The key facts
- K3 gasoline allows up to 150 mg/kg of sulfur, K5 — no more than 10 mg/kg
- Sulfur oxides in exhaust pollute the air and irritate the airways; people with asthma are vulnerable
- Sulfur reduces the efficiency of the catalytic converter and oxygen sensors, increasing emissions and fuel consumption
How Euro-3 differs from Euro-5
Gasoline of ecological class K3 (Euro-3) contains significantly more sulfur than K5 class fuel, and when burned it forms harmful compounds that pollute the air and can negatively affect health. This was told to Gazeta.Ru by Sergey Pestrikov, associate professor of the Department of Automobiles and Technological Machines at Perm Polytech. According to him, the ecological class reflects the content of harmful impurities — sulfur, benzene and aromatic hydrocarbons: the lower the class, the less strict the requirements for chemical composition. For K3, up to 150 mg/kg of sulfur is allowed, for K5 — no more than 10 mg/kg.
Danger to health and the car
The main danger of sulfur is associated with its combustion products: during engine operation, in particular, sulfur oxides are formed, which enter the atmosphere with exhaust gases. They contribute to air pollution and can irritate the airways; people with asthma and other respiratory diseases are especially vulnerable. In addition, according to the expert, sulfur negatively affects exhaust treatment systems: it reduces the efficiency of the catalytic converter and impairs the operation of oxygen sensors, which increases emissions of harmful substances and may increase fuel consumption.
How to determine the fuel class
Pestrikov emphasized that the ecological class and octane number are different characteristics: the AI-92 or AI-95 marking indicates knock resistance, while K3 or K5 indicates ecological properties. It is impossible to determine the class of gasoline by appearance; 'folk' methods with a sheet of paper or a transparent container do not allow reliably establishing the class. It is more reliable to check the marking on the fuel dispenser and the information in the gas station's documents.
