Coupled effects of atmospheric N2O and O3 on the Earth's climate

Insight into ozone profile climatology over northeast China from aircraft measurement and numerical simulation

Tropospheric ozone is a major pollutant that can harm human health, animals and plants. With a rapid development in Northeast China, ozone pollution has become an increasingly serious environmental challenge. To study the ozone distribution and the potential sources of ozone precursors in Northeast China, we analyzed vertical ozone profiles from the In-service Aircraft for a Global Observing System (IAGOS) in 2012-2014 and provided the climatological vertical structure of tropospheric ozone over Shenyang. The tropospheric ozone generally presents high in hot months, mainly due to the combined effects of the strong solar radiation and high volatile organic compounds emission in summer. While in cold months, the ozone is low because of weak solar radiation and high nitrogen oxides emission. Besides, a low-ozone center exists within lower troposphere in August, which is mainly caused by the East Asian summer monsoon prevailing in summer. To analyze the sources of ozone, typical ozone pollution episodes were studied and the results revealed the different pathways for the enhancement of ozone pollution in Shenyang: regional transport of anthropogenic emissions from North China Plain (NCP), long-range transport from Siberian biomass burning and local photochemical production. Modeling results show that the largest contribution to the surface ozone in Northeast China is local anthropogenic emissions (exceed 90%); the regional transport of NCP anthropogenic emissions contribute more to the pollutants around 2 km, and account for more than 50% pollutants during highly ozone polluted days; through long-range transport, Siberian biomass burning in the spring also have a nonnegligible effect on the near-ground ozone in Northeast China. Overall, this study provides tropospheric ozone climatology and its source attribution in Northeast China, and highlight the great importance of regional transport of anthropogenic and biomass burning emissions in ozone pollution.

Fe2O3 nanoparticles anchored in situ on carbon nanotubes via an ethanol-thermal strategy for the selective catalytic reduction of NO with NH3

Fe₂O₃ nanoparticles anchored in situ on carbon nanotubes via an ethanol-thermal strategy present an excellent DeNO_x performance.

Cross sections for the valence shell excitations of nitrous oxide studied by fast electron impact

The generalized oscillator strengths, differential cross sections, as well as the integral cross sections for electron impact excitation of the B (1)Delta, C (1)Pi, and D (1)Sigma(+) states of N(2)O have been determined at an incident electron energy of 2500 eV. A generalized oscillator strength analysis reveals that the B (1)Delta<--X (1)Sigma(+) transition is dominated by the quadrupolar component. From the comparison to the previous experimental results, it is found that the first Born approximation is not satisfied for the C (1)Pi excitation while it is valid for the D (1)Sigma(+) excitation at an incident electron energy of 200 eV. The BE-scaled integral cross section for the B (1)Delta excitation from its threshold to 5000 eV was calculated based on its generalized oscillator strength, and the present integral cross sections for the excitation of the C (1)Pi and D (1)Sigma(+) states are in good agreement with the calculations using the BEf-scaling approach.