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Atmospheric Particulate Matter

Avatar Student, Writer, Scientist, Kenya's Ambassador to Tunza Eco-Generation and W.Y.A. member.
Yvonne Wabai
Member since November 8, 2015
  • 31 Posts
  • Age 22

Atmospheric particulate matter (APM), also referred to as particulate matter or particulates, is the sum of all particles liquid and solid suspended in air. To refer to the mixture of particulates and air, the term aerosol is used. An example of these particulates includes gaseous contaminants, smoke, smog, dust, pollen, mold spores, viruses and bacteria.


A study done by J. Karue, A.M. Kinyua and L. Njau in 1990-1991 in conjunction with University of Nairobi, the Centre for Nuclear Science Techniques, the Kenya Medical Research Institute and the Kenya Meteorological Department found a total of 9 elements that composed of 20% of Nairobi's particulate matter. These 9 elements were: potassium, calcium, titanium, manganese, iron, zinc, bromine, zirconium and lead with zinc, lead and bromine having the highest percentages. Some other particulates found included the common cold virus and pollutant gases such as carbon monoxide, carbon dioxide, sulphur oxides and nitrogen oxides.

While much of urban air pollution is as a result of motor vehicle emissions, residential wood combustion is the major source of pollutants in the rural areas due to the use of wood energy is used for cooking It is important to note that the emissions from wood burning are higher than from oil or gas and therefore the air in urban areas is more polluted than that in rural areas.

Additionally, a study carried out in 1996 by Elisaveta P. Petkova, Darby W. Jack, Nicole H. Volavka-Close and Patrick L. Kinney found that of all countries in Eastern Africa, Kenya had the highest level of particulate matter while Tanzania had the lowest. Between December 1993 and October 1994, the total suspended particulates were reported to be ranging between 30 to 80 micrograms per metre cubed of air. By 2010, this number had increased to above 200 micrograms per metre. The increase was a result of increased industrial activities as well as an increase in the usage of motor vehicles.

1. Viruses and pathogenic bacteria cause diseases in human beings, plants and animals.

2. Carbon monoxide, when inhaled, interferes with oxygen transport in the body leading to hypoxia (oxygen deficiency), resulting in death.

3. Most of these particulates are ozone-depleting substances (ODS). ODSs include carbon monoxide, nitrogen oxides, sulphur oxides, chlorofluorocarbons (CFCs), bromine, chlorine, halon, organohalogens and bromoflourocarbons. The ozone layer absorbs most of the sun's ultraviolet (UV) radiation. The more it's depleted, the more UV radiation the earth is exposed to. UV radiation, even in small quantities, is harmful when absorbed by living things because it causes mutations in the cells which result to abnormal growths, tumours and cancers. Furthermore, UV radiation can cause chemical particulates as well as free radicals in the atmosphere to react with each other causing an even more toxic atmosphere.

4. Acidic gases such as sulphur oxides and nitrous oxides are corrosive. When inhaled, they corrode the surfaces of the respiratory systems. They also burn holes through plants, and in extreme cases, buildings. When it rains, the acidic gases dissolve in the rainwater causing a phenomenon known as acid rain.

5. Deposition of metallic elements in the lungs, as well as in other organs of the body, causes inflammation and metallic poisoning.

6. Aerosols in the air scatter light, causing fog and smog conditions. These reduce visibility and have been responsible for a number of accidents on the roads, airports, and harbours.
7. Fine particles of aerosols get inside the stomata of the leaves and interfere with the plant perspiration. Corrosive aerosols canscotch the leaves, while dust layers on the leaves reduce photosynthesis. Without photosynthesis and/or perspiration, plants will die. Plants are the producers in every food chain and if the producers die off, the rest of the organisms die off too.

8. Inhalation of dust, pollen and/or mold spores causes disturbances in the respiratory tract. This results in an increase in the amount of mucous that lines the respiratory tract and this leads to infection. The disturbances may also result to constriction of the respiratory tubes, leading to the affected person being unable to breathe properly, if at all. Consequently, the number of people suffering from respiratory diseases and disorders increases.


There are many ways to reduce the amount of atmospheric particulates. These include:

1. Creating awareness on the situation. Being educated about the situation enables us to act appropriately, wisely and responsibly in order to come to eradicate the problem.

2. Using public transportation and carpooling to reduce the number of motor vehicles being used and thereby reducing motor vehicle emissions. Walking and cycling should be done where possible.

Additionally, we should favour hybrid vehicles such as Prius which have better fuel mileages as opposed to fuel guzzlers. Some countries, Britain for example, charge higher taxes on fuel guzzlers and offer tax subsidies for hybrid cars as well as zero-emission cars such as solar-powered cars.

3. Reducing and totally doing away with products that contain ODSs. Despite the signing of the Montreal Protocol in 1987, there are still plenty of products in the market that contain ODSs. Before buying a product, make sure to check the list of ingredients. If it has ODSs, make a conscious effort not to buy it and go for the products without ODSs.

4. Introducing industrial laws against pollution. There are many ways for industries to purify their waste but most fail to do so because they want to maximize profits. There is a big problem when we find ourselves prioritizing money over the environment. We have to realize that we need the environment, not the other way round. Much of the environmental pollution studies done in Kenya are in water, soil, and vegetation, but very little has been done on air/precipitation pollution. Because of this, there are laws dealing with air pollution are close to nonexistent.

5. Creating and using air purification systems. In fact, there are a number of air purification systems that are in development. Read about them here.

1. GREEN FACTS.2. Air Pollution in Kenya: A Report by J. Karue, A.M. Kinyua and L. Njau.3. Air Qual Atmos Health (2013) 6:603� DOI 10.1007/s11869-013-0199-6 Pages 603-6144. Wikipedia.

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