOx emissions in the U.S.
- over half comes from combustion in motors vehicles - electrical utility and industrial combustion account for most of the rest
How are humans depleting ozone layer?
- ozone being depleted by human-made compounds derived from simple hydrocarbons (like ethane and methane), in which hydrogen atoms replaced by chlorine, bromine, or fluorine. - one class of compounds is chlorofluorocarbons (CFC). CFCs were mass produced by industry at a rate of a million metric tons a year and this rate was growing 20%; CFC deplete ozone in stratosphere by releasing chlorine atoms that split ozone molecules, creating 02 and CLO-0 - in 1985, scientists announced that ozone levels in Antarctica had declined 40-60% in previous decade, leaving thinned ozone concentration called ozone hole - ozone depletion increases skin cancer and has ecological effects, likeharm to crops and phytoplankton in ocean, the base of marine food chain - Even after great reduction in CFC, much of the 5 billion Kg of CFCs emitted into troposphere have yet to diffuse into stratosphere, and CFCs are slow to disspitate or break down. There will be long gap between implementation of policy and environmental improvement.
Photochemical smog
- photochemical process is one whose activation requires light - photchemical smog, or brown-air smog, is formed through light-driven chemical reactions of primary pollutants and nomral atmospheric compounds that produce a mix of over 100 different chemicals (tropospheric ozone often most abundant) - high levels of NO2 cause smog to form brownish haze - hot, sunny, windless days provide perfect condition for this smog. Exhaust from morning traffic releases large amounts of NO and VOC into air. sunlight promotes production of ozone and other particles - levels of photochemical pollutants typically peak in midafternoon and can irritate EN&t
Primary pollutants
- pollutants emitted into troposphere that can be directly harmful or that can react to form harmful substances - like soot and carbon monoxide
Asian Brown Cloud
- pollution from southern Asia has resulted in a persistent 2-mile thick layer of pollution that hangs over subcontinent through dry season each December through April - reduces sunlight reaching earth in that region by 10-15% - influences climate - decreases rice productivity by 5-10% - many thousands of deaths each year
What does atmosphere do for us?
- provides oxygen - absorbs bad solar radiation - burns incoming meteors - transports and recycles water and nutrients -moderates climate
Radon
- radioactive gas resulting from natural decay of uranium in soil, rock, or water - radon colorless and odorless - impossible to predict where it will occur without knowing details of area geology - only way to measure radon entering building is to use test kit - since 80s, 18 million U.S. homes tested for radon and 700,000 undergone radon mitigation. Over a million homes since 90s have been built with radon-resistant features
How do volcanic eruptions pollute?
- release large quantities of particulate matter - release sulfur dioxide and other gases - can blow matter into the stratosphere, where it can remain aloft for several years - sulfur dioxide reacts with water and oxygen, then condenses into fine droplets called aerosols, which reflect sunlight back into space and thereby cool the atmosphere and surface - 1991 eruption of Mount Piinatubo in Phillipins cooled global temp. by 0.5 degrees celsius.
Results of clean air acts
- since Clean Air Act of 1970, emissions of each of the six monitored pollutants have decreased, and total emissions of the six together have declined by 53% - these decreases in emissions have occurred despite increases in nations population, energy consumption, miles traveled by vehicle, and GDP
How are toxic air pollutants produced?
- some produced naturally (hydrogen sulfide gas in swamps and bogs) - most toxic air pollutants produced by human activities, such as metal smelting, sewage treatment, and industrial processes - range from heavy metal mercury (coal power plants), VOCs, methylene chloride (paint stripper) - 21 of these pollutants come from mobile sources (diesel exhaust) - 33 "urban hazardous" pollutants judged to pose the greatest health risks in urban areas
What determines how much solar radiation strikes each point on earth surface?
- spatial relationship between earth and sun
Why is Sunlight most intense when it shines directly overhead and meets planet surface at perpendicular angle?
- sunlight passes thru minimum of energy absorbing atmosphere - - earth surface receives maximum of solar energy per unit surface area - solar road Iari on hugest near equator
Acidic Deposition
- the deposition of acidic or acid-forming pollutants from atmosphere onto Earth's surface. - can take place either by precipitation (acid rain), by fog, by gases, or by deposition of dry particles - one type of atmospheric deposition, which refers to wet or dry deposition on land of pollutants, including mercury, nitrates, organochlorines, and others - acid deposition originates primarily with emission of SO2 and NOx, largely through fossil fuel combustion by automobiles, electric utilities and industry. - these pollutants can react w/ water, oxygen, and oxidants to produce compounds of low pH. these droplets might travel days or weeks in the troposphere.
What are the major pollutants whose emissions are measured and reported to EPA? Why aren't emissions for tropospheric ozone measured?
- the major pollutants whose emissions are measured include four criteria pollutants that are primary pollutants ( CO, SO2, particulate matter, lead) as well as all nitrogen oxides (NO reacts to form NO2 which is primary and secondary pollutant) - emissions for tropospheric ozone aren't measure as it is a secondary pollutant. Instead, emissions of volatile organic compounds which react to produce ozone and other secondary pollutants are monitored
Why does solar energy that approaches surface at oblique angle lose its intensity?
- traverses long distance through atmosphere - less intense when it reaches surface - solar radiation weakest at poles
Industrial smog or gray-air smog
- when coal/oil is burned, some portion is completely combusted, forming CO2; some is partially combusted producing CO; and some remains uburned and released as soot or particles of carbon - coal contains contaminants like mercury and sulfur - sulfur reacts oxygen to form SO2 which can become sulfuric acid and ammonium sulfate - these chemicals , along w/ soot, are main components of industrial smog -
Describes how natural sources pollute
- winds sweeping over arid terrains can send huge amounts of dust aloft . Every year hundreds of millions of tons of dust blown westward by trade winds across Atlantic Ocean from Northern Africa to the Americas. These dust storms bring nutrients to Amazon basin, as well as fungal and bacterial spores in Caribbean coral reefs
Smog
- word coined after british air pollutio during industrial revolution - describes unhealthy mixtures of air pollutants that often form over urban areas
Leading causes of lung cancer in developing world
1) cigarette smoke 2) radon (20,000 deaths per year...15% of lung cancer cases)
To what do people attribute the success of the Montreal protocol?
1. Policymakers engaged in industry in helping to solve problem. Gov't and industry worked together. Reduced tension. 2. Implementation of Montreal Protocol followed an adaptive management approach, altering strategies in response to new data, tech advances, or economic figures.
What faction of the earths diameter is the atmosphere?
1/100
Stratosphere
11 to 50 km, Ozone held here, absorbs UV radiation - similar in composition to troposhere, 1,000x drier and less dense - little vertical mixing of gases, so substances stay a long time here - maximum temp of -3 Celsius at highest altitude, but colder in lower points...why is that? Reason is that ozone and oxygen absorb and scatter UV radiation so much of UV penetrating upper atmosphere does not reach lower atmosphere
Atmospheric pressure at sea level
14.7 lb/in^2 or 1,013 millibars (mb)
Mesosphere
3rd layer of the atmosphere - extends 50-80km above sea level - air pressure low here - temp decreases w altitude, reaching lowest point on top of mesosphere
Thermosphere
4th layer of the atmosphere, above mesosphere - extends to an altitude of 500km (300miles)
Weather and climate
Both involve physical properties of troposphere like temp., pressure, humidity, loudness and wind - weather: ( in part driven by convective circulation) specifies atmospheric conditions over short time periods and small geographic areas - climate: pattern of atmospheric conditions across large geographic regions over long period of time (seasons, years, millennia)
Hadley Cell
Convection Currents that cycle between the equator, 30 degrees North and South. - intense sunlight at equator causes air to warm and rise, releasing moisture on equator, then heading north and south - air cools and descends at around 30 altitude north and south - because descending air has low humidity, regions around 30 latitude are arid (many deserts)
Doldrums, trade winds, westerlies
Doldrums: region with few winds near equator Trade winds: between equator and 30 degrees latitude. Blow east to west. Westerlies: from 30-60 degrees latitude. Blow west to east.
atmospheric pressure
Force per unit area produced by a column of air - de releases with altitude, as fewer molecules pulled down by gravity at higher altitudes
Air pollutants
Gases and particulate material added to atmosphere that can affect climate or harm people and organisms.
How many deaths are attributed to indoor air pollution? outdoor air pollution? which poses greater health effects.
Indoor air pollution poses greater health effects as indoor air has higher concentrations of pollutants than outdoor air. -2.2 million deaths due to indoor air pollution (6,000 lives a day) - 500,000 deaths due to outdoor air pollution
Troposhere
Layer closest to Earth - Movement of air in this layer largely responsible for weather. - provides air for breathing - thin layer 7mi, but 3/4 of atmosphere mass, because air is dense near surface - temp. declines by about 6 Celsius for each km in altitude, dropping to -52 Celsius at east point
ozone layer
Protective layer in atmosphere that shields earth from UV radiation (radiation can damage living tissue and create mutations in DNA) - most of atmosphere minute amount of ozone (O3) concentrates in portion of staroshere 17-30km above sea level
Coriolis effect
The effect of Earth's rotation on the direction of winds and currents. - as earth rotates, location on equator spin faster than those at poles. As result, north-south air currents of convective cells appear to be deflected from straight path as portions of globe beneath them move faster than others
Atmosphere
Thin layer of gases that surrounds earth - 78% nitrogen n gas (N2), 21% oxygen gas (02) and rest composed of argon and small concentrations of other gases ( include permanent gases, which remain at stable concentrations, and variables gases, with varying concentrations from time to time or place to place)
Front
Weather can change when air masses with different physical properties meet Boundary between air masses that differ in temp. And moisture is called a front Warm front: boundary along which a mass of warmer, lister air replaces, colder, drier air. Some of warm air rises over cold air mass and then cools and condenses to form clouds that produce light rain. Cold front: boundary along which colder, drier air mass displaces a warmer, moister air mass. Denser, colder air wedges beneath warmer air. Warm air rises and expands, then cools to form clouds that produce thunderstorms. Omar cold front passes, sky clears and temp and humidity drop.
What causes dust storms?
although they are natural, the immense scale of these events results from unsustainable farming and grazing practices that strip vegetation from the soil, promote wind erosion, and lead to desertification.
inversion layer
band of air in which temperature rises with altitude
What are the primary indoor threat risks in the developing world? developed world?
developing world: - particulate matter -chemicals from wood and charcoal smoke developed world: - cigarette smoke - radon
convective circulation
less dense, warmer air rises (creates vertical currents) - when air rises, it expands and cools as it is under less pressure - when air cools it descends and becomes denser. Air then picks up heat and moisture and rises again. - currents can also occur in water, magma or even simmering soup - influence weather and climate
Ferrel cells and polar cells
lift air and create precipitation at 60 degrees latitude north and south - cause air to descend in 30 altitude and polar regions
Nitrogen dioxide and nitrogen oxides
nitrogen dioxide: - highly reactive, foud-smelling reddish brown gas - contributes to smog and acid precipitation nitrogen oxides: - result when atmospheric nitrogen and oxygen react at high temperatures created by combustion engines - NOx
New source review
old plants exempt from new pollution requirements, as long as they installe the best avaialable current technology for pollution control if they ever upgraded their plants in the future - bush admin. proposed to drop new source review
what are criteria pollutants? what six does the EPA focus on?
pollutants judged to pose especially great threats to human health - EPA and states focus on Carbon Monoxide (CO)l Sulfur Dioxide (SO2), Nitrogen Dioxide (NO2), tropospheric ozone (O3), particulate matter, and lead (Pb)
relative humidity
the percentage of water vapor in the air compared to the maximum amount the air could hold (Ratio) In Guam, relative humidity can be 88%, whereas in Phoenix, az, it is 33%
