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Air Pollution Control and Air Chemistry

Air Pollution Control and Air Chemistry
Air Pollution Control and Air Chemistry: Introduction to fundamental processes in the atmosphere st (1 lecture) Detlev Möller Chair for Atmospheric Chemistry and Air Pollution Control Faculty of Environmental Sciences and Process Engineering Brandenburg Technical University Cottbus, Germany¾¾¾¾ Objectives: To describe the atmosphere as a chemical and physical system, controlled by solar radiation, terrestrial natural (biogenic and geogenic) processes as well anthropogenic activities. The atmosphere Air composition and problems Air pollution The climate systemsolar radiation ATMOSPHERE chemical system: physical system: composition and climate und structure weather emission deposition agriculture industry soil traffic water municipal fauna/flora TECHNOLOGY NATURESO2, CO, VOC HO H O 2 2 OH 2 NO x NO hv NOx HNOx 2+ SO Ca 2 HCl OX NO + x S(IV) S(VI) + H O 3 2+ Dust, e.g. Ca NO VOC VOC' + NO + H x OX + OX O , H O 2 2 NO2 + NH 4 NO VOC CO N O, NH 2 3 Industrial urban emission dry deposition agricultural emmision wet depositionDefinitions statements Air = chemical multiphase system consisting from gaseous species, particulate matter and droplets (= chemical system of the lower atmosphere. i.e. until the meso pause) Atmosphere = reservoir sourrounding the earth surface; including the high atmosphere where air is not longer defined The chemical composition of the atmosphere (i.e. “Air Chemistry”) is a result of emissions into the atmosphere, chemical reactions (transformation), transport processes (mixing) and energetic processes (“Physics of the Atmosphere”). The natural air chemistry is a result of the evolution of the biosphereatmosphere interaction. Manmade activities lead to a changing chemical composition of the atmosphere, which is called Air Pollution, i.e., x x = x present natural pollutant Effect Impact An is a results of an , which, however, is given by the total concentration (x + natural x ). Therefore, impact assessment needs a separation between natural and manmade influences pollutant suggesting abatement strategies. Coimpacts (external and internal) must be considered. Effects only occur when the impact exceeds a threshold. The impact to an ecosystem is a system of hiercharchic functional relationsships (Deposition as an example for atmospheric parameter): total impact = f(impact ) i impact = f(atmospheric, soil and internal parameters) i atmospheric parameters: precipitation radiation temperature humidity wind deposition: dry wet occult deposition = f(concentrations,meteorological and surface parameter) concentrations = f(emission, air chemistry, transportation, deposition) emission = f(society, etc) example for feedback relations: air chemistry depends from the ecosystem (i.e. the impact itself) in sense of emission and deposition fluxes Air chemistry is defined ... as the branch of atmospheric science concerned with the constituents and chemical processes of the atmosphere ... (Christian Junge, 1963)A clean atmosphere is a political target, i.e., an air chemical composition (defined in time and scale) which should provide a sustainable development. The natural atmosphere does not longer exist; it was the air chemical composition without manmade influence. However, the definition is not exactly because humans ar part of the nature... On the other hand, humans – by decoupling of her life cycle from only natural conditions – have altered „natural“ biogeochemical cycles. Vernadsky understood with noosphere a new dimension of the biosphere, developing under the evolutionary influence of humans on natural processes. composition of the dry remote atmosphere (global mean concentrations) substituent conventration remarek 4 ≡ (in ppm 10 ) a nitrogen N 780840 constant 2 a constant oxygen O 209460 2 a constant argon Ar 9340 carbon dioxide CO 360 increasing 2 constant neon Ne 18,18 constant helium He 5,24 methane CH 1,73 increasing 4 constant krypton Kr 1,14 constant hydrogen H 0,5 2 dinitrogen monoxid N O 0,31 steigend 2 carbon monoxid CO 0,120 increasing xenon Xe 0,087 constant ozone O 0,03 variabel 3 carbonylsulfid CSO 0,00066 increasing b nitric acid HNO variable ≤ 0,001 3 c radikals 0,00001 variable hydroxyl radikal OH 0,0000003 variable a related to the “clean” atmosphere O + N + Ar + CO 2 2 2 b and many other trace substances (NH , NO , HCl, NMHC, H O , DMS, CFC´s et. al.) 3 x 2 2 c e.g. HO , NO , Cl 2 3Atmospheric research Atmospheric environmental research Air chemistry Air pollution control Meteorology Air pollution Atmospheric physics SO , NOx, VOC, dust, etc. 2 Acidity Oxidation potential Biosphere research Climate forcing other geosciences Earth system research Physical and chemical properties of the atrmosphereCHEMICAL ENVIRONMENTAL RESEACH ecology chem. ecology geochemistry GEOSPHERE air chemistry atmosphere water chemistry hydrosphere fauna/flora pedosphere BIOSPHERE lithosphere ecological chem. biochemistry biogeochemistry Chemistry and physics being sciences of „observing“ the environment (our “senses”) „extern“ disciplins information interface „intern“ „human“ disciplin ↓ ↓ ↓ smell Substances Chemistry → taste Optics seeing Akustics hear → Biology ↑ Thermodynamics feel Physics → Mechanics touch Problems in spatial scale local dust local regional SO , aerosol 2 local global CO , CH , N O 2 4 2 local regional global O 3 space space „acid rain“ 1 2Atmospheric problems in temporal scale Positive climate forcing (greenhouse effect) 100 years Background ozone 50 years Negative climate forcing (aerosol) 2 weeks Sommermog 1 week Wintersmog 1 week Disaster 1 dayshorter longer 1 s 1 d 1 a time (s) 1,00E09 1,00E07 1,00E05 1,00E03 1,00E01 1,00E+01 1,00E+03 1,00E+05 1,00E+07 1,00E+09 1,0 0 E +0 6 global 1,0 0 E +0 4 1,0 0 E +0 2 1,0 0 E +0 0 1,00E02 1,00E04 1,00E06 local 1,00E08 1,0 0 E 10 chem. elementar reactions dissipation eddies turbulence clouds cloud systems, cyclons interhemispheric transport oxidation of SO 2 oxidation of methane decay of freons distance (km)The climate system solar radiation ATMOSPHERE CLIMATE SYSTEM energy substance (physical processes) (chemical processes) BIOSPHERE / GEOSPHERE ANTHROPOSPHEREclima Latin: slope κλίµα Greek climate Behind the meteorologists understand the sum of meteorological factors (elements) / the summary of weather / the mean (averaged) weather, mean status of the atmosphere describing the at a given site of the Earth surface, represented by the statistical total properties (mean values, frequencies, durations etc.) of a long enough time periode. (Julius v. Hann 1983, W. Köppen 1923, E. S. Rubinstein 1956, K. SchneiderCarius 1961, J. Blüthgen 1964, WMO 1979) is a function of space and time. Climate can not be described as a single unit. Climate Cosmos. Outline of a physical world description by Alexander von Humboldt First Volume. (1845)Climate definition by Humboldt (from: Kosmos, 1845) The term climate denotes in his most general sense all changes in the atmosphere, affecting our organs remarkable: the temperature, the humidity, die barometric pressure change, the silent air status or the impacts of windy airs, the size of electricity, the purity of the atmosphere or its mixing with more or less harmful gaseous exhalations and finally the degree of its transparency and sky blueness: which not only is important for the increased heat radiation of the soil, the organic development of plants and mature of fruits but also for the human feeling and his spititual welfare.Climate WMO definitions Synthesis of weather conditions in a given area, characterized by long term statistics (mean values, variances, probabilities of extreme values, etc.) of the meteorological elements in that area. Weather The state of the atmosphere mainly with respect to its effects upon life and human activities. As distinguished from climate, weather consists of the shortterm (minutes to about 15 days) variations of the atmosphere state. Meteorological Elements Any one of the properties or conditions of the atmosphere which together specify the weather at a given place for any particular time (for example, air temperature, pressure, wind, humidity, thunderstorm and fog) Atmosphere The envelope of air surrounding the Earth and bound to it more or less permanently by virtue of the Earth's gravitational attraction; the system whose chemical properties, dynamic motions, and physical processes Chemistry (chem. weather) constitute the subject matter of meteorology. Climatological Elements meteorological: • temperature • precipitation • wind • cloudiness • humidity • sun shine duration • air pressure • radiation physicochemical: • deposition (dry, wet) trace gas concentration (ozone, greenhouse gase etc.) • • aerosol (number, mass, surface, properties) • climate forcing acidifying potential • • oxidation potential climate system The term often is named by following terms: • natural Earth system, Ecosphere, Nature ( ), Alexander von Humboldt • Biosphere (Vladimir Iwanowitsch Vernadsky) or • GAIA (James Lovelock and Lynn Margulis). By influencing the natural system by humans it is changing and creating a new „anthropogenic (manmade) 1 system“ (anthroposphere ) which, however, is linked with the nature. We can state that new by humans modified Earth system has been developed, the 2 • Noosphere (Vladimir Iwanowitsch Vernadskij) . Earth System Thus, we define among climate system the : Earth system (= noosphere) = nature + anthroposphere. nature = climate system/natural Earth system anthroposphere = human life sphere (=culture) 1 Paul J. Crutzen proposed, to subdived the present epoch Holozän by Anthropozän.. 2 This term Vernadsky got from the french priest and philosopher Pierre Teilhard de Chardin (they met in Paris end of 1920er). V. understood with noosphere a new dimension of the biosphere, developing under the evolutionary influence of humans on natural processes. noosphere atmosphere climate system hydrosphere nature biosphere geosphere pedosphere lithosphere anthroposphere sociosphere technosphereSome examples for complex relationships resulting into climate change when system parameters are changing.anthroposphere The climate change feedback relation Emission gases, particulates direct forcing concentration change absorption, reflexion, albedo LWC, cover droplet size indirect forcing clouds and fog intensity, frequency, duration precipitation biosphere radiation / temperatureSun An example for the GAIA hypothesis radiation budget Charlson, R. J., J. E. Lovelock, M. O. Andreae und S. G. – aoud albedo Warren (1987) Oceanic phytoplankton, atmospheric sulphur, cloud albedo, and climate. Nature 326, 655661 global temperature CCN + anthropogenic climate feedback aerosol aerosol + + + SO 2 + or – () + greenhouse precurser DMS gases emissions + + + atmosphere continent continent ocean DMS + marine ecosystem + or – () + or – () – phytoplankton sea pollution (availibity/speziation)global water cycle precipitation on oceans (458) transport to clouds continents (45) condensation 3 3 (figures in 10 km ) evaporation (τ≈ 11 d) H2O evaporation (74) water vapor precipitation (17) on land (119) assimilation photosynthesis plant food waste water animal/human drinking and process water river/lakes (3) ground water river runoff (43) ocean underground runoff (2) (140.000) evaporation (503) respirationweather modification: 1. water resource 2. mitigate severe weather precipitation gases CCN water vapour chemical processor visibility fog deposition water ressource dew biosphere (interaction with atmosphere) condensation evaporation
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