Ambient air pollution

I need help with a Health & Medical question. All explanations and answers will be used to help me learn.

Discuss the main causes of ambient air pollution and the influence that urbanization has on ambient air quality and health. What actions can be taken to reduce air pollution emissions? Consider possibilities at the individual, community, national, and international levels. How can air quality be monitored and improved as a global initiative?

Please answer with a minimum of 300 words. Please cite any and all references used.