20-6 Effects of Air Pollution on Living Organisms and Materials
How Does Your Respiratory System Help Protect You from Air Pollution? Your Air Pollution Security System
Your respiratory system has a number of mechanisms that help protect you from much air pollution. Hairs in your nose filter out large particles. Sticky mucus in the lining of your upper respiratory tract captures smaller (but not the smallest) particles and dissolves some gaseous pollutants. Sneezing and coughing expel contaminated air and mucus when pollutants irritate your respiratory system.
But prolonged or acute exposure to air pollutants including tobacco smoke can overload or break down these natural defences. This can cause or contribute to various respiratory diseases. One that can start early in life is asthma, typically an allergic reaction causing muscle spasms in the bronchial walls and acute shortness of breath.
Years of smoking and breathing air pollutants can lead to other respiratory disorders including lung cancer and chronic bronchitis, which involves persistent inflammation and damage to the cells lining the bronchi and bronchioles. The results are mucus buildup; loud, painful coughing; and shortness of breath. Damage deeper in the lung can cause emphysema, which is irreversible damage to air sacs or alveoli leading to loss of lung elasticity and acute shortness of breath.
Case Study: Should We Use the Marketplace to Reduce Pollution? Emissions Trading
SO₂ Emissions Trading & Cap-and-Trade Summary:
Emissions Trading Policy (U.S. Clean Air Act, 1990):
Allows 110 major coal-burning power plants in 21 states to buy and sell SO₂ pollution credits.
Plants receive annual pollution limits (credits).
Surplus credits can be traded, saved, or sold (even to environmental groups or private citizens).
How It Works:
Market-based system promotes cost-effective pollution control.
Environmental groups can buy credits to retire them and reduce pollution.
Public can even buy credits (e.g., as novelty gifts).
Advantages (Proponents’ View):
Encourages innovation and efficiency.
Less expensive than government-mandated methods.
Can result in real reductions if the emissions cap is strict and decreases over time.
From 1990–2006, SO₂ emissions dropped 53%, at less than 10% of projected costs.
Criticisms (Environmentalists’ View):
Older plants may just buy credits instead of reducing emissions.
Can lead to pollution "hot spots" where air quality remains poor.
System relies on self-reporting, creating incentive to cheat.
Needs strict caps, annual reductions, surprise inspections, and strong penalties to work well.
Example of failure: Southern California's program (1993–2002) underperformed and was poorly managed, with overly generous caps and accounting abuses.
Other Pollutants:
Emissions trading has expanded to include NOₓ, particulate matter, VOCs, and mercury in various regions.
How Can We Reduce Outdoor Air Pollution from Coal-Burning Facilities? Prevention Is Best
Good news. Between 1980 and 2008, emissions of SO2 from electric power plants decreased by 59%, emissions of NOx emissions by 35%, and soot emissions by 31%. Emphasis has been on output approaches that add equipment to remove some of the particulate, NOx, and SO2 pollutants after they are produced. Pollution can also be reduced at the input stage by using cleaner coal technologies. One is fluidized-bed combustion, which reduces pollutant emissions and burns coal more efficiently by blowing a stream of hot air into a boiler to burn a mixture of powdered coal and crushed limestone. Another is coal gasification, which has a mixture of advantages and disadvantages. Environmentalists argue for much greater emphasis on prevention approaches to decrease the levels of these pollutants reaching the troposphere.
What Should We Do About Ultrafine Particles? Another Controversy
Research indicates that invisible particles—especially fine particles with diameters less than 10 microns (PM-10) and ultrafine particles with diameters less than 2.5 microns (PM-2.5)—pose a significant health hazard. Such particles come from a variety of sources.
They are not effectively captured by most air pollution control equipment and are small enough to penetrate the respiratory system’s natural defences against air pollution. They can also bring with them droplets or other particles of toxic or cancer-causing pollutants that become attached to their surfaces.