Blood alcohol concentration

Blood alcohol concentration (BAC), also known as blood alcohol level and blood alcohol content, is a measurement of the amount of alcohol (ethanol) present in a person's blood. It is usually expressed as a percentage by volume or by mass.

Measurement

BAC is typically measured with a breathalyzer, a device that estimates BAC from a breath sample. However, it can also be measured directly by analyzing a blood sample, which is the most accurate method. The legal limit for BAC when driving varies by country, but it is often 0.05% to 0.08%.

Effects on the body

The effects of alcohol on the body vary depending on the BAC level. At lower levels (0.01% to 0.05%), effects may include mild euphoria, relaxation, and decreased inhibition. As BAC increases, these effects become more pronounced and additional effects such as impaired motor control, confusion, dizziness, and even unconsciousness can occur. At very high levels (0.3% and above), alcohol poisoning can occur, which is a medical emergency.

Legal implications

In many jurisdictions, it is illegal to operate a motor vehicle with a BAC above a certain level. This is known as driving under the influence (DUI) or driving while intoxicated (DWI). Penalties for DUI or DWI can include fines, imprisonment, and loss of driving privileges.

See also

• Alcohol intoxication
• Alcohol law
• Breathalyzer
• Drunk driving

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