《环境化学》课程PPT教学课件讲稿（英文版）Unit 3 Air Pollution- Inorganic Gaseous Pollutants

Air Pollution- Inorganic Gaseous Pollutants

Air Pollution– Inorganic Gaseous Pollutants

Major inorganic gaseous pollutants Carbon monoxide( Co) · Sulfur dioxide(SO2) Nitrogen Oxide(No, No2)NOX=No+No2 ·Oz0ne(O3)

Major inorganic gaseous pollutants • Carbon monoxide (CO) • Sulfur dioxide (SO2) • Nitrogen Oxide (NO, NO2) NOx=NO+NO2 • Ozone (O3)

HK 1-hour Air Quality objectives for various air pollutants Air AQ AQ US AQ Pollutants ObjectivesObjectives Standards (ug/m3)(ppm) (ppm) Carbon 30000 262 35 mono×ide Sulfur 262 0.306 0.503 dioxide Nitrogen 35 0.159 005b dioxide Ozone 800 0.122 0.12 a:3-hr standard, b, annual arithmetic mean

HK 1-hour Air Quality Objectives for various air pollutants Air Pollutants AQ Objectives (mg/m3) AQ Objectives (ppm) US AQ Standards (ppm) Carbon monoxide 30000 26.2 35 Sulfur dioxide 26.2 0.306 0.50a Nitrogen dioxide 35 0.159 0.05 b Ozone 800 0.122 0.12 a : 3-hr standard, b : annual arithmetic mean

Carbon monoxide: health effect Co enters the blood stream and binds preferentially to hemoglobin, thereby replacing oxygen O-O Fe F O CO F 320 times stronger than hemoglobin-02 binding

Carbon monoxide: Health effect CO enters the blood stream and binds preferentially to hemoglobin, thereby replacing oxygen. Fe O2 CO Fe Fe C-O O-O 320 times stronger than hemoglobin-O2 binding

Carbon monoxide: sources and sinks Sources Such as automobiles Incomplete combustion(internal engine) Biomass burning Methane oxidation Oxidation of non-methane hydrocarbon Decay of plant matter Sink Reaction with OH radical OH+CO→C02+H H·+02+M→HO2:+M Removal by soil microorganism

Carbon monoxide: sources and sinks • Sources – Incomplete combustion (internal engine) – Biomass burning – Methane oxidation – Oxidation of non-methane hydrocarbon – Decay of plant matter • Sink – Reaction with OH radical .OH + CO → CO2 + H. H . + O2 + M → HO2. + M – Removal by soil microorganism Such as automobiles

CO formation from methane oxidation CH4+“OH→CH CH3OO° +No HO2 CO O

CO formation from methane oxidation CH4 + OH CH3 + H2O +O2 C O H H H CH3OO NO2 NO + O2 C H H O + HO2 hv H O + HO2 O2 HO2 CO

CO emission sources in Hong Kong u combustion generation (Industrial aircraft commercial domestic) -marine vessel motor vehicle

CO emission sources in Hong Kong Fuel combustion (Industrial, commercial & domestic) power generation aircraft marine vessel motor vehicle

Carbon monoxide: Atmospheric chemistry CO+OH+O,→CO2+HO HO+NO→NO2+OH no t hy>NO +o O+Q2+M→Q3+M Net: co+20+hv>CO+o The net reaction can be viewed as a catalytic oxidation of CO to co. Net formation of o, occurs

Carbon monoxide: Atmospheric chemistry CO + OH + O2 → CO2 + HO2 . HO2 . + NO → NO2 + OH NO2 + hv → NO + O O + O2 + M → O3 + M Net: CO + 2 O2 + hv → CO2 + O3 The net reaction can be viewed as a catalytic oxidation of CO to CO2 . Net formation of O3 occurs

Carbon monoxide: control strategies on the automobile source Employ a leaner air/fuel mixture(higher air/fuel ratio) Employ catalytic exhaust reactors Excess air is pumped into the exhaust pipe Air-exhaust mixture pass through a catalytic converter to oxidize co to co2 Addition of oxygenates to gasoline Examples of oxygenates: methanol, ethanol, MTBE

Carbon monoxide: control strategies on the automobile source • Employ a leaner air/fuel mixture (higher air/fuel ratio) • Employ catalytic exhaust reactors – Excess air is pumped into the exhaust pipe. – Air-exhaust mixture pass through a catalytic converter to oxidize CO to CO2. • Addition of oxygenates to gasoline – Examples of oxygenates: methanol, ethanol, MTBE

Sulfur dioxide: Health effect Produce irritation and increasing resistance in the respiratory tract Mucus secretion In sensitive individuals, the lung function changes may be accompanied by perceptible symptoms such as wheezing shortness of breath and coughing may also lead to increased mortality, especially if elevated levels of suspended particles are also present

Sulfur dioxide: Health effect • Produce irritation and increasing resistance in the respiratory tract. • Mucus secretion • In sensitive individuals, the lung function changes may be accompanied by perceptible symptoms such as wheezing, shortness of breath, and coughing. • may also lead to increased mortality, especially if elevated levels of suspended particles are also present