For example, members of environmental organizations tend to be among the more affluent Americans. A typical reader of Sierra, the magazine of the Sierra Club, earns twice the average American income. In other words, as people become more affluent, they become more interested in protecting environmental amenities. But in a system based on private property rights, several factors encourage people to limit pollution. One factor is the common law, specifically the legal doctrines of public and private nuisance, trespass, wrongful bodily invasion, and riparian law.
People have a right against invasion of themselves or their property by harmful pollutants.
This protection has never been perfect, but it has prevented or ended severe pollution. Second, over the long run, the profit motive encourages owners to reduce pollution. Over the short term, they may be able to lower costs by letting waste out the smokestack, but that waste costs them money. Similarly, companies can save money by saving expensive chemicals or metals rather than losing them in the waste stream. So there is an inexorable tendency to reduce pollution.