Air quality during a heat wave not only feels worse, it is worse. The combination of heat and sunlight creates a "chemical soup" that affects air quality and makes life outdoors nearly unbearable for many people. Find out how heat waves affect air quality, and what you can do to protect yourself from poor air quality and heat waves.
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Also Read:

• Smog: Frequently Asked Questions
• Americans Breathe Dangerous Levels of Smog
• More Than Half of U.S. Population Lives in Counties with Unsafe Air
• Ozone: The Good and Bad of Ozone
• What Causes Global Warming?
• How to Avoid and Treat Heat Exhaustion and Heat Stroke -- Sharon O'Brien, About.com: Senior Living

Hydroelectric dams harnessed U.S. rivers and brought light into the darkness in a cleaner, more sustainable way than most other power plants could claim. But the dams also created an impenetrable barrier that blocked migrating salmon, making it impossible for them to reach the sea or return to their spawning grounds. Over the past century, many wild salmon runs have been decimated or destroyed, but today many dams are being studied for possible removal, which could create a new era of restoration for wild salmon runs. Learn more about the relationship between dams and salmon, and what can be done to restore wild salmon runs without turning out the lights.

_{Photo by Matthew Hull}