南京冬季晴天及雾-霾天气纳米气溶胶粒子谱日变化比较

利用2017年12月南京气溶胶数浓度与气象参数资料，比较研究晴天及雾-霾天中10~1000nm纳米气溶胶粒子谱日变化规律及差异特征.结果表明，单峰谱型出现与污染加重有明显关系，分别出现在晴天午后、霾严重污染阶段和污染消散阶段、浓雾过程，峰值粒径分别为晴天（20~100nm）、霾天（27~144nm）和雾天（34~122nm）.3种天气条件下，晴天较强的太阳辐射和较低的湿度适合小粒子生成，核模态占比在晴天最高；霾天气象场适合爱根态粒子大量稳定存在，爱根态占比在霾天最高；雾天大量气溶胶吸湿增长，导致积聚态占比在雾天最高.在霾天污染物累积阶段，大量积聚态粒子对核模态、爱根态粒子的碰并增长作用抑制核模态、爱根态粒子生成，核模态和爱根态粒子浓度变化率为-91.0%和-62.5%，而积聚态为89.7%.浓雾过程对爱根态粒子清除作用最明显.

The comparison of diurnal variation of nanoparticle spectra in sunny and fog-haze days during winter in Nanjing

Based on observing data of aerosol number concentration and meteorological parameters in December 2017 in Nanjing, the diurnal variations and differences of 10~1000nm nanometer aerosol spectra were compared and studied in sunny and fog-haze days. The results showed that there was a significant relationship between the occurrence of unimodal distribution and pollution aggravation, which occurred in the sunny afternoon, haze serious pollution and pollution dissipation stage, and dense fog process, respectively. The peak particle sizes were sunny days (20~100nm), haze days (27~144nm) and foggy days (34~122nm). Under three weather conditions, strong solar radiation and low humidity in sunny days were suitable for the generation of small particles, and the proportion of nuclei mode was the highest in sunny days. The meteorological field in haze days was suitable for the stable existence of a large number of particles, and the proportion of Aitken mode was highest in haze days. A large amount of aerosols had hygroscopic growth in foggy days, resulting the proportion of accumulation mode was highest in foggy days. During the pollutant accumulation phase in haze days, the collision and growth effect of a large number of accumulated particles on nuclei and Aitken particles inhibits the generation of nuclei and Aitken particles. The variation rate of nuclei and Aitken mode particles concentration was -91.0% and -62.5%, while that of the accumulation mode particles was 89.7%. Fog removal was most effective on Aitken particles.