Alchohol• Use methanol or ethanol as a fuel– Already gone over ethanol

• Methanol is already in use at Indy 500 race– Proven that no significant loss of performance is

experienced (though they are in the process of switching to ethanol)

• About ½ the energy content of gasoline• Produces only CO2 and water– Some nitrogen oxides produced in the engine

• Can be manufactured from re-newable sources (biomass for example)

• Technologies exist now.

Disadvantages

• Very dangerous– Burns with no visible flame-needs a colorant

added– Fumes are toxic

• CO2 is a greenhouse gas• Currently made mostly from natural gas-a

non-renewable fossil fuel• Possibly more corrosive than ethanol to

engine parts

Use in liquid fuel cells• Another use is as a input to a

liquid feed fuel cell• In these cells, Methanol

replaces hydrogen• Methanol has a much higher

energy density and is easier to store than H

• Current methanol fuel cells produce power too low for vehicles, but can be used in cell phones, laptops etc

• Advantage is that they store lots of power in a small space, which they over a long period of time

Environmental effects of energy production

• All of our energy producing mechanisms have some effect on the environment– Production of waste products pollutes air, water

and ground– Disruptions to local ecosystems

• Our job is to understand and mitigate these effects to the best of our ability

• Philosophy : If it hurts (the environment) when you do that, don’t do that!

Air pollution• If its in the air, its in your body• Components of the Earth’s Atmosphere:– Nitrogen 78.08%– Oxygen 20.95%– Argon 0.93%– Also small amounts of Neon, Helium, Krypton,& Hydrogen

• In addition, there are compounds whose concentrations vary with height: water vapor, carbon dioxide, methane, carbon monoxide, ozone, ammonia

• These are naturally occurring concentrations, any additional influx or destruction of these compounds via human beings alters the system.

Profile of the Earth’s atmosphere

Atmospheric profile• Exosphere

– From 500–1,000 km (310–620 mi; 1,600,000–3,300,000 ft) up to 10,000 km (6,200 mi; 33,000,000 ft), contain free-moving particles that may migrate into and out of the magnetosphere or the solar wind.

• Exobase– Also known as the 'critical level', it is the lower

boundary of the exosphere.• Ionosphere

– The part of the atmosphere that is ionized by solar radiation stretches from 50 to 1,000 km (31 to 620 mi; 160,000 to 3,300,000 ft) and typically overlaps both the exosphere and the thermosphere. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere. Because of its charged particles, it has practical importance because it influences, for example, radio propagation on the Earth. It is responsible for auroras.

• Thermopause– The boundary above the thermosphere, it varies

in height from 500–1,000 km (310–620 mi; 1,600,000–3,300,000 ft).

Atmospheric profile• Thermosphere

– From 80–85 km (50–53 mi; 260,000–280,000 ft) to over 640 km (400 mi; 2,100,000 ft), temperature increasing with height. Although the temperature can rise to 1,500 °C (2,730 °F), a person would not feel warm because of the extremely low pressure. The International Space Station orbits in this layer, between 320 and 380 km (200 and 240 mi).

• Mesopause– The temperature minimum at the boundary

between the thermosphere and the mesosphere. It is the coldest place on Earth, with a temperature of −100 °C (−148.0 °F; 173.1 K).

• Mesosphere– From the Greek word meaning middle. The

mesosphere extends from about 50 km (31 mi; 160,000 ft) to the range of 80–85 km (50–53 mi; 260,000–280,000 ft). Temperature decreases with height, reaching −100 °C (−148.0 °F; 173.1 K) in the upper mesosphere. This is also where most meteors burn up when entering the atmosphere.

Atmospheric profile• Stratopause The boundary between the mesosphere and the

stratosphere, typically 50 to 55• Stratosphere

– From the Latin word "stratus" meaning spreading out. The stratosphere extends from the troposphere's 7–17 km (4.3–11 mi; 23,000–56,000 ft) range to about 51 km (32 mi; 170,000 ft). Temperature increases with height. The stratosphere contains the ozone layer, the part of the Earth's atmosphere which contains relatively high concentrations of ozone. It is mainly located in the lower portion of the stratosphere from approximately 15–35 km above Earth's surface, though the thickness varies seasonally and geographically.

• Ozone Layer– Though part of the Stratosphere, the ozone layer is

considered as a layer of the Earth's atmosphere in itself because its physical and chemical composition is far different from the Stratosphere. Ozone (O3) in the Earth's stratosphere is created by ultraviolet light striking oxygen molecules containing two oxygen atoms (O2), splitting them into individual oxygen atoms (atomic oxygen); the atomic oxygen then combines with unbroken O2 to create O3. O3 is unstable (although, in the stratosphere, long-lived) and when ultraviolet light hits ozone it splits into a molecule of O2 and an atom of atomic oxygen, a continuing process called the ozone-oxygen cycle. This occurs in the ozone layer, the region from about 10 to 50 km (33,000 to 160,000 ft) above Earth's surface. About 90% of the ozone in our atmosphere is contained in the stratosphere.

Atmospheric profile• Tropopause

– The boundary between the stratosphere and troposphere.

• Troposphere– From the Greek word meaning to turn or change. The

troposphere is the lowest layer of the atmosphere; it begins at the surface and extends to between 7 km (23,000 ft) at the poles and 17 km (56,000 ft) at the equator, with some variation due to weather factors. The troposphere contains roughly 80% of the total mass of the atmosphere. Fifty percent of the total mass of the atmosphere is located in the lower 5.6 km (18,000 ft) of the troposphere.

• The average temperature of the atmosphere at the surface of Earth is 20 °C (68 °F; 293 K).[1][2]

Thermal inversions and smog

• The temperature of the atmosphere decreases up to about 10,000 ft

• So warm air will naturally rise, including warm polluted air. Which means pollution from cars and factories should rise up into the atmosphere and be disperse where it causes no immediate effects on people

• Unless a condition occurs which inhibits the upward movement of warm air

Adiabatic Lapse rate

• The name given to the temperature-altitude relationship in the lower atmosphere– Adiabatic means no energy is gained or loss by a

volume of gas– Lapse means the temperature decreases with

increasing altitude• So warm air will rise and cool at a specific rate. It

will not exchange energy with the surrounding air and will expand because the air pressure surrounding it decreases as it rises.

ALR and inversions

• Now what happens if the meteorological conditions change the temperature height profile?

• If the temperature decrease faster with height than the ALR, then warm air rises indefinitely in to the atmosphere. This provides good mixing and naturally removes pollutants.

• If the temperature increases with height, warm air and the pollution in it is trapped near the surface. This is called a temperature inversion.

• Pollutants are trapped near the surface-causes smog

SMOG• Smoky Fog • First coined by Dr. Henry Antoine

Des Voeux in his 1905 paper, "Fog and Smoke”, in which he was describing the fog seen in London, which had different properties than the fog seen in the English countryside.

• Classic smog-primarily composed of particulates and sulfur oxides from coal burning-London famous for its thick smogs or peasoupers as they are called.

• Immortalized in literature and art

Smog• Photochemical smog-more

modern fog, results from the interaction of the sun and automobile emissions.

• Mixture includes: – Carbon monoxide– nitrogen oxides, such as

nitrogen dioxide– tropospheric ozone– volatile organic

compounds (VOCs)– peroxyacyl nitrates (PAN)– aldehydes (R'O)

Carbon monoxide• Most serious of all the pollutants• Formed from the incomplete combustion of carbon• Prime source is the gasoline fuel internal combustion

engine• Dangerous gas-colorless and ordorless• It combines with hemoglobin in the bloodstream

– Hemoglobin is a protein in the bloodstream that carries oxygen from the lungs to tissues

• CO is more likely to combines with hemoglobin than oxygen, so when it gets in the blood stream it inhibits oxygen flow

• Causes suffocation

Concentration and exposure• Like many pollutants, the effect of CO on a person is a function of both the

concentration and exposure level• Concentration is describe by ppm- parts per million• PPM-Denotes one part per 1,000,000 parts, one part in 106, and a value of 1 × 10–6.

This is equivalent to one drop of water diluted into 50 liters (roughly the fuel tank capacity of a compact car), or one second of time in approximately 11½ days.

• These are units of proportionality• So for CO, after 10 hours

– 100ppm you have a headaches and are unable to think clearly– 300ppm nausea and loss of consciousness– 600 ppm death

• If the concentration is 1000 ppm, loss of consciousness occurs in about 1 hours and death in 4

• Not just a problem from cars, CO is also released in in home gas appliances– Poses an increasing danger as homes are becoming more environmentally sealed to save

energy – Gas appliances need proper ventilation

Controls on CO and other emissions

• Environmental Protection Agency– Government agency that sets air quality standards

• Standards are called the National Ambient Air Quality Standards (NAAQS)

• Set by the Clean Air Act of 1970, and amended in 1990.• Clear Skies Act-proposed by the Bush administration in 2003 not

passed– Attempt to limit sulfur dioxide, nitrogen oxide and mercury emissions

from power plants – Criticized as weakening the clean air act by:

• Weakens the current cap on nitrogen oxide pollution levels from 1.25 million tons to 2.1 million tons, allowing 68 % more NOx pollution.

• Delays the improvement of sulfur dioxide (SO2) pollution levels compared to the Clean Air Act requirements.

• Delays enforcement of smog-and-soot pollution standards until 2015.

Other pollutants: Nitrogen oxides• Reddish brown gas that is responsible for the color of smog• Produced in internal combustion engines and coal plants• Can react with water vapor to produce nitric acid-leads to

acid rain (we will come back to this)• Nitrogen dioxide reacts with sunlight to produce nitrogen

oxide and oxygen• This oxygen reactions with molecular oxygen to produce

ozone• This ozone can react with nitrogen oxide and produce

nitrogen dioxide and molecular oxygen• At 0.5 ppm it can be smelled, 5 ppm it effects the

respiratory system, 20-50 ppm lung liver and heart damage can occur

Other pollutants-hydrocarbons• Recall hydrocarbons are compounds made of carbon and

hydrogen• Released into the atmosphere via:

– Auto exhaust– Evaporation of gasoline in the process of its refinement,

productions and handling– Chemical manufacturing– Manufacturing of dry cleaning fluids, ink and paint

manufacturing releases organic solvents– Industrial dryers, ovens and incineration of materials

• Hydrocarbons combine with ozone (formed from the nitrogen dioxide) to form complex molecules of hydrogen, oxygen and carbon called peroxyacyl nitrates or PANs.

Effects of Photochemical smog• PANs result in eye irritation, damage to vegetation and skin

cancer• Aggravates respiratory conditions • Suggestions that is results in lung cancer and pulmonary

disease• Plant diseases

– Smog injury-cells on the upper part of the leaf collapse. The leaf looks water soaked

– Grape stipple-blotched appearance of leaves, particularly tobacco or grape leaves

• Oxidants cause cracking and disintegration of stretched rubber, paints and fabrics loose their color and strength

• Visibility issues

Sulfur dioxide

• Colorless, nonflammable gas• Produced in the burning of fossil fuels– Coal and oil burning plants– Smelting operations

• Natural sources include decay of organic matter• There are natural processes that remove it from

the atmosphere, these include dry deposition (random air motions deposit the sulfur on the ground) , plant uptake and precipitation

Effects of sulfur dioxide

• Respiratory illness-including lung cancer• Cardiovascular illness• Marble, limestone and mortar dissolved• Protective coatings on metal loose their

protective ability• Plant damage• Note-effects are hard to distinguish from the

effects of sulfuric acid, but the sulfur dioxide helps to form sulfuric acid in the environment

Mitigation• For the coal fired plants:• Remove the sulfur before the coal is burned-

various methods- expensive• Use low sulfur content coal– May have to give up energy content as low sulfur coal

often has a lower energy content when burned• Control sulfur dioxide emission after the coal is

burned• For petroleum plants:– Hydrodesulfurization is used.

Earth Day• April 22 of each year• Designed as a day to become aware of and appreciate the Earth’s

environment• Started in reaction to population growth and overpopulation• Proposed by Senator Gaylord Nelson of Wisconsin• First Earth Day, April 22, 1970 is considered the beginning of the

modern environmental movement– Designed to be a teach in day at Universities– Protest and rallies against things like oil spills, polluting factories and

power plants, raw sewage, toxic dumps, pesticides, freeways, the loss of wilderness, and the extinction of wildlife were held across the nation.

• In 2000, focus shifted to global warming and clean energy

Particulates or aerosols

• Come from lots of natural and man-made sources

• Natural sources– Salt from ocean spray– Dust from fields– Volcanic eruptions– Forest fires

• It is worth noting that natural sources can often be far worse than man-made sources

Particulates or aerosols• Man-made sources– Fly ash from coal combustion– Ash from petroleum, but it occurs at 1/20 coal ash– Iron and steel mills– Cement manufacturing– Burning of wood and other materials– Coal dust from mining of coal (Black Lung)

• Measured in terms of the number of micrograms of particulates per cubic meter– Standard is no more than 50 ug/m3 for particles with sizes

greater than 10 microns in a year, but this does not account for chemical composition of the particulates

Map of particulate matter levels

Natural Dust

Volcanic eruptions• Eruptions put large amounts of

sulfur dioxide, hydrochloric acid and ash into the stratosphere.

• Hydrochloric acid is rained out of the atmosphere

• Sulfur dioxide reacts with water and forms sulfuric acid. The sulfuric acid condenses, forming aerosols. On the surface of the aerosols, chemical reactions occur which increase levels of chlorine which reacts with nitrogen and causes destruction of ozone in the stratosphere.

• This aerosol layer also reflects sunlight, and can cool the atmosphere.