Fly ash, vapors, smoke, fumes, gases, dust, odors. There shall be no emission of any smoke, fumes, gas, dust, odors or any other atmospheric pollutant which will disseminate beyond the boundaries of the lot occupied by such use; and further, there shall be no emission which can cause any damage to health, to animals or vegetation or to other forms of property, or which can cause any excessive soiling at any point. Emission from any chimney or otherwise or any solid or liquid particles in concentrations exceeding 0.2 grain per cubic foot of the conveying gas or air at any point is prohibited. For measurement of the amount of particles in gases resulting from combustion, correction shall be applied to a standard stack temperature of 500º F. and 50% excess air.