MQ-2-dat

STH1054-dat - MQ series gas sensors socket - STH1057-dat

mq-series-dat - mq-5-dat - mq-3-dat - mq-2-dat

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

datasheet - Sensor-dat/sensor-gas-dat/MQ-series-dat/MQ-5-dat/MQ-5.pdf