Air Pollution By: Rebekah Triolo

Thoughts? What do you think of when introduced to this general topic of air pollution?

Air Pollution The introduction of chemicals, particulate matter, or microorganisms into the atmosphere at concentrations high enough to harm plants, animals, and materials such as buildings

Layers of the Atmosphere General term of air pollution refers to Tropospheric pollution Pollution in the troposphere is also called ground-level pollution

Major Air Pollutants Three Major Air Pollutants: Sulfur Dioxide Nitrogen Oxides Carbon Oxides

Sulfur Dioxide SO2 Corrosive gas Primarily comes from combustion of fuels like coal and oil Respiratory irritant Adversely effects plant tissues Natural occurrence

Nitrogen Oxides Two Forms: NO and NO2 NO Colorless Odorless NO2 Pungent Reddish-brown

Carbon Oxides Carbon Monoxide (CO) Colorless Odorless Formed during incomplete combustion Natural gas heaters malfunction Poor ventilation Carbon Dioxide (CO2) Colorless Odorless Formed during complete combustion Absorbed in photosynthesis

WHAT IS THE PROBLEM? If all of these pollutants are naturally occurring,

Particulate Matter Also called particulates or particles – Solid or liquid particles suspended in air Particles can be from – Wood fires – Road dust – Vehicle exhaust – Volcanoes – Fossil-fuel burning power plant smoke

Particulate Size Size of the particles do range Measured in micrometers – micrometer = 1 meter – Micrometer (µm)\ Average particulates 0.01 µm to 100 µm 10,000 µm 50 µm

Effects of Particulate Matter Particulates can be deposited in the respiratory tract Absorb sunlight and can affect photosynthesis Can cause haze – Reduction in visibility

Lead and Mercury Lead (Pb) Occurs naturally in rocks and soils Added to gasoline Compounds were released into the air Lead based paint Mercury (Hg) Found in coal and oil Toxic to central nervous system Released into the air by combustion of fossil fuels Concentrates in the air and also water

Volatile Organic Compounds (VOC) Organic compounds that become vapors at typical atmospheric temperatures Most contain hydrocarbons (carbon-hydrogen bond) – Gasoline, lighter fluid, dry-cleaning fluid, oil based paints, perfumes, etc. Strong aroma Can lead to photochemical oxidants

Pollutants Two types: Primary and Secondary

Primary Pollutants Polluting compounds that come directly out of a smoke stack, exhaust pipe, or natural emission source These include: CO, CO2, SO2, NOX Many VOCs are also primary pollutants – Example: gasoline is volatized from liquid to vapor, some of which leaves the car without being combusted

Secondary Pollutants Primary pollutants that have undergone a transformation from – Sunlight – Water – Oxygen Creates the main components for acid decomposition

Anthropogenic Emissions Highest producers for the following emissions – Carbon monoxide = On-road vehicles – Nitrogen oxides = On-road vehicles – Sulfur dioxide = Electricity generation – Particulate matter = Road dust

Clean Air Act Provides standards for human health and welfare – Human health: health of the human population including elderly, children, and sensitive populations (asthma) – Welfare: visibility, status of crops, natural vegetation, animals, ecosystems, and buildings

National Ambient Air Quality Standards (NAAQS) Periodically sets concentration limits for each pollutant Each pollutant as a concentration level set that should not be exceeded within a certain period of time Particulate matter often exceeds NAAQS standards Lead has decreased significantly

Black Triangle Located in the large area of Germany, Poland, and Czech Republic Burn high-sulfur-content coal Emissions from power plants cause this area to be one of the most polluted areas of the world Causes respiratory illness and forest ecosystems damage

Hot air???

Temperature??

Thermal Inversion Relatively warm layer of air covers a layer of cold dense air below Inversion layer traps emissions and they accumulate beneath

How do we control pollution?

Controlling Sulfur and Nitrogen Oxide Emissions Sulfur Fluidized bed combustion Granulated coal is burned closely to calcium carbonate Heated calcium carbonate absorbs Sulfur Dioxide Produces calcium sulfate Calcium sulfate is used in the production of sheetrock Nitrogen Burn temperature of fuel that are high and have the presence of oxygen allow more NOX to form Work towards lowering the two Catalytic converter in cars reduces NOX emissions

Controlling Particulate Matter Most common means of pollution control Easiest method is gravitational settling – Relies on gravity to remove particulates as air travels up a smokestack – Results in ash deposits that have to be properly disposed of

Baghouse Filter Dirty air enters Dust particles are trapped in a series of filter bags Cleaner, filtered air exits Shaker mechanism activated periodically to remove particles from filters which can be collected at the bottom

Electrostatic Precipitator Dirty air enters Air passes negatively charged plates to give them a negative charge Negatively charged particles are attracted to positively charged collection plates Cleaner air exits Collection plates are periodically discharged and particles fall for collection

Scrubber Dirty air enters Combustion exhaust streams move upward through shower of mist water Mist collects particles and pushed them to bottom Dirty water moves to sludge removal system Sludge is separated from water Water is reused Clean air exits through screen

Indoor Pollution What is it?

Developing Countries People use wood, animal manure, and coal for heating and cooking Biomass and coal are usually burnt in open-pit fires that do not have the proper fuel and air mix for complete combustion Normally no ventilation or exhaust system 1.6 million deaths from indoor air pollution

Developed Countries People are spending more time indoors Working conditions Homes are more tightly insulated Materials in the home that are made from plastic and other petroleum-based compounds

Asbestos Long, thin, fibrous silicate mineral with insulating properties Cause respiratory disease like asbestosis and lung cancer Not dangerous until it is disturbed

Carbon Monoxide Much more dangerous as an indoor pollutant Occurs when there is a malfunction of natural gas heaters Colorless and odorless allowing it to build up quickly Causes interference with the oxygenation of the blood Extended exposure causes death

Radon Radioactive gas that occurs naturally from decay of uranium Seems into home through cracks in foundation Can be transported through groundwater Attaches to dust particles in the air 21,000 die from radon induced lung disease

VOCs in Home Products Used in building materials, furniture, glues, and paints Deodorizers and solvents can contain VOCs and should not be inhaled Plastic fabrics, construction materials, and carpets can release VOCs over time

Sick Building Syndrome Inadequate or faulty ventilation Chemical contamination from indoor sources like glues, carpeting, furniture, cleaning agents, and copy machines Chemical contamination from outdoor sources like vehicle exhaust transferred insides Biological contamination from indoors or outdoors like mold or pollen

Acid Deposition NOX and SO2 are released in the air Come in contact with atmospheric oxygen and water Through series of reaction, they are transformed into Sulfuric acid (H2SO4) and Nitric acid (HNO3) These breakdown further to produce sulfate and nitrate and hydrogen ions (H+)