Air Pollution and Meteorology 2010-1214 EPT PDF

Air Pollution and Meteorology 2010+1214 EPT Course content Contact No List of Theoretical and practical Topics Hours 1 Atmosphere and its c...

Air Pollution and Meteorology 2010+1214 EPT Course content Contact No List of Theoretical and practical Topics Hours 1 Atmosphere and its composition. 1 2 Sources and scales of air pollution 4 3 Effects of air pollution on human, animals, plants and structures. 4 4 Atmospheric chemistry and photochemical smog. 4 5 Ambient air sampling, measurement and analysis 2 6 Air pollution monitoring. 4 7 Role of meteorology on air pollution 4 8 Air quality criteria 4 9 Emission and emission standards 4 10 Stack gas sampling and analysis. 4 11 Dispersion of air pollutants 4 12 Emission inventory 4 13 Introduction to air pollution modeling. 2 Total 45 Course handouts ⚫ Provided by the instructor. ⚫ Environmental Pollution and Control, 4th Edition J. J. Peirce, P. A. Vesilind, R. Weiner. Student Assessment Activities Percentage of Total # Assessment task* Week Due Assessment Score 1 Quiz 4-5 5% 2 Mid Exam 1 7-8 15% 3 Quiz 14- 15 5% 4 Mid Exam 1 7-8 15% 5 Practical activities and Practical exam 16 10% 6 Attendance/ class activities/ assignment…etc weekly 10% 7 Final Exam 17 40% 100% Course Main Objective ⚫ The objective of this course is to provide the students with an overview of the field of air pollution. ⚫ The course will cover topics that are pertinent to the study of air pollution, such as air pollution meteorology, sources of pollution, pollutant fate and transport, effects of air pollution, ambient air monitoring, and pollution abatement. Regulatory models currently available for estimating pollutant emissions and air concentrations will be presented and discussed. ⚫ Meteorology represents one of the major influences that determines the scale and magnitude of the impact of releases of pollutants on a particular location Where to look for help ⚫ Use the study guides and online helps – Daily quizzes – Ask your instructor! Classroom Etiquette: Turn off pagers and cell phones ! Don’t be late Take out what you bring in. Talk to me, NOT your neighbor! Attendance is not optional 8  Lecture (1) The atmosphere and its composition  CONTENTS ⚫ Introduction ⚫ Vertical structure of the atmosphere ⚫ Gaseous composition of atmosphere Introduction ⚫ The atmosphere is a layer of gases surrounding the Earth, mainly oxygen and nitrogen, protecting it and supporting life. ⚫ Functions: – Protection: Shields Earth from harmful solar radiation and space debris – Regulation: Maintains Earth's temperature, enabling life. – Support: Provides the air we breathe and supports water cycles.  Terms Atmosphere: The gases, droplets, and particles surrounding Earth’s surface. Weather: refers to the atmospheric conditions at a specific place and time including temperature, humidity, precipitation, wind, and visibility.  Terms Climate: refers to the long-term patterns and averages of weather conditions in a particular region over an extended period, typically 30 years or more Climatology: is the scientific study of climate, including the statistical analysis of long-term weather patterns, trends, and variations.  CRAZY FACT -The total mass of the atmosphere is equivalent to 5.65 billion million tons. Vertical structure of the atmosphere: ❑ The vertical structure of the atmosphere is composed of several distinct layers, each with unique characteristics: o Troposphere o Stratosphere o Mesosphere o Thermosphere o Exosphere  Height (km) Pressure: 30 Higher elevation Less air above Lower pressure 20 Can be thought of as weight of air above you. (Note that pressure acts in all directions!) 10 So as elevation increases, pressure decreases. 0 Lower elevation More air above Higher pressure 1- Troposphere: ⚫ Height: Extends up to 8-15 km above Earth's surface. ⚫ Characteristics: Contains most of the atmosphere's mass, weather phenomena, and clouds. Temperature decreases with altitude.  Contains 80% of the atmospheric mass Tropopause Depth ranges from ~8 km at the poles to ~16 km in the tropics Troposphere The lapse rate is the average decrease Majority of the Rapid decrease in in temperature with weather occurs temperature with height ~ 6.5°C/km here height 2- Stratosphere: ⚫ Height: Extends from the troposphere up to about 50 km. ⚫ Characteristics: Contains the ozone layer, which absorbs and scatters ultraviolet solar radiation. ⚫ Temperature increases with altitude.  Contains ~19.9% of Stratopause the atmospheric mass Temperature increases with height from 20-~50 km (Temperature inversion) Stratosphere Ozone layer The ozone layer absorbs much of the incoming solar radiation, warming the stratosphere, and protecting us from harmful Isothermal in Little weather UV radiation lowest 10 km occurs here Lapse rate is 0 Ozone layer ⚫ The ozone layer is a crucial part of Earth's stratosphere, located approximately 10 to 30 kilometers (6 to 19 miles) above the Earth's surface. ⚫ It contains a high concentration of ozone (O₃) molecules, which are made up of three oxygen atoms. Importance of Ozone layer: ⚫ UV Radiation Protection: The primary function of the ozone layer is to absorb the majority of the Sun's harmful ultraviolet (UV) radiation. ⚫ These rays can cause skin cancer, cataracts, and other health issues, as well as harm wildlife and plants. Importance of Ozone layer: ⚫ Environmental Balance: : By filtering out UV radiation, the ozone layer helps maintain the balance of ecosystems and protects biodiversity. Ozone Depletion and Its Causes ⚫ Chlorofluorocarbons (CFCs): These are man- made chemicals, once widely used in refrigeration, air conditioning, and aerosol propellants. ⚫ When CFCs reach the stratosphere, they are broken down by UV radiation, releasing chlorine atoms that destroy ozone molecules. Ozone Depletion and Its Causes ⚫ Halons: Used in fire extinguishers, halons also release bromine atoms that can deplete the ozone layer. ⚫ Other Chemicals: Methyl chloroform, carbon tetrachloride, and other industrial chemicals contribute to ozone depletion. 3- Mesosphere: ⚫ Height: Extends from the stratosphere up to about 85 km. ⚫ Characteristics: The coldest layer of the atmosphere. ⚫ Meteors burn up in this layer. ⚫ Temperature decreases with altitude. 4- Thermosphere: ⚫ Height: Extends from the mesosphere up to about 600 km. ⚫ Characteristics: Temperature increases significantly with altitude, reaching up to 2,500°C or higher. ⚫ Contains the ionosphere, which reflects radio waves to Earth.  Neither of these layers have much Mesosphere interest for the Meteorologist Temperature once again decreases with height Thermosphere Temperature once again increases with height  5- Exosphere: ⚫ Height: Extends from the thermosphere up to about 10,000 km. ⚫ Characteristics: The outermost layer, where atmospheric particles are sparse and can travel long distances without collisions. ⚫ Transition between Earth's atmosphere and outer space.  Summary: Divide the atmosphere into several vertical layers based on temperature characteristics. Together with the change in density with height, this gives the atmosphere its structure. Thermosphere Mesosphere Temperature Inversion Stratosphere Stable layer Troposphere COMPOSITION OF ATMOSPHERE  Made up of: -Mixture of invisible gases. -Large number of suspended microscopic particles and water droplets.  R e l e v a n t Te r m s Homosphere: The lowest 80km of the atmosphere, in which the relative abundance of the permanent gases is constant. Heterosphere: The high atmosphere where gases are not well mixed but rather are stratified according to weight. Where lighter-weighing gases are found. Composition of the atmosphere 1. Permanent gases 2. Variable gases 3. Aerosols 1- Permanent gases: ⚫ Those gases whose relative abundance is constant within the homosphere. ⚫ Account for about 99% of the atmospheric mass. ⚫ Occur in a constant proportion in the lowest ~80 km of the atmosphere. ⚫ Although molecules exchange between the atmosphere and Earth, the total concentration remains the same (chemical homogeneity)  N2 + O2 = 99% of atmospheric volume below 80 km. They are chemically active. Ar, Ne, He, Xe < 1% and are chemically inert. ** The residence time of a gas is the average time an individual molecule remains in the atmosphere. ⚫ Nitrogen: N2 is added and removed from the atmosphere very slowly – a long residence time of ~42 million years. ⚫ N2 is relatively unimportant for most meteorological and climate processes ⚫ Oxygen: O2 is crucial to the existence of almost all forms of life currently on the Earth. Its residence time is ~5000 years 2- Variable gases: ⚫ Gases present in amounts that vary greatly in abundance, either vertically, horizontally, or seasonal. ⚫ distributions vary both in time and space ⚫ account for < 1% of the atmosphere below 80 km ⚫ some of these gases impact the behaviour of the atmosphere considerably. H2O + CO2 + O3 = 0.296% of atmospheric volume. ⚫ Water Vapor (H₂O): the most abundant variable gas and its concentration varies from 0% to about 4%. It plays a crucial role in the weather and climate. ⚫ Continually cycled between atmosphere and earth by evaporation, condensation and precipitation. (hydrologic cycle), And has a residence time of only 10 days. ⚫ WV absorbs radiant energy emitted from the Earth’s surface. (Greenhouse gas) ⚫ Carbon Dioxide (CO₂): it's considered a variable gas because its levels fluctuate due to natural processes and human activities. ⚫ It is removed through photosynthesis ⚫ CO2 has a residence time of ~150 yrs. ⚫ It is an effective absorber of longwave radiation emitted from the Earth’s surface. (Greenhouse gas) ⚫ Its concentration in the atmosphere has increased ~18% since 1958. 3- Aerosols: ⚫ are small solid particles or liquid droplets in the air. ⚫ They are formed by both natural and anthropogenic means. ⚫ Aerosols typically have residence times of a few days to several weeks. ⚫ aerosols play an important role as condensation nuclei, the core about which water can condense in clouds. ⚫ Formed from chemical reactions, wind-generated dust, volcanic ejections, sea spray, and combustion (e.g., fine ash) ⚫ Removed from the atmosphere in precipitation Composition of the atmosphere - recap 1. Permanent gases Name two permanent gases …………………………………………………... 2. Variable gases Name two variable gases …………………………………………………...… 3. Aerosols Name two ways aerosols form …………………………………………………….. THANK YOU !