A thesis sentence about air pollution should focus on the point the writer is trying to make and may be a statement about whether air pollution is good or bad, how this problem can be addressed or whether current measures to combat air pollution are sufficient. No matter what the paper is about, thesis statements should introduce the reader to the topic being discussed, present a summary of the argument that will be made in the paper and make a strong, clear claim that is supported in the paper's body paragraphs. A paper about air pollution needs to include a thesis statement that is clearly focused on air pollution.
Although the thesis statement should be included in the paper's introductory paragraph, it shouldn't necessarily be the first thing that a writer develops. Prior to formulating a thesis, writers can form opinions about air pollution by reading about things like smog, climate change, public health, the Kyoto Protocol and government regulation.
The thesis should directly address the writing prompt and include a specific statement that summarizes the paper's position on air pollution. For example, a student answering a prompt question, such as "Is air pollution a public health threat?" will want to write a thesis that clearly answers this prompt question.