3.1-3.7: air pollution Flashcards
6 air pollutants in need of control measures:
- Carbon monoxide
- Sulfur dioxide
- Toxic organics
- Particulates
- Nitrogen oxides
- Volatile organic compounds
Radon
naturally occurring radioactive gas, contributes to lung cancer
CO peak emissions (US) = 1970 =
~185 million metric tons/year
Major source of CO =
transportation
Health hazards: CO @ high levels =
asphyxiating poison
asphyxiating poison
- Displaces O2 bound to hemoglobin in blood proteins that transport O2 from lungs –> tissues
- Iron-binding sites in hemoglobin bind CO 230 times more tightly than O2
- normally = CO = 1% of hemoglobin binding sites
Air [CO] = 100 ppm = CO occupancy of hemoglobin binding sites =
16%
[CO] > 750 ppm =
loss of consciousness/death
main causes of CO poisoning
stoves/space heaters (poor circulation/malfunctions)
sulfur dioxide main sources
coal combustion, smelting metals (copper and nickel), transportation fuels (urban areas)
sulfur dioxide health hazards
Lung irritant/respiratory disease
Particulate matter-
SO2 as gas in air = H2SO4 attract water vapor –> droplets
- Secondary emissions from coal power plants
effects of sulfur dioxide
- impair visibility
- major contributor to acid rain (Corrodes artifacts, acidifies lakes/soils, dissolves limestone and stained glass, accelerates corrosion of iron/zinc)
Smokestacks
reduce sulfuric acid aerosols by dispersing plume
- Alleviates local problems
- Cause haze and acid rain downwind
Chemical scrubbers
remove SO2 by passing through limestone
Dry sorbent injection
injecting calcium hydroxide (Ca(OH)2) into combustion gas and a fabric filter collects particles
- ↓ volume CaSO3
Regenerable amine salt
scrubbing agent converts SO2 –> H2SO4 (commercial grade)
- Oxidized fertilizer
Clean air act (1990) highlights ___ hazardous air pollutants and __ priority targets
- 188
- 33
3 inhalable organics
aldehydes, benzene, polycyclic aromatic hydrocarbons (PAHs)
Formaldehyde (H2CO) causes
- eye/lung irritant (100 ppb)
- drowsiness, nausea, headaches, respiratory diseases, nasal/nasopharyngeal cancer
- Carcinogen to animals