Consists of several regions Troposphere

Main gases are N2 (78%) and O2 (21%) Weather occurs here Temperature and pressure decrease with altitude

Stratosphere Ozone layer found in lower levels

Mesosphere Thermosphere Exosphere

Each region is separated by a “pause” The atmosphere is a very thin layer.

Paraphrasing astronomer Carl Sagan, “If the earth were a globe covered with a coat of varnish, then the atmosphere would be like the varnish.”

Substances in the air that are In the wrong place At the wrong time In the wrong concentration

Outdoor pollutants Include smogs, particulate matter, acid

precipitation Indoor pollutants

Caused by a variety of chemical pollutants such as cigarette smoke, radon, formaldehyde, etc.

There are mechanisms in the biosphere which help to remove and recycle pollutants, but high concentrations of anthropogenic substances can overwhelm and use up these natural mechanisms.

Organisms also have the ability to tolerate certain amounts of pollution provided they don’t exceed the “threshold level”.

Primary - chemical added directly to the air through human or natural activities Mobile - the source is moving Stationary - the source remains in place

Secondary - due to chemical reactions, primary pollutants are converted into new compounds

Suspended particulate matter (particulates)

VOCs Nitrogen oxides (NOx) Sulfur oxides (SOx) Heavy metals Ozone (O3) Other toxic chemicals

Brown air Also known as photochemical smog Mixture of primary and secondary

pollutants Most often from motor vehicles (releasing

NOx and VOCs to produce O3, HNO3, PANs, and formaldehydes).

Direct relationship to temperature. Common in sunny, warm, and dry climates

with many cars. Think L.A. and Mexico City!!

Gray air Also known as industrial smog Contains mainly SO2 and suspended sulfur

particulates Released from the burning of fossil fuels and

the smelting of metal ores Often more of a problem in industrialized

areas or where burning of low grade coal is common

More common in Eastern European nations, China, India, and the Ukraine

Under certain conditions, a layer of cool air will become trapped underneath a layer of warmer air.

Mixing will not occur due to higher density of cool air which leads it to sink and warm air which is less dense and tends to rise.

Pollutants become trapped in the layer of cool air underneath

Climate and topography Population density Amount and type of industry Type of fossil fuels used

The result of secondary pollutants like sulfuric acid and nitric acid

SOx reacts with water to form sulfuric acid

NOx reacts with water to form nitric acid

Measures the concentration of H+ ions in a solution

Logarithmic scale An increase of 1 on the pH scale means a

tenfold increase in H+ concentration Natural precipitation has a pH of 5 to 5.6

due to the presence of carbon dioxide Due to acid rain, some areas have pHs as

low as 2.3

Acids Have more H+ ions than

OH- ions Have pH less than 7

Bases Have more OH- ions than

H+ ions Have pH greater than 7

If enough buffering ions (Ca2+ and Mg2+) are present, soil won’t be affected.

If soil has no buffers or too much exposure to acid deposition, then harmful Al3+ can be released.

Can be damaged directly or weakened so that they are susceptible to other damage such as from insects and disease.

Most susceptible are those on mountains with thin soils.

Can release toxic methylmercury which accumulates in fatty tissues of fish and other aquatic animals.

Can be biomagnified through food chains. Freshwater lakes have pH of 6 to 8. Egg, sperm, and developing embryos are most

sensitive. Death may occur within a 1 unit difference. Al3+ can be released in water which stimulates excess

mucus formation in fish and clogs their gills.

Contribute to respiratory diseases. Damage buildings, cars, statues, etc.

Sulfuric acid (H2SO4) - east coast Nitric acid (HNO3) - west coast Anthropogenic sources: burning of fossil

fuels produce primary pollutants (NOx and SOx) which are converted to secondary pollutants (nitric and sulfuric acids)

Natural sources: volcanoes, sea spray, lightning, burning of biomass, and

microbial processes. Anthropogenic amounts are greater.

A buffer is a substance that has the capacity to absorb hydrogen ions from a solution and help the pH to remain relatively constant.

Limestone (CaCO3) is a natural buffer. Areas with limestone

rock are more resistant to acid deposition. Acid shock - sudden influx of acid into a body of water

often due to melting of snow. Greatest problem in areas with low buffering capacity. Often coincides with spawning.

Ecosystems with thin, acidic soils lacking natural buffers or

those where buffers have been depleted suffer the most harm from acid deposition.

Clean Air Acts Federal regulations enforced by each state

which require set standards for 7 outdoor pollutants.

A maximum level is specified. The level is averaged over a specific period.

Pollution prevention over cleanup. Increase fuel efficiency standards. Require stricter emission standards for

fine particulates. Don’t give municipal trash incinerators

30 year permits. Stricter standards for air pollution

emissions from incinerators Reduce emissions of carbon dioxide

and other greenhouse gases

Provide pollution credits to industry and power plants.

Older, high polluting vehicles cause far more pollution than newer vehicles so pay the person for the car.

Have stricter emission laws for lawnmowers, chainsaws, leafblowers, etc. and provide incentives to trade older ones in.

Catalytic Converter exhaust passes through this device it is coated with platinum which acts as a catalys and oxidizes

the VOCs to CO2 and H2O.

Fewer pollutants are emitted today (about 75% compared to 1970), but there are more cars.

Secondary pollutant resulting from photochemical reactions.

Need to reduce NOx and VOC emissions from cars and various point sources.

Ozone at ground level is a pollutant harming people, animals, and plants

Major component of photochemical smog

Particulates - solid particles suspended in the air.

Ideally want no visible emissions. Instead of incinerating refuse, use landfills. To remove emissions from “smoke stacks”:

use filters and electrostatic precipitators, but these may

contain heavy metals and other toxins (what do we do with them?)

Still a number of sources not regulated: wood burning stoves,

wood and grass fires.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.QuickTime™ and aTIFF (Uncompressed) decompressorare needed to see this picture.

Coal washing - wash coal to remove sulfur (expensive and produces large amounts of polluted water).

Fluidized bed combustion - coal is burned with sand and lime and the sulfur combines with the lime and is removed with the ash (expensive to restructure old plants for this method).

Fuel switching - using to oil instead of coal (increase dependence on foreign oil) or use lower sulfur fuel (expensive).

Scrubbers - liquid filters that put exhaust fumes through a spray of water containing lime and precipitates out the sulfur (very effective and not too expensive except when retrofitting).

Alternative power plants - using nuclear or other source of energy (requires overhaul of energy policies and in the case of nuclear energy, what do we do with the waste?).

Reductions in consumption of electricity - using practice of conservation and more energy

efficient devices (again affects energy policies).

Often times indoor air concentrations are higher than those outside

Cigarette Smoke Formaldehyde Asbestos Radon Other Pollutants include

Fiberglass Carbon monoxide

Concern for smoker and second-hand smoke

Health effects include Heart disease, cancer, stroke, emphysema, bronchitis

Irritating gas Found in a variety of building materials,

carpeting, upholstery, wallpaper adhesives

Symptoms of exposure include Diziness Rash Headaches Sore throat Eye irritation Chronic breathing problems Nausea Cancer?

Colorless, odorless, radioactive gas Results from breakdown of uranium A problem when in buildings As the gas breaks down into solid,

radioactive particles that can be inhaled and expose lungs to radiation

Levels above 4 picocuries/Liter are a concern

20% of lung cancer cases of non-smokers linked to this element

A building is considered sick when at least 20% of the occupants suffer symptoms that disappear outside.

Symptoms include: Dizziness, Fatigue Headaches Coughing, Burning eyes Flulike symptoms, etc.

New buildings more likely to be sick than older ones. Electrostatic fields attract fibers and may cause those who

use computers to be more affected.

Fibrous silicate material Found in insulating materials,

soundproofing, pipes, and cloth The tiny fibers are a concern b/c they

can be inhaled deeply into the lungs and can cause lung cancer, mesothelioma, asbestosis

Biggest concern for workers and miners

Should it be removed or wrapped?

Ice core samples Sediment core samples Current temperature data and trends World-wide data Reaching a consensus

IPCC

Some of the energy reaching the earth from the sun is converted into infrared radiation (heat).

Clouds, water vapor, and gases (like CO2) are heated when they absorb this energy as it is transmitted back to space.

The clouds and greenhouse gases then radiate out the infrared energy in all directions.

Some of this energy radiates back into space, but some warms the earth’s surface and troposphere.

Evaporating water absorbs heat, rises, condenses high up in the atmosphere where it releases heat helping to cool the earth

Cloud cover helps to cool the earth Albedo effect (light colored surfaces reflect heat

back to space). Aerosols and dust in the atmosphere also help

to cool the earth (from pollution and volcanic activity)

Carbon dioxide Water Methane Chlorofluorocarbons Nitrous oxide Carbon tetrachloride Halons Hydrofluorocarbons Hydrochlorofluorocarbons

Carbon dioxide50-500 years 1 Methane 9-15 years 24 Nitrous oxide 120 years

360 CFCs 11-20 years 1500-

7000

Connection between rise in global levels in carbon dioxide and greenhouse effect.

Recorded at Mauna Loa observatory. Increase carbon dioxide levels are linked

to increase in global temps. Is this part of a natural cycle? Some

evidence suggests that carbon dioxide levels rise following temperature increases.

There have been periods of warming and cooling in the past (before humans had any influence). There seem to be natural cycles. Could this current period of warming be part of a natural cycle? Possibly connected to solar cycles (changes in solar radiation coming from the sun)?

Increase in certain greenhouse gases associated with human activities, especially the burning of fossil fuels.

Also other activities Deforestation and clearing of grasslands Raising of livestock which release methane in

digestion Rice paddies and use of of inorganic fertilizers

which release nitrous oxides

20th century was the hottest on record in past 1000 years.

Average global temperature on earth’s surface has risen 0.6 degrees Celsius.

Glaciers and sea ice are melting and shrinking at rates faster than they can be reformed.

Plants have been observed blooming earlier in spring.

Some animal and plant species are out of synch with each other

Polar ice caps and glaciers have a high albedo.If there is less snow and ice, there will be less

of an albedo effect and more warming.More warming means less snow and ice and so

on.Melting glaciers and land ice will contribute to

sea level riseMelting floating ice does not contribute to sea

level rise, but affect the salinity of salt water and can affect currents and weather patterns.

The poles experience greater climate change than anywhere else. Biggest concerns are ice sheets in Greenland and Antarctica.

Reduction in glaciers means reduction in fresh water supplies.

Releases large amounts of carbon dioxide and methane from the soil (both are greenhouse gases).

Damages man-made construction. Trees are dying and bent over. Spruce bark beetle is becoming prominent. Economic benefits include longer growing

season and more tourist dollars.

Extinct by the next century?? Melting sea ice makes it difficult for

them to hunt for seals Melting ice increases likelihood of

drowned bears.

Sea level rise (from melting glaciers and land ice and thermal expansion of water)

Salt water intrusion Extreme weather Loss of biodiversity Agriculture changes (areas become warmer and

drier…agricultural belts moving north?) Human Population (will it crash?) Human Health (diseases from the tropics

moving north?) Forests Water Resources (increases evaporation and

changes rainfall patterns)

Found in the lower stratosphere Absorbs about 95% of the harmful UV radiation

from the sun from reaching earth’s surface. Seasonal depletion occurs over the north and

south poles. Loss of ozone is a threat to living organisms

Discovered in 1930 Nonreactive, odorless, nonflammable, nontoxic,

and noncorrosive. AND inexpensive to make. Used as coolants in refrigerators and air

conditioners, as propellants in aerosol cans, cleaners for electronic equipment, bubbles in plastic foam, and as fumigants.

In 1974, Roland and Molina at the University of California discovered that the were lowering the ozone concentration in the stratosphere. In 1995, they received a Nobel Prize for their research.

Lasts 11 to 20 years in troposphere

CFCs break down in UV light Cl released breaks apart ozone into

oxygen molecules and oxygen atoms Each chlorine atom can damage as many

as 100,000 ozone molecules Cyclic process Can remain for 65 to 385 years in

stratosphere

halons and hydrobromofluorocarbons (in fire extinguishers)

methyl bromide (mold fumigant) hydrogen chloride (given off by the space

shuttles) carbon tetrachloride, methyl chloroform

(cleaning solvents)

A thinning of the ozone layer over the Arctic and Antarctic

Occurs in winter and spring months (October is the worst)

In the Antarctic can lose up to 50% of ozone

Arctic about 30%

Skin cancer and aging of skin Eye damage such as cataracts Immune system damage Reduction in phytoplankton Damage to the DNA in various life-forms

this has been as observed  in Antarctic ice-fish that lack pigments to shield them from the ultra-violet light (they've never needed them before)

Reduction in amphibian population Possibly other things too that we don't know about

at the moment

Montreal Protocol Copenhagen Protocol

Reduce energy use and increase efficiency. Switch to cleaner fuel sources. Remove sulfur from coal before burning or use lower

sulfur coal. Remove NOx and SOx form smokestacks and car exhaust. Addition of limestone or phosphates to “soak up” excess

H+ ions. Liming can kill some plankton and increase some

microbes that can deplete carbon.

Must set Ambient Standards - levels of pollution that need to be achieved to protect humans and the environment. These are covered by the National Ambient Air Quality Standards (NAAQS)

Primary standards - are based on the highest level of a pollutant that can be tolerated minus a margin of safety.

Averaging Time - the period of time over which concentrations are measured and averaged.

Additional toxic substances are covered by the National Emission

Standards for Hazardous Air Pollutants (NESHAPS): arsenic, asbestos, benzene, beryllium, coke oven emissions, mercury, vinyl chloride, and radionuclides.

The 1990 Act named 188 toxic air pollutants that must be tracked and regulated by the EPA.