Studies on the Gaseous Organics Emitted from Tropical Rain Forests.

为了解热带雨林挥发性有机物的大气化学特征，开展了以下研究工作；(1)建立了基于自动吸附采样和毛细管GC/MS的大气中异戊二烯的分析方法，(2)热带植物大型温室异戊二烯的测量及其排放速率的评估，(3)泰国热带森林异戊二烯的日变化测量，(4)异戊二烯消耗的评估，(5)用毛细管气相色谱/质谱仪分析几种典型热带植物的排放气体。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1 mg/m~2。在泰国的雨林中，异戊二烯的峰值浓度在中午前后达到约2 ppb。在傍晚和清晨，它的浓度几乎为零。由于其高排放，观察到的峰值浓度为2 ppb，低于预期，这表明其快速消耗是由于与OH自由基的反应。

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.