AirChapter 6

Humor Can Gain Attention!

• “I thought I saw a blue jay this morning. But the smog was so bad that it turned out to be a cardinal holding its breath.”

–Michael J. Cohen

• Complete the following sentence to gain attention about air pollution:

• “You know the air is polluted when…..”

What causes air pollutionChapter 6, Section 1

I.What is Air?

-a mixture of gases such as:• Nitrogen: 78% (78 parts out of a

100)

• Oxygen: 20% (21 parts out of a 100)

• Carbon Dioxide: 0.03% (3 parts out of a 1,000)

• Rare Gases (Helium, Argon, Krypton, Neon, Xenon and Radon together make up 0.97%)

• Water Vapor (the amount varies)

Air Pollutio

n• When harmful substances end

up in the air at unhealthy levels…the result is air pollution

• Substances that pollute the air can be in the form of solids, liquids, or gases

• Most air pollution is the result of human activities, but can also come from natural sources– Example: A volcano can spew clouds

of particles and sulfur dioxide that can harm animals.

– Natural pollutants also include dust, pollen, and spores.

Photo of Salt Lake City Smog!

Primary Pollutants are put directly into the atmosphere by human or natural activity Example: Soot from smoke

Primary Air Pollutants:

1. Carbon monoxide (CO)2. Nitrogen oxides (NOx)

3. Sulfur dioxide (SO2)

4. Volatile organic compounds (VOCs)5. Particulate matter (PM)

–See pg.152, Figure 6.2 for more information

Secondary pollutants are formed when a primary pollutant comes into contact with other primary pollutants, or even when naturally occurring substances like water vapor, and a chemical reaction take place.Ex. Ozone forms when oxygen in the air reacts with VOCs and other air pollutants from trucks, cars, and natural sources in the presence of the sun’s UV rays.

Air Pollution is Nothing New…

• 2,000 years ago: Seneca, a Roman philosopher and writer, complained about the foul air in Rome

• In 1273: England’s King Edward I decreed that burning a particularly dirty kind of coal was illegal, and one man was even hanged for disobeying this medieval “clean air act”

• The air-quality problem is much worse today because modern industrial societies burn such large amounts of fossil fuels. Most air pollution in urban areas comes from motor vehicles and industry

3 Main Sources of

Primary Air Pollutants:

• Household products

• Power plants/Industry

• Motor vehicles

Motor Vehicle Emissions• Over 1/3 of our air

pollution comes from gasoline burned by vehicles, so what is being done?– The Clean Air Act of 1970,

gives the authority to the EPA to regulate vehicle emissions in the US. The EPA required the gradual elimination of lead in gasoline, and as a result, lead pollution dropped by 78% between 1988 & 1995.

– California zero-emission Vehicle program…by 2016 at least 16% of vehicles sold in CA must be zero emissions vehicles (have no tailpipe emissions, no emissions from gasoline, etc…)

Industrial Air Pollution:

• Industries and power plants that generate electricity must burn fuel to get the energy they need. In most instances, this is a fossil fuel.

• Burning fossil fuels causes huge quantities of oxides to be released into the air…

• Electric power plants produce at least two-thirds of all sulfur dioxide, over one-third of all nitrogen oxides, and one-third of the particulates that pollute the air.

Industrial Air Pollution:

• The Clean Air Act requires many industries to use scrubbers or other pollution-control devices…scrubbers remove some of the more noxious substances that would otherwise foul the air.

• A scrubber moves gases through a spray of water that dissolves many pollutants.

Thermal Inversion• Air circulation in the atmosphere usually

keeps air pollution from reaching dangerous levels…– The sun heats the surface of the Earth and

the air near it, the warm air rises through the cooler air above, carrying pollutants away from the Earth’s surface and into the atmosphere.

Thermal Inversion• Sometimes pollution is trapped near the Earth’s surface by a thermal

inversion• Normally, air temperatures decrease with height, but in a thermal inversion,

the air above is warmer than the air below.– The warmer air above keeps the cooler air at the surface from moving

upward– In this way, pollutants are trapped below with the cooler air.– Cities located in valleys have a greater chance of experiencing thermal

inversion. • Example: Los Angeles, which lies on the Pacific coast and is surrounded on the other

three sides by mountains, has frequent thermal inversions that trap smog in the city.

SMOG• When air pollution hangs over urban areas

and reduces visibility, it is called SMOG. (smoke + fog)

• Smog results from chemical reactions that involve sunlight, air, automobile exhaust, and ozone.

• Cities that suffer most from smog have dense traffic and are located in dry, sunny areas.

• Examples of cities that have smog:– LA, Denver, Phoenix, and Mexico City

Household Cleaners…

Effects on Human HealthChapter 6, Section 2

Effects of Air PollutionShort-Term

• Many effects of air pollution are short term and are reversible if their exposure to air pollution decreases.

• Short-term effects include: headache, nausea, irritation to eyes, nose, and throat, tightness in chest, coughing, and upper respiratory infections (bronchitis and pneumonia).

Long-Term• Long-term effects on

health that have been linked to air pollution include emphysema, lung cancer, and heart disease.

• Long-term exposure to air pollution may worsen medical conditions suffered by older people and may damage the lungs of children.

Indoor Air Pollution• The quality of air inside a home

is sometimes worse than it is

outside.• Plastics and other industrial

chemicals (found in carpets,

building materials, paints, and

furniture) are major sources of

pollution.• Sick-Building Syndrome:

– Buildings that have very poor air quality have a condition called sick-building syndrome. It is most common in hot places where buildings are tightly sealed to keep out the heat.

Indoor Pollutants:• Radon Gas:

– Colorless, tasteless, odorless, Radioactive! (produced by the radioactive decay of Uranium, which occurs naturally in the Earth)

– Can seep through cracks and holes in homes, offices, schools, etc…Radon can make its way into a house, where it adheres to dust particles….when people inhale the dust, radon enters the lungs.

– Once in the lungs, radon can destroy the genetic material in cells that line the air passages and can lead to cancer (2nd leading cause of lung cancer in US)

Indoor Pollutants:• Asbestos:

– Asbestos is several silica minerals that form in long, thin fibers. Valued for strength and resistance to heat.

– Was used widely to reinforce cement and to make brake linings, vinyl floor tiles, residential siding, commercial buildings, and garments to protect firefighters.

– Was banned by US gov in 1970s because exposure to asbestos in the air is dangerous.

– Asbestos fibers that are inhaled can cut and scar the lungs, causing the disease asbestosis

• Victims find it harder to breathe and may eventually die of heart failure.

Think….Pair….Share!1. Think of 5 specific things you learned

last week in Environmental Science (Be specific not broad!) and write them down on a scratch sheet of paper.

2. Pair up with a partner and compare your notes…be sure to notice similarities and differences!

3. Share your ideas with the class….

Acid PrecipitationChapter 6, Section 3

Acid Precipitation: • Highly acidic precipitation (rain, sleet, snow)

that results from the burning of fossil fuels

• When fossil fuels are burned, they release oxides of sulfur and nitrogen as byproducts.

• When the oxides combine with water in the atmosphere, they form sulfuric acid and nitric acid, which falls as precipitation!

At what point do we consider rain to be acid rain?• Precipitation is

considered to be acid precipitation if it has a pH of less than 5.6.

• pH is a measure of how acidic or basic something is.

• In highly industrialized regions, acid precipitation can be extreme…the northeaster United States sometimes gets “soda-pop” rain with a pH of 3.5-4.0, similar to the pH of soft drinks!

So, what’s so bad about acid

precipitation?• Dissolves calcium carbonate in common building materials such as concrete and limestone…some of the world’s most prized and historic monuments are being eaten away by acid precipitation!

• But, even worse…

Negative effects on ecosystems!

So, what’s so bad about acid precipitation?

– Aquatic Ecosystems:• If acid precipitation falls on a lake and changes the water’s pH,

it can kill aquatic plants, fish, and other animals.• Also, acid precipitation causes aluminum to leach out of the

soil surrounding a lake…the aluminum accumulates on the gills of fish, stimulating mucus production…many fish slowly suffocate from the buildup of mucus on their gills.

• Effects of acid precipitation are worse in the spring, when acidic snow that accumulated all winter melts and rushes into lakes and other bodies of water…this sudden influx of acidic water causes Acid Shock, which can be so intense that entire populations of fish are wiped out

So, what’s so bad about acid precipitation?

– Forest Ecosystems:• Trees, like other organisms, can tolerate only specific pH

ranges. If the water they take up through their roots is too acidic, they will die.

• Millions of hectares (1 hectare = 2.471 acres) of forests in the Northeastern United States and Canada are dying, partly due to acid precipitation.

• As the tress and other plants die, the animals they support die too!

International Conflict….• One problem in controlling acid precipitation is that pollutants

may get released in one geographical area and fall to the ground hundreds of miles away because of weather patterns.

– Most of the acid precipitation that falls in Canada and New England results from pollution produced in the midwestern and eastern United States

– Emissions from the highly industrialized Ruhr Valley in Germany have spread over many of the other nations in Europe. Weather patterns usually carry pollutants northward toward the Scandinavian countries, which have the most serious acid precipitation problems in Europe!

…and Cooperation

• 1985: United Nations Helsinki Declaration was enacted, which requires countries to cut sulfur-oxide emissions by 30% over 10 years…the declaration was signed by 18 nations (US did not sign)

• 1988: 27 nations signed the United Nations Sofia Protocol, which required a reduction in nitrogen-oxide emissions (US signed in 1989)

• In 1990 and 1997: US strengthened its own clean-air standards• Later, the European Union, a coalition of European countries, mandated

the refineries reduce the sulfur content in diesel fuel by more than 30% by

1994 and by another 80% by 1996.

Even more international agreements such as these will be necessary to control the acid-precipitation problem.