This alcohol sensor is suitable for detecting alcohol concentration on your breath, just like your common breathalyzer. It has a high sensitivity and fast response time. Sensor provides an analog resistive output based on alcohol concentration. The drive circuit is very simple, all it needs is one resistor. A simple interface could be a 0-3.3V ADC.

Please review the datasheet for conversions to ppm then Wikipedia.org for BAC.

Features:

• 5V DC or AC circuit
• Requires heater voltage
• Operation Temperature: -10 to 70 degrees C
• Heater consumption: less than 750mW

• 16.8mm diameter
  
• 9.3 mm height without the pins

• Datasheet
• Arduino Tutorial in Portuguese