unit 7 - atmospheric pollution

SO2

cause: coal combustion
effects: respiratory irritation, smog, acid precip.

NOx

cause: ff combustion
effect: ozone, photochemical smog, acid precipitation

SO2

cause: coal combustion
effects: respiratory irritation, smog, acid precip.

NOx

cause: ff combustion
effect: ozone, photochemical smog, acid precipitation

CO

cause: incomplete combustion
effect: ozone and suffocation

PM

cause: ff & biomass combustion
effect: respiratory irritation, smog

O3

cause: photochemical oxidation of NO2
effect: resp irritatnt, plant damage ,smog

Pb

cause: metal plants and waste incineration
effect: neuroxicant - damages the CNS of small children

• found in the paint of old homes

• phased out of gasoline by the EPA’s Clean Air Act

primary air pollutants

emitted directly from a source

ex: NOx, SO2, CO

secondary air pollutants

primary pollutants that have transformed in presence of sunlight, water, or O2
ex: O3

photochemical smog

NO2 + VOCs + O3 + sunlight

urban heat island effect

urban areas tend to have higher temps due to lower albedo (concrete/asphalt absorbs sun energy)

thermal inversion

occurs when cold air at the surface is trapped beneath the warmer mass above, so convection won’t carry pollutants up & away

natural sources of air pollutants

• lightning strikes

• forest fires

• plant respiration

• volcanoes

• anaerobic/aerobic decomposition

asbestos

silicate particle previously used in insulation but phased out due to being linked to respiratory irritation

VOCs

chemicals used in home products that can can irritate eyes and lungs

ex: formaldehyde

dust & mold

natural indoor air pollutant that causes lung irritation

radon gas

radioactive gas released by decaying uranium that enters homes through underground cracks

acid rain

formed by SO2 and NOx from coal power plants and vehicle emissions

causes soil & water acidification

mitigated by limestone and renewables

vapor recovery nozzle

captures hydrocarbon VOCs released from gasoline fumes during refueling

catalytic converter

contains metals (platinum & palladium) that bind to NO_x and CO

crushed limestone

contains calcium carbonate that combines with SO2, reducing SO2 from coal power plants

fluidized bed combustion

allows coal to be combusted at lower temps, emitting less NOx

dry scrubbers

calcium oxide additive reacts with SOx, NOx, and VOCs to form calcium sulfite

wet scrubbers

mist droplets that mix with NOx, SOx, VOCs, PM and fall to bottom of scrubber or get trapped for disposal

electrostatic precipitator

neg charged particles stick to pos charged collection plates, trapping PM for disposal

urban noise pollution

any noise at great enough volume to cause physiological stress/hearing loss

ex: construction, seismic surveying