What are the sources of PAN And VOCs

Explanation:

Nitrogen dioxide comes from the engines of cars and trucks and from factories and power plants that burn coal. Other chemicals that help make PAN are called Volatile Organic Compounds (VOCs). VOCs get into the air from paint, gasoline, and other chemicals. Sunlight changes the VOCs into other chemicals.

the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.

the answer to this question is 3.