Studies on the Gaseous Organics Emitted from Tropical Rain Forests.

为了解热带雨林排放的挥发性有机物的大气化学特征，进行了以下研究：(1)建立了一种基于自动吸附采样和毛细管GC/MS的大气中异戊二烯分析方法；(2)热带雨植物大型温室中异戊二烯的测量及其排放率评估；(3)泰国热带森林中异戊二烯的日变化测量；(4)异戊二烯对OH自由基的消耗评估；(5)用毛细管GC/MS分析一些有代表性的热带植物的排放气体。温室内异戊二烯浓度变化显著，白天浓度较高，反映了光照强度对异戊二烯排放的影响。根据白天浓度的增加，计算出4月份异戊二烯的排放速率为1mg/m^2。在泰国的热带雨林中，中午前后观察到异戊二烯的峰值浓度约为2 ppb。在傍晚和清晨，它的浓度几乎为零。观测到的峰值浓度为2ppb，由于其高排放，低于预期，表明其与OH自由基反应消耗迅速。

In order to understand the atmospheric chemistry of volatile organics emitted from the tropical rain forests, the following studies were done ; (1) development of an analytical method for isoprene in the atmosphere based on automated adsorptive sampling and capillary GC, GC/MS, (2) measurements of is oprene in the large greenhouse of tropical rain plants and evaluation of its emission rate, (3) measurements of diurnal variation of isoprene in the tropical forests in Thailand, (4) evaluation of the consumption of OH radicals by isoprene, (5) analyses of the emission gas from some representative tropical plants with capillary GC/MS.Isoprene in the greenhouse showed significant variation with much higher concentration in the daytime, reflecting the influence of light intensity on the emission of isoprene. Based on the increase of concentration during the day, the emission rate of isoprene in April was calculated to be 1mg/m^2.In the rain forest of Thailand, peak concentration of about 2 ppb of isoprene was observed around midday. In the evening and early in the morning, its concentration was nearly zero. The observed peak concentration of 2ppb was lower than expected from its high emission, which suggests its rapid consumption due to the reaction with OH radicals.