Where can I find information, specifically data about ground level ozone in silver spring, maryland?

im doing an ap enviornmenta project and i presented an idea on how to gather information about pollution in my area to see how bad it is and my teacher said i coulndt do that project. She recommended that i go online and that there would be a site where i coul go and find data about the ozone in our area thats recorded monthly(or she thinks) and that way I could compare it. She mentioned something about the ICC but i am still looking. Do you know how to get this info online. PLEASE HELP!