What is smog
Classic smog results from large amounts of coal burning in an area and is caused by a mixture of smoke and sulfur dioxide.
In the 1950s a new type of smog, known as Photochemical Smog, was first described.
Smog is a problem in a number of cities and continues to harm human health.
Ground-level ozone, sulfur dioxide, nitrogen dioxide carbon monoxide are especially harmful for senior citizens, children, and people with heart and lung conditions such as emphysema, bronchitis, and asthma.
It can inflame breathing passages, decreasing the lungs' working capacity, and causing shortness of breath, pain when inhaling deeply, wheezing, and coughing.