The MICS6814 sensor measures changes in the concentration of gases including carbon monoxide (CO), nitrogen dioxide (NO2), and ammonia (NH3) with this Breakout Garden compatible I2C breakout.The breakout board uses a Nuvoton MS51 microcontroller to give you an I2C interface for the sensor(redundant huh!)

• SCL -> GPIO22
• SDA -> GPIO21
• 3.3v -> 3.3v
• GND -> GND
• int is not in use

import time
from machine import Pin, I2C
from mics6814 import MICS6814


i2c = I2C(1,scl=Pin(22),sda=Pin(21),freq=100000)
gas = MICS6814(i2c)

try:
    while True:
        readings = gas.read_all()
        print(readings)
        time.sleep(1.0)
except KeyboardInterrupt:
    pass

1. Pimoroni python library
2. Arduino library