北偏西大风对北京冬季生物气溶胶的影响

生物气溶胶对大气成云过程、生态系统演化和人体健康都有着重要的影响,目前对生物气溶胶浓度、组成和活性的变化规律认识不足.因此,在2013年1月和2015年1月在北京市清华大学校园内进行了采样和观测,以分析气象条件对生物气溶胶浓度和组成的影响.生物气溶胶浓度用生物气溶胶在线检测器WIBS-4A(waveband integrated bioaerosol sensor)测定,生物气溶胶中细菌群落的组成用16S rDNA测序的方法来测定.结果表明,北京冬季生物气溶胶数浓度范围在2~150 L~(-1).风是影响生物气溶胶的浓度和组成的重要因素.主导风向为北偏西30°,风速大于4 m·s-1的大风天气时,生物气溶胶的数浓度升高1个数量级,生物气溶胶中细菌群落的组成也发生急剧的变化.大风天气过后,生物气溶胶中细菌群落的组成缓慢恢复到大风前的状态.

Impact of Gusty Northwesterly Winds on Biological Particles in Winter in Beijing

Biological aerosol particles play a crucial role in cloud formation and succession of ecosystems and have a large impact on human health. However, the variations in the concentration, composition, and viability of biological particles remain unclear. This study, conducted in January 2013 and January 2015 in Beijing, explores the influence of meteorological conditions on the variations in the concentration and composition of biological particles. Concentrations of biological particles were measured by an online optical detector, waveband integrated bioaerosol sensor (WIBS-4A). The composition of bacterial communities within biological particles was measured by 16S rDNA sequencing. The results showed that the number concentration of biological particles ranged from 2 L^-1 to 150 L^-1 during winter. The wind could largely influence the concentration and composition of biological particles. During gusty northwesterly winds, when wind speed was above 4 m·s^-1 and wind direction was from the northwest (~30°), the concentration increased by one order of magnitude, and the composition of bacterial communities sharply changed. After the passage of gusty winds, the composition gradually changed back to its prior state.