| Pollen pollution of trees in the spring has been a universal and hard issue in the world , and the resolution to it has become necessary and ongoing task. In this paper the advanced machine of JWL— IIC Percussive Multifunctional Airborne Microbes Monitor was used to monitor the pollen of four kinds of trees including Magnolia denudataf, Pinus bungeana, Pinus bungeana and Ailanthua altissima in Beijing Forestry University, Beijing Tao Ranting Park, and Beijing Ming City Wall Ruins Park. And the pollen dispersal regulation and its affecting factors of spring trees in Beijing was studied. The results were as follows:(1) Pollen concentration showed unimodal or bimodal according to the earth's surface in a day. When the pollen was transmitted above a soft ground, the top peak of pollen concentration appeared at 14: 00, whereas it was at both 14:00 and 20:00 when it passed through a hard ground surface,.(2) The pollen concentration varied with the distance from the plant during the dispersal in the air. And the pollen concentration was related with the directions of wind, and it was highest with a unimodal of 20m before the wind. In the other directions where the magnitude of wind was excluded, pollen dispersal concentration was increased with the increment of distance until 10-15m far from the plants.(3) In the diurnal variation, there was a positive correlation between the pollen concentration and air temperature, ground temperature, light intensity. While the air relative humidity showed a negative correlation with the pollen concentration.(4) When landscape was tough, the ground heat was slowly accumulated and surface air convection was generated. Thereon the pollen spread increasingly with the rising air, which accounted mostly for the bimodal of the pollen dispersal in one day.(5) Wind speed had a direct influence to the pollen concentration in the air. Pollen dispersal was not affected at all by wind flow when wind was below 1.0m/s, and . When the wind flow ranged from1.0m/s to 1.5m/s, the diffusion concentration of pollen was elevated. However, when the wind was up to or more than 1.5m/s the pollen diffusion was furthered, which resulted in pollen concentration decreased nearby but increased far away, and made the monitoring unmeaning. (6) The major allergenic species, covering 13 families 29 genus were prelimilarily identified in Beijing and the characteristics of damage phonology table of the major allergenic species were mastered in Beijing.(7) According to the relationship between daily characteristic of pollen diffusion and the ground surface characteristics, some suggestions were provided. Staying at home was the best choice for pollinosis patients at 2pm .Especially the place with hard ground should be avoided around 8pm. Specifically, the tree species with a pollinosis pollen for people were inhibited by large scale in assemblages such as parks and residential areas. So it was proposed that unitaite accessories in the cities should be abstained and be covered by shrubs and herbs.(8) Further the research showed that pollen concentration in down the wind direction was obviously higher than other directions and reached its peak at 20m downwind. So it is suggested that,allergenic plants should be placed under wind direction in green plants configuration, and plant other plants between 20m far.The project was special social welfare study for the Ministry of Science and Technology, which chose spring flowering woody plants in Beijing as its targets to research the allergenic pollen dispersal time, pollen pollution decay cycle, pollen dispersal daily variation regulation, spreading distance in the area, and the relationship between air temperature, atmospheric humidity, ground temperature, wind speed and pollen concentration. It is an important relevant meaning and practical value for our capital urban forest construction, and sets a good theoretical basis for the construction and evaluation of urban forest in other areas in China. |
PDF Full Text Request