Change of photochemical oxidant concentration by increase of VOCs emission from vegetations due to global warming

摘要

VOCs emission experiments were conducted in a growth chamber in which temperature and luminous intensity can be controlled. Temperature was set at the typical summer temperature in Osaka and luminous intensity was set at 1000(μmol/m~2/s) during daytime. The standard VOCs emissions from four representative Japanese plant species (Cryptomeria japonica, Chamaecyparis obtuse, Pinus densiflora and Quercus serratd) and rice plants were measured. The species distributions and their leaf biomass densities in the Kinki district were determined by the forest database and the use of a geophysical information system. Consequently, the detail emission distributions of isoprene and monoterpenes were estimated. Photochemical oxidant concentration was simulated by considering VOCs emissions from forests and paddy fields that changed with temperature and luminous intensity. The simulated results of NO, NO_2 and O_3 reasonably agreed with the observed data at 12 monitoring locations. The numerical experiment of temperature increment by 1℃ that causes both the increment of VOCs and the promotion of photochemical reaction, could represent the recent increase of oxidant concentration by global warming.