Chemistry of the Atmosphere Reporters: Aberca, Marcus John A. Amores, Kian Shane D. Aytalin, Lindsey Fatima I. Bocalan, John Mark Barlongay, Mark Kenneth S. Caadan, Francine Reigne L. Cruz, Byron Ryan F. Dinglasan, James Red Dulce, Ralph Klarenz T. Feraro, Mark Daven H. What is Chemistry of the Atmosphere? • • • • • • Atmospheric Chemistry is the branch of atmospheric science. It focused on the process within Earth’s atmosphere. It consists of complex interactions of elementary reactions. Study the chemical composition of the natural atmosphere. Reciprocal interactions between the atmosphere and biosphere. Change in chemical and physical characteristics of the atmosphere. Chemistry of the Atmosphere Atmospheric chemistry plays an important role in determining the current state and the predictions of the future state of earth’s climate because a large number of agents that force earth’s climate are chemically active; it processes in the atmosphere determine the abundances and properties of atmospheric forcing agents. Particularly, it is genuinely for the species that need to be addressed for influencing the course of the earth’s climate in the near future. Layers of the Atmosphere • Troposphere • Stratosphere • Mesosphere • Thermosphere • Exosphere Troposphere The lowest layer of our atmosphere. Most of the mass (about 75-80 %) of the atmosphere is in the troposphere, most types of clouds are found in the troposphere and all weather occurs within this layer. The troposphere extends upward to about 10 km (6.2 miles or about 33,000 feet) above the sea level. The layer immediately above the troposphere is called the stratosphere; the boundary between the troposphere and stratosphere is called “tropopause”. Stratosphere The infamous ozone layer is found here. The bottom of the stratosphere is around 10 km (6.2 miles or 33,000 feet) above the ground at middle latitudes. The top of the stratosphere occurs at an altitude of 50 km (31 miles). Ozone, an unusual type of oxygen molecule that is relatively abundant in the stratosphere, heats this later as it absorbs energy from incoming ultraviolet radiation from the Sun. The upper boundary is called the stratopause. Mesosphere Where most of the meteors burn. The mesosphere is directly above the stratosphere and below the thermosphere; it extends from about 50 to 85 km (31 to 53 miles) above our planet. The coldest temperature in Earth’s atmosphere , about -90 degrees (-130 Fahrenheit) are found near the top of this layer; temperature decreases with height throughout the mesosphere. The boundary between the mesosphere and the thermosphere above it is called mesopause. Thermosphere It is the layer of very rare air. It extends from about 90 km (56 miles) to between 500 and 1,000 km (311 to 621 miles) above our planet. Solar activity strongly influences temperature in the thermosphere; it goes about 200 degrees (360 Fahrenheit) hotter in the daytime than at night, and roughly 500 degrees (900 Fahrenheit) hotter when the Sun is very active. The boundary between the thermosphere and exosphere above called the thermopause. Exosphere The uppermost layer of our atmosphere. Air in the exosphere is extremely thin – in many ways it is almost the same as the airless void of the outer space. The outmost limit of the exosphere places the uppermost edge of the Earth’s atmosphere around 190,000 km (120,000 miles), about halfway to the moon. The bottom of the exosphere is sometimes also referred to as the exobase. Functions of the Atmosphere • Supports life. • Protects living things from the harmful rays of the Sun. • Regulates the temperature in Earth. • Facilitates the water cycle. • Brings weather and causes weathering of rocks. • Allows sound to travel. Composition of the Atmosphere The atmosphere is composed of mix different gases such as: Nitrogen – 78% Oxygen – 21% Argon – 0.9 % Gases like carbon dioxide, nitrous oxides, methane, and ozone are trace gases that account for about a tenth of one percent of the atmosphere. Stratospheric Chemistry Stratospheric chemistry became environmental chemistry in the early 1970’s when scientists studied the potential stratospheric effects of supersonic aircraft (Crutzen, 1970; Johnston, 1971). They realized that human activity could affect the chemistry of this cold, remote region 10 to 40 km above the Earth. Of greatest concern was the destruction of stratospheric ozone, Earth’s protective shield against solar ultraviolet light. This concern sparked a flurry of activity that in 1987 led to an international treaty, the Montreal Protocol, for controlling the production and use of man-made chlorofluorocarbons (CFCs) that affect stratospheric ozone. The results from this simple model were later found to differ from the observed ozone in two ways. First, the calculated average total ozone column is more than twice as large as measured (Brewer and Wilson, 1968). This difference indicates a problem with the chemistry. Second, the model predicts that ozone concentrations should be largest in the tropics, where the ozone production is greatest whereas observations have shown that the ozone amount is greatest at high latitudes (Duetsch, 1968). This second difference indicates a problem with ozone transport. The Structure of the Stratosphere The stratosphere extends from the tropopause, a temperature minimum near 15 km in the tropics and 10 km at high latitudes, to the stratopause, a temperature maximum, at about 50 km. Temperatures at the tropopause are generally 190-215 K, while temperatures at the stratopause are 240-250 K. In the wintertime polar stratosphere, temperatures can drop to 175-180 K. Although stratospheric temperatures increase everywhere with height, the temperature values depend upon the location and the season, particularly in the lower stratosphere and upper stratosphere. Ozone Formation Stratospheric ozone is formed naturally by chemical reactions involving solar ultraviolet radiation (sunlight) and oxygen molecules, which make up 21% of the atmosphere. In the first step, solar ultraviolet radiation breaks apart one oxygen molecule (O2) to produce two oxygen atoms (2 O). In the second step, each of these highly reactive atoms combines with an oxygen molecule to produce an ozone molecule (O3). These reactions occur continually whenever solar ultraviolet radiation is present in the stratosphere. As a result, the largest ozone production occurs in the tropical stratosphere. So here is the figure that shows how Stratospheric ozone form. Tropospheric Formation Near Earth’s surface, ozone is produced by chemical reactions involving naturally occurring gases and gases from pollution sources such as household activities, factories, agriculture and transport. Ozone production reactions primarily involve hydrocarbon and nitrogen oxide gases, as well as ozone itself, and all require sunlight for completion. Fossil fuel combustion is a primary source of pollutant gases that lead to tropospheric ozone production. So here is the figure that shows how Tropospheric ozone form. Ozone Destruction It is gradually thinning of earths ozone layer in the upper atmosphere. Caused by the release of chemical compounds containing gaseous chlorine or bromine from industry and other human activities. Human activities with chlorofluorocarbons (CFCs) molecules is recognized to be one of the major source of chlorine. Common examples are the use of chlorine gases to disinfect swimming pools and wastewater, fossil fuel burning, and various industrial processes. Hydrofluorocarbons (HFC’s) activities such as refrigeration, air-conditioning, and insulating foams also destroys the upper atmosphere. Ways to Protect the Atmosphere Protecting the atmosphere is a broad and multidimensional endeavor that involving various sectors of economic activity, hence the options and measures will be described later are recommended for consideration and, as appropriate, implementation by those in authority and other bodies in their efforts to protect the atmosphere. The actions in protecting the atmosphere includes the following programs: 1. Address the uncertainties: Improving the scientific basis for decision-making. 2. Promote Sustainable Development a. Energy Development, Efficiency, and Consumption b. Transportation c. Industrial Development d. Terrestrial and Marine Resource Development and Land Use 3. Prevention of Stratospheric Ozone Depletion 4. Transboundary Atmospheric Pollution Address the Uncertainties: Improving the Scientific Basic for Decision-Making Activities: 1. Promote research related to the natural processes affecting and being affected by the atmosphere, as well as the critical linkages between sustainable development and atmospheric changes, including impacts on human health, ecosystems, economic sectors, and society. 2. Ensure a more balanced geographical coverage of the Global Climate Observing System and its components, including the Global Atmosphere Watch, by facilitating the establishment and operation of additional systematic observation stations, and by contributing to the development, utilization, and accessibility of these databases. 3. Promote cooperation in the following: a. The development of early detection systems concerning changes and fluctuations in the atmosphere. b. The establishment and improvement of capabilities to predict such changes and fluctuations and to assess the resulting environmental and socio-economic impacts. 4. Cooperate in research to develop methodologies and identify threshold levels of atmospheric pollutants, as well as atmospheric levels of greenhouse gas concentrations, that would cause dangerous anthropogenic interference with the climate system and the environment as a whole, and the associated rates of change that would not allow ecosystems to adapt naturally. 5. Promote, and cooperate in the building of scientific capacities, the exchange of scientific data and information, and the facilitation of the participation and training of experts and technical staff, particularly of developing countries, in the fields of research, data assembly, collection and assessment, and systematic observation related to the atmosphere. Promote Sustainable Development: Energy Development, Efficiency, and Consumption Activities: 1. Cooperate in identifying and developing economically viable, environmentally sound energy sources to promote the availability of increased energy supplies to support sustainable development efforts. 2. Promote the development at the national level of appropriate methodologies for making integrated energy, environment, and economic policy decisions for sustainable development, through environmental impact assessments. 3. Promote the research, development, transfer and use of improved energy-efficient technologies and practices, including endogenous technologies in all relevant sectors, giving special attention to the rehabilitation and modernization of power systems, with particular attention to developing countries. 4. Promote the research, development, transfer and use of technologies and practices for environmentally sound energy systems, including new and renewable energy systems, with particular attention to developing countries. 5. Promote the development of institutional, scientific, planning and management capacities, particularly in developing countries, to develop, produce and use increasingly efficient and less polluting forms of energy. Promote Sustainable Development: Transportation Activities: 1. Develop and promote, cost-effective, more efficient, less polluting, and safer transport systems, particularly integrated rural and urban mass transit, as well as environmentally sound road networks, taking into account the needs for sustainable social, economic and development priorities, particularly in developing countries. 2. Facilitate at the international, regional, subregional, and national levels access to and the transfer of safe, efficient, including resource-efficient, and less polluting transport technologies, particularly to the developing countries, including the implementation of appropriate training programs. 3. Strengthen efforts in collecting, analyzing, and exchanging relevant information on the relation between environment and transport, with particular emphasis on the systematic observation of emissions and the development of a transport database. 4. Evaluate and promote cost-effective policies or programs, including administrative, social, and economic measures, in order to encourage use of transportation modes that minimize adverse impacts on the atmosphere. 5. Develop or enhance mechanisms to integrate transport planning strategies and urban and regional settlement planning strategies, with a view to reducing the environmental impacts of transport. Promote Sustainable Development: Industrial Development Activities: 1. Evaluate and promote cost-effective policies and programs, that includes administrative, social and economic measures, in order to minimize industrial pollution and adverse impacts on the atmosphere. 2. Encourage industries to increase and strengthen their capacity to develop technologies, products and processes that are safe, less polluting and make more efficient use of all resources and materials, including energy. 3. Cooperate in the development and transfer of such industrial technologies and in the development of capacities to manage and use such technologies. 4. Develop, improve, and apply environmental impact assessments to foster sustainable industrial development. 5. Promote efficient use of materials and resources, taking account the life cycles of products, to be able to realize the economic and environmental benefits of using resources more efficiently and producing fewer wastes. Promote Sustainable Development: Terrestrial and Marine Resource Development and Land Use Activities: 1. In accordance with national socio-economic development and environment priorities, evaluate and promote cost-effective policies or program, that includes administrative, social, and economic measures, to encourage environmentally sound land-use practices. 2. Discourage inappropriate and polluting land-use practices and promote sustainable utilization of terrestrial and marine resources. 3. Promote the development and use of terrestrial and marine resources and land-use practices that will be more resilient to atmospheric changes and fluctuations. 4. Promote sustainable management and cooperation in the conservation and enhancement of sinks and reservoirs of greenhouse gases, that includes biomass, forests, and oceans, as well as other terrestrial, coastal, and marine ecosystems. Prevention of Stratospheric Ozone Depletion Activities: 1. Support further expansion of the Global Ozone Observing System by facilitating through a bilateral and multilateral funding of the establishment and operation of additional systematic observation stations. 2. Actively participate in the continuous assessment of scientific information and the health and environmental effects, as well as of the technological/economic implications of stratospheric ozone depletion considering further actions that prove warranted and feasible on the basis of the assessments. 3. Based on the results of researches on the effects of the additional ultraviolet radiation reaching the Earth's surface, it is important to consider taking appropriate remedial measures in the fields of human health, agriculture, and marine environment. 4. Replace CFCs and other ozone-depleting substances to contribute to solving one atmospheric or environmental problem. Transboundary Atmospheric Pollution Activities: 1. Establish and/or strengthen regional agreements for transboundary air pollution control and cooperate, particularly with developing countries to address the extent, causes, health and socio-economic impacts of ultraviolet radiation, acidification of the environment, and photo-oxidant damage to forests and other vegetation. 2. Establish or strengthen early warning systems and response mechanisms for transboundary air pollution from industrial accidents and natural disasters and the deliberate and/or accidental destruction of natural resource. 3. Cooperate to assess transboundary air pollution and elaborate and implement program identifying specific actions to reduce atmospheric emissions and to address their environmental, economic, social and other effects. Fact #1 Human effects such as the greenhouse effect, global warming, contamination of the air, destruction of the ozone belt, and acid rain are damaging the atmosphere. Fact #2 The WHO (World Health Organization) estimates that around 90% of people worldwide breath polluted air. Fact #3 According to the WHO (World Health Organization), as the ozone layer decreases in the atmosphere the rate of skin cancers continues to climb as the atmosphere is not able to properly absorb the ultraviolet radiation being given off by the sun. References: (n.d.). Retrieved January 29, 2021, from https://sedac.ciesin.columbia.edu/entri/texts/a21-09-atmosphere.html Auburn.(2017).”The atmosphere & Weather”. http://www.auburn.edu Center for Science Education.(2019).”Troposphere Overview”. https://scied.ucar.edu Center for Science Education.(2019).”Mesosphere Overview”. https://scied.ucar.edu Center for Science Education.(2019).”Stratosphere Overview”. https://scied.ucar.edu Center for Science Education.(2019).”Exosphere Overview”. https://scied.ucar.edu Center for Science Education.(2019).”Thermosphere Overview”. https://scied.ucar.edu Chemical Science Laboratory. (2010). 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