Take-home Quiz #2 KEY

1. [4 pts] Binary response curves show us a threshold stimulus intensity where the response rate switches immediately from 0% to 100%. The S-shaped Sigmoid response curve is a more realistic response by a population to some stimulus.
   
   
2. [4 pts] A(n) chronic exposure to an air pollutant happens when someone is exposed for years to a low concentration of the pollutant, and exposure to the pollutant at this concentration is not immediately harmful (otherwise, we would have a case of a(n) acute exposure from the short exposure time).
   
   
3. [5 pts] Briefly describe two disadvantages of toxicological studies, as compared to epidemiological studies.
   [short experimental run time, small sample size, lack of subject diversity, high cost, ...]
   
   
4. [5 pts] The alveolar sacs can be destroyed by exposure to lachrymators, resulting in a disease called pulmonary emphysema. [first blank is not a specific substance; instead, it is a classification of substances]
   
   
5. [4 pts] Carbon monoxide poisoning of the blood usually reaches a plateau after a period of exposure to a constant concentration of carbon monoxide, and can even be reversed upon removal of the carbon monoxide exposure. This is because carboxyhemoglobin-contaminated red blood cells are always being filtered out of the blood and replaced by fresh ones.
   
   
6. [6 pts] “Black Lung” and “Brown Lung” are diseases caused by inhaling excessive amounts of dust particles. The general term for these kinds of respiratory diseases is coniosis.
   
   
7. [7 pts] Alpha and beta particles are the result of radioactive decay events. The electromagnetic radiation released by these events is called gamma radiation. All of these together are classified as “ionizing radiation”.
   
   
8. [6 pts] In L.A. smog, carbon monoxide is a primary pollutant because it is emitted directly into the air by polluting activities. Much of the carbon monoxide comes from automobiles; one way to reduce the emission of carbon monoxide from this source is to add an oxygenation additive to the gasoline.
   
   
9. [7 pts] Prof. Haagen-Smit at the California Institute of Technology was the first to link the occurrence of photochemical smog in Los Angeles to automotive emissions. His experiment involved the use of a light source to simulate sunlight, oxides of nitrogen, and reactive organic gas to make ozone and other secondary pollutants. Later on, he became the first director of the newly founded California state agency for the regulation of air quality, now known as the California Air Resources Board.
   
   
10. [6 pts] Before carbon monoxide concentrations were brought below the clean air standard thresholds, most of carbon monoxide violations in the South Coast Air Basin were recorded just downwind of Los Angeles Airport. Meanwhile, most of the ozone air quality standard violations were posted around the city of Azusa.
11. [6 pts] A catalytic converter in the exhaust system of an automobile is capable of reducing emissions of carbon monoxide, oxides of nitrogen, and reactive organic gases, with little loss of performance from the engine (other than the requirement for unleaded gasoline). For reactive organic gas emission reduction or elimination, we could instead substitute a different fuel, such as compressed natural gas (CNG), that does not involved a volatile organic compound.
    
    
12. [13 pts] Air quality criteria are qualitative labels that describe the potential for harm from air pollution. The best air quality is called “good”, meaning the concentration of an air pollutant is low enough to not cause harm. This amount is also less than the amount required to violate the federal clean air standard, which corresponds to an Air Quality Index that is less than 100.
    
    
13. [6 pts] A first-stage alert for ozone in the South Coast Air Basin is issued when the ozone concentration exceeds 0.20 ppmv for one hour. This threshold level corresponds to an AQI value of 200.
    
    
14. [6 pts] The Environmental Protection Agency (EPA) is responsible for setting and enforcing air, land, and water quality rules at the national level in the United States. Recently, it has enacted a program called “Environmental Justice”, whereby all communities in a region are entitled to clean air, not just the ones far enough away from the pollution sources.