Answer the following question given this paragraph: Poor air quality started to become a serious problem after the Industrial Revolution. The machines in factories burned coal. This released a lot of pollutants into the air. After 1900, motor vehicles became common. Cars and trucks burn gasoline, which adds greatly to air pollution. Q: During what time period did poor air quality become a problem? A:
Choose your answer from:
a). Chernobyl disaster
b). coal industry boom
c). second world war
d). industrial revolution
d).