Atmospheric pressure is the force exerted on the surface from the weight of air above the surface. We wouldn't know this if it weren't for events that took place at the Puy de Dome Observatory in Central France. The atmosphere is a fluid layer of gases, surrounding the earth with a total weight of 5,600 trillion tons. At sea level, a vertical column of air one inch square, rising to the atmosphere weighs 14.7 pounds. French scientist and philosopher, Blaise Pascal didn't know this in 1648 when he instructed his brother-in-law to carry a barometer from the base of the Puy de Dome, 1465 meters to its summit which resulted in a fall of three inches of mercury. This established the rate of variation of the Earth's atmospheric pressure due to altitude. Two-hundred years later the Puy de Dome Observatory became the first permanent mountain observatory in Europe. in closing...Tuesday's frontal passage, may find your nose collecting a whiff from the paper plants northwest of Baton Rouge. Bad odors are often one of the more evident aspects of air pollution. Even small concentrations of odors can be easily detected. When 50% of the population can detect an odor, it's called the olfactory threshold and can be as small as one part per million, billion, or trillion, depending on the chemical species. In Madison, Wisconsin, on May 3, 1991, strong winds fanned a fire at the Central Storage and Warehouse. This building housed large quantities of cheese and meat products. The blaze erupted into a giant grease fire and despite a driving rainstorm, the inferno burned for three days. The following days included record-hot weather that enhanced quick rotting of the food residue. Residents held their noses as hardware stores sold out of clothes-pins.