Our lungs are among the body's primary points of contact with the outside world. We may drink two liters of liquid each day. We breathe in an estimated 15,000 liters of air, approximately 6 to 10 liters every minute, drawing life-giving oxygen across 600 to 900 square feet of surface area in tiny sacs inside the lung.
Tiny particles of dirt in the air of cities really can kill you.
Oxygen is necessary for our muscles to function. In fact, the purpose of
exercise training is to improve the body's ability to deliver oxygen. As a
result, when we exercise, we may increase our intake of air by as much as ten
times our level at rest.
An endurance athlete can process as much as twenty times the normal intake. Mouth breathing during exercise bypasses the nasal passages, the body's natural air filter.
These facts mean that when we exercise in polluted air, we increase our contact with the pollutants, and increase our vulnerability to health damage.
The interaction between air pollution and exercise is so strong that health scientists typically use exercising volunteers in their research. Research has found that air pollution can reduce breathing ability, cause chest pain, coughing, wheezing and other physical irritation.
Air pollution can interfere with the workings of the lungs, heart and other organs. It can aggravate asthma and other chronic lung diseases and heart diseases, can weaken the lung's defenses against infection and may cause lung diseases.
In pregnant women the fetus is especially vulnerable to the effects of the mother's inhalation of carbon monoxide.