2 Major components of air: Nitrogen (78%) and oxygen (21%)

Atmospheric Ecosystems Air Quality and Health Atmospheric Ecosystems

How Pollutants Enter Organisms A contaminant is a substance in an environment that occurs in concentrations that are higher than what would be expected.

A pollutant, is a substance in an environment that is harmful or could become harmful to people or other living things. Anything that is a pollutant is therefore a contaminant, but not everything that is a contaminant is a pollutant.

Pollutants can enter the body of an organism in one of three ways: 1. Pollutants can be ingested (eaten). 2. Pollutants can be absorbed through the organism’s surface layer, such as skin. 3. Pollutants can be inhaled (breathed in).

Food which has been sprayed Bioaccumulation in animals Pollutants can be ingested by: Food which has been sprayed Bioaccumulation in animals water

Ingested pollutants can irritate or damage the inner lining of the digestive system In other cases, the pollutants can be absorbed by the lining of the small intestine and carried by the blood to other organs, where they can cause harm.

Pollutants can be absorbed by: The skin The eyes

What are some pollutants that can be inhaled? 3. Pollutants can be inhaled (breathed in). What are some pollutants that can be inhaled? dust smoke gases

Inhaled substances can directly damage the lungs and the airway tubes that lead to them. Inhaled substances can also enter blood vessels (by diffusion) and be carried by the blood to other organs, where they can cause harm.

Major Air Pollutants Expelled from animals volcanoes An air pollutant is any gas or particle in the atmosphere that can cause harm or damage to organisms and to the environment. Air pollutants can come from natural sources as well as from human activities. Natural sources can include: Decaying plants volcanoes Expelled from animals

Pollutants that result from human activities are known as anthropogenic sources. Air pollutants from anthropogenic sources are classified as primary or secondary. Primary air pollutants are substances released directly into the atmosphere in amounts that pose a threat to health.

Refer to Table on the handout. This table shows the five primary air pollutants. On the back of the page, please write: As part of their air quality monitoring systems, Environment Canada and the provinces and territories refer to these air pollutants as criteria air contaminants (CACs).

Secondary air pollutants are the result of interactions between primary air pollutants and other primary air pollutants and other gases and particles that are naturally present in the atmosphere. The best example: smog

How Smog Forms The haze above or near densely populated areas. The haze is called smog – or photochemical smog. It forms when pollutants from the exhaust pipes of cars and trucks and the smokestacks of industrial plants react chemically in the presence of sunlight. This reaction takes place up to about 1 km above the ground.

Inversion: where air at ground level is trapped by warmer air above In 1952 a five-day temperature inversion trapped smog (from burning coal) killed more than 4000 people.

One of the main compounds that forms in the reaction is ground level ozone. Ground level ozone can irritate eyes, nose, throat, and lungs of people and other animals. It also has harmful effects on plants.

Do not confuse ground level ozone, which occurs close to Earth’s surface, with the ozone layer, which is nearly 30 km above Earth’s surface. The ozone in the ozone layer is beneficial to life on Earth, because it filters out harmful ultraviolet (UV) radiation. Ground level ozone, on the other hand, can cause harm to life.