What is air pollution?

-The presence in the air of substances which pose a potential threat to human health and/or the
environment.

-The presence of particles in the air which decrease visibility

• in such quantities and of such durations as may be or tend to be injurious to human, animal or plant
life, or property, or which unreasonably interferes with the comfortable enjoyment of life or property or
conduct of business.

Air Pollutant

It is a substance or effect dwelling temporarily or permanently in the air

-which adversely alters the environment by interfering with the health, the comfort, or the food chain, or
by interfering with the property values of people.

A pollutant can be solid, liquid or gas . It may originate from a natural or anthropogenic source

Central Case: Charging toward cleaner air in London*

• London has had bad air pollution for centuries that has killed thousands

• Today, smog from traffic is a problem

• The “congestion-charging” program charges drivers to drive into central London during the week

• Congestion decreased, fewer accidents occurred and the air became cleaner

The atmosphere*

Atmosphere = the thin layer of gases that surrounds Earth

• Absorbs radiation and moderates climate

• Transports and recycles water and nutrients

• 78% nitrogen gas, 21% oxygen gas, 1% other gases

• Its four layers differ in temperature, density and composition

Minute concentrations of permanent (remain at stable concentrations) and variable gases (varying
concentrations)

• Human activity is changing the amounts of some gases

The atmosphere’s composition

The first two layers of the atmosphere*

• Troposphere = bottommost layer

• Air for breathing, weather

• Temperature declines with altitude

• Relative humidity

• Tropopause = limits mixing between troposphere and the layer above it

• Stratosphere = 11-50 km (7-31 mi) above sea level

• Drier and less dense, with little vertical mixing

• Colder in its lower regions

• Contains UV radiation-blocking ozone, 17-30 km (10-19 mi) above sea level

The two highest levels of the atmosphere

• Mesosphere = 50-80 km (31-56 mi) above sea level

• Extremely low air pressure

• Thermosphere = atmosphere’s top layer

• Extends upward to 500 m

• Temperatures decrease with altitude (300 mi)

The atmosphere’s four layers

Solar energy heats the atmosphere

• The spatial relationship between the Earth and sun determines the amount of solar energy striking the
Earth

• Energy from the sun

• Heats air

• Moves air

• Creates seasons

• Influences weather and climate

• Solar radiation is highest near the equa (di ko alam anong kadugtong kse putol siya sa ppt)
The atmosphere drives weather and climate
•Weather = specifies atmospheric
conditions over short time periods
and within a small geographic areas
•Climate = describes patterns of
atmospheric conditions across large
geographic regions over long periods
of time
•Mark Twain said “Climate is what we
expect; weather is what we get

Thermal inversion*
Usually, tropospheric air temperature
decreases as altitude increases
• Warm air rises, causing vertical
mixing
• Thermal inversion = a layer of cool
air occurs beneath a layer of warmer
air
• Inversion layer = the band of air
in which temperature rises with
altitude
• Denser, cooler air at the bottom
of the layer resists mixing

Outdoor air pollution

• Air pollutants = gases and particulate material added to the
atmosphere
• Can affect climate or harm people
• Air pollution = the release of pollutants
• Outdoor (ambient) air pollution = pollution outside
• Has recently decreased due to government policy and improved technologies
in developed countries
• Developing countries and urban areas still have significant problems

Sources and Types of Air Pollution

Energy production from fossil fuels
-Carbon dioxide, sulfur oxides, particulates
-Increase in greenhouse gases, acidic precipitation

Automobiles, other transportation sources

-Carbon monoxide, nitrogen and sulfur oxides, products of
incomplete combustion
-Increase in greenhouse gases, acidic precipitation

Refrigeration devices including home, commercial, and vehicles

-Chlorofluorocarbons
-Destruction of the stratospheric ozone layer

Nitrogen Oxides
Smog, vegetation damage, respiratory irritant, visibility
Carbon monoxide

Sulfur Dioxide

Pollutants exert local and global effects

• Residence time = the time a pollutant stays in the atmosphere

• Pollutants with brief residence times exert localized impacts over short
time periods
• Particulate matter, automobile exhaust

• Pollutants with long

residence times exert
regional or global impacts
• Pollutants causing
climate change or
• ozone depletion

Natural sources pollute: dust storms*

• Dust storms = Hundreds of
millions of tons of dust are blown
westward across the Atlantic
Ocean by trade winds every year
• From Africa to the Americas
• Unsustainable farming and grazing,
erosion and desertification

Natural sources pollute: volcanoes*

• Release large quantities of
particulate matter, sulfur dioxide &
other gases
• Can remain for months or years
• Aerosols = reflect sunlight back into
space and cool the atmosphere and
surface
Natural sources pollute: fires*
• Pollutes atmosphere with soot and gases
• Over 60 million ha of forests and grasslands burn per year
• Severe fires are caused by human interaction
• Cleared forests, harsh droughts, and climate change (El Niño)

Types of outdoor air pollution

• Air pollution can come from mobile or stationary sources
• Point Sources = specific spots where large quantities of
pollutants are discharged (power plants and factories)
• Nonpoint Sources = more diffuse, consisting of many small
sources (automobiles)
• Primary Pollutants = directly harmful and can react to form
harmful substances (soot and carbon dioxide)
• Secondary Pollutants = form when primary pollutants interact or
react with constituents or components of the atmosphere
(tropospheric ozone and sulfuric acid)

(Categories of) Air Pollutants

A. Primary Pollutants: those directly produced/emitted from

sources.
Ex: ash from a volcanic eruption or the carbon monoxide gas
from a motor vehicle exhaust
(Categories of) Air Pollutants
B. Secondary Pollutants: those formed in the
atmosphere when primary pollutants react or
interact with each other or with the other
components of the atmosphere.

SMOG (Combination of smoke and fog)

Smog is a potentially hazardous condition which forms when
meteorological conditions combine with air pollutants.
sulfur oxides- from coal and petroleum
combustion
particulates- from burning fossil fuels; may contain lead, cadmium, mercury

PHOTOCHEMICAL SMOG
- Key ingredients are fossil fuels (containing
hydrocarbons, carbon monoxide, and
nitrogen oxides) burned in automobiles and
sunlight.
- The irradiation (by sunlight) and reaction
forms nitrogen oxides, ozone, and irritating
organic compounds.

Legislation addresses pollution

• The Clean Air Act RA 8749

• Strengthens standards for auto emissions, toxic air pollutants, acidic deposition,
stratospheric
ozone depletion
• Introduced emissions trading
• DENR/EMB sets nationwide standards for emissions of toxic
pollutants
• States monitor air quality and develop, implement, and enforce
regulations within their borders
• If a state’s plans for implementation are not adequate, the DENR can take
over enforcement
Air pollution has decreased since 1970
• Total emissions of the six monitored pollutants have declined
• Despite increased population, energy consumption, miles traveled, and gross
domestic product

Reasons for the decline in U.S. pollution

• Cleaner-burning vehicles and catalytic
converters decrease carbon monoxide
• Permit-trading programs and clean
coal technologies reduce SO2
emissions
• Scrubbers = technologies that
chemically convert or physically
remove pollutants before they leave
the smokestacks
• Phaseout of leaded gasoline
• Improved technologies and federal
Policies
Pollution in developing nations is high

Acid deposition is another transboundary issue

• Acidic deposition = the deposition of
acid, or acid-forming pollutants, from
the atmosphere onto Earth’s surface
• Acid rain = precipitation of acid
• Atmospheric deposition = the wet or dry
deposition on land of pollutants

Sources of acid deposition

• Originates from burning fossil fuels that release sulfur dioxide
and nitrogen oxides
• These compounds react with water to form sulfuric and nitric acids
Effects of acid deposition
• Nutrients are leached from topsoil
• Soil chemistry is changed
• Metal ions (aluminum, zinc, etc.) are
converted into soluble forms that pollute
water
• Widespread tree mortality
• Affects surface water and kills fish
• Damages agricultural crops
• Erodes stone buildings, corrodes cars,
erases writing on tombstones

Indoor air pollution*

• Indoor air contains higher concentrations of pollutants
than outdoor air
• 6,000 people die per day from indoor air pollution
• Exposed to synthetic materials that have not been
comprehensively tested
• To reduce heat loss and improve energy efficiency, building
ventilation systems were sealed off ventilation and windows
put in that did not open, trapping pollutants inside

Indoor air pollution in the developing world

• Stems from burning
• Wood, charcoal, dung, crop wastes
• Little to no ventilation
• Fuel burning pollution causes an
estimated 1.6 million deaths per
year
• Soot and carbon monoxide
 • Causes pneumonia, bronchitis,
allergies, cataracts, asthma, heart
disease, cancer and death

Volatile Organic Compounds (VOCs)

• The most diverse group of indoor air pollutants
• Released by everything from plastics and oils to perfumes and paints
• Most VOCs are released in very small amounts
• Also include pesticides, which are found indoors more often than
outdoors due to seepage
• Formaldehyde, which leaks from pressed wood and insulation, irritates
mucous membranes and induces skin allergies

Sources of indoor air pollution

Living organisms can pollute indoors*
• Tiny living organisms can also
pollute
• Includes dust mites and animal
dander worsen asthma
• Fungi, mold, mildew, airborne
bacteria cause severe allergies,
asthma, and other respiratory
ailments

Sick building syndrome = a

sickness produced by indoor pollution
with general and nonspecific
symptoms
Solved by using low-toxicity building
materials and good ventilation
SICK BUILDING SYNDROME
Building related illnesses - symptoms
of diagnosable illness are identified
and can be attributed directly to
airborne building contaminants.

We can reduce indoor air pollution

• In developed countries:
• Use low-toxicity material
• Monitor air quality
• Keep rooms clean
• Limit exposure to chemicals
• In developing countries:
• Dry wood before burning
• Cook outside
• Use less-polluting fuels (natural gas)

CLEAN AIR ACT OF THE PHILIPPINES (RA 8749) Air pollution control policy
The hole in the ozone*

• Ozone hole = ozone levels over Antarctica had declined by 40-

60%
• Depletion also in the Arctic and globally
• Causes skin cancer, harms crops and decreases ocean productivity

The Montreal Protocol addressed ozone depletion

• Montreal Protocol = 180 nations agreed to cut CFC production in
half
• Follow-up agreements deepened cuts, advanced timetables
and addresses other ozone-depleting chemicals
• Today, production and use of ozone-depleting chemicals has
decreased 95%
• The ozone layer is beginning to recover
• Challenges still face us
• CFCs will remain in the stratosphere for a long time
• Nations can ask for exemptions to the ban

Effects of Air Pollution and Global Warming

-Rising Sea Level
-Change of precipitation and local climate conditions;
acid rain
-Alteration of forests and crop yields
-Expansions of deserts into existing
rangelands
-More intense rainstorms
-Not all long-term effects can be determined

What Is Being Done: Alternatives

Changes In Vehicle Systems