Releasing Variation And Effects On Human Health Of Volatile Organic Compounds From Landscape Trees In Beijing

Urban green space is an important component of the ecosystem in a city, as it plays a vital role in beautifying landscape, cleaning atmosphere, improving environmental quality, maintaining ecological equilibrium of a city, and promoting physical and sentimental health of city residents. Aiming to elaborate the role of the volatile organic compounds (VOCs) of landscape trees in cleaning atmosphere, inhibiting the growth of airborne microorganisms, and caring health, experimental data were provided to landscape design of city in this paper with respect to city chemoecology. With multidisplinary methods, phyto-chemoecological, plant physio-ecological, microbiological, animal ethological and human physiological, combined with Thermal-desorption Cold Trap/Gas Chromatography/ Mass Spectrometry (TCT/GC/MS), we determined the composition, concentration, as well as seasonal variation of the VOCs released from several important landscape trees and in the air over these plants. Meanwhile interrelationship was established, based on bioassays, among the constituents and content of VOCs, airborne microorganisms and animal behavior, and human physiological response. The relationship between the constituents and content of VOCs and them and its affecting factors was investigated.1. The constituents, concentration, and seasonal variation of the VOCs from the major landscape trees in Beijing, Pinus tabulaeformis, Pinus bungeana, Sabina chinensis, Sophora japonica, Lonicera maackii Rupr. Maxim, and Prunus cerasifera Ehrh. f. atropurpurea Jacq. Rehd., were analyzed. The VOCs are a mixture of a number of micro-quantity VOCs in various concentrations and proportions. Their release and variability depend heavily on growth season of their releasers, as well as the environmental conditions. That is, trees release more VOCs in June and July than in winter and spring. The major VOCs of conifer species are monoterpenes, including D-limonene, p-pinene, a-pinene, camphene, y-terpinene, p-mentha-l,4(8)-diene, ocimene, which accounts for 80% of the total; while those of broadleaf species are Isoprene, 3-Hexen-1-ol, Acetate, Hexen-3-ol and a few monoterpenes, which accounts for 60-80% of the total.2. In the VOCs of Pinus tabulaeformis, Pinus bungeana, Sabina chinensis, Cedrus deodara and Picea koraiensis sampled in the air over the trees, 60-80% are monoterpenes, 5-20% are alkane compounds, and 3.4% are benzene compounds. In the air sampled from roadside, the VOCs contained 53.6% of benzene compounds and 0.9% of monoterpenes only. It is implied that the VOCs released by plants could increase the concentration of terpenoid compounds and decrease that of benzene compounds, thus purifying air environment.3. Counting airborne microorganisms over five conifer species using the method of natural sedimentation, it is found that the number of airborne microorganisms over the trees is significantly smaller than that in open land. According to microbe-inhibiting experiment, the extracts of Pinus tabulaeformis, Pinus bungeana, Sabina chinensis, Cedrus deodara and Picea koraiensis could inhibit the growth of bacteria and actinomycetes in the air but stimulate the growth of fungi when in low concentrations. Monomers of D-limonene, P-Pinene, nonaldehyde, decanal and benzaldehyde could inhibit the growth of airborne microorganisms, suggesting that the terpenoid compounds released by conifer species could inhibit growth of airborne microorganisms.4. Physiological parameters of human after smelling VOCs were tested using Powerlab ADInstruments. The VOCs released by the branches of Pinus tabulaeformis, Pinus bungeana, Sabina chinensis could lower human cardio velocity, systolic blood pressure and diastolic blood pressure, and relax human body, implying that the monoterpenoid compounds released by conifer species could protect human health avoid from high-strain.5. The effect of the flowers of Sorbaria kirilowii (regel) Maxim and Syringa reticulate Hara var. mandshurica (Maxin) Hara on the behavior, learning and memorial ability of rat is studied using open field...