Chemistry and physics are present everywhere, including the air we breathe. This course provides a comprehensive overview of the fundamental chemical and physical processes that govern the Earth's atmosphere, from the molecular to the global scale. Upon completion of this course, students will understand how a small molecule like ozone can impact the earth's ecosystem and human health by affecting regional air quality and global climate change. The course content includes an in-depth study of chemical cycles, reaction kinetics, thermodynamics, transport, photochemistry, radiative balance, gas-phase chemistry, and aerosol chemistry. Students will explore the chemistry and physics behind key environmental issues such as air pollution, acid rain, the ozone hole, and climate change.