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Aerosol technology and air quality

01USDND, 01USDNE, 01USDQD

A.A. 2022/23

Course Language

Inglese

Course degree

Master of science-level of the Bologna process in Ingegneria Energetica E Nucleare - Torino
Master of science-level of the Bologna process in Ingegneria Meccanica - Torino
Master of science-level of the Bologna process in Ingegneria Meccanica (Mechanical Engineering) - Torino

Course structure
Teaching Hours
Lezioni 33
Esercitazioni in aula 12
Esercitazioni in laboratorio 15
Teachers
Teacher Status SSD h.Les h.Ex h.Lab h.Tut Years teaching
Tronville Paolo Maria Professore Associato ING-IND/11 33 12 0 0 3
Teaching assistant
Espandi

Context
SSD CFU Activities Area context
ING-IND/11 6 D - A scelta dello studente A scelta dello studente
Valutazione CPD 2021/22
2022/23
Air pollution is recognized as one of the main risk factors for premature deaths and hospital admissions worldwide. Particulate matter (PM) affects strongly the quality of the air both outdoors and indoors. An aerosol is defined in its simplest form as a collection of solid or liquid particles suspended in a gas. Aerosols are also referred to as suspended particulate matter, aerocolloidal systems, and disperse systems. These aerosols affect visibility, climate, and our health and quality of life. Once inhaled, these particles can affect the heart and lungs and cause serious health effects. Aerosols, solid or liquid particles suspended in the air, play important roles in atmospheric sciences and air pollution. Material synthesis can be carried out by means of aerosol reactors, i.e. systems in which particulates are made by gas phase chemical reactions. Bioaerosols are another important area of application for aerosol technology, covering disease transmission. Nanotechnologies rely on instrumentation able to produce, sample, control and control airborne nanoparticles. This course covers aerosol mechanical, optical and electrical properties, and measurement and control technologies and their relationship with air quality.
Aerosol technology deals with the governing physical laws, measurement techniques and control technologies of very small liquid or solid particles in gases. We can refer to aerosols also as suspended particulate matter, aerocolloidal systems, and disperse systems. To quantify the number, size, shape, chemical composition, and transport of aerosol particles a specific knowledge is needed. Particulate matter (PM) and bioaerosols (bacteria and viruses) affect strongly the quality of the air both outdoors and indoors and are recognized as one of the main risk factors for premature deaths, hospital admissions and disease transmission worldwide. Once inhaled, these particles can affect the heart and lungs and cause serious health effects. Aerosols play important roles in atmospheric sciences because they affect visibility and climate change, while they represent one of the main concerns when speaking of air pollution. On the other hand, aerosol technology is employed to engineer useful aerosols, including spray technology, gas phase synthesis systems for commodity materials, and aerosol based coating and 3D printing processes. Material synthesis can be carried out by means of aerosol reactors, i.e. systems in which particulates are made by gas phase chemical reactions. Nanotechnologies and new additive manufacturing process design rely on instrumentation able to produce, sample and control airborne particles. The presence of viable or non-viable aerosol particles in enclosed spaces can be controlled by means of ventilation systems coupled with suitable air cleaning equipment. For reducing the risk of transmission of airborne diseases, source control (facemasks) of particulate pollutants should be the preferred method. In this way, the need of cleaning or ventilating large spaces with high airflow rates by means of Heating, Ventilating and Air Conditioning (HVAC) systems can be reduced. The course introduces aerosol properties and their measurement, together with the control technologies able to enhance the air quality.
The students understand the effects of airborne particulate on outdoor and indoor air quality. The students gain fundamental knowledge on laws governing mechanical, optical and electrical properties of aerosols. Aerosol behaviors including diffusion, coagulation, condensation, charging and evaporation are discussed. The students understand basic principles to generate, sample, measure and control airborne particles. The students learn state-of-the-art instruments for air-borne particles from micrometer to nanometer size range. The students learn about non-exhaust vehicle emissions and their impact on urban atmospheric pollution and on human health. The students learn how to model indoor particulate matter concentration and its control.
At the end of the course the students will be able to: -Understand the effects of airborne particulate on outdoor and indoor air quality and the basics of aerosols behavior including diffusion and charging. -Gain fundamental knowledge on the laws governing the mechanical and electrical properties of aerosols. -Learn about state-of-the-art instruments for airborne particles from micrometer to nanometer size range. -Understand basic principles to generate, sample, measure and control airborne particles. -Interpret a set of measured data by means of particle size statistics. -Learn how to model indoor particulate matter concentration and its control.
Basic concepts of Mathematics, Chemistry and Physics as obtained in the bachelor's degree program. Mandatory precedence of Fluid Mechanics, Thermodynamics and Heat Transfer courses
Basic concepts of Mathematics, Chemistry and Physics as obtained in the bachelor's degree program. Mandatory precedence of Fluid Mechanics, Thermodynamics and Heat Transfer courses. Basic IT applications: text editor, calculation spreadsheet and presentation tools.
PART A (15 hours) Aerosol fundamentals Gas and particle motion Particle size statistics Coagulation Condensation and evaporation Optical properties Electrical properties Laboratory (3 hours) PART B (9 hours) Sampling and measurement of concentration Mass concentration and single particle analysis Respiratory deposition Laboratory (3 hours) PART C (9 hours) Air quality guidelines and data Classes of air contaminants Vehicle non-exhaust emissions (brakes, tires, batteries) Air quality in subway systems PART D (15 hours) Particulate Matter Control Separation devices Electrostatic precipitators Fibrous filters Measurement of the performance of air cleaning devices Choice criteria Laboratory (6 hours) PART E (12 hours) Indoor air quality Airborne particulate contaminants found in indoor environments and their impact on human health Model for indoor PM control Laboratory (3 hours)
Aerosol technology applications and basic definitions. Particulate matter health effects on humans. Air quality standards for outdoor air. Indoor air quality. Categories of airborne contaminants. Particle properties and characterization. Equivalent sphere concept. Properties of gases. Kinetics theory of gases. Mean free path and Knudsen number. Particle Reynolds number. Mechanics of aerosol particles. Newton's and Stokes’s laws: terminal settling velocity, slip correction and aerodynamic diameter. Straight-line particle acceleration and curvilinear particle motion. Stokes number. Single and multiple impactors. Instruments measuring aerodynamic particle size. Particle size statistics. Probability density and cumulative distribution functions. Moments of a distribution and physical meaning for particle distributions. Lognormal frequency function and its properties. Conversion of parameters from one moment distribution to another. Adhesion of aerosol particles to surfaces. London-van der Waals and electrostatic forces. Surface tension of adsorbed liquid films. Detachment of particles. Resuspension. Particle reentrainment and bounce. Brownian motion and diffusion. Stokes-Einstein equation. Diffusion coefficient of an aerosol particle. Deposition by diffusion. Rate of particle deposition on surfaces: laminar and turbulent regimes. Diffusion batteries. Air filtration. Air filter elements, media and systems. Deep and surface filtration. Layer efficiency in fibrous filtration. Most penetrating particle size. Airflow resistance and quality factor of an air filter element. Deposition mechanisms: interception, inertial impaction, diffusion, gravitational settling, electrostatic attraction. Performance measurement and rating of air filters. Size range of a typical atmospheric aerosol and most common "loading" dusts. Surface and depth loading. PM based approach for air filters classification system with ePMx rating. Strategies for controlling indoor pollution. Typical ventilation system with components and operating modes. Design of a ventilation system and choice of air filters based on the mass balance of contaminants in a confined environment. Position and purpose of air cleaners. Bioaerosols: viable and non-viable. Bioaerosols size range, aerosolization and sampling. Aerosol emission by humans. Health effects of bioaerosols. Respiratory deposition and health hazards. Respiratory system. Particle clearance mechanisms. Inhalable, thoracic and respirable fractions. Performance assessment of personal protection equipment for respiratory tract, medical masks and community face coverings. Atmospheric aerosols. Natural and anthropogenic sources of particles. Charging ions in the atmosphere. Typical modal parameters for an urban aerosol. Nucleation, accumulation and coarse mode in urban aerosols. Global effects of atmospheric aerosols. Electrical properties of aerosols. Charging mechanisms. Corona discharge. Boltzmann equilibrium charge distribution. Electrostatic precipitators. Light scattering. Optical diameter. Mie theory. Optical particle spectrometers and photometers. Condensation Nuclei Counter. Electrical mobility diameter. Differential Mobility Analyzer. Scanning Mobility Particle Sizer (SMPS). Sources and contribution of vehicle non-exhaust emissions to PM pollution. Factors influencing PM emission levels from brakes and tires. Technological and non-technological measurements to reduce non-exhaust emissions. Laboratory applications: • Calculation of PM indoor concentration. Effect of supply airflow rate, air filter efficiency and internal generation on particulate contamination in the occupied environment. • Air filter performance assessment. Measurement of the resistance to airflow as a function of the airflow rate and correction to reference air density. Determination of the filter fractional efficiency values. Calculation of ePMx rating following a PM based approach. • Calculation of the properties of lognormal distributions using a set of plastic spheres to represent a polydisperse aerosol at 1000:1 scale. Students’ project: Use of low-cost PM sensors. Literature search. Analysis of a scientific paper taken as a reference for the students' final report. Working with the Arduino Module and importing data from sensors. Using software tools to import the data and analyze them. Support for assembling and programming the low-cost PM sensor module used for the project Exercises with application of the theory will be solved during dedicated exercise sessions.
Students will be given the opportunity to develop a hands-on project about particulate matter monitoring or measurement.
Students will be given the opportunity to develop a hands-on project about particulate matter monitoring or measurement.
Experimental activities will support theoretical lectures and application exercises related to the focus of the students’ study plan. Laboratory practice will help learn measurement techniques of airborne particles and understand mechanism of particle generation, transport and loss. The students will understand control technologies of airborne pollutants and learn how to choose among them. The students in teams will develop a research project related to an aerosol technology topic, with focus on air quality assessment and control. Students will develop a technical research report describing their motivation, literature review, methods, and results, and will summarize their research with a classroom presentation at the end of the semester. A guided visit to a measuring station and to a manufacturing facility will be carried out during the course.
Experimental activities will support theoretical lectures and application exercises. Laboratory practices will help learn measurement techniques of airborne particles and understand the mechanisms of particle generation, transport and loss. The students will understand control technologies of airborne pollutants and learn how to choose among them. The students in teams will develop a research project related to an aerosol technology topic, with focus on air quality assessment and control. They will develop a technical research report describing their motivation, literature review, methods, and results, and will summarize their research with a classroom presentation at the end of the semester. A guided visit to a measuring station and/or to a manufacturing facility will be carried out during the course, if the circumstances allow. Students will carry out three individual assignments, aimed primarily at encouraging critical thinking about some relevant topics covered in the course. Both the research project and the assignments will contribute to the final grade.
Hinds W.C., Aerosol Technology: Properties, Behavior, and Measurement of Airborne Particles, Wiley, 1999. Seinfeld J.H., Pandis S.N., Atmospheric Chemistry and Physics - from Air Pollution to Climate Change, Wiley, 2006. Lecture notes.
Hinds W.C., Aerosol Technology: Properties, Behavior, and Measurement of Airborne Particles, Wiley, 1999. Kulkarni P., Baron P., Willeke K., Aerosol Measurement: Principles, Techniques, and Applications, Wiley, 2011. Seinfeld J.H., Pandis S.N., Atmospheric Chemistry and Physics - from Air Pollution to Climate Change, Wiley, 2006. Lecture notes.
Modalità di esame: Prova orale obbligatoria; Elaborato scritto individuale;
Exam: Compulsory oral exam; Individual essay;
With reference to the above-mentioned project, students are expected to perform a detailed analysis and format their report as a formal research article/conference paper. As part of the exam, students will complete a final report (approximately one week in advance) and give a final presentation at the end of the semester. That includes also answering questions and clarifying doubts. The final mark is based on the quality of the outcome of the project and of its discussion (50% of the final mark). This part is intended to assess the student's ability to understand and put into practice the knowledge provided by the lectures and the laboratories. Two other specific questions about their experimental activities and the theoretical aspects presented throughout the semester will contribute to determine the final mark. This part has the purpose of evaluating the knowledge assimilated that cannot be evaluated through the project and its presentation.
Gli studenti e le studentesse con disabilità o con Disturbi Specifici di Apprendimento (DSA), oltre alla segnalazione tramite procedura informatizzata, sono invitati a comunicare anche direttamente al/la docente titolare dell'insegnamento, con un preavviso non inferiore ad una settimana dall'avvio della sessione d'esame, gli strumenti compensativi concordati con l'Unità Special Needs, al fine di permettere al/la docente la declinazione più idonea in riferimento alla specifica tipologia di esame.
Exam: Compulsory oral exam; Individual essay;
With reference to the above-mentioned project, students will perform a detailed analysis and format their report as a formal research article/conference paper. As part of the exam, students will complete a final report (one week in advance before the exam or the date agreed before the exam) and present it. That includes also answering questions and clarifying doubts. This part is intended to assess the student's ability to understand and put into practice the knowledge provided by the lectures and the laboratories. There will be three homework assignments during the course that will involve a combination of hand calculations, development of spreadsheets, and learning the basics of some software packages typically used in the field. The students will complete the homework before the final exam. This part has the purpose of evaluating the ability to apply what was learnt but cannot be evaluated through the project and its presentation. Course grades will be determined by the total number of points accumulated through project, assignments, and a lecture (including an exercise) at the exam on a topic explained during the course. The student will be informed about the topic three days before his exam. This part has the purpose of evaluating the knowledge digested that cannot be evaluated through the project and its presentation. The total number of points available in each category is listed here below as a percentage value. Project (report, presentation, discussion): 50% Homework assignments (report and discussion): 25% Lecture on a topic communicated 72 hours prior the exam with discussion: 25% Total: 100% Both the project presentation and the exam can be carried out remotely.
In addition to the message sent by the online system, students with disabilities or Specific Learning Disorders (SLD) are invited to directly inform the professor in charge of the course about the special arrangements for the exam that have been agreed with the Special Needs Unit. The professor has to be informed at least one week before the beginning of the examination session in order to provide students with the most suitable arrangements for each specific type of exam.
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