While ozone in the stratosphere acts as a barrier that protects the Earth from ultraviolet radiation, ground-level (or tropospheric) ozone is a dangerous trace gas that can cause serious health problems. This ozone is the result of photochemical reactions between nitrogen oxides and volatile organic compounds, which are two major air pollutants.
Click here for original story, New study shows link between hot and dry weather and air quality in Korea
Source: Phys.org