Environmental hazards include biological, physical, and chemical ones, along with the human behaviors that promote or allow exposure. Some environmental contaminants are difficult to avoid (the breathing of polluted air, the drinking of chemically contaminated public drinking water, noise in open public spaces); in these circumstances, exposure is largely involuntary. Reduction or elimination of these factors may require societal action, such as public awareness and public health measures. In many countries, the fact that some environmental hazards are difficult to avoid at the individual level is felt to be more morally egregious than those hazards that can be avoided. Having no choice but to drink water contaminated with very high levels of arsenic, or being forced to passively breathe in tobacco smoke in restaurants, outrages people more than the personal choice of whether an individual smokes tobacco. These factors are important when one considers how change (risk reduction) happens.

* contaminate: 오염시키다 ** egregious: 매우 나쁜