Changes in tropospheric air quality related to the protection of stratospheric ozone in a changing climate

Ground-level O-3 and PM are detrimental to human health, leading to several million premature deaths per year globally, and have adverse effects on plants and the yields of crops. The Montreal Protocol has prevented large increases in UV radiation that would have had major impacts on air quality.

Future scenarios in which stratospheric O-3 returns to 1980 values or even exceeds them (the so-called super-recovery) will tend to ameliorate urban ground-level O-3 slightly but worsen it in rural areas. Furthermore, recovery of stratospheric O-3 is expected to increase the amount of O-3 transported into the troposphere by meteorological processes that are sensitive to climate change. UV radiation also generates hydroxyl radicals (OH) that control the amounts of many environmentally important chemicals in the atmosphere including some greenhouse gases, e.g., methane (CH4), and some short-lived ozone-depleting substances (ODSs).