[Sources Apportionment of Oxygenated Volatile Organic Compounds (OVOCs) in a Typical Southwestern Region in China During Summer].

Oxygenated volatile organic compounds (OVOCs) are important intermediates in the troposphere and the most important sources of ozone. Proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOF-MS) was used to measure VOCs in the Chengdu Plain, Southwestern China. The diurnal variations, photochemical reactivity, O3 formation potential, and sources were also investigated. The mixing ratios of ten kinds of VOCs (acetaldehyde, acetone, isoprene, Methyl ethyl ketone, Methyl vinyl ketone and Methacrolein, benzene, toluene, styrene, C8 aromatics, and C9 aromatics) were (10.97±4.69)×10-9. The concentrations of OVOCs, aromatic hydrocarbons, and biogenic VOCs were (8.54±3.44)×10-9, (1.53±0.93)×10-9, and (0.90±0.32)×10-9, respectively. Isoprene, acetaldehyde, and m-xylene were the top three photochemically active species with the greatest O3 formation potentials. The dominant three OVOCs species (acetaldehyde, acetone, and MEK) were mainly derived from local biogenic sources and anthropogenic secondary sources, and acetone had a strong regional background level, indicating that pollution in this area is significantly affected by regional transmission. This study deepens the understanding of regional O3 formation mechanisms in southwest China and provides a basis for the scientifically informed control of O3 pollution.

[X-Ray Fluorescence Intensity Calculation for Micro-Particles via MCNPX and WDXRF Experiment].

In order to research the effect of X-ray fluorescence (XRF) analysis on the results in the sample's micro particles, MCNPX models had been established for an X-ray fluorescence analyzer in this paper. It had studied the characteristics of the samples with different particle sizes, the fluorescence peak counts, the peak to total ratios and the peak to source ratios. A micro particle analysis experiment had been designed for its verification. The results showed that: as for the relationship between the fluorescence intensity and the particle sizes, the MCNPX calculations were consistent with the theoretical, but contrary with the experimental results; the reason is that some hypotheses about samples in the MCNPX models were contrary with the actual states; the samples were crushed by grinding to small particles and tableting process, the MCNPX calculations and experimental results can be conversion; when the particle sizes of the samples reached the certain sizes, the fluorescence peak counts, the peak to total ratios and the peak to source ratios were stable value; within a particular size range, the influence of the particle size effects cannot be ignored, otherwise this influence can be ignored. The research methods and conclusions in this paper can provide a technical reference guide for X-ray analysis in practices.

[Analyzer Design of Atmospheric Particulate Matter's Concentration and Elemental Composition Based on ß and X-Ray's Analysis Techniques].

Monitoring atmospheric particulate matter requires real-time analysis, such as particulate matter's concentrations, their element types and contents. An analyzer which is based on ß and X rays analysis techniques is designed to meet those demands. Applying ß-ray attenuation law and energy dispersive X-ray fluorescence analysis principle, the paper introduces the analyzer's overall design scheme, structure, FPGA circuit hardware and software for the analyzer. And the analyzer can measure atmospheric particulate matters' concentration, elements and their contents by on-line analysis. Pure elemental particle standard samples were prepared by deposition, and those standard samples were used to set the calibration for the analyzer in this paper. The analyzer can monitor atmospheric particulate matters concentration, 30 kinds of elements and content, such as TSP, PM10 and PM2.5. Comparing the measurement results from the analyzer to Chengdu Environmental Protection Agency's monitoring results for monitoring particulate matters, a high consistency is obtained by the application in eastern suburbs of Chengdu. Meanwhile, the analyzer are highly sensitive in monitoring particulate matters which contained heavy metal elements (such as As, Hg, Cd, Cr, Pb and so on). The analyzer has lots of characteristics through technical performance testing, such as continuous measurement, low detection limit, quick analysis, easy to use and so on. In conclusion, the analyzer can meet the demands for analyzing atmospheric particulate matter's concentration, elements and their contents in urban environmental monitoring.