Has ozone destruction increased levels of UV-B light at the surface?
Yes, ozone destruction has increased surface levels of UV-B light (the type of UV light that causes skin damage). For each 1% drop in ozone levels, about 1% more UV-B reaches the Earth’s surface (WMO, 2002). Increases in UV-B of 6-14% have been measured at many mid and high-latitude sites over the past 20 years (WMO, 2002, McKenzie, 1999). At some sites about half of this increase can be attributed to ozone loss. Changes in cloudiness, surface air pollution, and albedo also strongly influence surface UV-B levels. Increases in UV-B radiation have not been seen in many U.S. cities in the past few decades due to the presence of air pollution aerosol particles, which commonly cause 20% decreases in UV-B radiation in the summer (Wenny et al, 2001).
