What think of my essay beginning ?

I'm not sure what grade you're in but it looks pretty decent. Be sure to clean up your grammer (example: there ARE about 4,000 chemicals not there IS about 4,000 chemicals) Also include all references to where you obtained the information in the paper (such as where did you find out there are 4,000 chemicals found in cigarette smoke which doesn't sound like a fact,BTW, I highly doubt there are exactly 4,000 chemicals found in cigarette smoke for every single brand of cigarette on the planet, where did you find out that fumes stay in the air for 30 minutes, which does not sound factual at all either BTW, I would think if you are smoking a cigarette in a small closet it may be longer, if smoking outside shorter. Other than that sort of stuff you should be in good shape, teachers tend to love anti-smoking, anti-drug, anti-alcohol, anti-whatever papers.