Air pollution may be defined as the presence in the air (outdoor atmosphere) of one or more contaminants 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.

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 (large or sub-molecular), liquid or gas .

It may originate from a natural or anthropogenic source (or both).

It is estimated that anthropogenic sources have changed the composition of global air by less than 0.01%.

However, it is widely accepted that even a small change can have a significant adverse effect on the climate, ecosystem and species on the planet.

Examples of these are acid rain, ozone in the lower atmosphere, and photochemical smog.

Some primary air pollutants may react with one another or with other chemicals in the air to form secondary air pollutants.

Air Quality Index (AQI) Values

Levels of Health Concern

151 to 200

201 to 300

301 to 500

Unhealthy

Very Unhealthy

Hazardous

0 to 50

51 to 100

101 to 150

Good

ModerateUnhealthy for Sensitive Groups

To human Plants Animals Buildings

Premature death

Aggravated asthma

Respiratory-related emergency room visits and hospital admissions

Acute respiratory symptoms

Chronic bronchitis

Decreased lung function (shortness of breath)

Decrease lung function. Irritate lungs. Long-term lower level exposures

can destroy lung tissue, leading to emphysema.

Children may also be especially sensitive to the effects of nitrogen oxides.

Seriously injure vegetation at certain concentrations. Effects include: • Bleaching or killing plant tissue. • Causing leaves to fall. • Reducing growth rate.

Deteriorate fabrics and fade dyes. Corrode metals (due to nitrate

salts formed from nitrogen oxides).

Reduce visibility (haze, smog)

Oxides of nitrogen, in the presence of sunlight, can also react with hydrocarbons, forming photochemical oxidants or smog.

Also, NOx is a precursor to acidic precipitation, which may affect both terrestrial and aquatic ecosystems.

Bad odor, it can irritate the respiratory system.

Exposure to high concentrations for short periods of time can constrict the bronchi and increase mucous flow, making breathing difficult.

Ozone acts as a powerful respiratory irritant at the levels frequently found in most of the nation's urban areas during summer months.

Ozone exposure may lead to:•Shortness of breath. •Chest pain when inhaling deeply. •Wheezing and coughing.

Clean Air ActClean Air Act

National Ambient Air Quality Standards (NAAQS)

National Ambient Air Quality Standards (NAAQS)

Primary and secondary standards

Emission Trading Policy

Primary and secondary standards

Emission Trading Policy

Reduce vehicle emissions:

Drive less

Keep cars well maintained and tires properly inflated

Turn off the engine when your vehicle is not in motion

Purchase low-emitting and fuel efficient vehicles

Share a ride, take public transportation bike, or walk

Cut your grass after 6 p.m.

Refuel your car after 6 p.m.

Combine errands into one trip

Conserve electricity:

do not over-cool or over-heat buildings

turn off lights and appliances when not in use

Purchase electronics/appliances with energy star labels