Unit 7 - Atomspheric Pressure

7.1 Introduction to Air Pollution

• air pollution: anything in the atmosphere that is harmful to organisms
• primary pollutants: emitted directly into the atmosphere
  • can be natural or anthropogenic (produced by humans)
  • ex. pollen, plant VOCs, volcanic ash, fossil fuel combustion
• secondary pollutants: forms after entering the atmosphere
  • as a result of interactions with other atmospheric gases or sunlight rays
  • ex. ozone, acid rain
• sources of pollution can be natural, mobile, or stationary
• NAAQS of Clear Air Act: established standards to identify air pollutants
  • includes SO2, PM, Pb, O3, NO2, CO
  • health effects of lead: anemia, lower IQ, nerve damage, behavioral issues, hypertension, cardiovascular disease, reading/learning disabilities
• combustion of fossil fuels → CO2 production that had not reached the atmosphere in millions of years
• coal contains many impurities collected from trapped sediments
  • coal combustion → sulfur dioxide (SO2) production + toxic metals (lead, mercury, etc) + PM
  • limited through filters, scrubbers, clean coal processes, etc.
• air pollution comes from plant matter: carbon, hydrogen, nitrogen, oxygen, sulfur
  • voc - volatile organic compounds
  • PM - particulate matter (course & fine particles)
  • irritates human body (ie. eyes, nose, throat)
  • exacerbate lung conditions and damage
  • damage to plant tissue

7.2 Photochemical Smog

• VOCs = volatile organic compounds
  • can vaporize at room temp
  • increased presence in the atmosphere
  • ex. formaldehyde, gasoline, trees, plant oils
• formation includes VOCs + sunlight/heat = PANS/O3
  • NO + VOC + O2 + UV = O3 + PANs
  • ozone peaks during the afternoon after temperature and sun intensity increases
  • higher in sunny warmer climates
  • higher in the summer
  • irritates eyes, nose, throat
  • worsens heart/lung conditions
  • cause lung cancer from long-term exposure
• tropospheric ozone
  • can worsen bronchitis and emphysema
  • triggers asthma
  • permanent lung damage
  • reduced life for plants from lead damage
  • reduction of photochemical smog:
• catalytic converters: NO → O2 + N2
• CO + hydrocarbons → CO2 + H2O
  • reduce VOCs: pumping gas at night, following gas refueling instructions
  • improve fuel efficiency
  • reduce the use of internal combustion
  • reduce health impacts

7.3 Thermal Inversion

• normal conditions: altitude increases = temperature decreases
  • reversed in thermal inversion occurring in upper Earth layers
• thermal inversion: hotter air near the surface traps cooler air above
  • traps cooler denser air and pollutants (PM)
• more prone in particular geographic areas
  • valleys, mountain ranges, coastal winds
  • intensified by pollution (ie. industrialization, urbanization, major vehicle usage)
  • ex. los angles, mexico city
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7.4 Atmospheric Pressure & CO2

• natural sources of CO2 emissions: respiration, diffusion, biomass decomposition, wildfires, volcanoes, etc.
  • considered fast carbon (not harmful to human health)
  • fossil carbon emissions → excess CO2 buildup → ecosystem disruption and health impacts
• particulate matter (PM): particles in the air that can be inhaled
  • inhalable → =< 10 microns (0.001 mm)
  • 2.5 < x < 10 → upper respiratory concern
  • <= 2.5 → lower respiratory concern
  • ex. pollen, spores, bacteria, dust, sea salt, dust mites, wildfire emissions, etc.
  • exacerbates lung conditions, pneumonia, stuffy nose, eye irritation, skin rash, etc.

7.5 Indoor Air Pollutants

• natural sources: mold, dust, radon
• human sources: asbestos, smoke
  • mold: found in places with poor ventilation
  • caused by water leakage + too much humidity
  • leads to eye, nose, and ear irritation and respiratory illness
  • dust: consists of particulates of different sizes
  • resolved by frequently changing home A/C filters
  • smoke: irritates and damages respiratory systems
  • comes from candles, fireplaces, gas stoves, heaters, cigarettes, wildfires
  • radon: decaying uranium in rocks & soil
  • seeps into buildings from cracks in basement walls & floors
  • can be carried in groundwater
  • can cause lung cancer through inhalation (2nd leading cause of cancer)
  • can be easily tested for and solved by sealing cracks and vents
  • asbestos: used for insulation
  • can cause lung cancer
  • has been banned from buildings and schools
• home building products can contribute to indoor air pollution
  • lead: found in older homes
  • VOCs: found in furniture, carpets, cleaning supplies, dryer sheets, etc.
  • formaldehyde: found in woods, carpets, glues, and resins
• combustion of carbon monoxide → CO poisoning
  • can be found in small engines, stoves, lanterns, fireplaces, cars, etc.
  • causes asphyxia = impairs RBC ability to carrying O2 in body → dizziness, nausea, suffocation

7.6 Reduction of Air Pollutants

• clean air act (CAA): regulates harmful emission of air pollutants
  • regulated at a national level with the help of state govs and tribes
  • create/enforce air quality standards
  • reducing vehicle emission: removing lead in gasoline, using cleaner technologies in transportation
  • reducing acid rain: setting pollution levels for industries, technologies to reduce sulfur/nitrogen oxide
  • pollutants that harm the ozone layer: removing greenhouse gases, regulating ground-level ozone
  • alternative fuels: increase the amount of renewable fuel that can be added to gasoline
  • ex. ethanol, propane, natural gas, biofuels, etc.
  • other solutions: energy efficiency, using water-based paints and cleaners, improved transportation planning, higher fuel standards, composting, recycling, carpooling, etc.
• vapor recovery nozzle: prevents fumes from escaping into the atmosphere when fueling a vehicle
  • captures the vapors → underground storage tank
  • ORVR (onboard refueling vapor recovering systems): added to cares to burn vapors in the car’s combustion chamber
• catalytic converters: reduces emission toxicity
  • converts CO NO2 and VOCs → O2, CO2, H2O, N2O
  • removes or adds oxygen based on gas being converted
  • hydrocarbons → CO2, H2O
• scrubbers: removes particulates or gases from industrial exhaust streams
  • removes gases such as sulfur and nitrogen oxides using a spray or mist to capture or change pollutants
  • sulfur oxide → limestone (buffer) + water → gypsum
  • dry: uses dry particles (reagents) → particles fall to the screen that collects them
  • not as effective as wet scrubbers
• electrostatic precipitators: adds a charge to pollutants → stick to chamber & allow clean air to leave the chamber
  • waste → sludge and ash that is taken to a landfill
  • leads to the contamination of large areas of land

7.7 Acid Rain

• pH → measures acidity + alkalinity in a substance

  • measured on a logarithmic scale
  • rainwater: 5.6
  • acid rain: 4.3

• NOx (vehicle emissions) + water → nitrous & nitric acid

  • natural sources of gases: volcanoes, geysers, hot springs
  • nitric + sulfuric acid → dry deposition + rain/snow
  • reacts with water (H2O) to create precipitation

• impacts communities that are downwind of coal-burning plants

• pollutants can travel long distances

• has many effects on natural ecosystems and human structures

  • aluminum toxicity: adds aluminum ions that are toxic to aquatic/plant life
  • calcium deficiencies: resulted from aluminum presence in soil → prevent calcium absorption → hinders regular cell processes →
  • reduced photosynthesis: nutrient deficiencies → changes in soil chemistry → photosynthesis less effective and productive
  • acidic lakes → death, deformities, and damaged eggs
  • erodes marble and limestone → destruction of human structures

• type of soil determines resistance to acid deposition

  • soils rich in magnesium, calcium carbonate, and limestone → neutralize acid → prevents acid from damaging soil
  • granite + poor nutrient soils → vulnerable to acid deposition (ie. high elevated areas)

7.8 Noise Pollution

• prolonged exposure to sound at high levels → physiological stress and hearing loss

  • comes from transportation, construction, and industrial activity in urban areas
  • measured in decibels (logarithmic scale)
  • dangerous to human hearing >= 86 dBAs

• transportation: railroads, mass transit, sirens, airports, heavy traffic, motocycles

• machinery from industry

• construction: trucks, jackhammers, nail guns

  • hearing loss: loud sounds → permanent damage to hair cells (curved and scattered)
  • can also cause stress, anxiety, depression, high blood pressure, heart disease

• primarily affects those in urban areas

• us noise control act (1972): allows EPA to regulate emissions from major noise pollution sources

• occupational safety and health association (osha): limits noise exposure in workplaces

• quiet communities act: provides funding for reducing noise in airports

• also affects animals negatively

  • induces stress → reduced reproduction, health decline, and disrupted communication
  • ex. dolphins rely on sound to communicate → interfered by vessels and machinery in the ocean
  • masks sounds between prey and predators
  • disrupts their symbiotic relationship
  • disturbs predators and exposes prey
  • alter migration routes: animals avoid areas of loud noise that were once filled with resource sto fulfill their survival needs

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