ENS195: Environmental Science and Engineering with Safety (MSU-ILIGAN) Lecture Notes PDF

msuiit influencing the future ENS195: Environmental Science and Engineering with Safety ANTHONY O. MAPUTI, M.Sc. Department of Chemical Engineering and Technology  msuiit influencing the future...

msuiit influencing the future ENS195: Environmental Science and Engineering with Safety ANTHONY O. MAPUTI, M.Sc. Department of Chemical Engineering and Technology  msuiit influencing the future LESSON Introduction to Air Pollution and Management 6 Department of Chemical Engineering and Technology LESSON 5 – Things you need to know 1. Air Environment 2. Development and Air Pollution 3. Basic Terminologies 4. Types of Air Pollutants 5. Sources of Air Pollutants 6. Measurement Units and Averaging Time 7. Asian and Global Air Pollution Status 3 Atmosphere The atmosphere is a critical system that helps to regulate Earth's climate and distribute heat around the globe. Together with the oceans, the atmosphere shapes Earth's climate and weather patterns and makes some regions more habitable than others. 4 Air Environment Earth atmosphere Troposphere (8-12 km): heated from the Earth surface, warmest near the bottom and gets colder with increasing height Stratosphere: heated from the top (ozone layer --> absorption of incoming UV) Mesosphere: temp. reduces with height (can be defined as a part of exosphere where light H2 and He lost to the space) Thermosphere (no defined upper limit): high temp. (solar radiation absorbed by a few N2 & O2 molecules --> 500 km, t = 1200 ℃) 5 Clean Air Composition Assuming binary composition --> Nitrogen (79%) and Oxygen (21%) 6 Roles of the Atmosphere Supply oxygen: Man’s biological need for air Heat and water transport media: Resting 12 kg/day Water cycle and heat transfer Light work 45 kg/day Heavy work 69 kg/day 15-20 times of food (1.5 kg/day) Waste disposal media Almost unavoidable exposure Redistribution of solar radiation: Filter solar radiation: Natural GHG effect: temp = 14-15℃ Harmful UV absorbed by O3 & O2 (instead of -18℃) 7 Atmospheric Processes and Air Pollution 8 Factors Affecting AP at a Location Emission: Sources: natural, man-made Degree of control/management Meteorology Transport/diffusion: air pollution dilution Transformation: secondary air pollution, etc. Sink: wet and dry removal Topography: affecting dispersion and sink/deposition 9 Environmental Kuznet’s Curve (EKC) Environmental degradation 10 Motorcycle Pollution Benefits – Acting Sooner Benefits from acting 5 years sooner 11 Kuznet Curve: Impact of Development STAGE 2 Stabilization of STAGE 1 air quality STAGE 3 Initial of Improvement of AP Concentration emission control air quality STAGE 0 Start of STAGE 4 industrial High technology development applied Environmental Standard Level of development 12 Definitions Air Contaminants All materials other than the normal clean composition of air Air Pollutants Contaminants causing damage, harmful effects Air Pollution Presence in the outdoor and indoor air of substances, in conc. and duration, sufficient to produce measurable adverse effects on human beings, animals, vegetation or materials 13 Definitions: Air Pollution Episodes ▪ Air Pollution Episodes Occurrences of high pollutant concentration coinciding with stagnant and persistent air conditions in densely populated areas causing sharply increased illness and mortality from respiratory diseases ▪ Examples of air pollution episodes: London sulfurous smog (winter type): SO2, Soot (PM) Los Angeles photochemical smog (summer type): NOx + HC + O2 + hv → oxidants O3 + haze Indonesian forest fire in 1997: fine PM 13 Air Pollution Episodes: Very High Pollutant Conc. ▪ Example: London killer smog (Dec. 1952) ▪ Why we need to study air pollution? Identification/prediction of Episodes ex. coal combustion during winter Implementation of Controls, ex. stop using coal Epidemiological Studies, ex. health impact studies 15 Air Pollution Episodes: Meuse Valley 1930 Trapped by an inversion, pollutants accumulated in this steep-sided valley of 15 miles length. Coke ovens, steel mills, blast furnaces, zinc smelters, glass factories and sulfuric acid plants produced an estimated SO2 concentration of 8 ppm. It was estimated that the SO2concentration was reached to 22,600 ug/m3. 16 Air Pollution Episodes: Meuse Valley 1930 With in a few days more than 600 people fell ill, and 63 people died from the polluted air. Unfortunately no measurements were made. The major culprit was sulfur dioxide which, with the help of fog droplets oxidized to sulfuric acid mist with a particle size small enough to penetrate deeply into the lungs. 17 Air Pollution Episodes:Poza Rica de Hidalgo 1950 Poza Rica de Hidalgo was the scene of a major air pollution disaster in 1950 when hydrogen sulfide at an oil field was accidentally vented into the air under a low-altitude temperature inversion. 22 persons were killed and 320 hospitalized. 18  Types of Air Pollutants 1. By generation sources: Nature Man-made 2. By aggregation state: Gaseous: CO, NOx, SO2, VOC (benzene, toluene, …), etc. PM: solid or liquid suspended in the air, ranging from the largest gas molecule to >100 μm Terminology: TSP, PM10, PM2.5, ultrafine, nano-particles, etc. 3. By nature: Chemical pollutants Biological: pathogens, bacteria, virus, pollens Physical: noise, EM waves, heat 4. By formation processes: Primary: as emitted Secondary: formed in atmosphere (e.g. secondary particles and ground level ozone) 16 Types of Air Pollutants 5. By chemical composition: S-containing N-containing etc. 6. By potential effects: Toxic Hazardous (flammable, explosive, etc.) Oxidants GHGs, Ozone depleting substances 7. By regulation (common): Secondary Sulfate Particles formed in Atmosphere Criteria pollutants Non-criteria pollutants 17 Common Classification: Major vs Hazardous AP ▪ MAP (Major Air Pollutants or Criteria pollutants) Particulate Matter (PM): TSP, PM10, PM2.5 Sulphur dioxide (SO2) Nitrogen dioxide (NO2) Carbon monoxide (CO) Lead (Pb) Ozone (O3) ▪ HAP (Hazardous Air Pollutants or Air Toxics): VOC and semi-VOC (PAH, PCB, pesticides), heavy metals, etc. Polycyclic Aromatic Hydrocarbons: e.g. benzo-a-pyrene 18 Common Atmospheric Pollutants 19 General Classification of Gaseous Pollutants Primary air pollutants: Pollutants that are formed and emitted directly from particular sources. Examples are particulates, carbon monoxide, nitrogen oxide, and sulfur oxide. Secondary air pollutants: Pollutants that are formed in the lower atmosphere by chemical reactions. The two examples are ozone and secondary organic aerosol (haze). 20 Particulate Matter (PM) Most important in term of health effects: mortality and morbidity High levels in developing countries Primary vs Secondary particles Particle size is important: health effects, dispersion, formation, light absorption and climate 21 Fine Particle (𝐏𝐌𝟐.𝟓) Particulate Matter with a diameter equal to or less than 2.5 μm (also called “fine particle”) PM2.5 are tiny particles in the air that reduce visibility and cause the air to appear hazy when levels are elevated 25 Particle Sizes and Terminologies 26 Mass Distribution of Ambient Particles Different modes in a typical atmospheric particle size distribution Coarse particle = PM10, TSP Fine particle = PM2.5 Primary PM Secondary PM 24 Black Carbon (BC) and Organic Carbon (OC) More More light-absorbing refractory Black Elemental Carbon Light- Carbon (EC) (BC) Absorbing Carbon Brown * * (LAC) Carbon Thermal-Optical (BrC) Classification Organic Carbon (OC) Light-absorbing Classification Less Less light-absorbing * Measurement technique-specific split point refractory 26 Sulfur Oxides Produced from the combustion of sulfur found in fuels Major compounds: SO2 and SO3 Effects: Acid precursor (H2SO4) Respiratory problems Eye damage Damage to plants and water 24 Nitrogen oxides (NOx) Formed from high-temperature combustion of fuel in cars Mixture of nitric oxide (NO) and nitrogen dioxide (NO2) Effects: Acid precursor (HNO3) Respiratory problems Reddish-brown color of the atmosphere https://www.iqair.com/newsroom/nitrogen-dioxide (IQAir Staff Writers) 24 Tropospheric Ozone Usually formed from precursors in the atmosphere, such as VOCs and NOx Major constituent of photochemical smog Effects: Affects lining of lungs and respiratory tract Eye irritation Damage to plants, buildings and other materials Credit: Christopher AuYeung Source: CK-12 FoundationLicense: CC BY-NC 3.0 24 Carbon Monoxide Produced from the incomplete combustion of fossil fuels. Effects: When it enters the bloodstream, it may disrupt the supply of oxygen to the body tissues. Reacts with hemoglobin →carboxyhemoglobin CO – carbon monoxide has a 20X higher attraction to hemoglobin than O2. Can kill us by limiting our oxygen https://www.wolffardis.com/carbon-monoxide-poisoning/ in blood. 24 Carbon Monoxide Produced from combustion processes from vehicle fuel systems Effects: Headache or nausea Damage to plants Carcinogenic DOI: 10.1016/j.chemosphere.2020.129386 24 Combustion: Main Sources of Air Pollution 34 Combustion Air Pollutant Formation 1. Burning carbonaceous matter with air Complete combustion: HC + O2 → H2O + CO2 Incomplete combustion emits PIC: CO, soot (PM), HC NOx formed from nitrogen in air @ high temperature 2. Non-HC matters: N2, S, heavy metals, ash Burning non-carbonaceous matter present in fuel such as S, heavy metals results in air pollution emission Non-combustibles (ash): particles NOx formed from nitrogen in fuel (high temperature combustion) 29 Sources of Manmade Emission (Emission Inventory) USA 30 Industrial Facilities Contribute to Air Pollution Significantly contributes to air pollution since the late 19th century (start of Industrial era) Refinery Coal-fired PP Cement Brick Kiln 31 Biomass Open Burning Chiang Mai, Thailand 2013 32 Household Emission 33 Mobile Sources Mobile sources contribute over 60-80% of urban air pollution in developing countries 40 Natural Sources Volcano Forest Fires Pollen Pollen: Seasonal phenomena Dust storm Green-tinged clouds over Moscow caused by massive pollen from blooming of alder and birch trees Blooming (due to sudden onset of spring and rapidly rising temperatures) released pollen The pollen poses danger to people suffering from allergies and asthma, discomfort to others Additional works to clean up 41 Man-made vs Natural Sources Man-made source contribution is less than natural sources (10-20% of PM from man-made sources) --> but cause imbalance of nature Increases through development processes: fast change in air composition since industrial revolution (̴ 250 years ago) Increasing in mass and new toxic air pollutants Located in vicinity of human activities --> more harmful effects 42 Global Aerosol Emission Flux: Natural vs Anthropogenic Source: Hinds W.C., Aerosol Technology, 2nd Edition, Wiley Interscience 37 Measurement Units and Averaging Time ▪ PM: Weight/Volume (μg/m3) ▪ Gases: Weight/Volume (μg/m3) Volume/Volume (ppm, ppb, etc.) Two units are convertible for a given temperature, pressure and pollutant molecular weight (MWpol) ▪ Temperature and pressure are indicated if Weight/Volume units are used 38 Standard Temperature and Pressure STP: Standard Temperature and Pressure Pressure = 1 atmosphere = 760 mmHg Temperature = 0℃ = 273K USEPA standard conditions for ambient air:*** Pressure = 1 atmosphere = 760 mmHg Temperature = 25℃ = 298K USEPA standard conditions for emission: Pressure = 1 atmosphere = 760 mmHg Temperature = 20℃ = 293K 41 General Formula for Unit Conversion General formula: C[mg/m3] = 10−3 × C[ppm] × MWpol × P/(RuT) P: pressure, atm; T: temperature, K R u = 0.08208 × 10−3m3. atmΤg − mole. K = universal gas constant At 0℃, 1 atm (STP): C[mg/m3] = C[ppm] × MWpol/22.41 At 25℃, 1 atm (SC): C[mg/Nm3] = C[ppm] × MWpol/24.45 39 Correction of Gas Volume for Temp and Pressure V1: volume at actual temperature (T1) and pressure (P1 ) e.g. from measurement condition V2: volume at reference temperature (T2) and pressure (P2) e.g. 298 K, 1 atm P1 T2 V2 = V1 ∙ ∙ P2 T1 40 Temperature Units and Conversion °R = ℉ + 459.67 K = ℃ + 273.15 °R = K × 1.8 ℃ = (℉ − 32)/1.8 42 Averaging Time Affecting Measurement Results ▪ How? Longer averaging/sampling time lower the average concentration ▪ Why? Longer time after pollutants released from a source --> more dispersion --> more dilution Source-activity change with time: maximum appears for short periods, such as rush hours Meteorology changes significantly over long period: wet removal, stagnant air, etc. ▪ It is essential to indicate the sampling (average) time of ambient air quality data 43 Averaging Time Effects on AP Concentration 44 Averaging Time Effects on AP Concentration 45 Conversion Factors For concentration at different averaging periods from industrial sources USEPA – AERMOD model outputs 1-hr concentration can be converted to other averaging periods (stack continuous emission) by the following factors: Time Period Multiply 1-hr value by 3-hr 0.9 8-hr 0.7 24-hr 0.4 Annual 0.03-0.08 46 Averaging Time of Ambient Air Quality Standard Physical processes leading to higher concentration at shorter averaging periods: emission, wind, etc. Instantaneous concentration is difficult to measure and for exposure assessment averaged concentration for a certain period is more important Exposure: higher concentration for short exposure and lower concentration for longer exposure period Examples: US NAAQS & Thailand AAQS 24-h PM2.5: 35 μg/m3 vs annual PM2.5: 12 μg/m3 (USA) 24-h PM2.5: 50 μg/m3 vs annual PM2.5: 25 μg/m3 (Thailand) 47 Asian and Global Air Pollution Status Urban population growth 48 Status & Trends in Urban Ambient Air Pollution 49 Air Pollution in Asia: Highlights High pollution & air quality is worsening in urban areas --> PM (TSP, PM10, PM2.5) is the most significant No systematic records on PM2.5 but high levels reported in urban and remote areas Fast increase in emission sources and intensity: traffic, industry, utility Increase in precursors emission to form secondary PM and ozone Impact on human health, crops/ecosystem --> economical effect is serious but not well studied Indoor air pollution is serious Trans-boundary issues caused by long range transport: acid rain, ABC, regional haze, dust storm, etc. 50 Sources of AP in Asian Developing Countries Road traffic: largest contribution in urban area (old fleets, bad maintenance, more cars VS not enough road expansion, etc.) Stationary sources: coal-based, limited end-of-the-pipe emission control Domestic and commercial fuel burning: solid fuels --> indoor air pollution Biomass and refuse open burning Other significant sources: Outdoor/Street cooking, incense burning Open markets, unpaved roads 57 Major Air Pollution Problems around the World Cooking and Heating with Solid Fuels Source: solar.lowtechmagazine.com 58 Major Air Pollution Problems around the World PM2.5 Episode Seoul Bangkok Emission Sources at AIT Los Angeles 59 Major Air Pollution Problems around the World Climate Change Source: climate.nasa.gov Source: EurekAlert! Source: noaa.gov 54 CHAPTER PROBLEMS Problem 1: CO measured at 25℃ and 1 atm is 25 mg/m3. What is the CO concentration in ppm? Problem 2: SO2 emission from a power plant has the conc. of 500 ppm. Estimate the SO2 concentration in mg/m3 in the flue gas at the flue gas temperature of 150℃ and pressure of 1 atm. Problem 3: What are the major factors affecting air pollution concentration in different locations? Problem 4: Measurement conc. of CO at an ambient air site, near an emission source, over 1 hour period is 50 ppm, estimate CO concentration in ppm for 8 hour sampling period and for 24 hour sampling period. How and why the concentration changes with the sampling time? 55 CHAPTER PROBLEMS Problem 5: How will you use the Kuznet’s curve to demonstrate the benefits of different air pollution control strategies on air quality? Problem 6: What are the differences between primary and secondary pollutants? Problem 7: What are the major differences between ozone in troposphere and ozone in stratosphere? 56