Ambient air samples were collected using Tenax-TA adsorbents at sites
of tunnels and urban areas in Tainan, Taiwan, and a remote recreation
area and national park in central Taiwan. A gas chromatograph equipped
with mass spectrometry was then used to analyze volatile aromatics in
the samples. Experimental data indicate that the airborne concentrati
on at the national park was very low, as expected. The concentrations
in motorcycle and car tunnels were significantly higher than those in
the background by two orders of magnitude. To further explore the impa
ct of vehicle exhaust on the airborne aromatic contents in Tainan, cha
racteristic ratios were used to evaluate the experimental data. The ch
aracteristic ratios for the tunnels, urban area, and the national park
were found to be different.