To simplify discussion:
Oceans: ignore pollution. (1000 Ekg)
[But see Spreading Dead Zones
Atomosphere: (6 Ekg)
Neglect pollutants in natural cycles.
Focus on man-made pollution that
accumulates causing most damage.
Thermodynamics teaches that any energy produced has accompanying heat, typically twice the energy.
Heat Islands. Cities are typically
degrees warmer than rural area. Two reasons:
(i) large consumption of energy and
(ii) large surfaces absorb energy that
reradiates or needs more cooling.
How bad is higher temperature?
dose ≡ potency × exposure;
health risk ≡ dose × exposed populations.
Pollutant's size matters
Nose rejects large particles; and lung tolerates, if with irritation, smaller ones. But lungs trap particles smaller than 2.5 µm; soluble ones pass into blood. (PM2.5)
Health risk is hard to set. Concentration levels are low and potency is hard to measure. Different countries, states and cities set different levels. State of the Air, American Lung Assoc.
Other nonattainment by location:
Current Nonattainment Areas
Many pollutants. In additions to the oxides of C, N & S, chemical processes supply dangerous elements: Pb, Cd, Ni, Be, Hg, As, V & Cr. Don't forget asbestos and polycyclic organic matter.
Where is safe? Rural areas are less polluted; less populated countries are better. But much pollution crosses boundaries.
Few can doubt pollutants are hazardous to human health and to the
whole ecoculture. The Clean Air Acts (1970, 1977, 1990) set standards
administered by EPA.
[CAA or CAAA, last "A" for Amendments]
For the "worst" five, sources are diverse:
|NO2||fuel combustion, industrial processes, transportation|
|mercury (Hg)||all combustion (fuel, stationary)|
|volatile organic compounds (VOC)||stationary combustion, transportation|
Worst states are OH, TX, PA, IN, KY
Cuyahoga, Franklin, Hamilton get F's (particulate).
Largest sources of NO2 in troposphere (within 5-9 miles of earth) are burning biomass, automobiles and ships at sea!
Long distance travelers. Ancient Asian dust in Greenland ice;
Asian haze covers Northern Hemisphere; Saharan sand in Miami;
American pollution reaches Britain, by jet stream?
The Phase I targets of CAAA largely met. NO2 is a disappointment &rarr even smaller decrease in ozone
|National Air Quality 1989-1998|
|Costs versus Benefits|
|Est. Compliance Costs||$7 B||$26 B||$27 B|
|Act. Compliance Costs||$2 B||$8 B||$9 B|
|Estimated Benefits||$110 B|
|( includes better health, visibility, crops)|
Most cost uncertainties were associated with reducing SO2. In the 1980s when CAAA was under active discussion there were fears that
Mere $0.8 B/yr produced reduction greater than requested. Most utilities switched to low-sulfur coal, altho many went for expensive scrubbers. Also coal transport cost dropped. But the real surprise was ...
Novel feature of 1990 CAAA was allowances: the right to emit ton of SO2 good in any year. At any year's end, company must "pay" as many allowances as its total emissions that year. The utilities could freely buy, sell, or bank allowances
Initially allowances granted yearly on historical basis. Renewable sources could earn allowances on basis of electricity generated, pollution avoided or set-asides (fraction of allowances).
Use.The 1992 price of $250/allowance dropped in a decade to $100. S-loaded Ohio sold many out of state.
Coal industry added western coal to its eastern and prospered. But historical lost of jobs in eastern coal mines continued.
Goals met at a cost less than expected. Clever engineering gets most of the credit for new, effective technologies: fluidized bed burners, scrubbers in combustion discharge stacks. Emission (allowance) trading also allowed flexibility to keep costs low.
Fuel switching was the unexpected event that kept cost low. Low-sulfur coal from Wyoming and Montana (& its 0.5% sulfur) produced automatic reduction over midwest coal (4-6% sulfur). As we return to midwest coal in the future, either future technological breakthru or added costs (financial or environmental) await.