Air ... like really whats that ... All around the earth there is a thick blanket of air called the atmosphere or air ... or short
Like other gases does not have a fixed shape It spreads out to fill any available space so nothing is really empty.
But air cannot escape from the atmosphere 
as the force of gravity keeps it from floating away from the earth ..... 
like a balloon 
Air pollution ... ever since people first gathered in settlements 
there has been pollution.
Pollution usually refers to the presence of substances that are either present
in the environment where it doesn't belong or at levels greater than it should be.
Air pollution is caused by any undesirable substance which enters the atmosphere air pollution is a major problem in modern society
Even though air pollution is usually a greater problem in cities, pollutants
contaminate air everywhere these substances include various gases and
tiny particles, or particulates that can harm human health and damage the
environment.
They may be gases, liquids, or solids. Many pollutants are
given off into the air as a result of human behavior. Pollution occurs on different levels: personal, national, and global ... some pollutants come from natural sources.
Forest fires emit particulates, gases, and VOCs (substances that vaporize into the atmosphere)
Ultra-fine dust particles created by soil erosion when water and weather loosen layers of soil, increase airborne particulate levels.
Volcanoes spew out sulfur dioxide and large amounts of pulverized lava rock known as volcanic ash .... the major types of air pollution are: Gaseous pollutants: A different mix of vapors and gaseous air pollutants is found in outdoor and indoor environments.
The most common gaseous pollutants are carbon dioxide, carbon monoxide, hydrocarbons, nitrogen oxides, sulfur oxides and ozone.
A number of sources produce these chemical compounds but the major man-made source is the burning of fossil fuel. Indoor air pollution is caused by cigarette smoking, the use of
certain construction materials, cleaning products, and home furnishings.
Outdoor gaseous pollutants come from volcanoes, fires, and industry, and
in some areas may be substantial.
The most commonly recognized type of
air pollution is smog. Smog generally refers to a condition caused by the
action of sunlight on exhaust gases from motor vehicles and factories ..... and is all very bad if you have lung condition
Thats why DEFRA have a daily air quality index for your area so you can see what the air qualty is going to be like in your area
