Environmental Science FEA 115 Lecture Notes PDF

2 NATURE OF ENVIRONMENTAL SCIENCE FEA 115 DEPARTMENT OF ARCHITECTURE, UNIVERSITY OF IBADAN DR. A. S. AJAYI POLLUTION CONTROL  POLLUTION  This is the introduction of contaminants into the environment that cause harm or discomf...

2 NATURE OF ENVIRONMENTAL SCIENCE FEA 115 DEPARTMENT OF ARCHITECTURE, UNIVERSITY OF IBADAN DR. A. S. AJAYI POLLUTION CONTROL  POLLUTION  This is the introduction of contaminants into the environment that cause harm or discomfort to humans or other living organisms or that damages the environment which can come in the form of chemical substances or energy such as noise, heat or light. ENVIRONMENTAL POLLUTION  The contamination of physical and biological components of the earth/atmosphere system to such an extent that normal environmental processes are adversely affected.  TYPES OF ENVIRONMENTAL POLLUTION  Air pollution  Water pollution  Noise pollution  Thermal pollution  Soil / land pollution  Radioactive pollution AIR POLLUTION  Air Pollution is an atmospheric condition in which certain substances like gases , particulate matter , radioactive substances etc. are present in concentrations which can cause undesirable effects on human environment. SOURCES OF AIR POLLUTION  mobile sources – such as cars, buses, planes, trucks, and trains  stationary sources – such as power plants, oil refineries, industrial facilities, and factories  area sources – such as agricultural areas, cities, and wood burning fireplaces  natural sources – such as wind-blown dust, wildfires, and volcanoes  CLASSIFICATION OF AIR POLLUTANTS  Air pollutants may be natural, such as wildfires, or may be synthetic (manmade). Air pollutants are classified as primary pollutants and secondary pollutants.  Primaryair pollutants are emitted directly into the atmosphere by the original source  Secondary air pollutants are formed because of reactions between primary pollutants and other elements in the atmosphere, such as the ozone. The common air pollutants are: · Carbon Monoxide - Carbon monoxide is a colorless, odorless gas. Carbon monoxide can be present in car exhaust and smoke. Carbon monoxide deprives humans of their oxygen supply, which causes headaches, fatigue, impaired vision, and even death. · Sulfur Dioxide - Sulfur dioxide is produced when coal and fuel oils are burned and is also present in power plant exhaust. Exposure to sulfur dioxide narrows the airways in the respiratory system, which causes wheezing and shortness of breath. · Nitrogen Dioxide - Nitrogen dioxide is both a primary and secondary air pollutant. Nitrogen dioxide is created when nitrogen reacts with oxygen in the atmosphere. Nitrogen dioxide can cause respiratory infections and other respiratory problems. · Particulate Matter - Particulate matter contains particles of different sizes that are released into the atmosphere from various sources, including fossil fuels, dust, smoke, and fog. Particulate matter can accumulate in the respiratory system, which can aggravate the heart and lungs and increase the risk of respiratory infections. · Ground-Level Ozone – Ground-level ozone is formed from automobile, power, and chemical plant exhausts. Ground-level ozone irritates the respiratory system and causes asthma by reducing lung function. · Smog - Smog is the combination of gases with water vapor and dust and forms when heat and sunlight react with gases, which is known as photochemical smog.  NATURE OF AIR POLLUTION  The pollutants present in the air have been identified and categorized so that appropriate measures can be adopted to combat pollution and they are:  Solid matter: light, fine and coarse particles, hydrocarbons, aromatics.  Liquid substances: smoke, soot, fly-ash, dust, mist, fumes, organic acids, inorganic acids.  Gases: sulfur dioxide, nitrogen oxide, carbon dioxide.  ADVERSE EFFECTS OF AIR POLLUTION  Health problems: optic irritation(PAN), bronchitis, lung carcinoma, change in blood chemistry, skin cancer, etc. in human beings.  Livestock damage: injury n death due to arsenic metals and fluorides.  Agriculture damage: leaf damage, stunting of growth, decreased size and less yield of fruit and destruction of flowers.  Material damage: damage of structural metals, surface coatings, fabrics, weathering of stone in buildings and monuments  Effect on climate: increase in carbon dioxide enhances the temperature of the earth melting polar ice caps and glaciers.  AIR POLLUTION CONTROL Pollution control is the process of reducing or eliminating the release of pollutants into the environment. It is regulated by various environmental agencies which establish pollutant discharge limits for air, water, and land. Air pollution control strategies can be divided into two categories, the control of particulate emissions and the control of gaseous emissions. There are many kinds of equipment which can be used to reduce particulate emissions. Physical separation of the particulates from the air using settling chambers, cyclone collectors, impingers, wet scrubbers , electrostatic precipitators, and filtration devices, are all processes that are typically employed. AIR POLLUTION CONTROL WATER POLLUTION  WATER POLLUTION Water pollution can be defined as the contamination of water bodies. Water pollution is caused when water bodies such as rivers, lakes, oceans, groundwater and aquifers get contaminated with industrial and agricultural effluents. When water gets polluted, it adversely affects all lifeforms that directly or indirectly depend on this source. The effects of water contamination can be felt for years to come.  SOURCES OF WATER POLLUTION The key causatives of water pollution are:  Urbanization.  Deforestation.  Industrial effluents.  Social and Religious Practices.  Use of Detergents and Fertilizers.  Agricultural run-offs- Use of insecticides and pesticides One of the primary causes of water pollution is the contamination of water bodies by toxic chemicals. As seen in the image in slide 14, the dumped plastic bottles, tins, water cans and other wastes pollute the water bodies. These result in water pollution, which harms not just humans, but the whole ecosystem. Toxins drained from these pollutants, travel up to the food chain and eventually affect humans. In most cases, the outcome is destructive to only local population and species, but it can have an impact on a global scale too. Nearly 6 billion kilograms of garbage is dumped every year in the oceans. Apart from industrial effluents and untreated sewage, other forms of unwanted materials are dumped into various water bodies. These can range from nuclear waste to oil spills – the latter of which can render vast areas uninhabitable.  Effects Of Water Pollution The effect of water pollution depends upon the type of pollutants and its concentration. Also, the location of water bodies is an important factor to determine the levels of pollution. 1. Water bodies in the vicinity of urban areas are extremely polluted. This is the result of dumping garbage and toxic chemicals by industrial and commercial establishments. 2. Water pollution drastically affects aquatic life. It affects their metabolism, behavior, causes illness and eventual death. Dioxin is a chemical that causes a lot of problems from reproduction to uncontrolled cell growth or cancer. This chemical is bio- accumulated in fish, chicken and meat. Chemicals such as this travel up the food chain before entering the human body. 3. The effect of water pollution can have a huge impact on the food chain. It disrupts the food-chain. Cadmium and lead are some toxic substances, these pollutants upon entering the food chain through animals (fish when consumed by animals, humans) can continue to disrupt at higher levels. 4. Humans are affected by pollution and can contract diseases such as hepatitis through faecal matter in water sources. Poor drinking water treatment and unfit water can always cause an outbreak of infectious diseases such as cholera, etc. 5. The ecosystem can be critically affected, modified and de-structured because of water pollution.  WATER POLLUTION CONTROL Water pollution, to a larger extent, can be controlled by a variety of methods. Rather than releasing sewage waste into water bodies, it is better to treat them before discharge. Practicing this can reduce the initial toxicity and the remaining substances can be degraded and rendered harmless by the water body itself. If the secondary treatment of water has been carried out, then this can be reused in sanitary systems and agricultural fields.  WATER POLLUTION CONTROL A very special plant, the Water Hyacinth can absorb dissolved toxic chemicals such as cadmium and other such elements. Establishing these in regions prone to such kinds of pollutants will reduce the adverse effects to a large extent.  WATER POLLUTION CONTROL Some chemical methods that help in the control of water pollution are precipitation, the ion exchange process, reverse osmosis, and coagulation. As an individual, reusing, reducing, and recycling wherever possible will advance a long way in overcoming the effects of water pollution. TO BE CONTINUED IN MODULE 3