Chapter 15 - Air Pollution Olivia K, Emily P, Nicole C
Case Study: When is a Lichen Like a Canary? -19th Century coal miners took canaries into mines as indicators of methane. -Once birds stop singing, miners need to get out of mine to avoid methane gas (odorless). -Lichens also warn us of polluted air. -Lichens absorb air for nutrients. -Biological indicators -Lichens were used to determine coal-burner pollutants in Lake Superior. -Lichens were indicators of radioactive pollution in Europe after accident at Chernobyl.
15-1 Structure and Science of the Atmosphere Atmosphere - layers of gases surrounding Earth (divided into spherical layers)
15-1 Structure and Science of the Atmosphere Troposphere - earth’s inner layer, consists mostly of nitrogen, oxygen, CO2, and water vapor - 75-80% of earth's air mass - 75% nitrogen - 21% oxygen - .01% water vapor - .038% carbon dioxide - less than 1% argon - analogous to the skin of an apple Stratosphere - 2nd layer, outside of troposphere -17-48 kilometers out -Ozone! (good and bad) - 3O2 + UV --> 2O3 - "sunscreen" prevents 95% UV radiation of sun
15-2 Outdoor Air Pollution Air Pollution - presence of chemicals in the atmosphere in concentrations high enough to harm organisms and materials and to alter climate - Pollution comes from natural sources (dust, forest fires, volcanoes, plant decay, sea spray) and human sources (burning fossil fuels, stationary source, and automobile combustion engine, mobile source)
15-2 Outdoor Air Pollution Primary pollutants - emitted directly into the troposphere in a potentially harmful form (soot/ carbon monoxide). Secondary pollutants - primary pollutants that have combined with one another or with components of air to form new pollutants
15-2 Outdoor Air Pollution According to the World Health Organization (WHO), 1/6 of people live in an urban area with outdoor air that is unhealthy to breathe. - Linfen, China --> Cities are pollution melting pots. Wind spreads air pollutants.
15-2 Outdoor Air Pollution -Indoor air pollution comes from infiltration of polluted outdoor air, or chemicals inside -Biggest health threat comes from indoor air pollution, where poor people must burn wood, charcoal, coal, or dung to heat their dwellings and cook -Poverty = poor air for poor people -U.S. and developed countries set maximum allowable atmosphere concentration standards. - Volatile Organic Compounds (VOCs) mostly hydrocarbons, play a role in development of photochemical smog -Carbon dioxide and other gases have the ability to increase the temperature of the troposphere. -Oil and coal companies don't want carbon dioxide classified as a pollutant -Carbon dioxide emissions should be regulated
15.3 Photochemical Smog • Photochemical reaction-under the influence of the sun • Photochemical smog- nitrogen oxides+volatile organic hydrocarbons+sun+heat= a mixture of pollutants • Formed by a complex series of reactions • Engines + industrial plants at high temperatures • Nitrogen + Oxygen react in air=NO2 • NO2 and hydrocarbons mix • Photochemical smog produced • Ozone, nitric acid, other secondary pollutants
15.3 Photochemical Smog • More heat=more smog • China in 2050- 400 million gasoline powered cars • Traffic adds to smog
15.3 Industrial Smog • Industrial Smog- Coal and oil burned=sulfur dioxide+sulfuric acid+solid particles • Technology limits this smog "Asian brown cloud" from industry, homes, tree burning and dust
15.3 Types of Air Pollutants • Sulfur Dioxide (SO2) • colorless, complete combustion of sulfur fuels • acid deposition and irritation • breathing problems, from coal burning, ecosystems killed by acid rain • Nitrogen Dioxide (NO2) • brown, photochemical smog, acid deposition • lung irritation, colds, low visibility, corrodes • Carbon Monoxide (CO) • colorless, odorless, poisonous to animals • cigarettes, incompletely burned fossil fuels, cars • reacts with red blood cells, bronchitis
15.3 Reducing Smog • Rain and snow cleanses • Sea spray washes out • Wind sweeps away
15.3 Increasing Smog • urban buildings slow wind speed • hills and mountains reduce flow • high temperatures increase chemical reactions • grasshopper effect
15.3 Temperature Inversions • Warm air lays on cool air close to ground • Cool air does not rise and pollutant is trapped in ground • Cities in valleys surrounded by mountain
15.4 Acid Deposition • smoke stacks emit sulfur dioxide, nitrogen oxides high into troposphere • less local pollution, more regional pollution • acidic substances remain in atmosphere • wet deposition-acid rain • dry deposition- acidic particles • western US forests affected by acidic fog • acidic soil without buffer • Asia 59% energy from coal
15.4 Effects of Acid Deposition • contributes to respiratory diseases • runoff of toxic metal into tap water • corrodes buildings, cars and monuments • destroys national monuments and parks • aquatic systems ruined • some northern European lakes lack fish • acidic soil kills vegetation
15.4 Reducing Acid Deposition • improve energy efficiency-less coal used • more natural gas and renewable resources • low sulfur coal • remove SO2 from smokestacks • remove nitrogen oxides from car emissions • tax SO2 emissions • neutralize acidic lakes and fertilizers
15-5 Indoor Air Pollution ~Levels of 11 common pollutants in the air generally are two to five times higher in homes and commercial buildings than outdoors and as much as 100 times higher in some cases ~Air pollution levels inside cars in traffic clogged urban areas can be as much as 18 times higher than outside ~The health risks from exposure to such chemicals are magnified because most people in developed countries typically spend 70-90 percent of their time indoors or inside vehicles ~Air pollution causes as much as 6,000 premature cancer deaths per year in the US ~Air pollutants are linked to dizziness, headaches, coughing, sneezing, shortness of breath, nausea, burning eyes, chronic fatigue, irritability, skin dryness and irritation, and flu-like symptoms known as the sick building syndrome. ~EPA studies indicate that almost one in five of the 4 million commercial buildings in the US is considered “sick.” ~Mold spores in damp places are probably the greatest cause of allergic reactions to indoor air pollution ~A solution: Not give up on improving the energy efficiency in buildings, but instead heat exchangers should be used to provide a healthy flow of air inside homes and other buildings without affecting overall heat gains and losses
15-5 Indoor Air Pollution Cont. ~Having outdoor vents in kitchens and bathrooms also helps reduce the indoor buildup of moisture and air pollutants from cooking. ~Gas and oil furnaces should be checked for carbon monoxide production, and homeowners should install carbon monoxide detectors, and warning devices near bedrooms. According to the EPA, the four most dangerous air pollutants are: cigarette smoke formaldehyde radon-222 gas very small fine and ultra fine particles ~Developing countries most difficulty: formaldehyde, a colorless, extremely irritating gas widely used to manufacture common household materials ~Sources of this gas include: building materials, furniture, drapes, upholstery, adhesives in carpeting and wallpaper, urethane-formaldehyde insulation, fingernail hardener, and wrinkle-free coating on permanent-press clothing. ~EPA estimates that as many as 1 of every 5,000 people living in formaldehyde homes for 10 yrs develops Cancer. ~developing countries: the indoor burning of wood, charcoal, dung, crop residues and coal in open fires or in poorly-vented stoves for cooking causes harsh exposure
15-6 Harmful Effects of Air Pollution -615-6 v Science: How Does Your Respiratory System Help Protect You From Air Pollution Our respiratory system has several ways to help protect you from air pollution, but some air pollutants can overcome these defenses. –~Hundreds of thousands of tiny mucus-coated hairline structures called cilia line your upper respiratory tract •~They continually wave back and forth and transport mucus and the pollutants they trap to your throat •~Years of smoking and breathing air pollutants can lead to lung cancer, and chronic bronchitis, which involves persistent inflammation and damage to the cells lining the bronchi and bronchioles. •~Damage deeper in the lung can cause emphysema, which irreversible damage to air sacs or alveoli leads to abnormal dilation of air spaces, loss of lung elasticity, and acute shortness of breath •Science: Harmful Health Effects of Key Air Pollutants •~Air pollutants damage materials and human lungs and worldwide prematurely kill at least 3 million people each year •~In the US, the EPA estimates that annual deaths related to indoor and outdoor air pollution range from 150,000-350,000 people equivalent to one in two fully loaded 400 passenger jumbo jets crashing each day, with no survivors.
15-7 Reducing and Preventing Air Pollution •Congress •~The US Congress passed the Clean Air Acts in 1970, 1977, and 1990, and with these laws, the federal gov established key air pollution regulations that are enforced by each state and major cities •~One limit, called a primary standard, is set to protect human health. Another limit, called a secondary standard is intended to prevent environmental and property damage. •~According to a 2003 EPA report, aggregate emissions of the six criteria air pollutants decreased by 48% between 1970 and 2002 even with significant increases in gross domestic product, vehicle miles traveled, energy consumption and population •Politics: Improving US Air Pollution Laws •~The reduction of air pollution in the US since 1970 has been a remarkable success story and it occurred because of two factors: •US citizens insisted that laws be passed and enforced to improve air quality •The country was affluent enough to afford such controls and improvements •~Congress has failed to increase fuel -efficiency standards for cars, sports utility vehicles, and light trucks •~Regulation of emissions from inefficient two-cycle gasoline engines remains inadequate •~The acts have done little to reduce emissions of carbon dioxide and other greenhouse gases--mostly because CO2 has not been classified as an air pollutant •~According to a 2002 government study, more rigorous enforcement would save about 6,000 lives and prevent 140,000 asthma attacks each year in the US
Economic Perspective •Economics Case Study: Using the Marketplace to Reduce Air Pollution •~Each year, a coal-burning power plant is given a certain number of pollution credits, or rights that allow it to emit a certain amount of SO2 •~Proponents argue that this system allows the marketplace to determine the cheapest, most efficient way to get the job done instead of having the government dictate how to control air pollution. •~One of the neat things about the SO2 emissions market is that anyone can participate, environmental groups can buy up such rights to pollute and not use them •~You could personally reduce air pollution by buying a certificate allowing you to add .9 metric ton (1 ton) of SO2 into the atmosphere and hanging it on the wall •~Between the years 1990 and 2002, the emissions trading system helped reduce SO2 emissions from electric power plants in the US •~The EPA also created an emissions trading program for smog-forming nitrogen oxides in a number of states in the East and Midwest •~in the year 2002, the EPA reported results from the country’s oldest and largest emissions trading program, in effect since 1993, in southern California.
Proposed Solutions •Simple but effective: Reducing Outdoor Air Pollution •~Approx 20,000 older coal-burning plants, industrial plants and oil refineries in the US have not been required to meet the air pollution standards required for new facilities under the clean air acts. •~Over the next 10-20 years, air pollution from motor vehicles should decrease from increased use of partial zero-emissions vehicles that emit almost no air pollutants thanks to their improved engine and emissions systems.