학과목집진공학 (Particulate Control Engineering, 集塵工學 ) 담당교수장혁상 (810-2547) 단원의주제서론 ( 입자상물질의특성 ) Page 1 대기오염의정의 정의 환경은자연상태에서사물이나일련의관계가서로질서를유지하고있는상태를말한다 그리고환경오염이라는것은이러한질서상태가파괴된것혹은파괴가진행되어가는것을말한다 여러환경중에서 대기환경은대기조성이적정농도로평형을이루어질서를유지한가운데안정화되어있는상태를 말하며대기오염은이러한대기환경의질서가파괴된것을말한다 이를달리표현하여정의하면 대기오염은사람의건강 복지 동식물 재산에해로운영향을주거나실외오락을포함한생활과소유를불합리적으로방해하는다량의오염물질 또는 개이상의오염물질들이실외대기중에존재하는현상이다 미국 주의법률상정의 대기오염은대기중에인위적으로배출된오염물이한가지또는그이상존재하여 오염물질의양 농도및지속시간이어떤지역의불특정다수에게불쾌감을일으키거나해당지역에공중보건상위해를끼치고 인간이나동물 식물등의활동에해를주어생활과재산을향유할정당한권리를방해받는상태로정의한다 의정의
학과목집진공학 (Particulate Control Engineering, 集塵工學 ) 담당교수장혁상 (810-2547) 단원의주제서론 ( 입자상물질의특성 ) Page 2 대기오염의규제기준 대기환경기준 특정지역에서특정기간동안법률적으로초과해서는안되는오염물의농도수준을규정 하는기준으로사람이호흡하는공기의질을규정한다 대기환경기준이되는대기의조성 가스의종류 농도용적 중량비 질소 산소 아르곤 탄산가스 네온 헬륨 메탄 크립톤 일산화질소 수소 크세논 배출허용기준 당해지역의대기질을유지개선하기위해오염원으로부터배출될수있는오염물의양또는농도를실제적으로규제하는기준 대기환경기준을달성하기위한주요수단인배출허용기준은개별적인오염물질배출시설에적용되는규제기준으로서오염물질배출의최대허용치혹은최대허용농도라고할수있다 배출허용기준은오염물질에대한직접규제수단중가장핵심이되는것으로환경기준과배출허용기준은목적과수단이라는상호관계가있으므로배출허용기준은환경기준에따라달라질수있다 대기오염의규제기준의대상항목 가스상대기오염물질 입자상대기오염물질 악취
학과목집진공학 (Particulate Control Engineering, 集塵工學 ) 담당교수장혁상 (810-2547) 단원의주제서론 ( 입자상물질의특성 ) Page 3 대기오염의제어원칙 대기오염제어의최종적인목표는오염물배출을완전제어 하는데있다 하지만제어과정에서필요로하는비용지출문제때문에이상적으로추구하는완전제어는현실적으로불가능하고일정의배출허용기준을정해두고이에만족하는최선의제어방법을추구하게된다 그러므로현실적의미에서의적절한대기오염제어는대기오염방지기술개발 적용하여설정된배출양기준만족하게하므로서대기질기준에만족하는 대기상태를유지하는작업을의미한다
학과목집진공학 (Particulate Control Engineering, 集塵工學 ) 담당교수장혁상 (810-2547) 단원의주제서론 ( 입자상물질의특성 ) Page 4 입자상오염물질의성질 입자상물질은입경을가지며입경에따른입자상물질의물리화학적성질 변화가있다 가 기하학적입경 나 역학적입경 공기역학적입경 다 광학적입경 라 전기적입경
학과목집진공학 (Particulate Control Engineering, 集塵工學 ) 담당교수장혁상 (810-2547) 단원의주제서론 ( 입자상물질의특성 ) Page 5 입자상오염물질의 입경대비 물리화학적거동 물리적성질 입자상물질은밀도가높고크기가클수록관성이크다 화학적성질 대기중부유분진의화학적조성은입자크기별로서로다른특성을가진다 첨부참조 광학적성질 대기중부유분진은입자크기별로광산란도를다르게가진다 Light scattering efficiency 0.01 0.1 1 10 d p (mm)
학과목집진공학 (Particulate Control Engineering, 集塵工學 ) 담당교수장혁상 (810-2547) 단원의주제서론 ( 입자상물질의특성 ) Page 6 대기오염물질의질량적표현 대기오염도의표현단위 혹은 μ 부피농도 질량농도 Pr 상온 에서부피농도 과 의관계
학과목집진공학 (Particulate Control Engineering, 集塵工學 ) 담당교수장혁상 (810-2547) 단원의주제서론 ( 입자상물질의특성 ) Page 7
학과목집진공학 (Particulate Control Engineering, 集塵工學 ) 담당교수장혁상 (810-2547) 단원의주제서론 ( 입자상물질의특성 ) Page 8
What and where is Aerosol? 에어로졸? Contamination (or Pollution)
Chemical Characteristics of Aerosol
Physical Characteristics of Aerosol
Optical Characteristics of Aerosol
Thermal Characteristics of Aerosol
What is aerosol? Reading: Chap. 1 2016-07-13 Environmental Aerosol Engineering Laboratory 1
Traffic jam in Bangkok Wheatfield under clouds (Van Gogh) Uncontrolled stack emissions Nanosized Fe particles generated by aerosol processes 2016-07-13 Environmental Aerosol Engineering Laboratory 2
Q: Is this an aerosol? (a) a book, (b) an O 2 molecule Definition: Type of Particulate Suspensions Suspending Types of Suspended Particle Medium Gas Liquid Solid Gas - Fog, Mist, Spray Fume, Dust Liquid Foam Emulsion Suspension, Slurry Solid Sponge Gel Alloy 2016-07-13 Environmental Aerosol Engineering Laboratory 3
Why do we want to study aerosols? Air Pollution: Pittsburgh, Seoul, Bangkok Toxic metals Dioxin formation Visibility Great Smoky Mt. Magnitogorsk along Ural river, Russia produces 12 Mton/yr of steel with 50,000 employees (compare 7,500 workers with 7 Mton/yr in US) 2016-07-13 Environmental Aerosol Engineering Laboratory 4
Manufacture: Pigment Cosmetics Magnetic powder Pharmaceutical 2016-07-13 Environmental Aerosol Engineering Laboratory 5
Health: Deposition in inhalation system Drug delivery Work place, papermill, mining, pesticide, welding 2016-07-13 Environmental Aerosol Engineering Laboratory 6
Atmosphere: Volcano: St. Helen, Pinotube Extinction of dinosaurs Venus Stratospheric Ozone depletion 2016-07-13 Environmental Aerosol Engineering Laboratory 7
How do we characterize an aerosol? Ans: Microscopy Optical, Electronic Primary & Agglomerate Velocity Settling velocity Time of flight Chemical analysis XRD, FTIR, PIXE, ICP d p =1 m d p =2 m p =4g/cm 3 p =1g/cm 3 V = 1 cm/s V = 1 cm/s 2016-07-13 Environmental Aerosol Engineering Laboratory 8
Light scattering intensity Light scateringeficiency Units: cgs system: cm, g, sec yardstick: m (=10-4 cm = 10-6 m); submicron & supermicron 0.01 0.1 1 10 d p ( m) Particle size is the most commonly used one - Figure 1.6 2016-07-13 Environmental Aerosol Engineering Laboratory 9
How do we characterize aerosols? Concentration: Number concentration by counting Mass concentration by weight measurement Size: Monodisperse & Polydisperse Ex: Particles in room air: N = 10 4 #/cc M = 5.236 10-6 g/cc d p = 10-3 cm = 10 m Q: Does this mean all the 10 4 particles in 1 cc air are 10 m? What is the effect if we use this size to represent the system? (e.g. in inhalation system) How can we better describe this aerosol system? 2016-07-13 Environmental Aerosol Engineering Laboratory 10