Unit 7: Atmospheric Pollution Flashcards
The Air Pollutants
- NOSCLP
- Nitrogen Oxides (NO or NO2)
- Ozone
- Sulfur Dioxide
- Carbon Monoxide
- Lead
- Particulate Matter
CO2: Carbon Dioxide
- GREENHOUSE GAS
- Technically, it’s not a pollutant!
- CO2 is a produce of cellular respiration, and a reactant for photosynthesis, so we care more about the concentration in the air and its anthropogenic emission sources
- Natural sources: respiration, decomposition, volcanic eruptions
- Anthropogenic sources: extraction/combustion of fossil fuels (esp. coal)
CO: Carbon Monoxide (CO)
- Primary pollutant
- Formed during incomplete combustion of most matter
- Anthropogenic sources: Vehicle exhaust, furnaces, fireplaces
- Especially dangerous when fuels such as manure, charcoal, and kerosene are burned indoors
Nitrogen Oxides (NO, NO2)
- Primary pollutant
- Natural sources: forest fires, lightning, soil microbes
- Anthropogenic sources: motor vehicle and fossil fuel combustion
SO2: Sulfur Dioxide
- Primary pollutant
- Natural sources: forest fires and volcanic eruptions
- Anthropogenic sources: combustion of coal and oil
H2SO4: sulfuric acid and HNO3: nitric acid
- Secondary pollutants
- This is acid rain!
- Anthropogenic sources: combustion of coal and oil
CH4: Methane
- GREENHOUSE GAS
- Primary pollutant
- Natural sources: livestock (cows!), decomposition
- Anthropogenic sources: landfills, fracking, combustion of natural gas
Pb: Lead and Hg: Mercury
- Lead: from gasoline (phased out by 1996), paint in older buildings, water pipes (Flint!)
- Mercury: combustion of coal and oil
- Primary pollutants
- Both of these are toxic to the central nervous system of living organisms
VOCs: Volatile Organic Compounds
- Primary pollutant
- Holds special distinction as the #1 indoor pollutant
(by concentration) - Evaporates/sublimates at room temperature
- Natural sources: Trees
- Anthropogenic sources: gasoline, vapors from furniture, paneling, carpets, formaldehyde
- VOCs exist as vapors
PM: Particulate Matter
- Primary pollutant
- Natural sources: fires, dust storms, volcanic eruptions
- Anthropogenic sources: construction sites, combustion of fossil fuels
Hydrocarbons and PANs
Hydrocarbons:
- primary pollutants
- Hydrocarbons are a type of volatile organic compound (VOC)
- Hydrocarbon emissions result from fuel that does not burn completely in the engine
PANs - Peroxyacyl nitrates:
- Secondary pollutants
- Family of compounds composed of N, O, C, and H atoms
- Sources include: motor vehicles, tobacco smoke, fossil fuel combustion
Different Ways that Pollutants are Emitted in Houses
- Underlying bedrock (rocks/soil) has uranium that decays into Radon (Rn) gas (lung cancer)
- Leaky/poorly ventilated stoves, furnaces, fireplaces can produce
CO (asphyxiant -> death) and PM (respiratory irritant) - Office equipment emits
VOCs (respiratory irritant, carcinogen) - Pipe insulation, floor + ceiling tiles have asbestos (lung disease/cancer)
- New furniture releases
formaldehyde (VOC) (respiratory irritant, carcinogen) - Heating & cooling ducts support the growth of mold, mildew, bacteria, and dust
- Old paint may have lead - Pb (neurotoxin)
- Cleaning fluids, pesticides, paints, etc. produce VOCs (respiratory irritant, carcinogen)
- Pets shed/leave behind animal dander (allergies)
Radon
- Radon-222 (most stable isotope; half-life ~4 days)
- naturally occurring radioactive gas
- produced by the decay of uranium found in rocks and soils
- Moves up through soil and enters homes via the basement or cracks in the walls or foundation
- Dissolves in groundwater that enters homes through a well
Noise Pollution
- Sound at levels high enough to cause physiological stress and hearing loss
- Noise pollution is measured in decibels (dB) on a logarithmic scale (like the pH scale)
Noise Pollution’s Harmful Effects on Ecological Systems
- stress
- masking of sounds used to communicate, mate, and/or hunt
- damaged hearing
- changes to migratory routes
How Does Ozone Form Naturally
NORMALLY:
In the presence of SUNLIGHT:
NO2 breaks down to NO + O
Then the O combines with O2 from the air in the troposphere and becomes O3 (bad ozone)
When there is less sunlight/during the night:
O3 + NO (formed during the day) → NO2 + O2
How Does Photochemical Smog Form
“Bad” ozone builds up & smog forms during peak hrs of sunlight:
NO bonds with VOCs -> NO-VOCs
NO-VOCs are photochemical oxidants (PANs)
combo of NO-VOCs + O3 → accumulation of “SMOG”
How to Reduce Air Pollutants
- drive less, use mass transit
- promote the use of electric and hydrogen fuel cell vehicles
- Maintain your car properly (i.e. emissions check during inspection)
- Fill up your gas tank during the cooler hours of the day (less VOCs emitted during hours of a lot of sunlight)
Thermal (or Temperature) Inversions
- Phenomenon where the air temperature at the Earth’s surface is cooler than the air at higher altitudes then another layer of cool air
- Typically takes place over a few hours; could be over a few days in extreme circumstances
- These conditions can lead to an accumulation of pollutants close to the ground
Three Conditions that Lead to Thermal (or Temperature) Inversions
- If the area is: located in valleys (between mountains) so the hot air gets trapped between the mountains and the pollutant that come from the city gets trapped underneath that
Note: Particulate matter is most concerning for humans because PM 2.5 or under is extremely dangerous - If the area has a high pressure system that keeps the warm air from rising
- If a cool sea breeze (this is dense COLD air) wedges itself underneath the warm air layer
Catalytic Converters
- device for internal combustion engines that converts pollutants in exhaust into less harmful molecules
- converts CO, NOx, and hydrocarbons into the less harmful CO2, N2, O2, and H2O
- Note that CO2 is still a greenhouse gas but it is not a toxin
Vapor Recovery Nozzle
- designed to capture and prevent gasoline vapors from escaping into the atmosphere during refueling at gas stations
Results in Less Emissions of:
- Volatile Organic Compounds (VOCs) – Key contributors to smog and ground-level ozone
Wet and Dry Scrubbers
- Removes particulates and/or gases from coal-burning power plants
- Wet scrubbers use water or limestone + water slurry; dry scrubbers do not
- Wet scrubbers remove more pollutants vs. dry
- but disposal issue is created with wet scrubbers b/c the “slurry” ends up in a landfill or is stored on site
Results in Less Emissions of:
- Sulfur dioxide (SO₂) – A major contributor to acid rain.
- Particulate matter (PM) – Small solid and liquid particles that can cause respiratory issues.
- Hydrogen chloride (HCl) and other acid gases – Harmful to both health and the environment.
Electrostatic Precipitators
- used to reduce emissions of particulate matter on coal-burning power plants
- Uses electrical charge to remove PM from exhaust stream
Acid Rain
- When SOX & NOX combine with water vapor, H2SO4 and HNO3 form
- secondary pollutants
- Large risk to downwind communities
- Kills plantlife, pollutes rivers and streams, and erodes stonework
- acidification of surface water and soil → this is minimized if limestone is present in the bedrock (remediates acidity by neutralizing it!)
- affects plants’ abilities to absorb nutrients from soil → this is minimized if limestone is present in the bedrock (remediates acidity by neutralizing it!)
- damages sculptures, buildings, car paint
How to Fix Acid Rain
- reduce SOx and NOx emissions
- Wet and dry scrubbers remove these gases from industrial exhaust (installed in coal-burning power plants)
- Develop “cleaner” fuel burning vehicles → electric cars and hydrogen fuel cell vehicles!
Global/large-scale Solutions for Air Pollution
- Energy-efficient power generation and buildings
- Improve waste management
- Greener and more compact cities
- Reduce agricultural burning
- Access to clean, affordable fuels
- Safe and affordable public transit
