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.
Ozone pollution is a form of pollution which is characterized by high concentrations of ozone, a form of oxygen, at ground level. Exposure to ozone can cause serious health problems in plants and people, and ozone pollution is a major problem in some regions of the world. It tends to increase during periods of high temperatures and sunny skies, which is why bad air advisories are often issued on seemingly nice days.
Precursors of Photochemical Smog. Ozone, the most common chemical in urban smog, is the result of a complex photochemical reaction between nitrogen oxides and hydrocarbons. The main source of nitrogen oxide pollution is motor vehicle exhaust, according to the Environmental Protection Agency.n the early 1900's, the British coined the term 'smog' to describe the thick, sulfuric smoke that spewed from London's industrial chimneys and hung in the fog. Today's smog also contains sulfur, but the major chemical in fog is ground-level ozone, according to the Environmental Protection Agency.