The state of Iowa plans to take legal action early next year against any citizen who would "allow, cause, or permit the emission of objectionable odors into the atmosphere." But what is the legal definition of an objectionable odor? The six members of the state's air-pollution-control commission have been pondering that question, and at one meeting they even spent the better part of an hour debating whether an objectionable odor exists if no one is there to smell it. They decided that it does.

In more practical terms, the commissioners decided that an objectionable odor is legally objectionable if it lasts more...