https://www.wired.com/story/la-emissions-block-by-block/

Hovering above the iconic Hollywood sign is Southern California’s other icon: smog. After decades of gains fighting the menace, LA is now losing ground, clocking a 10 percent rise in deaths from ozone pollution between 2010 and 2017. Cars, of course, are the major contributor to smog, but vehicles (and power plants and industry and airports) also put out an invisible menace—the CO2 that's warming the planet.

Problem, though: You can't just train a satellite on LA to quantify the emissions coming from each street. For one, you’d have a hard time telling vehicle sources of CO2 from trees along the road, which are respirating their own carbon dioxide. Plus, the wind is blowing the greenhouse gas all over the place, so it’d be hard to tell the origin of a plume in a gusty day.