(21-22) Unit 7- Air Pollution

Acid

Acid

A substance that produces hydrogen ions in solution; less than 7 on the pH scale.

Acid deposition

The accumulation of acidic substances on the surface of the Earth.  consists of rain, snow, dust, or gas with a pH lower than 5.6.

Acidification

The lowering of pH of a solution.

Acute

Rapid onset and shorter duration

Air pollutant

Substances found in the atmosphere that cause harmful effects to the environment and/or humans.

Ambient

The immediate surroundings

Anthropogenic

Caused by human activities

Asbestos

Heat-resistant fibrous material that is used for insulation but is harmful if inhaled.

Asphyxiant

A material that causes the victim to suffocate.

Atmosphere

The thin layer of gases that surrounds Earth.

Carbon dioxide

A colorless, odorless gas produced during respiration and by combustion of organic compounds.

Carbon monoxide

A toxic colorless, odorless gas that is produced by incomplete combustion of organic compounds. Can’t see or smell it

Carcinogen

A substance that causes cancer.

Catalytic converter

1. Required on all vehicles after 1975

2. Contains metals (platinum & palladium) that bind to NOx and CO

   • CC converts NOx, CO, and other hydrocarbons into CO2, N2, O2, and H2O

3. A device that reduces carbon monoxide and NOx emissions from vehicles.

Chronic

Long lasting and persistent

Clean Air Act

1970 law that set emission standards for cars and limited the release of air pollutants.

Electrostatic precipitator

A device used for removing particulates from smokestack emissions by attracting charged particles to an oppositely charged metal plate.

EPA

The Environmental Protection Agency, an independent federal agency established to coordinate programs aimed at reducing pollution and protecting the environment.

Formaldehyde

An indoor air pollutant that is a colorless chemical used to manufacture building materials and many household products, such as particleboard and hardwood plywood paneling.

Heavy metals

Metals of relatively high density that can be toxic to organisms in small quantities.

Industrial smog

Type of air pollution resulting from emissions from factories and other sources due to the burning of fossil fuels.

Lead

A heavy metal air pollutant that has been greatly reduced due to its removal from gasoline, and now primarily enters the atmosphere through industrial processes. Can cause brain damage

Limestone

A hard sedimentary rock, composed mainly of calcium carbonate.

Mercury

A heavy metal air pollutant that is mainly produced through coal combustion.

Mitigation

Actions that reduce the severity of effects of something.

Mold

Fungi that are a common indoor air pollution source.

Neutralize

when an acid and a base come in contact with each other bringing the pH closer to neutral.

Nitric acid

A common component of acid precipitation that forms when NOx combine with water in the air.

Nitrous oxides

Also known as NOx, includes NO2 and NO3 that are emitted from industry and vehicles.

Noise pollution

Unwanted or potentially damaging sounds

Ozone

A gas molecule that is made up of three oxygen atoms that is formed naturally in the stratosphere but when formed in the troposphere is considered a pollutant.

PANs

Peroxyacyl nitrates, a group of chemicals that are found in photochemical smog.

Particulate Matter

Solid and liquid matter suspended in the air reduces visibility & causes respiratory irritation.

pH scale

A range of values used to show the amount of hydrogen ions in a solution, or how acidic/basic it is.

Photochemical smog

Form of air pollution that is created from the interaction between chemicals in the air and sunlight.

Primary pollutants

Pollutants that are put directly into the air by human or natural activity.

Radioactive

Elements that spontaneously emit radiation.

Radon

A gas that occurs naturally in the soil due to the decay of Uranium and is a common indoor air pollutant.

Remediation

Containment or treatment of an area that has been contaminated.

Respiratory

Related to breathing and the lungs.

Secondary Pollutants

Pollutants that form from chemical reactions that occur when emitted pollutants come in contact with water vapor or sunlight. Result of a chemical reaction

Sulfur dioxide

A colorless, corrosive gas produced during the combustion of fossil fuels that is directly damaging to living things as well as a precursor to acid precipitation. Coal combustion (electricity)

Resp. irr. | smog | acid precip.

Sulfuric acid

Formed when sulfur dioxide emissions react with water vapor in the air, creating acid precipitation.

Thermal inversion

A condition that occurs when warm air traps cooler air (and pollution) at the surface of the earth.

Tropospheric ozone

A secondary pollutant formed near the surface of the Earth by the interaction of sunlight, NOx, and VOCs, which is a major component of smog that can injure living tissues and cause respiratory problems.

VOCs

Volatile Organic Compounds are chemicals that can easily evaporate and become a gas.

Wet scrubbers

Fine mists of water vapor used to trap air particulates in smokestacks from burning fossil fuels. (HAS WATER)

COPD (chronic obstructive pulmonary disease)

A group of lung diseases that block airflow and make it difficult to breathe.

Sick Building Syndrome (SBS)

Situation in which building occupants experience acute health and comfort effects that appear to be linked to time spent in a building but no specific illness or cause can be identified.

Bag house filter

a fabric filter that allows gases to pass through but not particles (effective for removal of PM 10 and PM 2.5)

vapor recovery nozzle

an air pollution control device on a gasoline pump that prevents fumes from escaping into the atmosphere when fueling a motor vehicle

Dry Scrubber

A column filled with chemical agents that trap and neutralize SO2, VOCs, and NOx in emissions from coal power plants. Calcium oxide is a common chemical agent that traps and neutralizes these pollutants.

fluidized bed combustion

1. a clean-coal technology in which crushed coal is mixed with limestone to neutralize the acidic sulfur compounds produced during combustion

2. Jets of air bring more O2 into rxn, making combustion more efficient and bringing SO2 into more contact with calcium carbonate in limestone

3. Also allows coal to be combusted at lower temp, which emits less NOx

pollution credits

Credits that can be earned and then sold by companies that emit pollutants below established standards.

Troposphere

1. The lowest layer of Earth's atmosphere

2. Contains all weather and most of the gases in the atmosphere [greatest air pressure]

Dust and soot are examples of this type of pollutant

Particulate Matter

Photochemical smog forms when primary pollutants and secondary pollutants react in the presence of this.

Sunlight

These two pollutants contribute the most to acid deposition

nitrogen oxides and sulfur dioxide

This occurs when a layer of warm air traps cooler air below it and commonly occurs in this west coast city

thermal inversion of Los Angeles

The pollutants commonly targeted by electrostatic precipitators and scrubbers respectively

particulate matter and sulfur oxides

This pollutant reduces the bloods ability to carry oxygen, causing headaches, dizziness, and even death

carbon monoxide

Furniture stuffing, paneling, and foam insulation are all sources of this pollutant

Formaldehyde

The four most dangerous indoor air pollutants according to the EPA.

asbestos, radon, cigarette smoke, and formaldehyde

The criteria for determining if a building is sick

20%1 or more people complaining of symptoms such as headaches, nausea, fatigue, and coughing2 while in a building3 but feeling better when they leave4

This pollutant comes from the radioactive decay of uranium and its remediation technique

radon and proper ventilation

The layer of the atmosphere that contains this helpful ozone

the stratosphere

The thinning of the ozone layer is occurring primarily over this continent at this time of year

Antarctica in October/spring

Much of the ozone thinning has been caused by this chemical and specifically this element

chlorofluorocarbons (CFCs) and the chlorine molecule

Less ozone means increased exposure to this radiation which causes

UVB radiation which causes skin cancer

The first meeting to reduce CFC emissions was held in this location and established this agreement

Montreal and the Montreal Protocol

The most abundant and variable nonanthropogenic greenhouse gas

water vapor

The percent increase in carbon dioxide from 283 ppm in 1790 to 383 ppm in 2007

30-38%

The greenhouse gas that is a product of anaerobic respiration, livestock gas, and landfills

Methane

This makes a greenhouse gas more potent than CO2

GHG's ability to absorb more heat energy

The type of radiation that is absorbed by Earth's surfaces that is re-emitted as this type of radiation

visible light and infrared

The region of Earth that will experience the most significant changes in temperature as warming continues

the poles

A possible effect of the rapid ice loss in the arctic is the shutdown of this process because of the inundation of melting freshwater

the oceanic conveyor belt

Since 1900, the Earth's temperature has risen by about this amount

0.6-0.8°C? (1°C or 1.5°F is acceptable)

The reason that the melting of Earth's ice (glaciers, ice sheets, ice caps) will cause to the further increase in Earth's temperature

the lower albedeo of water compared to ice

The reason that infectious tropical diseases are likely to spread to higher latitudes as Earth's average temperature increases

rising temperatures allow disease-carrying mosquitoes to move into new areas

6 criteria pollutants that the EPA is required to set limits for in Clear Air Act

Sulfur dioxide (SO₂), nitrogen oxides (NO and NO₂), particulate matter (PM), carbon monoxide (CO), ozone (O₃), and lead (Pb)

Stratosphere

Contain ozone layer, which blocks UV radiation

Which is not one of the 6 criteria pollutants in the Clean Air Act?

CO₂. Does not directly* lower air quality from a human health standpoint. CO2 is a greenhouse gas; it does lead to earth warming, and thus env. and human health consequences

• Not toxic to organisms to breath

• Not damaging to lungs/eyes

• Does not lead to smog, decreased visibility

Coal Combustion

Releases more air pollutants than other FFs; ~35% of global electricity

• Releases CO, CO2, SO2, NOx toxic metals (mercury, arsenic, lead), and PM (often carries the toxic metals)

  • Impacts of SO2

    • Respiratory irritant (inflammation of bronchioles, lungs), worsens asthma & bronchitis

    • Sulfur aerosols (suspended sulfate particles) block incoming sun, reducing visibility & photosynthesis

    • Forms sulfurous (grey) smog

    • Combines with water & O2 in atmosphere to form sulfuric acid → acid precip.

Nitrogen Oxides

Released by combustion of anything, especially FFs & biomass

• NOx refers to nitrogen oxides (both NO, and NO2)

  • NO forms when N2 combines with O2 (esp. during combustion)

  • NO can become NO2 by reacting with O3 or O2

  • sunlight converts NO2 back into NO

Env. & Human Health Impacts

• Resp. irritant

• Leads to tropospheric ozone (O3) formation, which leads to photochemical smog

• Combines with water & O2 in atm. to form nitric acid → acid precipitation

• All FF combustion (gas esp.)

  O3 | photochem smog | acid precip.

EPA & Lead

Before CAA, lead was a common gasoline additive; EPA began phaseout of lead from gasoline in 1974

• Vehicles made after 1974 are required to have catalytic converters to reduce NOx, CO and hydrocarbon emissions (lead damages catalytic converters)

  • Also a known neurotoxicant (damages nervous systems of humans)

Primary Air Pollutants

• Emitted directly from sources such as vehicles, power plants, factories, or natural sources (volcanoes, forest fires)

• NOx, CO, CO2*, VOCs, SO2, PM, hydrocarbons

Secondary Air Pollutants

• Primary pollutants that have transformed in presence of sunlight, water, O2

• Occur more during the day (since sunlight often drives formation)

• Tropospheric O3 (Ozone)

• Sulfuric acid (H2SO4) & sulfate (SO42-)

• Nitric acid (HNO3) & nitrate (NO3-)

Photochemical smog conditions

Sunlight - Drives O3 formation by breaking down NO2 → NO + O; then free O atom binds with O2

Identify major molecular components of air, and give the percentages of the major components.

Composition of Atmosphere

1. 78% nitrogen

2. 21% oxygen

3. 1% other (argon, carbon dioxide, water vapor, trace gases)

Identify THREE sources of marine noise pollution

commercial shipping, sonar systems, and seismic surveys

Order of atmospheres from top to bottom

Thermosphere → Mesosphere →Stratosphere →Troposphere

Impacts of Smog

Environmental:

Reduces sunlight; limiting photosynthesis

O3 damages plant stomata and irritates animal resp. tracts

Humans:

Resp. irritant; worsens asthma, bronchitis, COPD; irritates eyes

Decreasing the number of vehicles on the road decreases NO2 emissions

Economic:

Increased health care costs to treat asthma, bronchitis, COPD

Lost productivity due to sick workers missing work or dying

Decreased agricultural yields due to less sunlight reaching crops & damage to plant stomata

Reduction of Smog

Vehicles:

Decreasing the number of vehicles on the road decreases NO2 emissions

Fewer vehicles = less gas = fewer VOCs

Carpooling, public transport, biking, walking, working from home

Energy:

Increased electricity production from renewable sources that don’t emit NOx (solar, wind, hydro)

Nat. gas power plants release far less NOx than coal

What layer of the atmosphere houses “bad” ozone?

Troposphere

Explain the difference between a primary and secondary pollutant using acid rain as an example.

A primary pollutant is directly emitted from a source, whereas a secondary pollutant is indirectly emitted from a source. Acid rain is considered to be a secondary pollutant because it occurs when sulfur dioxide or nitrous oxides react with water.

List one secondary pollutant and how it forms. (must be different than the following slide)

One secondary pollutant is ozone. Ozone forms when NO2 is broken by sunlight and free O binds to O2.

What are the 3 components you need to form photochemical smog?

VOCs, NOx, and sunlight

What two conditions need to be met in order for photochemical smog to form?

There needs to be VOCs and NOx in the air.

Write out the chemical process (or explain) that creates

a. NO

NO2 is emitted from vehicles due to fossil fuel combustion. Sunlight breaks up NO2 into NO + O.