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  2. Detailed Syllabus: Unit 1 Introduction, definition of air pollutant, general nature of air pollution problem, effects of major pollutants on human, vegetation and other materials, global air pollution impact e.g. global warming, depletion of ozone layer, acid rain etc. Weather and climate role in air pollutant mechanism. Unit 2 Meteorology, lapse rate, stability conditions, wind velocity profile, stack plumes, plume rise, calculation of plume rise, effective stack height Air quality monitoring; sampling duration, selection of sampling sites, principle of sampling instruments, measurement units, sampling and analysis of SPM, RSPM, SOx, NOx, and CO. Unit 3 Dispersion of pollutant in the atmosphere, factors affecting the desperation phenomena, eddy diffusion model, Gaussian dispersion equation, reduction of Gaussian dispersion equation to ground level C/L concentration and for line sources, assumptions and limitations Unit-4 Introduction, gaseous pollutants control devices and their working principle, absorption, adsorption, combustion and condensation, SOx control and NOx control, process control, in combustion process and treatment of flue gases, catalytic converters. Unit 5 Introduction, particulate control equipments; gravity settling chambers, cyclone separators, fabric filters, electrostatic precipitators and wet scrubber, working principle, design, advantage, and disadvantages and limitations of equipments. Design of ventilation system, basics of hood and duct design. Gate syllabus and Net Syllabus: whatever you are going to add You can also add using track change in word file
  3. Suggested Books : Air Pollution and Control, Crawford, McGraw Hill Series Environmental Engineering, Peavy and Rowe, McGraw Hill Series Air Pollution, Neol De Nevers, Tata McGraw Hill Pvt. Ltd. New Delhi India Fundamentals of Air Pollution (Fourth Edition), Daniel A. Vallero Introduction to Environmental Engineering, Masters & Masters, Printice Hall
  4. DEFINITION occurs when the air contains gases, dust, fumes or odor in harmful amounts.  it is when concentrated gases exceed safe limits Air Pollution can be defined as: The introduction of any chemical, physical or biological agent into an atmosphere that has the potential to cause adverse impacts. TYPES OF AIR POLLUTION All types of air pollution can be divided into two basic types Primary Air Pollutants are emitted directly into the atmosphere. For example, carbon monoxide is emitted by cars and light-duty trucks. Secondary Air Pollutants are formed within the atmosphere by chemical reactions involving precursors that are emitted into the atmosphere. Ozone a primary component of “smog” is formed by sunlight-driven reactions involving volatile organic compounds (VOC) and nitrogen oxide precursors. Outdoor Air Pollution o Smog o Particulates o Acid Rain o Greenhouse Gases Indoor Air Pollution
  5. For regulatory purposes The U.S. Clean Air Act, its amendments and subsequent litigation separates air pollutants into three categories Criteria Pollutants are common pollutants that were known to produce adverse health effects at the passage of the Clean Air Act Amendments (CAAA) of 1970. These include: ozone, particulate matter, sulfur dioxide, carbon monoxide, nitrogen dioxide, and lead. EPA was required to develop and update National Ambient Air Quality Standards (NAAQS) for each of these compounds. Hazardous Air Pollutants or air toxics are compounds proven, or expected to be, carcinogenic, mutagenic, teratogenic or capable of producing other adverse health or environmental effects. The CAAA of 1990 specified 187 air toxics for regulation. Greenhouse Gases or Radiatively Important Trace Substances (RITS)
  6. CAUSES Natural Sources e.g. smoke that comes from wildfires, volcanoes, methane, dust Human Sources  e.g. power plants and automobiles, fumes, burning wood stoves, fireplaces, and furnaces Pollutants Carbon Dioxide Carbon Monoxide  Sulfur Dioxide Nitrogen Dioxide
  7. Primary Mechanism Formation of VOC Biological generation of VOC Formation of liquid aerosol droplets Anthropomorphic generation of particulate aerosol Biological formation of particulate aerosols Particulate aerosol formation
  8. Secondary Mechanism  Condensation  Adsorption  Nucleation
  9. How are These Agents Introduced into the Atmosphere? • There are four types of sources that emit air pollutants – Stationary Sources – Mobile Sources – Area Sources – Natural Sources • There are four primary ways in which pollutants can be emitted into the atmosphere – Combustion and Thermal Processes – Evaporation – Physical (Mechanical) Processes – Biological (Metabolic) Processes
  10. What is Particulate Matter? Particulate matter (PM) describes a wide variety of airborne material. PM pollution consists of materials (including dust, smoke, and soot), that are directly emitted into the air or result from the transformation of gaseous pollutants. Particles come from natural sources (e.g., volcanic eruptions) and human activities such as burning fossil fuels, incinerating wastes, and smelting metals. Image from module3/distribu/distribu.htm
  11. How is PM Regulated? PM is one of the six EPA “criteria pollutants” that have been determined to be harmful to public health and the environment. (The other five are ozone, sulfur dioxide, nitrogen dioxide, carbon monoxide, and lead.) EPA is required under the Clean Air Act to set national ambient air quality standards (NAAQS) to protect public health from exposure to these pollutants. Areas that exceed the NAAQS are designated as nonattainment, and must institute air pollution control programs to reduce air pollution to levels that meet the NAAQS.
  12. PM Where Does PM Originate? VOCs NO2 SO2 Sources may emit PM directly into the environment or emit precursors such as sulfur dioxide (SO2), nitrogen dioxide (NO2), and volatile organic compounds (VOCs), which are transformed through atmospheric chemistry to form PM. Ammonia (NH3) Ammonia (NH3)
  13. Sources of PM and PM Precursors Mobile Sources (vehicles) VOCs, NO2, PM Stationary Sources (power plants, factories) NO2, SO2, PM Area Sources (drycleaners, gas stations) VOCs Natural Sources (forest fires, volcanoes) PM
  14. Determinants of PM Concentration • Weather patterns • Wind • Stability (vertical movement of air) • Turbulence • Precipitation • Topography • Smoke stack height and temperature of gases Nearby natural and built structures may lead to downward moving currents causing aerodynamic or building downwash of smokestack emissions.
  15. • Air pollution is a multi-step process – Compounds are emitted into the atmosphere by both man-made and natural sources (emissions sources) – The compounds are mixed, dispersed and transported by meteorological conditions (transport phenomena) – As these components are being mixed and transported, they are undergoing chemical reactions that can remove, transform or produce new compounds (atmospheric chemistry) – At some point this parcel of air will reach an individual who, through normal respiration, will bring a portion of this parcel into his/her lungs where the compounds will have an opportunity to interact with the lung tissues before being exhaled (respiration) – These compounds can have an influence on the individual (health effects) General Discussion

Notas do Editor

  1. This lecture is intended to provide a broad overview of air pollution and its potential human health effects. While the “chain-of-events” may seem trivial, it is important to note that each one of these processes carries its own set of physical, chemical and biological principles and with it, some degree of uncertainty in estimating the evolution of each process. This is generally a good time to point out the end goal of our process (i.e. a health impact assessment) is unlikely to be strictly deterministic due to the uncertainties in estimating each step and thus such assessment are almost always statistical in nature.