Unit Seven

SO₂

• sulfer dioxide

• formed during coal combustion

• causes respitory irritation and acid rain

NOx

• nitrous oxide

• comes from fossil fuel combustion

• causes particulate matter, ozone depletion and leads to acid rain

CO

• carbon monoxide

• incomplete combustion

• lethal to humans

Pb

• lead

• released by waste incinerations and metal plants

• nerotoxicant

O₃

• ozone

• photochemical oxidation of NO2

• causes respitory irritation, smog, or plant damage

PM

• particulate matter

• caused by fossil fuel/biomass combustion

• causes respitory irritation or smog

air pollutants versus greenhouse gasses

because CO₂ does not directly cause problems to human health, rather the damage is indirectly caused by global warming it is not considered an air pollutant.

coal combustion

• releases the most amount of air pollutants

• releases CO, SO₂, CO_2, NOx, PM, and other toxic metals

Damags of SO₂

• respitatory irritation

• blocks sunlight

• reducses visibility and photosynthesis

• forms sulfric smog

• acid precipitation

EPA & Lead

• before Clean air act, it was common to have lead in gas

• this began to phase out in 1974, as lead is a neurotoxin

nitrous oxides

• relased by combustion of anything, but mostly fossil fuels, and biomass

  • Nitrous oxide = Nitrogen and Oxide

  • NO₂= Nitrogen and O_2/3

  • Sunlight will convert NO₂ into NO

Primary Air pollutants

• emitted directly from sources

  • CO, SO2, CO2, NOx, PM, VOCS, and other hydrocarbons

Secondary Air Pollutants

• pirmary pollutants that have either mixed with sunlight, H₂O, or O₂ which is typically done during the dane

• such as ozone, sulfric acid and sulfate, nitrate and nitric acid

Photchemical smog Precosurs and conditions

• nitrous oxide, which is broken into N and O, which binds with VOCS (such as gasoline and clean fluids, or pine trees)

• forms when the NO2 is broken by sunlight and combines with ozone

what environmental conditions are required for smog

• sunlight

• warmth

Normal ozone Formation vs PM SMOG

• Normal: After the energy is converted into ozone, which peaks in the afternoon, it will drop overnight

• Smog: the VOCS bond with nitrous oxide to form photochemical oxidents

  • sine there is no NO to react with, this builds up ozone.

Factors that increase photochemical smog

• increased traffic

• higher VOC emissions

• warmer temperatures and more sunlight

• more electricity demand due to NOx emissions from power plants

enviormental impacts on smog

• reduces sunlight

• limits photozynthesis

• ozone damages plant stanamia and irritates animal respitory tracts

Human impacts of smog

• respitory irritants

• eye irritant

• increase healthcare costs for asthma and bronchotis

• loss of productivity due to sick workers

• decreased agriculture yeilds

how to reduce smog

• reduce the amount of vehicles with carpooling, public transit, buking, walking, or working from home

• increase electricity production from renewable sources that don’t emit NOx (solar/wind/hydro)

• natural gas power plants release far less NOx than coal.

urban areas are often warmer than other areas because

• lower abeldo

• areas with more concrete absorb sun more than areas with lots of vegitation, which reflects sunlight

• less evapotranspiration (water evaporating from surfaces and transpiration from plants)

regular temperature

• typically the atmosphere is warmest closest to earth’s surface, and cools as altitude rises, dispersing air pollutants

Thermal Inversion

• In thermal inversion the cooler mass is trapped near earth’s surface

• due to a warm front moving in over it (or the urban surfaces cooling overnight will radion during the day is being released.)

• can be worse near mountain ranges

effets of thermal inversion

• air pollutants are trapped closer to the earth

• respitory irritation/increased hospitalization

• decrease in tourism

• decrease in photosynthetic rate

natural sources of air pollutants

• lighting strikes (converts n₂ into NO_x)

• forest fires (CO, PM, NO_x)

• plants (emits VOCS)

• volcanoes (SO_2, PM, CO, NO_x)

natural sources of Carbon Dioxide and PM

• Respiration (releases CO₂)

• natural PM Sources (Sea Salt, Ash, and leads to haze)

• areobic decompistion (of organic matter than releases carbon dioxide)

• anaerobic decomposition (with no oxygen or little oxygen, releasing methane)

PM₁₀ vs PM_2.5

• PM₁₀ smaller than ten micrometers, such as dust pollen, or ash.

  • to small to be filtered out, and can cause damage

• PM_2.5 from combustion and are small and easily goes into lunghs

  • associated with chornic bronchotis and increased risk of lung chancer

Pollution in developing nations

• use subsistence fuels such as wood manure or biomass

  • these biomass fuels release CO₂ PM, NO_x, and VOCS (and can cause deforestation)

• often cumbsted indoors with poor ventilation, leading to high concentrations

  • this can results in 3.5-4.5 billion deaths annually.

Pollution in developed nations

• developed nations use more commerical fuels (coal, oil, natural gas) which are supplied with utilities

  • typically burned in close, but vetalied spots.

• major indoor pollutants come from chemcals in products, adhesives in funerture, cleaning supplies, insulation, and lead paint.

PM and Asnestos

• PM are a common indoor air pollutant, such as smoke

• aestosades are a long, silicate particle previously used in insluatoin

  • can be linked with lung cancer, and asbestois

• phased out of use, but is in older buildings

  • not dangerous until the insulation is disturbed, and the asbestos particles enter air and the respitory tract

  • should be removed by trained professionals only

Carbon Monoxide

• formed by the incomplete combustion of any fuel

  • mostly due to low oxygen or temp, but not always

  • can cause suffocation due to the carbon monoxide binding to hemoglobin in blood, which displaces oxygen

  • lethal in high concentration, and since its orderless and colorless it hard to detect

VOCS

• Chemicals used in home products

  • cleaners, adhesives, formaldchyde, plastics, and fabrics

• can enter air and irritate eyes, lungs, and bronchotis

Radon Gas

• radioactive gas released by the decay of uranaiam naturally found in underground rocks

  • usually enters home through foundational cracks, and dispersed from up there or the basement

  • also found in groundwater sources

• second leading cause of lung cancer

  • prevented by sealing cracks and detectors.

Dust and Mold

• Dust- small particles that enter naturally, when disturbed by movement, and enters the respitory tract

• mold - develops in dark and damp areas and that aren’t well ventilated.

lead

• formally used in paint, which could be eaten by children, or inhaled as dust, or in water

  • damages nervous system of children

• can be removed by removing lead plant, and using copper pipes

reducing emmsions

• reducing air pollutions

  • driving less or walking/biking/uses buses more

  • convserving electricity

  • eating less met

  • renewable resources

Clean air act

• allows EPA to set acceptable levels for critera air pollutants

  • monitors emmison levels from power plants and other facilities

  • can use taxes, sues, or fines to companies who violate this law.

CAFE Vehicle Standars

• cooperate averave dual economy

• raising the amount of miles per gas

Pollution credits

• companies who earn less emmisons get benefits, and those who go over receive punishments

Vapor Recovery Nozzle

• capures hydrocarbon VOCs from gasoline fuels, which reduces VOCs and benzene

Catalyic Converter

• required to be added to all vehicles in 1975

• converts NO_x and CO into non-dangerous gasses

Crushed Limestone

• used to reduce sulfur dioxide

  • crushes coal with limestone, and limits the emmissions it to SO₂

Fluidized Bed Combustion

• fluidizng jets of air pumped into commbustion

• this brings oxygen into the rxn, and is more efficient than sulfer dioxide

  • allows for coal to be comusted at a lower temperature and less nitrous oxide.

wet and dry scrubberes

• Dry scrubbers reduce NOX, SOX, and VOCS

  • large tun with chemicals that neutralize this

• wet scrubber (NOX, SOX, VOCs, and PM)

  • may use chemicals to neutralize the above elments

Electrostatic Precipitator

• the negative charges stick to positive charges and this traps them, and uses to protect PM

Baghouse Filter

• large, fabric bag filters that trap PM in the air

• shaker device knocks trapped particles loose into the collection below, which is taken to landfull

Sources of NOx and SO₂

• pirmary pollutants for acid precipitation

• sources of NOx- vehicle emmisons, desieal generators, coal power plants

• sources of SO₂- Coal fired power plants, metal factories, and vehicles that burn diseal fuel

Limiting Acid Rain

• reudce NOx and SO₂

  • higher CAFE standards

  • more public transit

  • efficent energy

  • renewable resources

• The clean air act decreased acid rain significantly.

enviromental affects of acid rain

• soil/water acidification

  • H ions displace/leech soil nutrients

  • they also make toxic metals more soluable in soil and water, which can kill plants.

Mitigating Acid Rain

• Limestone (human made or chemically made)

• Limiting SO₂ and NO_x

urban noise pollution causes

• construction

• transportation,

• industrial activity,

• domestic activity

urban noise pollution effects

• can disrupt

  • animal communication

  • migration

• causes hearing damage

noise pollution on aquatic life

• comes from ship engines, military sonar, or seismic air blasts looking for oil

• causes physiological stress (hearing loss, disrupted communication)

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