Airliners gather some air measurements, at least CO2. Don't know how widely: https://journals.ametsoc.org/view/journals/atot/25/10/2008jtecha1082_1.xml https:/

Airliners gather some air measurements, at least CO2. Don't know how widely: https://journals.ametsoc.org/view/journals/atot/25/10/2008jtecha1082_1.xml https://journals.ametsoc.org/view/journals/atot/25/10/2008jt... https://newsroom.usra.edu/commercial-airliners-monitoring-carbon-dioxide-emissions-from-cities-worldwide/ https://newsroom.usra.edu/commercial-airliners-monitoring-ca... Airline routes are not sampling evenly though, and flying at 10 km height means ground level resolution is very very low.