COVID-19疫情期间成都市地面臭氧污染特征及气象成因分析

受COVID-19疫情影响,我国各地采取了一系列封锁管控措施,由此导致大气污染物排放强度降低.本文以成都市为例,分析了2020年上半年的气象条件和大气污染浓度特征,并重点对臭氧浓度变化及同期对比结果进行了细致分析.结果表明：①与2019年同期相比,除O₃外的5种污染物（NO₂、CO、SO₂、PM₁₀、PM_2.5）浓度均降低,降幅分别为13.60%、8.96%、6.30%、4.56%、1.80%,而O₃浓度却异常升高,升幅最大值分别出现在2月（35.1%）和5月（36.1%）.②2020年上半年,O₃浓度高值出现时间较2015—2019年提前,气象条件较有利于臭氧的生成.100 hPa和500 hPa位势高度为正距平,气温、日照时数较往年升高,相对湿度和降水量下降,以静小风为主.③2020年4月25日—5月6日臭氧污染持续时间长,主要是由于复工复产导致臭氧前体物排放增加,以及稳定的天气形势,使成都长时间处于高温（>30℃）、低湿（40%~60%）、静小风（1.3 m·s^-1）等不利扩散的气象条件下.气团后向轨迹和污染潜在源区表明研究区受到来自成都偏东一带及川南地区高污染气团短距离输送的影响.     

基于WRF-Chem和EMI指数的新冠肺炎疫情期间沈阳市大气污染物浓度变化原因分析

利用2015—2020年沈阳市空气质量监测数据、地面气象观测资料、环境气象评估指数（EMI）产品、NCEP再分析资料及WRF-Chem数值模式,分析新冠肺炎疫情防控期间沈阳市主要大气污染物和气象要素的变化情况,研究空气质量对污染物减排和气象要素变化的响应.结果表明：疫情防控导致沈阳市PM_2.5、PM₁₀和NO₂质量浓度下降,但O₃质量浓度小幅增加;PM_2.5和NO₂对人为减排的响应更敏感;防控期内沈阳市气象条件有利于污染物的清除,气象条件使PM_2.5质量浓度下降16.37%,防控减排措施导致PM_2.5质量浓度下降22.96%;在疫情防控的背景下,不利的气象条件和污染物排放的突然增加共同造成重污染天气发生,其中不利气象条件的贡献大于排放增加的贡献;减排措施对防控期间重污染天气过程污染物峰值浓度有明显的削弱作用.     

厦门湾空气质量对新冠疫情管控的响应

通过对厦门湾城市群在COVID-19封锁前后6周内（2020-01-11~2020-02-21）的空气污染物浓度变化进行分析,以确定影响本区域空气质量的主要人为污染源.在春节假期与封锁叠加期间,SO₂、NO₂、CO、PM₁₀和PM_2.5浓度相比于节前1周的下降幅度分别为6%~22%、53%~70%、34%~48%、47%~64%和53%~60%,而O₃浓度变化没有一致的规律性;与2018~2019年历史同期相比,PM_2.5、PM₁₀、CO和NO₂的下降幅度更大,但SO₂的下降幅度相当;在复工复产后,NO₂的反弹幅度最大（38%~138%）,远高于SO₂（2%~42%）,显示交通源相对于固定源更易受到疫情管控的影响;春节后风速增大和降水增多也为SO₂、NO₂和PM的下降提供了正向影响.利用反距离插值权重法,得到管控前后厦门湾城市群不同污染物的空间分布变化特征,显示NO₂浓度高值区的变化与交通源高度相关,CO和SO₂空间分布特征保持稳定,复工后PM_2.5和PM₁₀在人口与路网密集区变化不明显,而在工地相对集中区域有明显上升,O₃空间分布的低值区与NO₂的高值区具有较好的空间匹配性,显示NO₂对O₃滴定作用明显,可为进一步O₃污染减排措施的制定提供参考.     

新冠肺炎疫情下的环境应急管理研究

新型冠状病毒肺炎疫情(以下简称"新冠肺炎疫情")是一次具有较大环境风险的复合性危机事件,评估总结应对疫情的环境应急管理政策实践进展,识别我国在面对重大疫情时环境应急管理存在的短板具有重要意义。本文通过对新冠肺炎疫情产生的环境影响以及应急措施的进展分析,总结了重大疫情下环境应急管理的经验与不足,建议要健全针对重大疫情的环境应急响应机制,加强环境应急基础能力建设,加快完善支撑保障体系。     

Screening maternal serum alpha-fetoprotein levels and human parvovirus antibodies

The association between gestational infection with human parvovirus (B19) and fetal loss has increased interest in this virus and demand for diagnostic testing. However, serological assays for B19 are not yet widely available. Maternal serum alpha-fetoprotein (MSAFP) testing is commonly used during the second trimester to screen for various fetal defects. We attempted to determine whether an elevated level of MSAFP would be an appropriate indication for B19-specific tests. Over a 26-month period, MSAFP tests were performed at Michigan State University for 21 392 women. Sera remaining after that testing were stored frozen. Of these, 22 case samples—from women with MSAFP levels greater than 3·0 multiples of the median (MOM) and pregnancies that ended in fetal loss—and 44 matched control samples—from women with MSAFP levels greater than 0·4 and less than 2·2 MOM and live births at term—were tested for B19 antibodies. None of the 66 samples was IgM positive, while 33 (50 per cent) were IgG positive. The presence of IgG was not significantly associated with case or control status (matched odds ratio=0·77, 95 per cent confidence interval 0·28–2·11). These findings are consistent with other studies indicating prior infection in approximately half of adults and suggest that elevated screening MSAFP levels, in the absence of other evidence of B19 infection, should not prompt B19-specific testing.     

Ring 19 mosaicism detected during prenatal diagnosis

A ring chromosome 19 was found in 14 of 20 metaphases (67 per cent) derived from amniotic fluid cell cultures following amniocentesis because of increased maternal age. Elective termination of the pregnancy revealed a hypotrophic female fetus with mild dysmorphic signs, but no congenital malformations. The case is discussed in relation to three reports in the literature of ring chromosome 19 mosaicism in a phenotypically normal girl, a mentally retarded man, and a boy with normal psychomotor development and minor dysmorphic features.     

Environment and COVID-19 incidence: A critical review

The coronavirus disease 2019 (COVID-19) pandemic is an unprecedented worldwide health crisis. Many previous research studies have found and investigated its links with one or some natural or human environmental factors. However, a review on the relationship between COVID-19 incidence and both the natural and human environment is still lacking. This review summarizes the inter-correlation between COVID-19 incidence and environmental factors. Based on keyword searching, we reviewed 100 relevant peer-reviewed articles and other research literature published since January 2020. This review is focused on three main findings. One, we found that individual environmental factors have impacts on COVID-19 incidence, but with spatial heterogeneity and uncertainty. Two, environmental factors exert interactive effects on COVID-19 incidence. In particular, the interactions of natural factors can affect COVID-19 transmission in micro- and macro- ways by impacting SARS-CoV-2 survival, as well as human mobility and behaviors. Three, the impact of COVID-19 incidence on the environment lies in the fact that COVID-19-induced lockdowns caused air quality improvement, wildlife shifts and socio-economic depression. The additional value of this review is that we recommend future research perspectives and adaptation strategies regarding the interactions of the environment and COVID-19. Future research should be extended to cover both the effects of the environment on the COVID-19 pandemic and COVID-19-induced impacts on the environment. Future adaptation strategies should focus on sustainable environmental and public policy responses.     

Identifying the impact of the COVID-19 pandemic on driving behavior using naturalistic driving data and time series forecasting

Introduction: COVID-19 has disrupted daily life and societal flow globally since December 2019; it introduced measures such as lockdown and suspension of all non-essential movements. As a result, driving activity was also significantly affected. Still, to-date, a quantitative assessment of the effect of COVID-19 on driving behavior during the lockdown is yet to be provided. This gap forms the motivation for this paper, which aims at comparing observed values concerning three indicators (average speed, speeding, and harsh braking), with forecasts based on their corresponding observations before the lockdown in Greece. Method: Time series of the three indicators were extracted using a specially developed smartphone application and transmitted to a back-end platform between 01/01/2020 and 09/05/2020, a time period containing normal operations, COVID-19 spreading, and the full lockdown period in Greece. Based on the collected data, XGBoost was employed to identify the most influential COVID-19 indicators, and Seasonal AutoRegressive Integrated Moving Average (SARIMA) models were developed for obtaining forecasts on driving behavior. Results: Results revealed the intensity of the impact of COVID-19 on driving, especially on average speed, speeding, and harsh braking per 100 km. More specifically, speeds were found to increase by 2.27 km/h on average compared to the forecasted evolution, while harsh braking/100 km increased to almost 1.51 on average. On the bright side, road crashes in Greece were reduced by 49% during the months of COVID-19 compared to the non-COVID-19 period.     

一组表达安全创新的新概念及其关联问题

为提升安全创新能力和水平及公正评价安全成果,本文从表达安全创新的新概念创设开始,以科学学思想为指导,以元概念演绎法和双向思维法,创设了正负“元事物”“元创事物”“颠覆性元创事物”等系列新概念,将表达安全创新的“负元事物”“负元创事物”和“负颠覆性元创事物”等概念与商业和科技等颠覆性创新对等起来,并推论出正负两类“颠覆性元创事物”所涉及的重要科学问题。之后,通过正负两类“颠覆性元创事物”的比较,并以近期发生的新冠肺炎为典型案例,得到一些发展和鉴别“负颠覆性元创事物”的方法与途径。研究结果对安全科技创新发展和评价等具有重要的理论意义。