International Laboratory for Air Quality and Health, Queensland University of Technology, GPO Box 2434, Brisbane, QLD 4001, Australia.
International Laboratory for Air Quality and Health, Queensland University of Technology, GPO Box 2434, Brisbane, QLD 4001, Australia.
Environ Pollut. 2018 Feb;233:552-560. doi: 10.1016/j.envpol.2017.10.102. Epub 2017 Nov 5.
Studying the characteristics of new particle formation (NPF) is important as it is generally recognized as a major contributor to particle pollution in urban environments. We investigated NPF events that occurred during a 1-year period in the urban environment of Brisbane, Australia, using a neutral cluster and air ion spectrometer (NAIS) which is able to monitor both neutral and charged particles and clusters down to a size of 0.8 nm. NPF events occurred on 41% of days, with the occurrence rate of 7% greater in the summer than in the winter. We derived the first diurnal event distribution of NPF events anywhere in the world and showed that the most probable starting time of an NPF event was near 08:30 a.m., being about an hour earlier in the winter than in the summer. During NPF days, 10% of particles were charged. The mean neutral and charged particle concentrations on NPF days were, respectively, 49% and 14% higher than those on non-event days. The mean formation rate of 2-3 nm particles during an NPF event was 20.8 cm s. The formation rate of negatively charged particles was about 10% higher than that of positively charged particles. The mean particle growth rate in the size range up to 20 nm was 6.2 nm h. These results are compared and contrasted with corresponding values that have been derived with the scanning mobility particle sizer (SMPS) at the same location and with values that have been reported with the NAIS at other locations around the world. This is the first comprehensive study of the characteristics of NPF events over a significantly long period in Australia.
研究新粒子形成（NPF）的特征很重要，因为它通常被认为是城市环境中颗粒物污染的主要贡献者。我们使用中性簇和气溶胶离子光谱仪（NAIS）研究了澳大利亚布里斯班城市环境中持续一年的 NPF 事件，该仪器能够监测到大小为 0.8nm 的中性和带电粒子和簇。NPF 事件发生在 41%的天数中，夏季的发生频率比冬季高 7%。我们得出了世界上首次关于 NPF 事件的日变化分布，并表明 NPF 事件最有可能开始的时间是上午 08:30 左右，冬季比夏季早一个小时左右。在 NPF 日，有 10%的粒子带电荷。NPF 日的中性和带电粒子的平均浓度分别比非事件日高 49%和 14%。NPF 事件期间 2-3nm 粒子的平均形成速率为 20.8cm s。带负电荷的粒子的形成速率比带正电荷的粒子高约 10%。在 20nm 以下的粒径范围内，粒子的平均生长速率为 6.2nm h。将这些结果与在同一地点使用扫描迁移率颗粒谱仪（SMPS）得出的相应值以及在世界其他地方使用 NAIS 报告的值进行了比较和对比。这是在澳大利亚首次对 NPF 事件的特征进行的长时间、全面的研究。
