Abstract: In order to investigate the effects of atmospheric temperature and humidity on chemical components in mainstream cigarette smoke (MCS),cigarettes were smoked in an environment of controlled temperatures and humidities. The aroma components in particulate and gas phases of MCS were trapped by Cambridge filter, and XAD-2 sorbent tube in series with-50℃ isopropanol/dry ice trap respectively. The variation of routine chemical indexes and aroma components in particle and gas phases of MCS was analyzed. The results showed that:1)Routine chemical indexes were mainly influenced by environmental humidity,the contents of TPM, tar and moisture increased and pH of MCS condensates decreased with the increase of environmental humidity. 2) Particulate phase and gas phase under different conditions contained the same kinds of aroma components, however,the contents of the aroma components varied in dependence on atmospheric conditions. 3) Total content of aroma components in either particulate phase or gas phase decreased with the increase of environmental humidity. Total content of aroma components in particulate phase at 30℃ was significantly lower than that at 20℃;while that in gas phase showed no remarkable relationship with environmental temperature. 4) With the increase of environmental humidity,in particulate phase,total contents of aldehydes and ketones, phenols,lower fatty acids, and nitrogenous compounds decreased and those of higher fatty acids and their esters increased;in gas phase,total contents of aromatic hydrocarbons,aldehydes and ketones,nitrogenous compounds and organic acids decreased and those of alkenes and phenols increased first and then decreased.