Number concentration and size distributions of submicron particles in jinan urban area: characteristics in summer and winter.

The aerosol number concentration and size distribution were measured with the newly developed Wide-range Particle Spectrometer in summer and winter of 2006 at the urban site of Jinan City. Here reported the characteristics of fine particles of the different observation seasons. Relative high number concentrations for the particles in the diameter range of 10-500 nm were observed in both seasons. It was found that the dominant number distributed in particle diameter smaller than 100 nm and the percentage over the number concentration of all air particles is much higher than what has been measured in other urban sites over the world. The number mean diameter in summer was much smaller than in winter, strongly suggesting the different origin of ultrafine particles in different seasons. That is, particles in ultrafine mode mainly came from nucleation and new particle formation in summer while from traffic emission in winter. The diurnal variation also supported this point. Number concentration in the diameter range of 10-200 nm got their peak values at noontime, well correlated with the mixing ratio of SO2 and the intensity of solar radiation in summer. While in winter, those in the same diameter range showed the main peaks during the traffic hours happened in the morning and evening.

[Ozone pollution, influence factors and their correlation at urban area in summer].

Based on the observational data of near surface O3, NO, NO2, CO and meteorological factors in the urban area of Ji'nan during summer 2003, the 03 concentrations and their temporal variation characteristics were studied. The correlation between O3 and its precursors (NO, NO2, CO) and related meteorological factors (solar radiation, temperature) was analyzed. The results show that O3 pollution during summer was very serious in Ji'nan, and the levels of O3, NO, NO2, NOx and CO were quite high during the observational period. O3 concentrations were well negatively correlated with NO, NO2, NO, and CO during day time. As to the meteorological factors, O3 concentrations correlated well with solar radiations, but showed no obvious correlation with the temperatures. Consequently, based on the above data and results, a regression equation that relates ozone concentrations observed in the day time to its precursors and solar radiation was constructed. The results show that the calculated values were in good agreement with the observed values.