Pollution from car exhaust, factory emissions, fuel combustion and other sources can hang a brown cloud over some cities. Air pollution not only contributes to respiratory diseases in humans and damages buildings, it can also affect plants. The effects of air pollution on plants develop over time and can't be undone.

According to MedlinePlus.com, the average adult takes about 8 to 16 breaths each minute. Air enters your body through your nose and travels down your bronchial tubes and into your lungs. Phlegm works with your respiratory system, interacting with the air you breathe.

With the passage of so many new smoking bans and other smoking ordinances, there has been a new wave of publicity about the dangers of smoking. You may be aware that smoking is the second leading cause of death in the United States.

As humans ascend higher into the atmosphere, air density declines. While air composition remains similar, the drop in air pressure, and in return, air volume, effectively makes the respiratory system work much harder in order to supply the same levels of oxygen to the blood stream.

An upper respiratory infection can affect any of the breathing mechanisms of your head and chest, including the nose, throat and sinuses. In addition to difficulty breathing, you may experience a sore throat, nasal congestion, cough, watery eyes, headache and ear stuffiness as a result of this infection.

Benign lung nodules are small, noncancerous masses of tissue typically discovered incidentally on a chest x-ray or CT scan. One out of every 500 to 1,000 chest x-rays reveals an unexpected lung nodule.

Hyperventilation is defined as rapid breathing. The normal breathing rate is 14 to 18 breaths per minute. Carbon dioxide is the gas that normally regulates the rate of breathing. A rapid rate of breathing can occur normally after exercise.

Lunges are a compound exercise, which articulate your knee and hip joints and activate over 10 different muscles in your lower body. The primary muscles used in lunges are your quadriceps. Each quadricep muscle comprises four smaller muscle segments, which attach to different parts of lower body skeletal structures.

When an airway in the lungs becomes blocked and causes such alarming symptoms as breathlessness, wheezing, chest tightness and coughing, immediate medical intervention is necessary.

A normal heartbeat consists of 60 to 100 beats per minute, according to Medline Plus. Irregular heartbeat, also called arrhythmia, has the heart racing, pounding or skipping beats. The effects often are felt in the chest, throat and neck.

Breathing is important throughout all functions of life and for every form of exercise. According to Beth Shaw, founder and author of YogaFit, because most people have stressful work and lives, commonly they only use the upper third of their lungs to breathe. This “chest breathing” tends to be very shallow.

Healthcare providers often need to know how well your lungs are functioning in transferring oxygen to your blood. Cells, tissues and organs need oxygen to function, and lack of it can cause a host of complications throughout your body.