Lynchburg is located in the deep, narrow James River Valley at the foothills of the Blue Ridge Mountains in Central Virginia. Since 1945, there have been complaints about smoke, odors, and smog in Lynchburg, Virginia. This was climaxed by an incident of paint blackening on a group of houses in 1958. Following the appraisal of the problem it seemed advisable to carry out a pilot study to obtain initial data on the general air pollution levels in Lynchburg. The study was planned to provide intensive air pollution sampling for seven days, February 9-15, including one weekend and one all-night sampling period.