If you were the state epidemiologist and it was suspected that smoke from the local toy factory was connected to adverse health outcomes among the town's residents, what type of cohort study would you

If you were the state epidemiologist and it was suspected that smoke from the local toy factory was connected to adverse health outcomes among the town's residents, what type of cohort study would you conduct to further investigate this concern? Why? What limitations exist in your choice of study? Remember to cite sources where necessary. 

a page and half please