In Why Is the Air Dirty?, Isaac Asimov explains the causes and effects of air pollution and discusses how we can help prevent it.
For general information on the “Ask Isaac Asimov” series, see What Is a Shooting Star?
On the whole, the environmental books in the “Ask Isaac Asimov” series fare better with me than the astronomical books; perhaps this is because Asimov doesn’t cover environmental issues elsewhere for young children except in the relatively obscure Earth: Our Crowded Spaceship. As a result, I’m a bit less resentful of the incredible cost of this particular book.
In particular, it’s got a really spectacular shot of the Hagia Sophia in Istanbul orange through the smog and is, in general, well-illustrated. It’s definitely worthwhile for its target audience.