If you work outdoors in summer, you know that air quality can be a concern.  High ozone levels near the surface (as opposed to the upper-level ozone which protects us from ultraviolet rays) are caused by interactions of sunlight and air pollution, particularly from emissions from automobiles but also to some extent from agriculture and other sources.  There are normally a few days a year in which high levels of ozone make breathing difficult for sensitive individuals.  A recent study from the National Center for Atmospheric Research shows that under current trends in climate, the number of days with harmful levels of ozone is expected to increase by 70 percent over the next 35 years.    These dangerous levels of ozone are likely to affect the health of both livestock and outdoor workers.  You can read the story in the EarthSky blog here.