In the news:
https://earthobservatory.nasa.gov/images/89609/cleaning-up-cookstoves
https://www.eurekalert.org/pub_releases/2017-01/uoca-cbr012017.php
https://arstechnica.com/science/2017/05/excess-diesel-vehicle-emissions-killed-38000-people-in-2015-study-estimates/