We calculated the organic matter to organic carbon mass ratios (OM/OC mass ratios) in PM2.5 collected from 14 Chinese cities during summer and winter of 2003 and analyzed the causes for their seasonal and spatial variability. The OM/OC mass ratios were calculated two ways. Using a mass balance method, the calculated OM/OC mass ratios averaged 1.92± 0.39 year-round, with no significant seasonal ...

Sorption-desorption of two different hydrophobic fungicides, penconazole and metalaxyl, by a series of clay minerals layered and non-layered (montmorillonite, illite, kaolinite, muscovite, sepiolite and palygorskite) modified with the two-chain cationic surfactant, dihexadecyldimetylammonium (DHDDMA) was studied by first time in this work. DHDDMA-clays showed a good capacity to sorb both fungic...

We determined the fluxes of total mercury (HgT), total organic carbon (TOC), and dissolved organic carbon (DOC) from five upland/ peatland watersheds at the watershed outlet. The difference between TOC and DOC was defined as particulate OC (POC). Concentrations of HgT showed moderate to strong relationships with POC (I?* = 0.77) when ah watersheds were grouped. Although POC only accounts for 10...

Surface sediment cores from Oriole Lake (CA) were analyzed for organic carbon (OC), black carbon (BC), and their δ(13)C isotope ratios. Sediments displayed high OC (20-25%) and increasing BC concentrations from ∼0.40% (in 1800 C.E.) to ∼0.60% dry weight (in 2000 C.E.). Petrographic analysis confirmed the presence of fire-derived carbonaceous particles/BC at ∼2% of total OC. Natural fires were t...

balance among different fractions of a carbon sources is of paramount importance in maintenance of very important in soil quality and environmental health. on the other hand, rapid growth of world population, degradation of agricultural soils, along with release of greenhouse gasses are some of the main challenges of the 21st century. the aim of this study was to investigate the extent of chang...

Prescribed burning is a significant source of fine particulate matter (PM2.5) in the southeastern United States. However, limited data exist on the emission characteristics from this source. Various organic and inorganic compounds both in the gas and particle phase were measured in the emissions of prescribed burnings conducted at two pine-dominated forest areas in Georgia. The measurements of ...

A spectroscopic analysis of 115 wintertime particulate matter samples collected in rural California shows that wood smoke absorbs solar radiation with a strong spectral selectivity. This is consistent with prior work that has demonstrated that organic carbon (OC), in addition to black carbon (BC), appreciably absorbs solar radiation in the visible and ultraviolet spectral regions. We apportion ...

Sustainability of the rice–wheat rotation is important to Asia’s food security. Intensive cropping with no return of crop residues and other organic materials results in loss of soil organic matter and is not sustainable. We evaluated effect of eight treatments comprised of various combinations of green manure (GM), wheat straw (WS), rice straw (RS), farmyard manure (FYM) and urea alone (contro...

Japanese cedar pollinosis has been recognized recently as a serious social problem because of its high prevalence in Japan. It is well-known that the pollen grains of Cryptomeria japonica pollen (so-called Japanese cedar pollen) usually exist as coarse particles about 30 μm. However, it was supposed that the major allergen Cry j 1 (Cry j 1 particles) could be released to the atmosphere as respi...