Vertical distribution of sand-dust aerosols and the relationships with atmospheric environment

The vertical distribution of aerosols in the troposphere is important for determining their effects on cli- mate. The vertical distribution of aerosols under different atmospheric conditions in the free troposphere was di- rectly observed using a surface micro-pulse LIDAR （MPL） and a TP/WVP-3000 microwave radiometer at the Semi-Arid Climate ＆ Environment Observatory of Lanzhou University （SACOL, 35.95~N, 104.10~E） in the western Loess Plateau, China, in the spring of 2008. The results showed two possible transportation paths of a sandstorm from May 1 to May 4 in 2008. In one path, sand-dust aerosols were transported toward the east from the Taklimakan Desert to the Badain Jaran Desert and the Tengger Desert by a westerly wind and then toward the southeast to Jingtai and Lanzhou. A weak aerosol index （AI） indicated another possible transport path toward the east from the Taklimakan Desert to the Qaidam Basin and through the Tibetan Plateau eastward to SACOL. The aerosol profile of sandstorm processes over the SACOL area displayed three patterns： a single peak distribution under stable at- mospheric conditions, indicating urban aerosol distribution; an exponential decrease under unstable atmospheric conditions in the presence of a sandstorm; and a slight change in the mixed layer during the first and last stages of the sandstorm, indicative of thorough mixing during lifting and deposition stages. Analyses of the aerosol layer height （ALH） showed that there are two types of ALH diurnal variation. The ALH during the first sandstorm stage was complex and disordered, and affected by atmospheric circulation. While the ALH had obvious diurnal variation in the other stage, the ALH and aerosol extinction coefficient （AEC） had a single peak, and was higher in the af- ternoon and lower in the morning. In the second case the ALH was in agreement with the atmospheric boundary layer height （BLH） variation. As a result of the development of the atmospheric boundary layer （ABL） during day and maintenance at night, ALH during sandstorm-free days showed obvious diurnal variations. Multiple vertical distribu- tion patterns of sand-dust aerosols will result in different climate effects; therefore, the vertical distribution patterns can be used to parameterize climate and aerosol models.

Cross-Sectional Online Survey on Depression and Anxiety Among the Population Infected or Non-Infected with COVID-19——China,December 2022

Summary What is already known about this topic?The psychological impact of the large-scale infection of the population resulting from the end of lockdown measures in China during the coronavirus disease 2019(COVID-19)pandemic is unknown.What is added by this report?Among all participants,55.7%had depression symptoms,with a significant difference between the infected and non-infected groups,and 30.1%had anxiety.Those who were young,unvaccinated,had lower incomes,and experienced chronic diseases were more likely to experience negative emotions.What are the implications for public health practice?Government officials should take into account the effect of policies on public sentiment during similar public health events and implement tailored community interventions to address any negative sentiment.