AP Environmental Science: Unit 7 Review - Air Pollution

Introduction to Air Pollutants

• primary pollutants - emitted directly into atmosphere 
• particulate matter PM - particles suspended in air due to combustion and dust mobilization, can create respiratory/heart problems along with smog/haze
• nitrogen oxides NOx - colorless or reddish brown gases, occurs with combustion, respiratory irritant and a precursor to ozone, also can form secondary pollutants like nitric acid in the atmosphere
• sulfur oxides SOx - corrosive gas that forms when sulfur combines with oxygen during coal combustion, respiratory irritant that can harm plan tissue and also form secondary pollutants like sulfuric acid in the atmosphere 
• mercury  - trace metal found in coal/oil and waster due to mining/combustion, impairs central nervous system and bioaccumulates in the food chain
•  lead - trace metal found in old paint, gasoline, coal, impairs central nervous system and affects learning abilities especially in small children
• CO2  - colorless gas that occurs with combustion of fossil fuels and clearing land, increases greenhouse gas concentrations
•  CO  - colorless gas that occurs with incomplete combustion, very deadly
• secondary pollutants - form once in atmosphere
• volatile Organic Compounds VOCs - organic compounds that exist as gases in the atmosphere and act as a pollutant
• sulfuric acid H2SO4 - formed from sulfur oxides reacting with water vapor in the air
• nitric acid HNO3  - acid that forms in the atmosphere from oxides of nitrogen 
  
• smog  - mixture of oxidants and particulate matter, scatters light and reduces visibility
• ozone  - secondary pollutant formed from sunlight, water, oxygen, VOCs, NOX, can effect lung/respiratory functions

(SPLONC) - Pollutants of The Clean Air Act

• The Clean Air Act - the Environmental Protection Agency regulates the emission of air pollutants that affect human health
• sulfur dioxide (SO2)
• particulate matter (PM) 
• lead (PB) 
• ozone (O3) 
• nitrogen dioxide (NO2) 
• carbon monoxide CO) 

Photochemical Smog

• formation - nitrogen oxides and volatile organic hydrocarbons (VOCs) react with heat and sunlight to produce a variety of pollutants 
• often forms in urban areas because of the large number of motor vehicles there
• human health - respiratory problems and eye irritation
• reduction - through the reduction of nitrogen oxide and VOCs

Thermal Inversion

• thermal inversion - warmer layer on top of cooler surface
• traps cooler, denser air, pollutants do not disperse (photochemical smog, PM)

Stratospheric Ozone

• stratospheric ozone layer -  important to the evolution of life on Earth, protects us from harmful ultraviolet light from the sun
• causes of depletion - caused by both anthropogenic and natural factors, such as chlorofluorocarbons (CFCs) and ice crystals forming in the atmosphere
• ozone hole -located in Antartica
• solutions - replacing ozone-depleting chemicals with substitutes that do not such as Hydrofluorocarbons (HFCs) 

Reduction of Air Pollutants

• solutions - regulatory practices, conservation practices, and alternative fuels
• catalytic convertor - device for internal combustion engines that converts pollutants in exhaust into less harmful molecules
• wet dry scrubbers - devices that remove harmful particulates and/or gases from industrial exhaust streams
• vapor recovery nozzle - device on a gasoline pump that prevents fumes from escaping into the atmosphere when fueling a motor vehicle

Acid Rain

• nitrogen oxides - that  cause acid deposition come from mainly motor vehicles
• sulfur dioxides -  that cause acid deposition come from coal-burning power plants
•  can lead to the acidification of soil & water, damage to plants, damage to man-made structures, decrease in biodiversity

Noise Pollution

• noise pollution - include transportation, construction, and domestic and industrial activity.
• effects on animals - include stress, the masking of sounds used to communicate or hunt, causing changes to migratory routes
• effects on humans -  levels high enough to cause physiological stress & hearing loss

Indoor Air Pollutants

• carbon monoxide (CO) - formed with incomplete combustion, classified as an asphyxiant
• carbon dioxide (CO2) - colorless gas that occurs with combustion of fossil fuels and clearing land, increases greenhouse gas concentrations
• formaldehyde - from building materials, furniture, upholstery, and carpeting
• radon 222 - naturally occurring radioactive gas that is produced by the decay of uranium found in some rocks and soils, that leak into the house, can lead to lung cancer
• lead - from paints
• asbestos - long, thin, fibrous silicate material with insulating properties, can cause respiratory diseases 
• VOCs- from furniture, paneling, carpets