air pollution & control presentation
TRANSCRIPT
Air Pollution and Control The Breath of AirTOPIC
Contents
Chemistry & Composition (atmosphere)
Atmosphere Layers
Concept of Air Pollution
Air Pollutants & Sources4
1
2
3
Part I
Contents
Greenhouse Effect & Global Warming
Effects of Air Pollutants
Methods of Air Pollution Control
5
6
7
Part II
Air Pollution…
Comes From Many Sources
Smog hanging over cities is the most familiar and obvious form of air pollution. But there are different kinds of pollution — some visible, some invisible —that contribute to global warming. Generally any substance that people introduce into the atmosphere that has damaging effects on living things and the environment is considered air pollution.
Chemistry & Composition Atmosphere
Atmospheric Composition
Atmospheric Chemistry
Branch of atmospheric Branch of atmospheric sciencescience
Multidisciplinary field of Multidisciplinary field of researchresearch
Chemistry of the Earth’s atmosphere & that of the other planets is studied.
Draws on environmental chemistry, physics, meteorology, computer modeling, oceanography, geology & volcanology and other disciplines.
Minor constituents:
Nitrogen, N2 - 78.084%
Oxygen, O2 – 20.946%
Argon – 0.934%
Note: The mean mol. mass ofair is 28.97 g/mol.
- seeks to understand the causes of acid rain, photochemical smog & global warming.
CO2, Ne, He, CH4, Kr, H2, H2O(g)
It is of importance because of the interactions between the atmosphere and living organisms.
What is in air...?
Atmosphere Layers
Exosphere
Thermosphere
up to 85 km
up to 51 km
7 – 17 km
104 km
up to 693 km
Mesosphere
Stratosphere
Troposphere
Earth's atmosphere can be divided into five main layers. These layers are mainly determined by whether temperature increases or decreases with altitude.
Atmosphere Layers
Other Layers• part of the troposphere, near the earth’s surface affected through turbulent diffusion.
• forms the inner edge of the magnetosphere, ionized by solar radiation.
Ozone Layer
Ionosphere
Homo/hetero-sphere
Planetary boundary• defined by whether the atmospheric gases are well-mixed.
• 90% ozone is contained in the stratosphere (15 -35 km)
Concept of Air Pollution
Air pollution and weather are linked in two ways. One concerns the influence that weather conditions have on the dilution and dispersal of air pollutants. The second connection is the reverse and deals with the effect that air pollution has on weather and climate.
Air is never perfectly clean. Volcanic ash, salt particles, pollen and spores, smoke, and windblown dust are all examples of “natural air pollution.” One of the most tragic air-pollution episodes occurred in London in December 1952, when more than 4000 people died.
Concept of Air Pollution
• Photochemical smog, a noxious mixture of gases and particles, is produced when strong sunlight triggers photochemical reactions in the atmosphere.
• Ozone is the major component of photochemical smog.
• primary pollutants, which are emitted directly from identifiable sources
• secondary pollutants, which are produced in the atmosphere when certain chemical reactions take
place among primary pollutants
Air
Pollutants• airborne particles and gases that occur in concentrations that endanger the health and well-being of organisms or disrupt the orderly functioning of the environment.
Pollutants2 categories
Smog
Concept of Air Pollution
Economic activity, population growth, meteorological conditions, & regulatory efforts to control emissions all influence the trends in air pollution. The Clean Air Act of 1970 mandated the setting of standards for four of the primary pollutants—particulates, sulfur dioxide, carbon monoxide, & nitrogen oxides—as well as the secondary pollutant ozone.
The most obvious factor influencing air pollution is the quantity of contaminants emitted into the atmosphere. Two of the most important atmospheric conditions affecting the dispersion of pollutants are (1) the strength of the wind and (2) the stability of the air.
Concept of Air Pollution
When an inversion exists and winds are light,
diffusion is inhibited and high pollution
concentrations are to be expected in areas where pollution sources exist.
the greater the mixing depth, the
better the air quality.
Inversions aloft are associated with sinking air that characterizes
centers of high air pressure.
• Mixing depth – a vertical distance between Earth’s surface and the height to which convectional movements extend; Temperature inversions in w/c the atmosphere is very stable and the mixing depth is restricted.
Atmospheric stability
Concept of Air Pollution
Acid PrecipitationAcid Precipitation
• formed when sulfur & nitrogen oxides produced as by-products of combustion and industrial activity are converted into acids during complex atmospheric reactions.
producing water that is toxic to fish, acid precipitation has also detrimentally altered complex ecosystems.
the damaging effects of acid precipitation on the environment include the lowering of pH in
thousands of lakes.
Acid
Rain Snow
Air Pollutants & Sources
Major Air Pollutants
Text in hereproduced by burning of fossil fuels (e.g. fuel oil and coil). A large proportion is
produced by power stations and metal smelters which burn sulphur-containing
coal, and also by the manufacturing industries
which burn fuel oil.
Carbon Monoxide
produced by the incomplete burning of carbon-
containing fuels, such as petrol, coal and wood.
Particulates
produced by refuse incineration, factories, diesel vehicles, construction sites, and coal/charcoal burners.
Particulates are solid or liquid particles which are so
small that they remain suspended in the air for a
long period of time.
Ozone produced by the reaction of
oxygen gas with free atoms of oxygen which are formed from the reactions between nitrogen
oxides and hydrocarbons in sunlight.
produced by petrol- or diesel-burning engines and
coal/oil furnaces.
Nitrogen oxides
Hydrocarbons
Sulphur dioxide
formed from the evaporation of materials
such as petrol, diesel and solvents when exposed to
air.
Greenhouse Effect & Global Warming
Greenhouse Effect & Global Warming..
Effects of Air Pollutants
Interferes with photosynthesis, carbohydrate production
Cancer, asthma, birth defects, eye & respiratory system irritation, and genetic mutation.
contribute to sick building syndrome indoors
Acid rain: soil, buildings & materials, forest & aquatic life.
prolonged exposure to high CO concentrations, unconsciousness,
convulsions and death would occur; severe effects on the baby
of a pregnant woman.
It is important to remember that air pollutants are transboundary , i.e. they know no borders and travel easily from their sources towards other locations spreading pollution throughout the world.
Air Pollution Effects..
Methods of Air Pollution Control
NOx ControlMechanical Collectors (dust cyclone)
VOC abatementElectrostatic Precipitators
Acid Gas/SO2 controlBaghouses
Mercury ControlScrubbers
Devices
Control
Pollution
The following items are commonly used as pollution control devices by industry or transportation devices. They can either destroy contaminants or remove them from an exhaust stream before it is emitted into the atmosphere.
Mechanical Collectors
Dust Cyclone
Electrostatic precipitators
Baghouses
Scrubbers
Cyclone Spray
Mechanically aided
Ejector Venturi
Wet Scrubber
Methods of Air Pollution Control(Some things you can do for CLEAN air)
Limit Your Family Size
Eliminate Toxic Chemical Use at
Home
Conserve Energy
Reduce Waste
Methods of Air Pollution Control(Some things you can do for CLEAN air)
No Burn Barrels Cut Back/
Eliminate Lawn Mowing
Modify Your Transportation
Plant leafy trees and shrubs
No Burn Barrels
No Burn Barrels
No Burn Barrels
No Burn Barrels
No Burn Barrels
Cut Back/ Eliminate Lawn
Mowing
Cut Back/ Eliminate Lawn
Mowing
Cut Back/ Eliminate Lawn
Mowing
Modify Your Transportation
Modify Your Transportation
Modify Your Transportation
Plant leafy trees and shrubs
Plant leafy trees and shrubs
Plant leafy trees and shrubs
Plant leafy trees and shrubs
Thank You!The roots of education are bitter, but the fruit is sweet.
Aristotle