In urban areas, volatile organic compounds are important ambient pollutants because of their detrimental effects on human health and their role in the chemistry of atmosphere as precursors of ozone and other oxidants. The concentration of C[EQUATION]H[EQUATION] was analyzed by Fourier transform infrared spectroscopy. The variation of the long-time trends of the C[EQUATION]H[EQUATION] concentrations in Beijing may be ascribed to the emission changes from the plane and the motor vehicle. During Beijing Olympic Games, the C[EQUATION]H[EQUATION] concentrations in Beijing Capital Airport may be ascribed to the emission changes of planes, and the C[EQUATION]H[EQUATION] concentrations have good relativity with the quantity of planes.