From Arbor Day Site (https://www.arborday.org/trees/treefacts/) :

Global forests removed about one-third of fossil fuel emissions annually from 1990 to 2007.
share U.S. Forest Service, 2011

Trees remove pollution from the atmosphere, improving air quality and human health.
share U.S. Forest Service, 2013

In Los Angeles, trees remove nearly 2,000 tons of air pollution each year.
share U.S. Forest Service, 2011

In Chicago, trees remove more than 18,000 tons of air pollution each year.
share U.S. Forest Service, 2013

In Greater Kansas City, trees remove 26,000 tons of air pollution each year.
share U.S. Forest Service, 2013

Roadside trees reduce nearby indoor air pollution by more than 50%.
share Lancaster University, United Kingdom, 2013