Online Measurement Of Inorganic Water Soluble Ions In Fine Particle In Jinan

In order to understand the chacacteristics of inorganic water soluble ions in fine particle in Jinan, the capital of Shandong Province, one-year observation from December 2007 to October 2008 was carried out. Samples collected and analyzed by Ambient Ion Monitor (AIM, URG Corporation, URG-9000B), the rapid collection system of fine particle. At the same time, this paper carried out a systematic study combined with meteorological data and some of the gaseous precursors such as SO2, NO2 and O3. The main conclusions listed as following:1. PM2.5 pollution of Jinan is serious. SO42-, NO3- and NH4+are the most important water soluble ions, and annual average concentrations of these three ions in PM2.5 are 38.90,15.91,20.72μg/m3 respectively, constituting more than 80% of water soluble chemical. Cl-, K+, NO2-, Na+content is higher among other inorganic ions, and the average annual concentrations are 4.37,2.32,2.11,1.58μg/m3 respectively. These four ions constituting 10% of inorganic water-soluble ions. The water soluble ions compositions of PM2.5 appeared seasonal variation obviously, higher concentrations in summer and winter, lower concentrations in spring and autumn.2. The comparison experiments between on-line measuring systems and off-line analysis on filter samples were conducted and the main result is that inorganic water souble ions concentrations of these two different measuring systems have well correlation except NO2-.3. Using correlation analysis between SO42-, NO3- and their gaseous precursors, this paper find that the correlations between SO42- to SO2 and NO3- to NO2 showed poor throughout the year, while in specific season, the correlations are good.This showed that the conversion rate of SO2 to SO42- and NO2 to NO3- are different in each season, and the correlations of SO2 and SO42- is better than the correlations of NO2 and NO3- maybe due to the conversion of NO2 to NO3- greater impact by the meteorological factors. At the same time, the correlations between NO3- and NO2 are different both in daytime and nighttime, higher in daytime and lower in nighttime, indicting that homogeneous reaction are more important in daytime. 4. The correlations between NH4+, SO42-, NO3- and RH are significant positive. High concentrations weather in summer and winter is usually accompanied by high relative humidity. The increase in relative humidity is conducive to the formation of inorganic water-soluble ions, especially in the relative humidity above 60%, the formation of inorganic water-soluble ions were more significant.5. The total water-soluble ions concentration ratios of haze and clean days of spring, summer, autumn and winter are 1.89,2.12,1.71,3.01 respectively, and the pollution in winter is the most serious. The relevance of NO3-, SO42- and NH4+, K+in haze days is better than clean days. The secondary ion such as NO3-, SO42-and NH4+ are an important reason for Jinan's haze. The existence shapes of the secondary ion such as NO3-, SO42- and NH4+in different seasons are different. Rich ammonia is most serious in winter, and coal-fired emission Cl" is combined with NH4+, which exist as (NH4)2SO4, NH4NO3 and NH4Cl form.6. Analyzing the relative between atmospheric visibility and impact factors, this paper demonstrate that RH, BC, SO42-, NO3-, Cl-,NH4+, K+are the main factors significantly reduce the atmospheric visibility. Using multiple linear regression models to simulate the visibility, the results of simulations is relatively lower than experimental data. RH, SO42-, NO3- and NH4+are the most important contributors to visual range degradation.