[N2O exchange fluxes from wheat-maize crop rotation system in the North China Plain].

N2O exchange fluxes from the intensively cultivated winter wheat-summer maize crop rotation system in the North China Plain were measured by the static chamber technique under normal fertilization treatment and normal fertilization combined with straw returning treatment. The results indicated that the cumulative emissions of N2O from normal fertilization treatment and normal fertilization combined with straw returning treatment were 7.61 kg x hm(-2) and 12.

Effect of pyrene on denitrification activity and abundance and composition of denitrifying community in an agricultural soil.

Toxicity of pyrene on the denitrifiers was studied by spiking an agricultural soil with pyrene to a series of concentrations (0-500 mg kg(-1)) followed by dose-response and dynamic incubation experiments. Results showed a positive correlation between potential denitrification activity and copy numbers of denitrifying functional genes (nirK, nirS and nosZ), and were both negatively correlated with pyrene concentrations. Based on the comparison of EC(50) values, denitrifiers harboring nirK, nirS or nosZ gene were more sensitive than denitrification activity, and denitrifiers harboring nirS gene were more sensitive than that harboring nirK or nosZ genes.

[Measurement of near-UV absorption cross sections of CS2].

The UV-absorption cross sections of CS2 are reported. The absorption spectra were measured by using a diode array spectrometer over the wavelength range of 220-380 nm at room temperature (298 +/- 3)K. The maximum absorption cross section appeared around 315 nm with the value of sigma (315 nm) = 7.

[Contribution of isoprene emitted from vegetable to atmospheric formaldehyde in the ambient air of Beijing city].

Methacrolein (MACR) and methyl vinyl ketone (MVK), which are the characteristic products of isoprene photooxidation in the atmosphere, as well as formaldehyde, were determined during March to November of 2006 in the ambient air of Beijing city. Cartridges coated with 2, 4-dinitrophenylhenylhydrazine (DNPH) were used to collect those carbonyls in ambient air and a high pressure liquid chromatography (HPLC) was used for quantification. Distinct amounts of MACR and MVK were detected during vegetable growing seasons from April to October with ambient levels in ranges of 0.

Temperature dependence of the absolute rate constant for the reaction of ozone with dimethyl sulfide.

Absolute rate constants for the reaction of ozone with dimethyl sulfide (DMS) were measured in a 200-L Teflon chamber over the temperature range of 283-353 K. Measurements were carried out using DMS in large excess over ozone of 10 to 1 or greater. Over the indicated temperature range, the data could be fit to the simple Arrhenius expression as kDMS = (9.

[Methane emission from aquatic vegetation zones of Wuliangsu Lake, Inner Mongolia].

To quantify the variations of methane fluxes from different aquatic vegetation zones, two-year measurements were measured at different aquatic vegetation zones and water depths using static chamber technique during two growing season from April to October in 2003 and 2004. Results showed that the average emission flux of CH4 from Potamogeton pectinatus (submerged macrophyte) growing zones was (3.44 +/- 1.

Surface-exchange of NOx and NH3 above a winter wheat field in the Yangtze Delta, China.

A four-dynamic-chamber system was constructed to measure NOx and NH3 surface-exchange between a typical wheat field and the atmosphere in the Yangtze Delta, China. The average fluxes ofNO, NO2 and NH3 were 79, -5.6 and -5.

Vertical distributions of COS and CS2 in Beijing City.

Vertical distributions of COS and CS2 were measured at a meteorological tower in Beijing City. The mixing ratios of COS and CS2 are in the range of 371-1681 pptv and 246-1222 pptv, respectively. The significant high mixing ratios of the two compounds at ground level and distinct vertical distributions indicated the existence of strong anthropogenic sources of COS and CS2 in Beijing City.