Effect of humidity on atmospheric VOCs measurement

Abstract Trace volatile organic compounds (VOCs) play an important role in physic-chemical processes of the troposphere. Accurate measurement of ambient VOCs is needed. However, the determination of VOCs is difficult due to the large amount of water in atmosphere. A dynamic dilution and humidifying system was developed to study the impact of water on ambient VOCs measurement. Result showed that the deviation of aldehydes and ketones was much larger comparing with the BTEX compounds. And the C10-C11 compounds were more susceptible to air humidity compared with C6-C8 compounds. This showed that the hydrophilic compounds and compounds with high carbon number were more susceptible to air humidity comparing with hydrophobic compounds and compounds with lower carbon number.