Before , lead was added to gasoline as a lubricant to reduce wear on engine valves. Leaded gasoline was completely phased out of the U. Manufacturers recommend the grade of gasoline for use in each model of a vehicle. In addition to the different grades of motor gasoline, the formulation of gasoline may differ depending on the location where it is sold or the season of the year.
Federal and state air pollution control programs that aim to reduce carbon monoxide, smog, and air toxins require oxygenated, reformulated, and low-volatility gasoline. Some areas of the country are required to use specially formulated gasoline to reduce certain emissions, and the formulation may change during winter and summer months. These area-specific requirements mean that gasoline is not a homogenous product nationwide. Gasoline produced for sale in one area of the United States might not be authorized for sale in another area.
The main difference between winter- and summer-grade gasoline is vapor pressure. Gasoline vapor pressure is important for an automobile engine to work properly. During winter months, vapor pressure must be high enough for the engine to start easily.
In the summer, a lower vapor pressure is required in many areas to reduce air pollution. Gasoline evaporates more easily in warm weather, releasing more volatile organic compounds that contribute to health problems and to the formation of ground-level ozone and smog. To cut down on pollution, the U. Environmental Protection Agency requires petroleum refiners to reduce the vapor pressure of gasoline during summer months.
The characteristics of the gasoline depend on the type of crude oil that is used and the setup of the refinery where the gasoline is produced. Gasoline characteristics are also affected by other ingredients that may be included in the blend, such as ethanol.
Most motor gasoline sold in the United States contains some fuel ethanol. Essentially, the higher the octane rating, the lower the likelihood that detonation happens at the wrong time.
On occasion, this occurrence will likely not harm your vehicle. However, if it happens frequently it may quicken the decline of your engine's performance. Engines with high compression ratios or turbochargers often require high octane fuel found in premium gas for optimal performance and fuel efficiency.
However, the majority of cars on the road today are optimized to run on regular gas. The detergent additives in your gasoline are far more important than the octane level, as they help clean your engine and optimize performance. Each retailer offers a different blend of additives, used across all grades. When it comes to additives, some hold themselves to a higher standard.
Today, there are two primary sources of octane used in the U. Knock is virtually unknown to modern drivers. This is primarily because fuels contain an oxygenate that prevents knock by adding oxygen to the fuel.
This oxygenate is commonly referred to as octane. At most retail gasoline stations, three octane grades are offered, 87 regular , 89 mid-grade , and premium.
The higher the octane number, the more resistant the gasoline mixture is to knock. Doing so would increase vehicle efficiency and lower greenhouse gases through decreased petroleum consumption. In the early 20th century, automotive manufacturers were searching for a chemical that would reduce engine knock. In , automotive engineers working for General Motors discovered that tetraethyl lead better known as lead provided octane to gasoline, preventing engine knock.
While aromatic hydrocarbons such as benzene and alcohols such as ethanol were also known octane providers at the time, lead was the preferred choice due to its lower production cost.
Leaded gasoline was the predominant fuel type in the United States until the U. Environmental Protection Agency EPA began phasing it out in the mids because of proven serious health impacts. Early in its use as a fuel additive, health concerns were raised regarding the use of lead in gasoline. In , 15 refinery workers in New Jersey and Ohio died of suspected lead poisoning.
As a result, the Surgeon General temporarily suspended the production of leaded gasoline and convened a panel to investigate the potential dangers of lead use in gasoline. Despite these warnings, the Surgeon General set a voluntary standard of lead content, which the refining industry successfully met for decades. It was not until the s, following extensive health research, that the devastating health impacts of low-level lead exposure were established.
The health impacts of lead exposure in children include anemia, behavioral disorders, low IQ, reading and learning disabilities, and nerve damage. In adults, lead exposure is associated with hypertension and cardiovascular disease. Prior to the lead phase-out in gasoline, the total amount of lead used in gasoline was over , tons per year.
Congress passed the Clean Air Act in , setting in motion the formation of the EPA and, ultimately, the removal of lead from gasoline. EPA estimates that between and , 68 million children were exposed to toxic levels of lead from leaded gasoline alone. The phase-out of lead from gasoline subsequently reduced the number of children with toxic levels of lead in their blood by 2 million individuals a year between and Credit Cards Credit card reviews.
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