Smell Worries

Hi, my flat roof is in need of a replacement soon and I am very worried about the installation and outgassing smells that will follow. I am very sensitive to smells and live with someone with asthma. I live in New England and am not certain what the current material is, but it looks to be a single-ply material. What is the best material for flat-roofs to limit installation and long term exposure to smells? The roof is less than 800 sq feet and there is no attic. Thank you very much.