The terrestrial end-Permian mass extinction in the paleotropics postdates the marine extinction.

The end-Permian mass extinction was the most severe ecological event during the Phanerozoic and has long been presumed contemporaneous across terrestrial and marine realms with global environmental deterioration triggered by the Siberian Traps Large Igneous Province. We present high-precision zircon U-Pb geochronology by the chemical abrasion-isotope dilution-thermal ionization mass spectrometry technique on tuffs from terrestrial to transitional coastal settings in Southwest China, which reveals a protracted collapse of the Cathaysian rainforest beginning after the onset of the end-Permian marine extinction. Integrated with high-resolution geochronology from coeval successions, our results suggest that the terrestrial extinction occurred diachronously with latitude, beginning at high latitudes during the late Changhsingian and progressing to the tropics by the early Induan, spanning a duration of nearly 1 million years.

[Oxidative Capacity of the PM and PM in Beijing During 2014 APEC].

In order to evaluate the effect of the joint air pollution prevention and control program on the toxicity of the airborne particles in Beijing during the APEC conference, we collected the PM and PM (particulate matter with aerodynamic diameters of less than 10 μm and 2.5 μm respectively) from October to December in the urban district of Beijing, and analyzed the oxidative capacity of the particles by plasmid scission assay. The results indicated that the oxidative capacity of PM was higher than that of PM during the APEC conference, and that the damage rate of supercoiled DNA by the samples increased with their experimental dose levels.

[Sulfuration character of individual particulates of PM10].

SEM/EDX was used to analyze the component and sulfuration characteristics of individual mineral particulates of PM10, which were collected at different times in summer of Harbin. The results indicate that, the 29 species of mineral were identified in summer of Harbin, in which the proportion of clay minerals is over 40%; There are almost no changes in sulfuration in the noon-time period samples, however, the samples collected in the morning and evening show universal sulfuration. In all samples, clay minerals have the highest sulfuration incidence, the average ratio of S/Ca value is 1.

[Individual particle morphology and bioreactivity of PM10 in Beijing during the 2008 Olympic Games].

Inhalable particulates, including PM10 and PM2.5, were collected on the campus of China University of Mining and Technology during the Summer Olympic Games of Beijing in 2008. The mass concentrations of PM10 and PM2.

[Investigations of microscopic morphology of individual inhalable particulates in Macao in summer].

By means of high resolution field emission scanning electron microcopy (FESEM) and image analysis (IA), microscopic morphologies and the number-size and volume-size distributions of different types of individual inhalable particles collected in Macao in summer of 2007 were investigated. The results showed that the soot aggregates and mineral particles were ubiquitous in the PM10 of Macao in July, 2007. The mineral particles mostly showed an irregular morphology and the soot aggregates displayed chain-like and fluffy morphology.

[Morphology and bioreactivity of PM10 in air of Zhengzhou].

PM10 was collected at the urban and suburban sites of Zhengzhou city during autumn. High solution field emission scanning electron microscopy (FESEM) and image analysis (IA) were used to analyse the morphology and size distribution of individual particles in PM10. Plasmid DNA assay was employed to investigate the bioreactivity of PM10.

[Physical and chemical characteristics of individual mineral particles in an urban fog episode].

Field emission scanning electron microscopy (FESEM) and scanning electron microscopy with energy dispersive X-ray detector (SEM-EDX) were used to study the four aerosol samples collected in Beijing air during the fog and non-fog episodes in winter. Size-distribution of mineral particles in fog sample displayed two major peaks at the size range of 0.1-0.

Mineralogical characterization of airborne individual particulates in Beijing PM10.

This work mainly focuses on the mineralogical study of particulate matter (PM10) in Beijing. Samples were collected on polycarbonate filter from April, 2002 to March, 2003 in Beijing urban area. Scanning electronic microscopy coupled with energy dispersive X-ray (SEM/EDX) was used to investigate individual mineral particles in Beijing PM10.