I am doing this project because I want to know how pollution affects the amount of stomata on a tree depending on particulate matter.

What EPA (Environmental Protection Agency) is doing is regulating inhalable particles in the air to reduce some particulate matter. There isn’t much we can do since we can't control PM (particulate matter) that is in the air. But we can reduce our exposure to PM by using air quality alerts to protect ourselves from PM when it reaches high and harmful levels.