Measurements in a highly polluted Asian mega city: observations of aerosol number size distribution, modal parameters and nucleation events
Measurements in a highly polluted Asian mega city: observations of aerosol number size distribution, modal parameters and nucleation events
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DOI：
10.5194/acpd-4-5407-2004
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发表时间：
2004-09
影响因子：
6.3
通讯作者：
P. Mönkkönen;I. Koponen;K. Lehtinen;K. Hämeri;R. Uma;M. Kulmala
中科院分区：
文献类型：
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作者：
P. Mönkkönen;I. Koponen;K. Lehtinen;K. Hämeri;R. Uma;M. Kulmala
摘要。研究了2002年10月和11月印度新德里高度污染城市环境中气溶胶粒子数大小分布（粒径3 ~ 800nm）和模态参数（几何标准差、几何平均直径和模态粒子浓度）的日变化。使用差分迁移率粒度仪（twin DMPS）连续监测两周以上，时间分辨率为10min。结果表明，交通高峰时段艾特肯模式颗粒（25-100nm）明显增加，但接近傍晚时艾特肯模式颗粒较早晨增多。此外，仅在夜间检测到高浓度的积累模式颗粒（bbb100 nm）。在晚上，生物质/垃圾燃烧和烹饪是交通旁边可能的来源。我们还表明，在这种大气中可能发生成核事件，尽管在农村地区观察到的清晰成核事件无法检测到。观测事件中3nm颗粒（J3）的形成速率在3.3 ~ 13.9cm-3s-1之间变化，生长速率在11.6 ~ 18.1nm -1之间变化，表现出生长快、形成速率高的特点，在城市地区较为典型。
Abstract. Diurnal variation of number size distribution (particle size 3-800nm) and modal parameters (geometric standard deviation, geometric mean diameter and modal aerosol particle concentration) in a highly polluted urban environment was investigated during October and November 2002 in New Delhi, India. Continuous monitoring for more than two weeks with the time resolution of 10min was conducted using a Differential Mobility Particle Sizer (twin DMPS). The results indicated clear increase in Aitken mode (25-100nm) particles during traffic peak hours, but towards the evenings there were more Aitken mode particles compared to the mornings. Also high concentrations of accumulation mode particles (>100nm) were detected in the evenings only. In the evenings, biomass/refuse burning and cooking are possible sources beside the traffic. We have also shown that nucleation events are possible in this kind of atmosphere even though as clear nucleation events as observed in rural sites could not be detected. The formation rate of 3nm particles (J3) of the observed events varied from 3.3 to 13.9cm-3s-1 and the growth rate varied from 11.6 to 18.1nmh-1 showing rapid growth and high formation rate, which seems to be typical in urban areas.