Acid Rain in Sandton, Johannesburg

That time, we saw that our car was fully covered with white and black innumerable spots. My long experience in environmental research revealed to me that this is something interesting related to air pollution, and I photographed the whole horizontal area of the car body. Those 3 photographs are enclosed here.

This was cold and calm morning, almost no wind, relative humidity about 85% and sky was partially cloud-covered. What are these spots? To understand this event, we know that South Africa is producing large percentage of power by thermal power plants. The coal used in such plants has sulphur content about 1.0 to 1.5 percent. These plants are spewing thousands of tons of sulphur dioxide in the environment.