ideas, SO2 sensor

[gurumelo]

Hello.
Do you have ideas about connect a SO2 sensor to A20 an read values?
I live in a city with very much polution from factories. SO2 and arsenic.
Some suggestion about so2 sensor?

Thanks

[MBR]

I'v tried to google SO₂ sensors and most of them (e.g. this one on http://www.aliexpress.com/store/product/Semiconductor-type-gas-sensor-module-detects-sulfur-dioxide-SO2-qualitative-detection-sensor-module/727356_1256473095.html) seem to have some kind of an analog output, so the voltage is proportional with the gas concentration. So you will need an ADC to connect it to A20.