The By Source of Exposure category focuses on health effects due to specific sources of exposure to tobacco products, including:

• Cigarette smoking,
• Cigar smoking,
• Pipe smoking,
• Smokeless tobacco, and
• Secondhand smoke.

• Topics focused on specific types of tobacco-related effects are organized in Health: Specific Substances: Tobacco: Effects.
• Topics focused on public policy issues are listed in Society: Issues: Health: Tobacco.