Understanding Pollution and Its Impact on the Environment

• Pollution is the addition of a substance or an agent to an environment by human activity, at a rate greater than that at which it can be rendered harmless by the environment and which has an appreciable effect on the organism within it.

• Basically… contamination of nature which affects living organisms.

• Substances exposed to the atmosphere and littering by humans.

POINT SOURCE POLLUTION (Coming from a direct source)

• The pollutants are coming from clear identifiable sources: sewage into a river.

• Easier to see who is polluting.

• Easier to manage and monitor.
  

NON-POINT SOURCE POLLUTION (NPS)

• Release of pollutants from numerous sources: car fumes, etc.

• Almost impossible to detect the origins of the pollutants.

• Rain can collect various forms of nitrates and phosphates and help them travel through soil.

1. Can travel kilometers before going into a body of water.

2. Increase of concentration of nitrates and phosphates in water.

3. Eutrophication occurs.

4. Not easy to spot which farmer is using too much fertilizer (nitrates and phosphates).

• Air pollution can be carried by the wind hundreds of kilometers: limit use of fertilizers, monitoring industry emissions.
  

POLLUTANTS RELEASED BY HUMAN ACTIVITIES

• Primary pollutants:
  

1. Goes into the atmosphere directly from the combustion of fossil fuels.

2. Can cause headaches, fatigue, and even death.
   

• Secondary pollutants
  

1. Primary pollutants changed by chemical and/or photochemical reactions in the atmosphere.

2. Same cause… or worse: headaches, eutrophication, acid rain…

Photochemical Smog: a combination of primary and secondary pollutants: pollutants cause pollution.

PRIMARY POLLUTANTS

• Carbon Monoxide (CO), Odorless, colorless, poisonous gas, created by incomplete combustion (especially bad with older cars).

• Oxides of nitrogen (NOx, NO), No nitric oxide, emitted directly by autos, industry.

• Sulfur oxides (SOx), produced largely through coal burning, responsible for acid rain problems.

• Volatile organic compounds (VOCs), highly reactive organic compounds, released through incomplete combustion and industrial sources, particulate matter (dust, ashes, salt, particles)
  

SECONDARY POLLUTANTS

• Sulfuric and H2SO4, can cause respiratory problems.

• Nitrogen dioxide NO2, gives air a brownish coloration.

• Ozone O3, colorless gas, has a sweet smell, is an oxidizing agent-lung tissue to rubber products.