The paper discusses historic emissions of volatile organic compounds (VOCs) and nitrogen oxides (NOx) in the U.S. from 1900 to 1985. Total VOC emissions have increased over the study period with peaks around 1930 and 1970. In 1900, transportation sources contributed 2% of the total emissions. By 1960, these sources contributed nearly 50% of the total VOC emissions. Also, the percentage contribution of industrial processes increased from about 3% in 1900 to 26% in 1960 and 39% in 1980. External fuel combustion was a major category from 1900 to 1940, but the percentage contribution has decreased since then. Similarly, the contribution by miscellaneous other sources has also decreased with time. The percentage contribution of solid waste disposal appears to have remained nearly constant over time. NOx emissions have increased nearly steadily since 1900, while SO2 emissions have gradually increased from 1900 to 1980 with considerable changes during certain shorter periods of time. VOCs have also increased, but the rate of increase appears to be less than that of NOx and more than SO2, at least on the national level.