ARB Fact Sheet: Air Pollution Sources, Effects and Control

This page reviewed December 2, 2009.

Where does air pollution come from? How does it effect people and the environment? How can we control, or better yet, prevent it? The following table summarizes the sources, effects and prevention and control methods for ten of the most important air pollutants in California.





Ozone (O3)

Formed when reactive
organic gases (ROG)
and nitrogen oxides
react in the presence
of sunlight. ROG sources
include any source that
burns fuels, (e.g., gasoline,
natural gas, wood, oil)
solvents, petroleum
processing and storage
and pesticides.

Breathing Difficulties,
Lung Tissue Damage,
Damage to Rubber
and Some Plastics

Reduce motor vehicle
reactive organic gas
(ROG) and nitrogen
oxide emissions through
emissions standards,
reformulated fuels,
inspections programs
and reduced vehicle use.
Limit ROG emissions from
commercial operations
and consumer products.
Limit ROG and NOx
emissions from industrial
sources such as power
plants and refineries.
Conserve energy.

Respirable Particulate
Matter (PM10)

Road Dust, Windblown
Dust (Agriculture) and
Construction (Fireplaces)
Also formed from other
pollutants (acid rain, NOx,
SOx, organics). Incomplete
combustion of any fuel.

Increased Respiratory
Disease, Lung Damage,
Cancer, Premature
Death, Reduced Visibility,
Surface Soiling

Control Dust Sources,
Industrial Particulate
Emissions, Wood Burning
Stoves and Fireplaces
Reduce secondary
pollutants which react
to form PM10.
Conserve energy.

Fine Particulate
Matter (PM2.5)

Fuel Combustion in Motor
Vehicles, Equipment
and Industrial Sources,
Residential and Agricultural
Burning. Also formed from
reaction of other pollutants
(acid rain, NOx, SOx,

Increases Respiratory
Disease, Lung Damage,
Cancer, Premature Death,
Reduced Visibility,
Surface Soiling

Reduces Combustion
Emissions from Motor
Vehicles, Equipment,
Industries and Agriculture
and Residential Burning.
Precursor controls, like
those for ozone, reduce
fine particle formation
in the atmosphere.

Carbon Monoxide (CO)

Any source that burns
fuel such as automobiles,
trucks, heavy construction
equipment, farming
equipment and
residential heating.

Chest Pain in Heart
Patients, Headaches,
Reduced Mental Alertness

Control motor vehicle
and industrial emissions.
Use oxygenated gasoline
during winter months.
Conserve energy.

Nitrogen Dioxide (NO2)

See Carbon Monoxide

Lung Irritation and Damage.
Reacts in the atmosphere
to form ozone and acid rain

Controls motor
vehicle and industrial
combustion emissions.
Conserve energy.


Metal Smelters, Resource
Recovery, Leaded Gasoline,
Deterioration of Lead Paint

Learning Disabilities,
Brain and Kidney Damage

Control metal smelters,
no lead in gasoline.
Replace leaded paint
with non-lead substitutes.

Sulfur Dioxide (SO2)

Coal or Oil Burning
Power Plants and
Industries, Refineries,
Diesel Engines

Increases lung disease
and breathing problems
for asthmatics. Reacts
in the atmosphere to
form acid rain.

Reduces the use of high
sulfer fuels (e.g., use
low sulfer reformulated
diesel or natural gas).
Conserve energy.

Visibility Reducing

See PM2.5

Reduces visibility
( e.g., obscures
mountains and other
scenery), reduced airport
safety, lower real estate
value, discourages tourism.

See PM2.5


Produced by the
reaction in the air of
SO2 (see SO2 sources),
a component of acid rain.

Breathing Difficulties,
Aggravates Asthma,
Reduced Visibility

See SO2

Hydrogen Sulfide

Geothermal Power Plants,
Petroleum Production
and Refining, Sewer Gas

Nuisance Odor
(Rotten Egg Smell),
Headache and Breathing
Difficulties (Higher Concentrations)

Control emissions from
geothermal power plants,
petroleum production and
refining, sewers, sewage
treatment plants.

If you have questions or comments regarding this web page, please contact Barbara Weller
at (916) 445-1324 or via email at


ARB Fact Sheet