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. Ground level or bad ozone is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of sunlight.
Acid rain, caused by nutrient pollution in the air, damages lakes, streams, estuaries, forests and grasslands across the country. Air pollution. Airborne nitrogen compounds like nitrogen oxides contribute to the formation of other air pollutants such as ground-level ozone, a component of smog which can restrict visibility. Wind and weather can carry ozone many miles from urban to rural areas. Ozone pollution can damage trees and harm the appearance of vegetation and scenic areas.