AICE Environmental Management Unit 7: Air Pollution

Carbon Dioxide (CO2)

greenhouse gas; waste product of combustion & decompostion

acid deposition

as a mix of air pollutants

that deposit from the atmosphere as acidic

wet deposition (with a pH <5.6) or acidic dry

deposition

wet deposition

snow, rain, hail, fog

dry deposition

- dust and gases

outline the formation of acid deposition

1. fossil fuels contain sulfur compounds

2. combustion of fossil fuels releases sulfur dioxide

gas

3. sulfur dioxide gas reacts with water and oxygen

in the atmosphere to form sulfuric acid

4. nitrogen from the atmosphere reacts with

oxygen in the high temperatures of vehicle

engines to form nitrogen monoxide gas

5. nitrogen monoxide gas is released into the

the atmosphere in vehicle emissions

6. nitrogen monoxide gas reacts with oxygen and

water in the atmosphere to form nitric acid

impacts of acid deposition on aquatic environments

affects fish gills and fish populations

Impacts of acid deposition on vegetation and crops

defoliation and reduced crop yield (think plant experiment)

impacts of acid rain on stone and brick buildings

enhanced chemical weathering

Photochemical smog

a mixture of air pollutants and particulates, including ground level ozone, which is formed when oxides of

nitrogen and volatile organic compounds (VOCs)

react in the presence of sunlight

ground level ozone

a secondary pollutant that forms when some of the pollutants released during fossil fuel combustion react with atmospheric oxygen in the presence of sunlight

impacts of photochemical smog

eye and respiratory irritation

• decreased crop yields

• deterioration of plastics and rubber

strategies for managing air pollution

• reduced use of fossil fuels

• reducing emissions of:

- sulfur dioxide by flue gas desulfurisation and

fuel desulfurisation

- oxides of nitrogen by catalytic converters

- particulates using electrostatic precipitators

- volatile organic compounds (VOCs)

○ safe usage, storage and disposal of

household products

• restricting vehicle use in urban areas

• legislation

- local, national and international legislation

(detailed knowledge of specific legislation

and agreements is not required)

- polluter pays principle

Gas desulfurization

set of technologies used to remove sulfur dioxide (SO2) from exhaust flue gases of fossil-fuel power plants, and from the emissions of other sulfur oxide emitting processes such as waste incineration.

catalytic converters

a device incorporated in the exhaust system of a motor vehicle, containing a catalyst for converting pollutant gases into less harmful ones.

electrostatic precipitators

A device used for removing particulates from smokestack emissions. The charged particles are attracted to an oppositely charged metal plate, where they are precipitated out of the air.

volatile organic compounds (VOCs)

Organic compounds that exist as gases in the atmosphere and act as pollutants, some of which are hazardous.

reducing VOCs

safe usage, storage and disposal of

household products

Montreal Protocol (1987)

A treaty put together to cut emissions of CFCs by 35% between 19889 and 2000.

outline how ozone depletion occurs

• chlorofluorocarbons (CFCs) from aerosols and

refrigerants are unreactive compounds and are

not broken down in the troposphere

• CFCs move into the stratosphere and break down

in the presence of ultraviolet light to release a

chlorine atom

• rapid reactions between chlorine atoms and

ozone breaks down ozone (O3) to oxygen (O2),

causing ozone depletion

• chlorine atoms remain in the stratosphere and

can continue to destroy ozone

detailed chemical mechanisms are not required

the Dobson Unit

state that ozone concentration is measured

ozone hole

the term as an area where the

average concentration of ozone is below 100

Dobson Units ---NOT CLIMATE CHANGE

explain why ozone depletion has been greatest

over Antarctica

temperature, polar vortex, polar

stratospheric clouds (PSCs)

polar vortex

A huge swirling mass of very cold air that is isolated from the rest of the atmosphere until the sun returns a few months later.

stratospheric clouds (PSCs)

clouds in the winter polar stratosphere at altitudes of 15,000-25,000 m (49,000-82,000 ft).

Why is the ozone hole over Antarctica?

damage occurs due to the presence of chlorine and bromine from ozone-depleting substances in the stratosphere and the specific meteorological conditions over the Antarctic.

impacts of ozone depletion due to

the increased amounts of ultraviolet radiation

• human health (cataracts, skin cancer)

• decreased crop yields

• biodiversity of terrestrial and aquatic ecosystems

• degradation of materials used in clothing and

construction

Was the Montreal Protocol successful?

The Montreal Protocol has been successful in slowing and reversing the increase of ozone-depleting gases (halogen source gases) in the atmosphere. An important measure of its success is the change in the value of effective stratospheric chlorine.

alternatives to ozone depleting substances

• hydrochlorofluorocarbons (HCFCs)

• fluorinated gases (F-gases)

Hydrochlorofluorocarbons (HCFCs)

Group of chemicals containing hydrogen, chlorine, fluorine, and carbon, produced as a potential substitute for CFCs

Fluorinated gases (F-gases)

greenhouse gas emitted during industrial process including refrigeration

Fluorinated gases (F-gases)

man-made gases that can stay in the atmosphere for centuries and contribute to a global greenhouse effect.

Rowland-Molina hypothesis

this hypothesis proposes that long living halogen compounds can cause ozone depletion

• initially the main hypothesis was not accepted

• some of the auxiliary hypotheses were not

backed up by experimental evidence

• the hypothesis led to further research and data

collection by other scientists, which confirmed

that CFCs are ozone depleting

this shows the importance of experimental evidence

to support a hypothesis

Great Smog London (1952)

A smog that was so dense for 4 days, the people in London could not see what was in front of them; 4000 people died.

Donora Smog of 1948

In late October of 1948, the Donora Smog rocked the small Pennsylvanian community. Instead of another ‘average’, hazy day that came and passed, large clouds of polluted air from the nearby zinc plant were trapped by a weather inversion from readily moving along. Of Donora’s 14,000 total residents, 6,000 were afflicted by toxic air – 26 lost their lives. To this day, the Donora Smog crisis is considered the worst air pollution incident to occur in the United States and one of the worst in the world.

Management of the Great Smog of London

Slow to act at first, the British government ultimately passed the Clean Air Act four years later, in 1956, as a direct response to the lethal fog. The act established smoke-free areas throughout the city and restricted the burning of coal in domestic fires as well as in industrial furnaces.

Management of Donora Smog Event

Following the deadly smog, President Truman convened the first national air pollution conference in 1950. Congress didn't pass its first Clean Air Act until 1963, but progress continued steadily after that, with President Nixon creating the Environmental Protection Agency in 1970, the same year that Congress passed a more comprehensive Clean Air Act. But the work of protecting the environment is never entirely finished, as new industries and technologies take the place of previous ones.

Sulfur Dioxide (SO2)

Air pollution Formed when fossil fuels, which contain sulfur, are burned

Has the ability to dissolve in water vapor to form sulfuric acid and interact with the particulate matter and gases in the air to form other products

Primary Pollution

carbon monoxide

a colorless, odorless toxic flammable gas formed by incomplete combustion of carbon.

Paris Agreement (2015)

Agreement made between the United Nations countries to cut down on the emissions of greenhouse gases in an attempt to slow down global warming. More wealthy and producing countries have to cut down more

Particulate Matter (PM)

Solid or liquid particles suspended in air; also known as particles and particulates.

Lead pollution

At the national level, major sources of lead in the air are ore and metals processing and piston-engine aircraft operating on leaded aviation fuel. Other sources are waste incinerators, utilities, and lead-acid battery manufacturers. The highest air concentrations of lead are usually found near lead smelters

Clean Air Act of 1970

Required EPA to develop and enforce regulations to protect the public from airborne contaminants; forced states to follow and make sure the laws for followed in relation to the EPA. States allowed to decide officials for enforcement.