[On-line analysis and mass concentration characters of the alkali metal ions of PM10 in Beijing].

The mass concentration characters and the sources of water-soluble alkali metal ions in PM10 in 2004 and 2005 in Beijing were analyzed by using the system of rapid collection of particles. The result showed that the average concentration of Na+, K+, Mg2+ and Ca2+ was 0.5-1.4, 0.5-2.5, 0.1-0.5 and 0.6-5.8 microg/m3, respectively. The highest and lowest concentration appeared in different seasons for the alkali metal ions, which was related to the quality and source. The concentration of alkali metal ions was no difference between the heating period and no heating period, which meant the heating was not the main source. Sea salt and soil were the important sources of Na+. The source of K+ came from biomass burning and vegetation. Soil was the large source of Mg2+ and Ca2+. The alkali metal ions appeared different daily variation in different seasons. Precipitation could decrease the concentration of Na+, K+, Mg2+ and Ca2+, which was 10%-70%, 20%-80%, 10%-77%, 5%-80% respectively.

[Water-soluble chloride in aerosol PM10 in Beijing].

Water-soluble chloride is one of the most important components in aerosols. The chloride in PM10 measured from January to December 2004 in Beijing was determined using a system by combing rapid collection of fine particles and ion chromatography (RCFP-IC). The results showed that the annual average concentration of water-soluble chloride at the urban area in Beijing was about (3.1 +/- 1.7) microg x m(-3); the average concentration of chloride during the heating period was (4.6 +/- 2.1) microg m(-3) while it was (2.6 +/- 1.6) microg x m(-3) during the period no heating. The lowest concentration of (1.3 +/- 0.8) microg x m(-3) appeared in May, and the highest concentration appeared of (5.8 +/- 5.3) microg x m(-3) in December. Trends of the diurnal variation of water-soluble chloride depended on seasons. In autumn and winter, the higher concentration appeared in the daytime and the lower concentration appeared at night. In spring and summer, the higher concentration appeared at forenoon and the lower appeared at afternoon. Overall, the concentration of chloride in autumn and winter was higher than in spring and summer.

An improved gas chromatography for rapid measurement of CO2, CH4 and N2O.

Combining improved injector, gas line and valve-driving modules, a GC equipped with FID and ECD, could simultaneously measure CH4, CO2 and N2O in an air sample within 4 min. Test results showed that the system has high sensitivity, resolution and precision; the linear response range of the system meets the requirement of in situ flux measurements. Thus, the system is suitable for monitoring fluxes of main greenhouse gases in terrestrial ecosystem since it is easy to use, efficacious, stable and reliable to collect data.

[Trends and variation of CFC-11 in the atmosphere of Beijing].

In recent years, concentration of CFC in the atmosphere has undergone rapid changes especially in association with human activities. For the influence of CFC on climate changes and environment changes, the concentration of atmospheric CFC-11 in Beijing is continuously observed and analyzed by a gas chromatography-mass spectrometry. The seasonal variation concentration and trends of CFC-11 are reported. The results show that the seasonal variation of CFC-11 was basically similar from 1999 to 2003. There was one peak value in the seasonal variation of CFC-11 in 1999-2003. The highest monthly average concentration of CFC-11 was 1149.5 +/- 531.9 x 10(12) ( V x V(-1)) in summer and the lowest monthly average concentration of CFC-11 was 487.5 +/- 131.5 x 10(-12) (V x V(-1)) in spring. The annual average concentration of CFC-11 was increasing in Beijing atmosphere from 1995 to 1998, and the average increasing ratio was 17.9%. The annual average concentration of CFC-11 was slowly decreasing from 1999, and the average decreasing ratio was 10.7%. The average concentration of CFC-11 in the atmosphere of Beijing was 3 to approximately 5 times of the average concentration of CFC-11 in the atmosphere of Mauna Loa Station of U.S.A.

[Measurement and study on the atmospheric trace BTEX in Beijing].

Atmospheric trace BTEX in Beijing was observed by a gas chromatography/mass spectrometry in the latest 4 years. The diurnal, lunar and annual concentration variations of these pollutants were reported. In winter and spring, the diurnal profiles exhibited two peak values corresponding to the daily rush hours 08:00-10:00 am and 17:00 pm; in autumn, there was the third peak value in the night at 22:00; the highest concentration of BTEX in summer appeared in the midday and totally three daily maxima were in the sampled day. In the lunar variation of the BTEX from 2000 to 2002, the average concentration was about (44.1 +/- 24.5) nmol/mol (C unit), and the seasonal maximum value appeared in summer. The trend of BTEX was decreased greatly from 1999 to 2002.