One more of a few dozen Apple sensor patents: "CHEMICALLY ROBUST MINIATURE GAS SENSORS” Sensing on a single chip: nitrogen dioxide, nitrogen monoxide, sulfur dioxide, carbon monoxide, methane, volatile organic compounds. Why? What till you find out... http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=1&f=G&l=50&co1=AND&d=PG01&s1=20190025271.PGNR.&OS=DN/20190025271&RS=DN/20190025271 …pic.twitter.com/x97Zpuytne