Natural Science 13 DLS – College of Saint Benilde Hand-out 9: The Atmosphere Lecturer: Mr. Jose Mari Balines Gonzales M.Sc. in I.T. for Natural Resources Management Objectives: To describe and discuss the components of the atmosphere. To determine the impact of human activities on the quality and structure of the atmosphere. To formulate ways and means to adopt existing air quality measures. Introduction What if one morning you went for a jog, and along the way you read an advisory on a warning sign saying, “Don’t jog, air polluted. Jog at your own risk!” Does it sound silly to think that this may one day happen? In August, 2004, then Health Secretary Manuel Dayrit cited results from a study conducted from January to May, 2003 involving the quality of air in Metro Manila. The study indicated that areas where air pollution is highest, cases of respiratory diseases also increased. Dayrit affirmed that there is a direct relationship between air quality and the people’s health, “if you live in a place where the air is bad outside, then you are also affected indoors. Outside, you could be inhaling lead mostly from motor vehicles. This affects the nervous system. You could also be affected by particulates that could get into the respiratory tract and can cause bronchitis.” Other cited respiratory illnesses linked to bad air were cough, colds, chest tightness, wheezing, sinusitis, acute bronchitis, pneumonia and asthma. Motor vehicles were reportedly the major source of particulate pollution in Metro Manila areas. Areas that were highly exposed to air pollution were Caloocan, Valenzuela and Quezon City. The report even went to say that “those who jog in the polluted areas of Quezon City may be doing more damage to their health due to the presence of pollutants.” When asked for what kind of advisory Dayrit may give out, he suggested a warning sign with the advisory mentioned above. (Manila Bulletin Online, 2006 – See Appendix A for details of this report) However, human health is not the only victim of air pollution. For us to determine what else is affected we must understand first what the atmosphere is and how it contributes in sustaining life here on Earth. This will also help us identify major human activities that inflict damage on the atmosphere. Hand-out 9: The Atmosphere 1 Natural Science 13 DLS – College of Saint Benilde Nature and Function of the Atmosphere It is a mixture of gases surrounding the Earth. 78% nitrogen 21% oxygen 01% carbon dioxide, methane, nitrous oxide Layers of the atmosphere, where each layer blend into each other (Fig.9-1). 1. Troposphere Closest to the lithosphere and hydrosphere, and is the most dense among the other layers of the atmosphere. Extends about 8 miles from the Earth’s surface. Contains: air we breathe, our weather systems. Where greenhouse effect occurs. 2. Stratosphere Extends from 8 to 30 miles. Where ozone is formed. Where most UV light is filtered out. Figure 9-1. Layers of the atmosphere. How far does the atmosphere stretch into space? In what layer of the atmosphere is it hottest? (Diagram downloaded using the Google search engine) 3. Mesosphere Extends about 30 to 50 miles. Absorbs gamma and X-rays. 4. Thermosphere Farthest from the Earth. Stretches out from 50 to 600 miles. Absorbs gamma and X-rays. What is an Electromagnetic Spectrum? It is the entire range of radiation (or energy) produced by the sun. It interacts with the atmosphere. Hand-out 9: The Atmosphere 2 Natural Science 13 DLS – College of Saint Benilde It consists of the following radiation (Fig.9-2). Gamma rays X-rays Ultraviolet (UV) rays Visible light (ROYGBIV) Infrared Microwave Radiowave Figure 9-2. The electromagnetic energy is the ray that comes from the sun and reaches the biosphere. However, not all of its parts reach the biosphere. From the illustration, determine what radiation of the sun’s rays reaches the biosphere? Why do you think these are the only ones allowed by the atmosphere? (Diagram downloaded using the Google search engine) Air Pollution Presence of impurities in the atmosphere which have negative effects on organisms and their habitats. Major sources: combustion, evaporation and friction. Kinds of pollutants: 1. Outdoor pollutants. 2. Indoor pollutants. Hand-out 9: The Atmosphere 3 Natural Science 13 DLS – College of Saint Benilde Major air pollutants and their sources. MAJOR POLLUTANTS Carbon monoxide Formaldehyde Paradichlorobenzene Methyl chloride Tetrachloroethylene Ammonia Hydrocarbons Asbestos Particulates Bacteria, fungi SOURCES Cigarette smoke, stoves/heaters, automobiles Particle board, furniture, carpeting, foam insulation Mothballs Paint thinner Dry-cleaning fluids Cleaning agents Solvents, adhesives Insulation, fire proofing materials Cigarette smoke, pollen, burning wood, coal Heating/cooling ducts Smog Smoke + fog. Also known as air pollution or dirty air. A combination of chemicals that may result in a murky, brown haze. Components of smog: COMPONENTS Carbon Monoxide Hydrocarbon Lead Nitrous Oxides Ozone Particulate Matter Smoke Soot Sulfur Dioxide DESCRIPTION Colorless, odorless, highly poisonous gas. Formed by the increased burning of fossil fuels. Also known as volatile gas compounds (VOCs) . Produced by chemical plants, dry cleaners, gas pumps, automobiles, bakeries (yeast), source of photochemical smog. Heavy metal particulate; results mainly from the use of leaded gasoline; also from paints, metal refineries, and the manufacture of lead storage batteries. Group of gases from power plants, metal refineries and automobiles; a major source of photochemical smog. A sharp smelling, pale-blue gas consisting of three oxygen atoms. Solid and liquid pollutants that exist as very small particles light enough to remain in the air. Includes dust, soot, ash, metals, mists and sprays. A form of air pollution consisting of particulate matter. A fine dispersion of black particles produced by increased combustion. Colorless gas emitted largely by industrial sources. It is the main cause of acid rain. Hand-out 9: The Atmosphere 4 Natural Science 13 DLS – College of Saint Benilde Photochemical Smog A kind of smog caused by chemical reaction in the air. The electromagnetic energy from the sun causes the chemical reaction. Reaction: NOx + O2 SUNLIGHT O3 (Ozone) Inversion Layer (or Temperature Inversion) A layer of warm air (in the atmosphere) lies over a layer of cooler air, trapping pollutants at ground level. Due to geographical and meteorological conditions like mountainous areas and cold weather (Fig.9-3). The Clean Air Act It is a federal law in the USA that forms the basis for the national air pollution control effort. This act includes national air quality standards for major air pollutants, air toxic standards, acid rain control measures, and enforcement provisions. This is an example of laws other countries may set in their respective territories. Figure 9-3. Inversion layer threatens human health. In what way? (Image downloaded using the Google search engine) Ozone (O3) A gas made up of molecules that have three oxygen atoms. Mainly produced in the stratosphere. Process of formation: Sun’s electromagnetic energy cause normal oxygen molecules (O2, oxygen molecule we inhale) in the atmosphere to bond with a single oxygen atom (Fig.9-4). Figure 9-4. Ozone molecules form in the atmosphere to create the ozone layer. This layer protects us from the harmful UV rays of the sun. (Diagram downloaded using the Google search engine) Hand-out 9: The Atmosphere 5 Natural Science 13 DLS – College of Saint Benilde Concentration of this gas is called Ozone Layer, which shields the Planet Earth from UV radiation. Depending on its location, sometimes referred as: Good Ozone – produced in the stratosphere forming the Ozone Layer. Bad Ozone – major component of photochemical smog and is formed when air pollutants (such as NOx) and oxygen, plus sunlight, interact. Ozone depletion: - Decrease in the amount of ozone in the stratosphere. - Sometimes referred to as the thinning or “hole” in the ozone. - Caused by human activities that involve release of CFCs, or chloroflourocarbons (Fig.9-5). Figure 9-5. The diagram above demonstrates how CFCs contribute in destroying ozone molecules in the atmosphere. With low concentrations of ozone molecules in the atmosphere it results in the thinning of the ozone layer. (Diagram downloaded using the Google search engine) Montreal Protocol: - An international policy to reduce worldwide CFC emissions. - Formerly known as the Montreal Protocol on Substances that Deplete the Ozone Layer. - This protocol was signed by the world’s leading CFC-producing nations at Montreal, Canada in 1987. - After two more meetings (due to further research findings) the nations agreed to phase out CFCs and other ozone-destroying chemicals. Greenhouse Effect Normal warming of the Earth. Due to trapping of heat energy by certain greenhouse gases in the atmosphere. A natural process to keep the temperature of the planet habitable. Hand-out 9: The Atmosphere 6 Natural Science 13 DLS – College of Saint Benilde (b) (a) Figure 9-6. The greenhouse effect is a normal phenomenon in the biosphere. (a) A normal greenhouse tends to trap a portion of the heat from the sun to help regulate temperature thereby aiding plants grow in cold countries. (b) Similarly, the earth is capable of such a mechanism to regulate global temperature. What do you think will happen if this mechanism is enhanced, or hastened? (Diagrams downloaded using the Google search engine) Greenhouse gases: GREENHOUSE GAS DESCRIPTION Carbon Dioxide Chlorofluorocarbons (CFCs) Methane Nitrous Oxides A group of gases consisting of chlorine, fluorine and carbon atoms. The only greenhouse gas that is not naturally produced. Its primary use: refrigerants and aerosol propellants. Has the greatest ability to trap infrared radiation compared to other greenhouse gases. A natural gas produced from: Stomachs of cattle Burning of fossil fuels Termite activities Decomposition of landfills (garbage) Laughing gas Used as dental anesthetic Results mainly from nitrogen-based fertilizers Also produced by vehicles and industrial processes Trace gases Water Vapor Enhanced greenhouse effect: - Increased amount of greenhouse gases in the atmosphere. - Cause greater retention of infrared radiation. Hand-out 9: The Atmosphere 7 Natural Science 13 - DLS – College of Saint Benilde Increase is due to: 1. Burning of fossil fuels. 2. Deforestation. 3. Use of nitrogen-based fertilizers. 4. Raising cattle. 5. Decomposition of garbage in land fills. 6. Use of refrigerators and air conditioners. Global warming - Gradual warming of the Earth as a result of the enhanced greenhouse effect. Earth Summit: - Meeting of world leaders in 1992 at Rio de Janeiro, Brazil. - Discussed only environmental issues, including global warming. END References: Bush, M.B. 1997. Ecology of A Changing Planet. Prentice Hall, Upper Saddle River, New Jersey, USA. Brewer, R. 1994. The Science of Ecology, 2nd Ed. Saunders College Publishing, USA. Cunningham, W.P. and Cunningham, M.A. 2006. Principles of Environmental Science, 3rd Edition. McGraw-Hill Companies. New York, USA. Enger, E. and Smith B. 2006. Environmental Science: A Study of Interrelationships, Tenth Edition. McGraw-Hill Companies, Inc. New York, USA. Web sites: The Manila Bulletin Online http://www3.mb.com.ph/issues/2004/08/19/MTNN2004081916659.html Hand-out 9: The Atmosphere 8 Natural Science 13 DLS – College of Saint Benilde APPENDIX A Respiratory diseases linked to city pollution By Jenny F. Manongdo Respiratory diseases have increased over the past year due to highly polluted air in Metro Manila, the Department of Health (DoH) reported yesterday. Health Secretary Manuel Dayrit cited the Public Monitoring Study of the Metro Manila Air Quality Improvement Sector Development Program supported by the Asian Development Bank (ADB). The study presented the high, medium and low risk areas for exposure to air pollution. Dayrit said that there is a direct relationship between air quality and the people’s health. "If you live in a place where the air is bad outside, then you are also affected indoors. Outside, you could be inhaling lead mostly from motor vehicles. This affects the nervous system. You could also be affected by particulates that could get into the respiratory tract and can cause bronchitis." He also highlighted smoking as a household health risk that can contribute to respiratory problems. The study listed Caloocan, Valenzuela and Quezon City as areas highly exposed to air pollution while Pasig, Pateros and Taguig fall under the medium risk areas. Antipolo was solely considered as an exposure with the lowest exposure to air pollution. Professor Elma Torres of the University of the Philippines (UP) Public Health said that Antipolo has a low prevalence of air pollution because it is far from Metro Manila while Valenzuela is on the high level because it is an industrial zone. The study was done from January to May 2003, and indicated that motor vehicles are the major source of particulate pollution in Metro Manila areas highly exposed to air pollution also have more cases of persons with cough, colds, chest tightness and wheezing. Similarly, these areas have a large number of persons with respiratory diseases such as sinusitis, acute bronchitis, pneumonia and asthma. The DoH reported 694,836 cases of bronchitis nationwide in 2001. The study said that in 2002, there is a 10,000 excess cases of the disease that may be attributed to air pollution," Torres said. Dayrit recommended the installation of monitoring equipment for the quality of air in the country. If the equipment prompts unhealthy air levels, then advisories will be put up in areas where air pollution is at its peak. But Dayrit said that level of air pollution varies according to time of the day. It is highest during the day where there are a lot of vehicles moving and industries that are operating. Hand-out 9: The Atmosphere 9 Natural Science 13 DLS – College of Saint Benilde He said that advisories are important to preserve the health of the people. Those who jog in the polluted areas of Quezon City may be doing more damage to their health due to the presence of pollutants. Asked what kind of advisories he may give out, Dayrit said that a warning sign may be placed in these areas that may likely say "Don’t jog, air polluted. Jog at your own risk." http://www3.mb.com.ph/issues/2004/08/19/MTNN2004081916659.html Hand-out 9: The Atmosphere 10