Suppose you lived in one of those cities that have suffered in recent years form regular attacks of smog. (If you don't live in such a city, you soon may, for many more cities are working up to it). You wake up to a clear, sunny morning. About 9:00 a.m a murky haze begins to form, getting thicker and thicker until it blots out the sun. In the early afternoon a breeze may blow all, or most, of it off to the mountains or it may stay on day after day. You go about your business coughing and dabbing at your garden, you flowers and grass, become discolored and show signs of burning and necrosis. People with lung ailments die unexpectedly.