You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "when did environmental pollution began to emerge as a problem in the united states?" whose answer is the 1960s.
Each document should contain about 30 words, and these documents should contain useful information.

Query: when did environmental pollution begin to emerge as a problem in the united states
Useful Output:

Doc 1: Some would assign it to the start of agriculture 11,000 years ago, while others tie it to the advent of the nuclear era in 1945, but most
Doc 2: It became commonplace to think that environmental problems started during the industrial period (throughout the 1700s and 1800s) when there was
Doc 3: In 1950, we see the first conference on air pollution by the Public Health Service. President Eisenhower speaks to the issue of pollution in his
Doc 4: In April 1970, the first Earth Day engaged millions of people in thousands of events around the US. Those events reflected the emergence of a
Doc 5: Along with amazing technological advances, the Industrial Revolution of the mid-19th century introduced new sources of air and water pollution.