Calf Muscles. 1  The calf muscles are six in number: the gastrocnemius, the soleus, the popliteus, the tibialis posterior, the flexor digitorum longus, and the flexor hallucis longus. 2  The gastrocnemius and the soleus run between the knee and the ankle. 3  One of the calf muscles, the soleus, has a special ability.
Air pollution leads to ozone pollution and acid rain. CFC compounds, used in aerosol sprays prior to 1995, destroy the ozone layer. Ozone pollution can cause damage to human respiratory tracts. Ozone can damage the vascular system of plants.
Traffic is the main source (>50%) of ozone precursors. It may sounds curious, but it is a fact that most of the times ozone levels are higher in rural areas than in cities. This is sometimes called the 'ozone paradox'. Ozone can be degraded by the compounds (NOx) by which it is also formed. This degradation occurs more often in cities than in rural areas, because there is more NO in cities (see further).