Atmospheric Composition and Air Pollution

The air in Earth's atmosphere is made up of approximately 78 percent ______ and 21 percent oxygen.

[Blank] pollutants may be more appropriately defined as substances that exist in the air in insufficient concentration to cause an unwanted effect.

Air pollutants maybe in the form of ______ or suspended particulate matter (liquid or solid particles).

Secondary ______ pollutants are formed because of reactions between primary pollutants and other elements in the atmosphere.

Air pollutant is also classified into ______ matter (PM) and gaseous according to chemical composition and size.

Air pollutants are classified as ______ pollutants and secondary pollutants according to their formation.

Sulfur dioxide, ______ is a primary pollutant.

Oxides of nitrogen, ______ are secondary pollutants.

Incomplete combustion of carbon containing compounds produces ______.

High concentrations of ______ can cause dizziness, confusion, unconsciousness, and death.

Ozone, ______ shields the earth from harmful ultraviolet (UV-B) rays generated from the sun.

Acid rain harms ______ ecosystems.

Composition of Air

Air consists of approximately 78% nitrogen and 21% oxygen.
Air also contains small amounts of other gases, including carbon dioxide, neon, and hydrogen.

Classification of Air Pollutants

Air pollutants are substances that exist in the air in concentrations sufficient to cause an unwanted effect.
Air pollutants can be classified into:
- Primary pollutants: directly released into the air
- Secondary pollutants: formed through reactions between primary pollutants and other elements in the atmosphere
- Indoor and outdoor pollutants: classified according to source
- Particulate matter (PM) and gaseous pollutants: classified according to chemical composition and size

Types, Sources, and Hazards of Gaseous Air Pollutants

Sulfur Dioxide (SO2)

Sources: fossil fuel power generation, nonferrous smelters, oil refining, and pulp manufacture
Hazards:
- Affects the respiratory system, causing asthma and chronic diseases
- Damages foliage and decreases plant growth
Concentration ranges:
- Cleanest areas: 10-60 μg/m³
- Polluted areas: 68-275 μg/m³

Oxides of Nitrogen (NOX)

Sources: combustion in power generation
Hazards:
- Affects the respiratory system
- Causes asthma and acid rain, harming sensitive ecosystems
- Longer exposures cause asthma
Concentration ranges:
- Cleanest areas: 0.053 ppm
- Polluted areas: 150-200 ppm

Carbon Monoxide (CO)

Sources: incomplete combustion of carbon-containing compounds
Hazards:
- Displaces oxygen in the blood, depriving the heart and brain
- Causes dizziness, confusion, unconsciousness, and death at high concentrations
Concentration ranges:
- Cleanest areas: 50 ppm or 50 mg/l per day
- Polluted areas: 100-120 ppm

Ozone (O3)

Shields the earth from harmful ultraviolet (UV-B) rays generated from the sun

This quiz covers the composition of air in the Earth's atmosphere and the classification of air pollutants. Learn about the percentages of nitrogen, oxygen, and other gases, as well as the unwanted effects of air contaminants.