Response of PM2.5-bound elemental species to emission variations and associated health risk assessment during the COVID-19 pandemic in a coastal megacity

The coronavirus (COVID-19) pandemic is disrupting the world from many aspects. In this study, the impact of emission variations on PM_2.5-bound elemental species and health risks associated to inhalation exposure has been analyzed based on real-time measurements at a remote coastal site in Shanghai during the pandemic. Most trace elemental species decreased significantly and displayed almost no diel peaks during the lockdown. After the lockdown, they rebounded rapidly, of which V and Ni even exceeded the levels before the lockdown, suggesting the recovery of both inland and shipping activities. Five sources were identified based on receptor modeling. Coal combustion accounted for more than 70% of the measured elemental concentrations before and during the lockdown. Shipping emissions, fugitive/mineral dust, and waste incineration all showed elevated contributions after the lockdown. The total non-carcinogenic risk (HQ) for the target elements exceeded the risk threshold for both children and adults with chloride as the predominant species contributing to HQ. Whereas, the total carcinogenic risk (TR) for adults was above the acceptable level and much higher than that for children. Waste incineration was the largest contributor to HQ, while manufacture processing and coal combustion were the main sources of TR. Lockdown control measures were beneficial for lowering the carcinogenic risk while unexpectedly increased the non-carcinogenic risk. From the perspective of health effects, priorities of control measures should be given to waste incineration, manufacture processing, and coal combustion. A balanced way should be reached between both lowering the levels of air pollutants and their health risks.     

双ZBS2型酒杯塔输电线路雷电绕击特性研究

通过建立缩小比例为25:1的双ZBS2型酒杯塔输电线路模型,对其进行长间隙放电,研究了塔头、避雷线保护角、地面倾斜度等因素对雷击绕击率的影响。结果表明:杆塔对雷电先导具有吸引作用,雷击杆塔附近时,线路绕击率较低,从杆塔到档距中央,绕击率呈现一种先增大后减小的趋势;随着避雷线保护角由正到负变化,绕击概率随之降低;线路绕击概率随地面倾斜角增大,而呈现先增大后减小的趋势。本研究结果可指导企业输配电线路的雷电防护工作,为线路绕击防护装置的研发提供数据支持。     

海南地区新型雷电预警系统预警效率的评估与分析

基于2017年5-8月全国雷电监测定位系统ADTD探测到的闪电定位数据,根据标准IEC-62793中对雷电预警系统预警效率评估的定义,对海南地区部分雷电预警站点的预警效率进行了统计分析。海南地区新型雷电预警系统的平均有效预警率(MPOD)约为85%,高于大部分雷电预警系统的有效预警率;对闪电事件的预警率平均可达到95%,表明可以对发生在预警站点有效覆盖范围内95>的闪电提供有效预警;平均错误预警率(MFAR)约为73%,与各类预警系统相比,错误预警率偏高;预警提前期的平均值和中值分别为13.9min和9.6min。     

Source apportionment of perfluoroalkyl substances in surface sediments from lakes in Jiangsu Province, China: Comparison of three receptor models

Receptor models have been proved as useful tools to identify source categories and quantitatively calculate the contributions of extracted sources.In this study,sixty surface sediment samples were collected from fourteen lakes in Jiangsu Province,China.The total concentrations of C_4–C_(14)-perfluoroalkyl carboxylic acids and perfluorooctane sulfonic acid(∑_(12)PFASs) in sediments ranged from 0.264 to 4.44 ng/g dw(dry weight),with an average of 1.76 ng/g dw.Three commonly-applied receptor models,namely principal component analysis-multiple linear regression(PCA-MLR),positive matrix factorization(PMF) and Unmix models,were employed to apportion PFAS sources in sediments.Overall,these three models all could well track the ∑_(12) PFASs concentrations as well as the concentrations explained in sediments.These three models identified consistently four PFAS sources:the textile treatment sources,the fluoropolymer processing aid/fluororesin coating sources,the textile treatment/metal plating sources and the precious metal sources,contributing 28.1%,37.0%,29.7% and 5.3% by PCA-MLR model,30.60%,39.3%,22.4% and 7.7% by PMF model,and 20.6%,52.4%,20.2% and 6.8% by Unmix model to the ∑_(12) PFASs,respectively.Comparative statistics of multiple analytical methods could minimize individual-method weaknesses and provide convergent results to enhance the persuasiveness of the conclusions.The findings could give us a better knowledge of PFAS sources in aquatic environments.     

居民对室内空气质量安全认知程度的调查研究

为了解山西省城市居民对室内空气质量安全的认知情况和室内空气质量现状,在山西省太原、大同、晋城和吕梁随机选取786户居民进行问卷调查,并对有检测意愿的86户居民进行室内甲醛含量检测.结果表明,山西省居民室内空气质量安全认知得分15.37,得分率为51%;山西省居民平均室内甲醛浓度(0.197 mg/m3)超过国家标准(0.1 mg/m3);四市中太原市的情况最好.山西省居民在室内空气质量安全方面的认知水平和室内空气质量都不高,为保障山西省居民健康,应对山西省城市居民进行室内空气质量安全知识的普及.     

石化控制室雷击风险评估系统设计与开发

介绍了石化控制室雷击风险评估模型及相应软件系统的结构、工作流程及系统功能,使评估程序更加规范化、科学化,提高了评估速度和准确性。     

城市餐厨垃圾资源化处理必要性研究

随着中国城市经济快速增长,餐厨垃圾产出量日益增多。不科学的处理不仅会造成环境污染、危害人民身体健康,同时也是对资源的巨大浪费。通过对国内外餐厨垃圾处理现状对比及对兰州市餐厨垃圾资源化处理现状的分析,提出国内城市对餐厨垃圾进行资源化处理的必要性。     

气体样品前处理方式的优化

环境中有机气体样品通常用活性炭采样管和硅胶管采样,样品采集后将活性炭或者硅胶转移至容量瓶或者比色管中加有机溶剂解析,实际操作中通常将解析后的样品过0．45μm滤膜除去活性炭、硅胶和玻璃毛,转移至色谱瓶进行样品分析。将采样管中活性炭取出,转移至具塞离心管中,准确加入解析液,振荡,静置,解析30min然后取上层解析液注入气相色谱仪进行分析。本文通过实验直接将样品移入色谱瓶解析,选取《空气和废气监测分析方法》中三种常规分析的样品将两种方法进行比对,得出本方法从溶剂的用量、操作过程到样品分析时间都优与常规的前处理分析,能满足环境检测有机样品前处理分析。     

大型浮顶储油罐雷击事故分析及防范对策

对几起典型的大型浮顶储油罐雷击事故进行了分析,总结了这些事故存在的共性问题。通过开展大型浮顶储油罐的直击雷及雷电感应模拟试验,找出大型浮顶储油罐导电片等现有防雷设施在设计和安装中存在的问题,提出了取消二次密封装置上的导电片、安装等电位连接装置等技术措施,以有效减少大型浮顶储油罐火灾事故的发生。     

广东省低碳城市评价体系研究

以广东省21个地级市为研究对象,根据低碳发展理念与目标,结合广东省的低碳发展路径,选取与低碳城市发展密切相关的14个基础指标,构建广东省低碳城市评价指标体系进行综合评价。结果表明:(1)广东省低碳城市评价较好的城市主要有广州、深圳、珠海、佛山、惠州等。(2)参与评价的城市得分均较高,整体上具备良好发展势头。(3)排名越靠后的城市,制约指标越多,新能源与可再生能源比例是广东省低碳发展最受制约的指标。(4)单位土地面积碳排放量指标各城市间的反差最大,主要是由于各城市的市域面积不一,能源消费与经济发展不平均而造成的。