Chapter 12

Air and Air Pollution

Fig. 18.3

The Atmosphere

  

78% Nitrogen, 21% Oxygen Varnish on globe



5 different layers

    

Exosphere Thermosphere Mesosphere Stratosphere Troposphere 120 110 100 90 80 70 60 50 40 30 20 10 (Sea Level) 0 –80 Atmospheric pressure (millibars) 0 200 400 600 800 1,000 75 Temperature Pressure 65 Thermosphere Mesopause Heating via ozone Mesosphere Stratopause Stratosphere Tropopause Ozone “layer” Heating from the earth Troposphere 15 5 –40 0 40 Temperature (˚C) 80 120 55 45 35 25 Pressure = 1,000 millibars at ground level

Let’s talk layers…

• Troposphere: – Contains 75% of the Earth’s air – It is the lowest layer that surrounds us now – Think of the earth as an apple, it would be as thick as the skin of the apple

Continued…

• Contains a constantly changing mixture of gases • Mainly 99% of clean, dry air with 1% polluted and containing moisture • This part of the atmosphere contains mass and gives the properties that are unique to suction…how?

Stratosphere:

• The second layer of the atmosphere • Contains less mass than the troposphere but contains a unique gas: Ozone • The ozone layer is the global sunscreen – It blocks UVA and UVB radiation • The O 3 is only found in the stratosphere

Major Air Pollutants

• Air pollutants vary from one another • An air-pollutant is something in the wrong place in the wrong concentration • Ex.) Ozone: Good in the stratosphere – Horrible in the troposphere (kills everything)

History of Air Pollution

• Nothing new – 2000 years ago Seneca complained about the foul air of Rome – 1273 King Edward I ordered “dirty” coal to no longer be burned • One man was evened hanged for disobeying the first “clean air act”

Primary Pollutants:

These are pollutants that arise from: 1.) Humans (activities from humans, VOC’s) 2.) Earth’s natural processes (dust storms, volcanoes, SO 2 )

Secondary Pollutants:

• These are primary pollutants that mix together – Ex.) Acid Rain (Car exhaust and dust mixed with water) Pollution of both kinds have been here forever but have increased more dramatically since the industrial revolution

Who is more polluted?

• Cities tend to be more polluted with secondary pollutants…why?

• These areas are also prone to Smog: – Industrial – Photochemical

The smog brothers…

• Photochemical: smog activated by light – This is smog formed by the mixing of primary and secondary by light – N 2 + O 2 = 2NO (this creates the brown smog) • Industrial: (Gray-Air smog) caused by sulfuric acid drops in the air – Caused by burning coal, rarely a problem today

Temperature Inversions

A factor that influences smog creation and problems -An inversion is when cold air is trapped below a layer of warm air -This inhibits winds from blowing and moving pollutants through the air

Figure 18-11

Industrial Air Pollution:

• • Emits high levels of SO2 and NO – Why?

– Very inefficient processes are used to generate electricity and power

Cleaning it up

: – Smoke stack scrubbers (machine that sprays water) – Electro static Precipitators (electrically charged dust)

12-3: Acid Precipitation

Air Pollution from Acid Deposition

•

Acid deposition

: When dry chemicals such as SO 2 mix with water they create acid rain – Acidity is expressed in ph – <7 = acid – >7= basic – 7= neutral *This shows up all over the US (East coast is 10 times more acidic with a ph of 4.3)

What are the effects?

• Harmful ecological effects – Destroys aquatic environments (next slide) – Ruins tree foliage and makes them more susceptible to disease, winter and summer • Harmful to humans • Respiratory illnesses (asthma and bronchitis) • Weakens structures (buildings and statues)

Acid Deposition and Aquatic Systems

• • •

Fish declines Water boatman Whirligig Undesirable species Yellow perch Lake trout Brown trout Acid shock Salamander (embryonic) Mayfly Smallmouth bass Mussel 6.5

6.0

5.5

5.0

pH 4.5

4.0

3.5

Acid Deposition, Plants, and Soil



Nutrient leaching



Heavy metal release



Weakens trees Fig. 18-14

What can we do?

• First, is it serious? (1990) – Gov’t: Yes but not a crisis – Coal and Oil: Costs more than the health risks – Since the Clean Air act was passed things have changed. Oil and Coal are required to watch SO 2 levels released – Acid rain rates since then have fallen 35%

12-2: AIR POLLUTION

• Indoor air pollution usually is a greater threat to human health than outdoor air pollution.

– People spend 70-80% more time indoors then outdoors • According to the EPA, the four most dangerous indoor air pollutants in developed countries are: – Tobacco smoke.

– Formaldehyde.

– Radioactive radon-222 gas.

– Asbestos

Inside Air pollutants:

• Have been linked to many diseases • Also causes: “sick building syndrome” – When at least 20% of individuals are chronically sick • Formaldehyde is the #1 culprit to sick building syndrome

1.) Formaldehyde:

• Used in dissection materials • How does it get in your house?

– Plywood – Paneling – Particle Board *Causes rashes, dizziness, and headaches

2.) Radioactive Radon

Sources and paths of entry for indoor radon-222 gas.

•

Radon-222

: radioactive gas found in some soils and rocks – can seep into some houses and increase the risk of lung cancer – 2 nd leading cause of lung cancer

Figure 18-18

3.) Asbestos

• A commercially used product – Fire retardant and insulator • Can cause lung cancer and mesothelioma • Banned now but not always – Roseau High School

Noise Pollution:

• Noise can also cause air pollution – Measured in decibels (dB) • Ex.) Traffic, cities – Permanent deafness results after 120 dB

Light Pollution:

•

Does not

present a direct hazard to health – Hurts aesthetic value • Results from inefficient lighting uses – Wastes energy – Burns more fossil fuels

Using the Marketplace to Reduce Outdoor Air Pollution

• To help reduce SO 2 emissions, the Clean Air Act authorized and emission trading (cap-and-trade) program.

– Enables the 110 most polluting power plants to buy and sell SO 2 pollution rights.

– Between 1990-2002, the emission trading system reduced emissions.

– In 2002, the EPA reported the cap-and-trade system produced less emission reductions than were projected.

PREVENTING AND REDUCING AIR POLLUTION

• Environmental scientists point out several deficiencies in the Clean Air Act: – The U.S. Congress has failed to increase fuel efficiency standards for automobiles • Obama has now increased all motor vehicle standards – Regulation of emissions from motorcycles and two cycle engines remains inadequate.

– There is little or no regulation of air pollution from oceangoing ships in American ports.