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European Centre for Medium-Range Weather Forecasts Re-Analysis Interim （ERA-Interim） reanalysis data and satellite data, and trajectory model were applied to analyze the dynamical, thermo-dynamical, and chemical structure in the upper tropo- sphere and lower stratosphere （UTLS） of an intense cut-off low （COL） event occurring over East Asia during June 19-23, 2010, and to characterize the process and transport pathway of deep stratospheric intrusion. The Atmospheric Infrared Sounder （AIRS） ozone data and the Global Positioning System Ozone （GPSO3） sonde data showed that the air mass originating from the polar formed a region with relatively high values of potential vorticity （PV） and ozone in the center of COL, and a second- ary ozone peak appeared in the upper troposphere during mature stage of the COL. Forward trajectory simulation suggested that during the first stage of COL, deep stratospheric intrusion associated with strong northerly wind jet on the west side of the upper-level trough transported ozone-rich air from the polar lower stratosphere into the middle and lower troposphere in the mid-latitude, and increased the ozone concentration there. During the mature stage of the COL, stratospheric air was trans- ported counterclockwise into the troposphere. Backward trajectory model was used to find the source regions of air mass within the COL during its mature stage. Model results show that air masses with high ozone concentration in the center of the COL have two source regions： one is the subpolar vortex which lies in northern part of Center Siberia, where ozone-rich air plays a major role in increasing the ozone concentrations, and the other is the strong shear region which is near by the cyclonic side of the extratropical jet axis （west of 90~E, near 50~N）. The air masses with low ozone concentration around the COL also have two source regions： one is the anticyclonic side of the extratropical jet axis, where the air mass with the relatively low ozone concentration at the bottom of the COL is mainly controlled by horizontal movement, and the other is the warm area of the south side of COL, where the air mass on the east and west side of the COL is mainly dominated by upward motion.

We present combined Mie lidar, ozone lidar and wide-range particle spectrometer observations which were carried out in Beijing, north China during two periods—one haze period before the Asia-Pacific Economic Cooperation（APEC） meeting and one moderate pollution period during the meeting in 2014. High extinction coefficient, moderate ozone concentration and variable particle number concentration were obtained throughout the first haze observation period. The mean extinction coefficients in the two pollution periods were 0.52 and 0.23 km？1, respectively, at 532 nm. The ozone concentration during the first haze phase was more various with a higher average value of 49 ppb compared with that in the second pollution observations（32 ppb）. Compared with the same metrological condition occurring at the end of October, the sharply decreased aerosol extinction coefficient and ozone concentration show the effectiveness of the emission-cutting measures implemented during APEC in November. The comparison of aerosols and ozone in different heights indicate different pollution sources and the complicated ozone process of generation and disappearance. The correlation between the scattering coefficient and particle number concentrations of various diameter depended on the ambient humidity. Especially the particle number concentration（500 nm–1μm） contributed most to PM2.5 concentration. The four-day back trajectories from a Hybrid Single-particle Lagrangian Integrated Trajectory（HYSPLIT） model indicate that the air masses in the lower boundary layer before and during APEC were advected from the densely populated south regions of China and the long pollution transportation passing through northern China.

This study simulates the effective radiative forcing （ERF） of tropospheric ozone from 1850 to 2013 and its effects on global climate using an aerosol-climate coupled model, BCC_AGCM2.0. I_CUACE/Aero, in combination with OMI （Ozone Monitoring Instrument） satellite ozone data. According to the OMI observations, the global annual mean tropospheric col- umn ozone （TCO） was 33.9 DU in 2013, and the largest TCO was distributed in the belts between 30°N and 45°N and at approximately 30°S; the annual mean TCO was higher in the Northern Hemisphere than that in the Southern Hemisphere; and in boreal summer and autumn, the global mean TCO was higher than in winter and spring. The simulated ERF due to the change in tropospheric ozone concentration from 1850 to 2013 was 0.46 W m-2, thereby causing an increase in the global annual mean surface temperature by 0.36°C, and precipitation by 0.02 mm d-1 （the increase of surface temperature had a significance level above 95%）. The surface temperature was increased more obviously over the high latitudes in both hemispheres, with the maximum exceeding 1.4°C in Siberia. There were opposite changes in precipitation near the equator, with an increase of 0.5 mm d- 1 near the Hawaiian Islands and a decrease of about -0.6 mm d- 1 near the middle of the Indian Ocean.

The summertime ozone valley over the Tibetan Plateau is formed by two influences,the Asian summer monsoon（ASM） and air column variations.Total ozone over the Tibetan Plateau in summer was ～33 Dobson units（DU） lower than zonal mean values over the ocean at the same latitudes during the study period 2005-2009.Satellite observations of ozone profiles show that ozone concentrations over the ASM region have lower values in the upper troposphere and lower stratosphere（UTLS） than over the non-ASM region.This is caused by frequent convective transport of low-ozone air from the lower troposphere to the UTLS region combined with trapping by the South Asian High.This offset contributes to a ～20-DU deficit in the ozone column over the ASM region.In addition,along the same latitude,total ozone changes identically with variations of the terrain height,showing a high correlation with terrain heights over the ASM region,which includes both the Tibetan and Iranian plateaus.This is confirmed by the fact that the Tibetan and Iranian plateaus have very similar vertical distributions of ozone in the UTLS,but they have different terrain heights and different total-column ozone levels.These two factors（lower UTLS ozone and higher terrain height） imply 40 DU in the lower-ozone column,but the Tibetan Plateau ozone column is only ～33 DU lower than that over the non-ASM region.This fact suggests that the lower troposphere has higher ozone concentrations over the ASM region than elsewhere at the same latitude,contributing ～7 DU of total ozone,which is consistent with ozonesonde and satellite observations.

We present validation studies of MLS V2.2 and V3.3 water vapor （WV） and ozone profiles over the Tibetan Plateau （Naqu and Lhasa） and its adjacent region （Tengchong） respectively by using the balloon-borne Cryogenic Frost point Hygrometer and Electrochemical Concentration Cell ozonesonde. Coincident in situ measurements were selected to compare the MLS V2.2 and V3.3 WV and ozone profiles for understanding the applicability of the two version MLS products over the region. MLS V2.2 and V3.3 WV profiles respectively show their differences within -2.2±15.7% （n=74） and 0.3±14.9% （n=75） in the stratosphere at and above 82.5 hPa. Accordingly, at 100 hPa, the altitude approaching the tropopuase height, differences are within 9.8± 46.0% （n=18） and 23.0±45.8% （n=17）, and they are within 21.5±90.6% （n=104） and 6.0±83.4% （n=99） in upper troposphere. The differences of MLS ozone are within -11.7±16.3% （n=135, V2.2） and 15.6±24.2% （n=305, V3.3） at and above 82.5 hPa. At 100 hPa, they are within -3.5±54.4% （n=27） and -8.7±41.6% （n=38）, and within 18.0±79.1% （n=47） and 34.2±76.6% （n=160） in the upper troposphere. The relative difference of MLS WV and ozone profile has significant oscillation and scatter at upper troposphere and lower stratosphere partly due to the stronger gradients of WV and ozone concentrations here as well the linear interpolation of sonde data for the intercomparison. At and below 70 hPa, the relative differences of MLS ozone are significantly larger over Lhasa during the Tibetan Plateau ＂ozone valley＂ season, which is also the Asian Summer Monsoon period. The MLS ozone differences over the three sites are similar in their vertical distributions during that period. A simple linear correlation analysis between MLS and sonde profiles indicates that the sensitivity of MLS profile products is related to concentrations at each pressure level. The MLS V3.3 product sensitivity is slightly improved for WV at and above 82.5 hPa, whereas it is not obvious for ozone. The possible factors contributing to the differences of the MLS profile products of WV and ozone are discussed.

As an important anthropogenic volatile organic compound（VOC）, m-xylene has attracted numerous attentions due to its potential in secondary organic aerosol（SOA） formation. In this study, effects of aluminium dust seeds（boehmite and alumina） on SOA yield and aerosol size in m-xylene/NOx photo-oxidation were investigated in a 2 m3 smog chamber at 30°C and 50% relative humidity. Compared to the seed-free system, the presence of aluminium seeds resulted in an increase in the SOA yield, and also enhanced the O3 concentration in the chamber. The photolysis of O3 is a major source of OH radical, which is the most important oxidant of m-xylene. The increase in O3 concentration could result in the generation of more OH radicals, and finally contribute to the SOA formation. Seed particles influence the SOA size mainly by acting as condensation nuclei. Semi-volatile organic compounds（SVOCs） were condensed onto these nuclei, resulting in the increase in SOA size. However, when aluminium seeds with high concentrations were introduced into the system, SVOCs that had been condensed onto each particle were dispersed by these seeds, leading to the reduction in aerosol size.

To the Editor： A 54-year-old woman with no significant history of a headache or hypertension underwent epidural oxygen-ozone injection at a concentration of 30ug/ml （3 ml） for cervical disc herniation at cervical vertebra （C6-C7） level. Throughout the procedure, the routine monitorings of blood pressure, heart rate, and blood oxygen saturation were perfomled. One minute following the end of the injection, tile patient developed a high-intensity headache mimicking symptoms of a ruptured cerebral aneurysm. The patient described the location of a headache as present in the l~ontoparietal and occipital areas accompanied by nausea and vomiting. The presumptive diagnosis of inadvertent epidural puncture was made. The patient was immediately treated oxygen therapy and bed rest. Monitoring showed vital signs of blood pressure （149/83 mmHg）, heart rate （86 beats/min）, pulse oxygen saturation （SpO2, 96%）, blood sugar （6.3 mmol/L）, and body temperature （36.6℃）. Subsequently, metoclopramide 10 mg and midazolam 1 mg were injected intravenously.

The effects of E1Nifio Modoki events on global ozone concentrations are investigated from 1980 to 2010 E1 Nifio Modoki events cause a stronger Brewer-Dobson （BD） circulation which can transports more ozone-poor air from the troposphere to stratosphere, leading to a decrease of ozone inthe lower-middle stratosphere from 90~S to 90~N. These changes in ozone concentrations reduce stratospheric column ozone. The reduction in stratospheric column ozone during E1 Nifio Modoki events is more pronounced over the tropical eastern Pacific than over other tropical areas because transport of ozone-poor air from middle-high latitudes in both hemispheres to low latitudes is the strongest between 60°W and 120°W. Because of the decrease in stratospheric column ozone during E1 Nifio Modoki events more UV radiation reaches the tropical troposphere leading to significant increases in tropospheric column ozone An empirical orthogonal function （EOF） analysis of the time series from 1980 to 2010 of stratospheric and tropospheric ozone monthly anomalies reveals that： E1 Nifio Modoki events are associated with the primary EOF modes of both time series. We also found that E1 Nifio Modoki events can affect global ozone more significantly than canonical E1 Nifio events. These results imply that E1 Nifio Modoki is a key contributor to variations in global ozone from 1980 to 2010.

A steady-state ID macro-homogeneous model is developed to illustrate the combustion process of methane with ozone in the reactor composed of Pd-exchanged zeolite X. The model is validated by comparing the predicted results with the measured data. The methane conversion increases with decreasing the inlet methane concentration and gas space velocity and increasing the inlet ozone concentration and temperature. As the reactor length reduces, the methane conversion varies little if the reactor is too long but decreases when the reactor is too short. Therefore, the reactor should he properly designed to balance costs and the methane-conversion efficiency.

The relationship between the emission of ozone precursors and the chemical production of tropospheric ozone （03） in the Pearl River Delta Region （PRD） was studied using numerical simulation. The aim of this study was to examine the volatile organic compound （VOC）- or nitrogen oxide （NO~ =NO＋NO2）- limited conditions at present and when surface temperature is increasing due to global warming, thus to make recommendations for future ozone abatement policies for the PRD region. The model used for this application is the U.S. Environmental Protection Agency＇s （EPA＇s） third-generation air-quality modeling system; it consists of the mesoscale meteorological model MM5 and the chemical transport model named Community Multi-scale Air Quality （CMAQ）. A series of sensitivity tests were conducted to assess the influence of VOC and NO~ variations on ozone production. Tropical cyclone was shown to be one of the important synoptic weather patterns leading to ozone pollution. The simulations were based on a tropical- cyclone-related episode that occurred during 14-16 September 2004. The results show that, in the future, the control strategy for emissions should be tightened. To reduce the current level of ozone to meet the Hong Kong Environmental Protection Department （EPD） air-quality objective （hourly average of 120 ppb）, emphasis should be put on restricting the increase of NOx emissions. Furthermore, for a wide range of possible changes in precursor emissions, temperature increase will increase the ozone peak in the PRD region; the areas affected by photochemical smog are growing wider, but the locations of the ozone plume are rather invariant.