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Air pollution can be defined as the presence of any harmful material in the air and the atmosphere that can cause damage to human beings and other living organisms. * Air pollution could also be in the form of disturbances to the normal composition of the air such that there is an undesired effect on the environment or living things. * Under normal circumstances, the earth’s atmosphere consists of nitrogen (??78%), oxygen (??21%), small amounts of carbon dioxide (??0. 03%) and other gases like water vapor and some tiny particles of liquid/solid matter like dust.
Natural Sources Of Air pollution A. Volcanic Eruptions * Carbon dioxide and sulfur dioxide are the primary gases that are released during volcanic eruptions. Other gases like hydrogen sulfide, hydrogen chloride, hydrogen fluoride, carbon monoxide, halocarbon and some metal chlorides are also released into the atmosphere. * Besides the volcanic gases, there is also volcanic ash. Volcanic ash can move hundreds to thousands of miles downwind from a volcano. B. Forest Fires * All forest fires emit carbon monoxide, sulfur dioxide, nitrogen dioxide, ozone, and particulate matter.
C. Wind Erosion * Acts by picking up loose particles of dirt and soil, mostly where plants are o sparse to hold the soil together. D. Radon Expulsion * Nuclear elements like uranium are found inside the earth’s surface, and when these elements decompose they release a noble gas known as Radon into the atmosphere. E. Methane Expulsion * Farm animals like cattle release methane into the atmosphere during the end stages of their digestive cycles. * Methane is also produced by the natural rotting of plants.
Factors Affecting Air Quality such as Weather, Wind and Geography * Turbulence mixes pollutants into the surrounding air. * Wind speed also contributes to how quickly pollutants are carried away room their original source. Inversions – Temperature inversions occur when a stable layer of warm air overlays cooler air, reversing the normal temperature decline with increasing height, and preventing convection currents from dispersing pollutants. Dust Domes and Heat Islands – Sparse vegetation and large amounts of concrete and glass create warm, stable air masses, heat islands, over large cities.
Concentrates pollutants in a “dust dome”. * An urban heat island (CHI) is a metropolitan area that is significantly warmer than its surrounding rural areas due to human activities. The dome-shaped formation of stagnant and polluted air above a city is known as a dust dome.
Welfare Effects: contribute to the formation of smog. 2. Sulfur Dioxide Description: colorless gas that dissolves in water vapor to form acid, and interact with other gases and particles in the air. Sources: petroleum refineries, manufacture of sulfuric acid, coal-fired power plants. Health Effects: eye irritation, wheezing, chest lightness, shortness of breath, lung damage. Welfare Effects: contribute to the formation of acid rain, plant and water damage and aesthetic damage. 3. Nitrogen Dioxide Description: reddish, brown, highly reactive gas.
Sources: motor vehicles, electric utilities, and other industrial Health Effects: irritation of the lung and respiratory symptoms (e. G. , cough, chest pain, difficulty breathing) Welfare Effects: contribute to the formation of smog, acid rain and global arming. 4. Ozone Description: gaseous pollutant when it is formed in the troposphere. Sources: vehicle exhaust and certain other fumes. Formed from other air pollutants in the presence of sunlight. Health Effects: eye and throat irritation, coughing, respiratory tract problems, asthma, lung damage Welfare Effects: plant and ecosystem damage 5.
Particulate Matter (PM) Description: very small particles of soot, dust, or other matter. Sources: diesel engines, power plants, industries, windblown dust, wood stoves. Health Effects: eye irritation, asthma, bronchitis, lung damage, cancer, cardiovascular effects. Welfare Effects: atmospheric deposition, aesthetic damage.