Preventing Bad Air Days Answer Key 1. What happens to the temperature of the air in the troposphere? As elevation increases, the temperature of the air decreases. 2. With the normal atmospheric temperature profile (temperature decreasing with altitude), what will happen to hot air emitted from a smokestack? The hot smoke will rise. 3. Explain your answer. Hot air rises. It is less dense than the surrounding air.
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4. Take a snapshot showing a temperature inversion. How did you get the model to show a temperature inversion? I got the model to show a temperature inversion by making the wind come from the water. The water is cooler than the land, so the lowest air level cools when the wind is coming from the water.
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Preventing Bad Air Days Answer Key, continued
6. What natural occurrence (not an air pollution event) results from a temperature inversion? A natural occurrence that results from a temperature inversion is fog. 7. Are thermal inversions more likely in valleys or on hills? valleys
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5. Take a snapshot showing a smog event. Use arrows to show the paths of some pollutants. What conditions are necessary for a long-lasting smog event? A long-lasting smog event will result when there is no precipitation and when there is a temperature inversion. If the temperature inversion could occur without there being a breeze, then the pollution directly over the city would be quite bad. Instead, it looks like the pollution is blowing into the mountains on the edge of the city, but that’s still a long-lasting smog event for the mountain area.
Preventing Bad Air Days Answer Key, continued 8. Explain your answer. Valleys are more likely to experience thermal inversions than hills are because cold air sinks. The valley is a low place, so the cold air sinks there. As the upper layers of air heat up, the cold air is still trapped at the surface. WIth cold air at the surface and warmer air above, you get a temperature inversion and fog (or smog, if there are many pollutants in the air). The air on a hill is also more likely to be mixed by the wind. The winds may not reach the valley because the sides of the valley may pose a geographic barrier to the wind. 9. Based on this model, is it more important for air quality to have pollution control devices on cars or on power plants? cars 0. Explain your answer. 1 It is more important to have pollution control devices on cars because they produce more emissions than power plants in the model. When I tested with the model with the maximum level of cars and power plants and pollution control devices only on the cars or only on the power plants, the total pollution level was higher when only the power plants had pollution control devices. The pollution level when only cars had pollution control devices was lower. Therefore, to keep the pollution levels lower, it is more important to have pollution control devices on the cars. 1. How certain are you about your claim based on your explanation? 1 Student answers will vary.
3. What happens to the pollutants that are removed by scrubbers? 1 Scrubbers remove pollutants by chemical reactions. The pollutants are oxidized and neutralized within the scrubber. 4. How does a catalytic converter reduce pollutant emissions? 1 Pollutants react and are chemically changed before exiting the tailpipe.
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2. Explain what influenced your certainty rating. 1 Student answers will vary. Scientific evidence includes: specific reference to experiments done with the model. Students may state that power plants emit more pollutants than cars, but depending on the number of cars, the emissions from cars may be greater. Students may also express uncertainty that the model is similar to real-world power plant and car emissions.
Preventing Bad Air Days Answer Key, continued 5. Which commuting option is best for preventing poor air quality events? 1 electric car
7. How certain are you about your claim based on your explanation? 1 Student answers will vary. 8. Explain what influenced your certainty rating. 1 Student answers will vary. Scientific evidence includes: specific reference to the graphs. Students may state that the electric car is not shown as an option and that the electric car statistics may be very different than the statistics for an electric trolley bus. Students may also want to know how many passengers are riding in the car or bus, as the bus looks like a better alternative when there are many people on it.
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6. Explain your answer. 1 The emissions of NOx, VOCs, greenhouse gases, and particulate matter are lowest for the electric option, though that’s for an electric trolley bus. The diesel bus is a better option than the gasoline-fueled car because emissions of NOx, VOC, and greenhouse gases are lower for diesel buses than for gasoline-fueled cars. However, the particular emissions of the diesel bus are much higher than for a gasoline-fueled car.
