Table of Contents
TOPIC| PAGE NUMBER(S)|
DEFINITION | |
COMMON AIR POLLUTANTS | |
MAN-MADE SOURCES| |
NATURAL SOURCES| |
TECHNICAL BRIEF OF THE GAME| |
REFERENCES | |
This is also known as atmospheric pollution. It can be classified as ambient (outdoor) air and indoor air. Many materials that are considered contaminants and pollutants are found naturally existing in the atmosphere. A definition for air pollution must cover the various parameters that exist and could pose a threat on human health and the environment. Air pollution according to the World Health Organization can be defined as the presence of materials in the air which are harmful to the living beings when they cross their threshold concentration levels. Essentially this means that these contaminants can exist in the environment as long as they pose no threat to any organism that depends on the interaction of the atmospheric environment.
COMMON AIR POLLUTANTS
Some of the most common air pollutants can be classified as ground level Ozone, Particulate matter, Carbon monoxide, Nitrogen oxides, Sulphur oxides and Lead.
Ground level Ozone – these are formed by photochemical (in the presence of sunlight) reactions in the atmosphere between oxides of nitrogen (NOx) and volatile organic compounds. Some sources of ground level ozone are industrial plant emissions, motor vehicle exhaust etc. Many urban areas have high ozone level densities. Inhalation can trigger chest pain, coughing, throat irritation and congestion.
Particulate Matter – these are named after the particle size by diameter usually pm10 and pm2.5 (measured in micrometers). Pm10 are inhalable coarse particles made up of various components and can be trapped by nostril hairs. Pm2.5 is much finer particles and can enter deeper into the respiratory system. These can cause increased respiratory symptoms, decreased lung function, irregular heartbeat and nonfatal heart attacks (they can diffuse into bloodstream).
Carbon Monoxide (CO) – this is a colorless and odourless gas that is very lethal once exposed to it continuously over a long period of time. It is emitted from complete and incomplete combustion processes. Motor vehicles are usually associated with carbon monoxide emissions. CO can cause reduced oxygen delivery to organs and tissues and even death.
Nitrogen Oxides – this is a group that contains three highly reactive gases i.e. nitrogen dioxide, nitrous oxide and nitric acid. This component is closely monitored since it forms quickly and is associated with photochemical reactions to form ozone. Diverse respiratory effects including airway inflammation and increased respiratory symptoms in people with asthma can be due to NOx exposure.
Sulphur oxides – these reactive gases are found mainly in the burning of fossil fuels and their range of sources can be from small vehicles to large ships and locomotives, including industrial plants etc. These also cause respiratory effects, and lead to bronchoconstriction.
Lead – this is a metal found naturally as well as manufactured products. Lead emissions today are found from ore and metals processing. Lead is distributes in the body by blood and accumulates in bones. It is responsible for retarding the nervous system, kidney function, immune system, reproductive and developmental systems and the cardiovascular system.
The earth is capable of cleaning itself from pollution but manmade pollutants have become to numerous for the earth’s natural mechanism to remove. Some well-known pollution that exists today is burning of fossil fuels, smog, landfills, pesticides and aerosol sprays.
The burning of fossil fuel is a very commonly existing cause of air pollution, especially in the urban areas. When fossils are...