Any use of land, building and structures or any industrial process that may be offensive, noxious or injurious by reason of the production or emission of dust, smoke, heat, glare, refuse matter, odor, gas, fumes, noise, vibration or similar substances or conditions is prohibited. Emission of smoke, as measured at the point of emission, which is darker or more opaque than Number 1 on the Ringelmann Smoke Chart published by the United States Bureau of Mines, is prohibited, except that smoke not darker or more opaque than Number 2 on said chart may be emitted for periods not longer than four minutes in any 30 minutes.