Aspen 2 and Aspen 4 are virtually free from harmful substances such as benzene, aromatic hydrocarbons or olefins; substances that can cause serious health problems. Aspen alkylate petrol also keeps the spark plugs and combustion chamber cleaner. Aspen can be stored for a long time without any deterioration in quality, which makes your engine easy to start even after standstill periods. There are numerous environmental benefits, such as reducing the formation of ground-level ozone (smog) by about 40%.