摘要
Number concentrations and distributions of 10-10,000 nm particles in a large city （Jinan） in the North China Plain were measured in winter 2009. The mean number concentrations of nucleation mode （10-20 nm）, Aitken mode （20-100 nm）, and accumulation mode （100-1000 nm） particles, as well as total particles were 925, 6898, 2476, and 10,299cm-3, respectively. Two severe haze episodes, with elevated concentrations caused by pollutants accumulating, were observed. Accumulation mode particle concen- trations were significantly higher during the episodes than on clear days, and nucleation mode particle concentrations were pronouncedly higher on clear days than during the episodes. The peaks of domi- nant number, surface area, and mass size distributions were around 30-50, 200-300, and 200-400 rim, respectively, both during the haze episodes and on clear days, but elevated mass and surface area con- centrations around 500-600 nm were also observed during the haze episodes, suggesting these particles had significant contributions to haze formation. These particles were probably formed through larger droplets in cloud and fog evaporating. Two new particle formation events, probably triggered by strong photochemical processes on clear days and significant traffic emissions during haze episode 2, were found. Significant insights were made into haze formation in a oolluted Chinese urban area.
Number concentrations and distributions of 10-10,000 nm particles in a large city （Jinan） in the North China Plain were measured in winter 2009. The mean number concentrations of nucleation mode （10-20 nm）, Aitken mode （20-100 nm）, and accumulation mode （100-1000 nm） particles, as well as total particles were 925, 6898, 2476, and 10,299cm-3, respectively. Two severe haze episodes, with elevated concentrations caused by pollutants accumulating, were observed. Accumulation mode particle concen- trations were significantly higher during the episodes than on clear days, and nucleation mode particle concentrations were pronouncedly higher on clear days than during the episodes. The peaks of domi- nant number, surface area, and mass size distributions were around 30-50, 200-300, and 200-400 rim, respectively, both during the haze episodes and on clear days, but elevated mass and surface area con- centrations around 500-600 nm were also observed during the haze episodes, suggesting these particles had significant contributions to haze formation. These particles were probably formed through larger droplets in cloud and fog evaporating. Two new particle formation events, probably triggered by strong photochemical processes on clear days and significant traffic emissions during haze episode 2, were found. Significant insights were made into haze formation in a oolluted Chinese urban area.
基金
The authors gratefully acknowledge the NOAA Air Resources Laboratory for providing the HYSPLIT transport and dispersion model and access to the READY website （httP：nready.arl.noaa. gov）, which were used in this study. The authors also acknowledge support provided by the Shandong Province Natural Science Foun- dation （ZR2010DQ022）, the Independent Innovation Foundation of Shandong University （2012TS041）, a China Postdoctoral Science Foundation funded project （20060400982）, and the Shandong Post~ doctoral Science Innovation Foundation （200601003）.
