Rejuvenating fog seals have been used on pavements for decades to help restore the aged asphalt properties back to or better than the original conditions. Asphalts in paving mixtures change in composition and performance with time. The rate and degree of change depends on their chemical compositions, environmental condition and length of exposure. Originally rejuvenating fog seal consisted of special blends of petroleum oils and resins or maltenes, emulsified to help in the spray application of the products. In recent years the products have incorporated special blends of petroleum oils and resins with asphalts and compatible polymers, also emulsified. The applications of rejuvenating fog seals are usually done by a calibrated distributor truck, spraying a light application 0.23 to 0.68 L/m2 (0.05-0.15 gal/yd²) of diluted emulsion.