p618

Figure 19.1 The Greenhouse Effect The normal greenhouse effect warms Earth to a hospitable temperature. An increase in greenhouse gases intensifies the greenhouse effect, trapping more heat and raising Earth’s temperature. Figure 19-1 p621

Air pollution endangers the well-being of more than half of Americans, including many city dwellers. p623

Renewable energy sources, such as wind, can provide more environmentally friendly alternatives. However, individual choices and behaviors also have an impact on the state of our world. p624

p625

Portable metal containers are a “greener” alternative to disposable plastic water bottles. p626

Secondhand smoke puts everyone, including babies, at risk of serious health problems. p627

Read the labels on common cleaning products and follow instructions for use and storage to avoid possible health risks. p629

Figure 19.2 Greening Your Space Figure 19-2 p631

Pesticides protect crops from harmful insects, plants, and fungi but may endanger human health. p633

Although laboratory studies on animals indicate that EMFs affect human cell membranes, research on humans has found only a weak connection between EMFs and disease. p634

Besides listening to the music at your next concert, tune into the noise level and how your ears are feeling. p636

Figure 19.3 Louder and Louder The human ear perceives a 10-decibel increase as a doubling of loudness. Thus, the 100 decibels of a subway train sound much more than twice as loud as the 50 decibels of a rushing stream. Figure 19-3a p637

Figure 19.3 Louder and Louder The human ear perceives a 10-decibel increase as a doubling of loudness. Thus, the 100 decibels of a subway train sound much more than twice as loud as the 50 decibels of a rushing stream. Figure 19-3b p637