Study on OC and EC Characteristics of Atmospheric Particulate Matter in Harbin

In order to investigate the carbon components of atmospheric particles, TSP, PM10 and PM2.5 were collected and analyzed in July 2008 to June 2010. The results shows that the OC variation of three particles presents of the lower concentration in the middle and the higher on both sides with the highest point in January which is 5 to 7 times of July. The monthly change of concentration was very obvious in PM2.5 and OC was mainly from fuel combustion. The monthly variation of EC is not very clear in TSP, PM10 and PM2.5 with the range of 3.06 ± 1.23 μg/m3, 2.44 ± 1.18 μg/m3, 1.55 ± 0.50 μg/m3. EC mainly came from the direct emissions of combustion sources. The concentration of EC was stable in the year. OC / EC is more than 2 in major months, which indicates that secondary chemical reaction has occurred and it is strongest in January and December.

Thiosulfate formation and associated isotope effects during sulfite reduction by Clostridium pasteurianum

During growth of Clostridium pasteurianum on sulfite, approximately half the sulfite was reduced to sulfide and half to thiosulfate. Sulfide was enriched in 32S or 34S at different stages of growth and thiosulfate was enriched in 32S, particularly in the sulfane atom.It is suggested that thiosulfate in these bacterial cultures arose from a secondary chemical reaction. The chemical formation of thiosulfate from sulfide and sulfite was also accompanied by sulfur isotope fractionation. The implications of these results with respect to 'inverse' isotopic effects are discussed.