Examining the Experiences and Challenges of Haze-Fog Governance in China

With the rapid development of industrialisation and urbanisation, China is facing the challenge of severe HF (Haze-Fog) pollution. This essay compares the advantages and disadvantages of China’s HF management and summarizes the important lessons China can teach the rest of the world about applying this tactic. China’s capabilities in the digital economy, National Innovation Demonstration Zones, and urban innovation systems are examined in this article, along with its shortcomings in information mechanisms and pollution sources. This essay also summarizes China’s achievements, particularly regarding local autonomy. The essay goes on to say, however, that China is probably going to be under more pressure to manage HF in the future, both in terms of long-term solutions and the economy.

Analysis of Climatic Characteristics of Fog and Haze Weather in Shaoyang in the Past 60 Years and Its Forecast

Based on conventional observation data and NCEP reanalysis data at 10 national basic stations and reference stations of Shaoyang City during 1951-2014,300 cases of typical regional dense fog process appeared in the history were selected. From meteorological factors and weather situation,temporal-spatial distribution characteristics and trend change characteristics of dense fog in Shaoyang were analyzed. The results showed that（ 1） temporal-spatial distribution of dense fog in Shaoyang region was uneven,and interannual variability of fog days had large volatility and bad periodicity; dense fog days in Shaoyang region was obviously more in winter half year and less in summer half year. Dense fog was the most in November and the least in July. Dense fog mostly concentrated during 03： 00-09： 00; appearance time mostly concentrated during 05： 00-07： 30,and dissipation time mostly appeared after 08： 30. Dense fog appeared early and dissipated late in winter half year,and vice verse in summer half year.（ 2） Seen from meteorological factors,ground and 850 h Pa of wind velocity was generally 0-3 m/s,which was all small. Moreover,there existed temperature inversion from ground to 850 h Pa. Relative humidity on dense fog day was larger,and precipitation or cloudy day mostly appeared in prior day.（ 3） There were four kinds of ground weather situation forming dense fog： uniform pressure field type,cold and high pressure bottom type,cold and high pressure rear type,frontal type. Based on grasping change characteristics,rule and formation reason of dense fog,some forecast focus was found.

The Impact of Haze Weather on Health: A view to Future

In January 2013, China suffered large-scale haze weather four times, affecting 30 cities in all. The average number of haze weather days in many regions was higher than the same period in every year since 1961. PM2.s, which is defined as fine particulate matter with an aerodynamic diameter of 2.5 micrometers or less, is the main health hazard in the context of haze weather. It can carry large amounts of poisonous and harmful substances, and penetrate deep into the lungs and blood circulation through the respiratory tract, thereby affecting human health.

HAZE-TO-FOG TRANSFORMATION DURING A LONG LASTING,LOW VISIBILITY EPISODE IN NANJING

Haze-to-fog transformation during a long lasting,low visibility episode was examined using the observations from a comprehensive field campaign conducted in Nanjing,China during 4-9 December 2013.In this episode,haze was transformed into fog and the fog lasted for dozens of hours.The impacts of meteorological factors such as wind,temperature(T) and relative humidity(RH) on haze,transition and fog during this episode were investigated.Results revealed significant differences between haze and fog days,due to their different formation mechanisms.Comparison was made for boundary-layer conditions during hazy days,haze-to-fog days and foggy days.Distributions of wind speed and wind direction as well as synoptic weather conditions around Nanjing had determinative impacts on the occurrences and characteristics of haze and fog.Weakened southerly wind in southern Nanjing resulted in high concentration of pollutants,and haze events occurred frequently during the study period.The wind speed was less than 1 m s^(-1) in the haze event,which resulted in a stable atmospheric condition and weak dispersion of the pollutants.The height of the temperature inversion was about 400 m during the period.The inversion intensity was weak and the temperature-difference was 4℃ km^(-1) or less in haze,while the inversion was stronger,and temperature-difference was about 6℃ km^(-1),approaching the inversion layer intensity in the fog event.Haze event is strongly influenced by ambient RH.RH values increased,which resulted in haze days evidently increased,suggesting that an increasing fraction of haze events be caused by hygroscopic growth of aerosols,rather than simply by high aerosol loading.When RH was above 90%,haze aerosols started to be transformed from haze to fog.This study calls for more efforts to control emissions to prevent haze events in the region.

Characterization of Bioaerosol Bacterial Communities During Hazy and Foggy Weather in Qingdao, China

This study was conducted to evaluate the impact of hazy and foggy weather on the bacterial communities in bioaerosols, for which samples were collected from the Qingdao coastal region on sunny, foggy, and hazy days in January and March 2013. Bacterial community compositions were determined using polymerase chain reaction denaturing gradient gel electrophoresis(PCR-DGGE). The bacterial community diversity was found to be high on foggy and hazy days, and the dominant species differed during hazy weather. The Shannon-Wiener index revealed that the bacterial community diversity of coarse particles was higher than that of fine particles in the bioaerosols. The bacterial community diversity of fine particles significantly correlated with relative humidity(RH; r^2 = 0.986). The cluster analysis results indicated that the bacterial communities on sunny days differed from those on hazy and foggy days. Compared with sunny days, the bacterial communities in the fine particles during hazy weather exhibited greater changes than those in the coarse particles. Most of the sequenced bacteria were found to be closely affiliated with uncultured bacteria. During hazy weather, members of the classes Bacilli and Gammaproteobacteria(Pseudomonas and Acinetobacter) were dominant. The DGGE analysis revealed that Proteobacteria and Firmicutes were the predominant phyla, and their relative percentages to all the measured species changed significantly on hazy days, particularly in the fine particles. Haze and fog had a significant impact on the bacterial communities in bioaerosols, and the bacterial community diversity varied on different hazy days.

Applying Anomaly-based Weather Analysis to the Prediction of Low Visibility Associated with the Coastal Fog at Ningbo-Zhoushan Port in East China

Low visibility episodes (visibility < 1000 m) were studied by applying the anomaly-based weather analysis method. A regional episode of low visibility associated with a coastal fog that occurred from 27 to 28 January 2016 over Ningbo- Zhoushan Port, Zhejiang Province, East China, was first examined. Some basic features from the anomalous weather analysis for this case were identified:(1) the process of low visibility mainly caused by coastal fog was a direct response to anomalous temperature inversion in the lower troposphere, with a warm center around the 925 hPa level, which was formed by a positive geopotential height (GPH) anomaly in the upper troposphere and a negative GPH anomaly near the surface;(2) the positive humidity anomaly was conducive to the formation of coastal fog and rain;(3) regional coastal fog formed at the moment when the southwesterly wind anomalies transferred to northeasterly wind anomalies. Other cases confirmed that the low visibility associated with coastal fog depends upon low-level inversion, a positive humidity anomaly, and a change of wind anomalies from southwesterly to northeasterly, rain and stratus cloud amount. The correlation coefficients of six-hourly inversion, 850?925-hPa-averaged temperature, GPH and humidity anomalies against visibility are ?0.31, 0.40 and ?0.48, respectively, reaching the 99% confidence level in the first half-years of 2015 and 2016. By applying the anomaly-based weather analysis method to medium-range model output products, such as ensemble prediction systems, the anomalous temperature?pressure pattern and humidity?wind pattern can be used to predict the process of low visibility associated with coastal fog at several days in advance.

A Distinguishing Method and Distribution Characteristics of Fog and Haze Days in Fuzhou

For data of atmospheric composition missing, fog and haze days were distinguished based on the standard of meteorological industry Observation and Forecasting Levels of Haze （QX/T113-2010） and four user-defined standards, and using data of surface meteorological factors in Fuzhou City, China from 2005 to 2011, temporal distributions of fog and haze days were analyzed respectively to provide methods for fog and haze forecast. The results showed that there were 28.9 fog days and 89.7 haze days per year in Fuzhou. Both fog and haze days were variable, and there might be a day difference of twice to thrice among the years. They were the most in 2007, and then decreased in recent years. Both fog and haze days were more in winter and spring, accounted for 94.1% and 70.1% respectively, while in summer and autumn, they only accounted for 5.9% and 29.9% respectively. In a day, fog mainly occurred from night to early morning, while haze occurred mainly at about noon, which demonstrated that fog and haze are different synoptic phenomena. The mass concentration of PM2.5 in fog days was 34 μg/m^3, while it was 61 μg/m^3 in haze days, and in 22% of haze days it was larger than 75 μg/m3, which was above the national second-grade ambient air quality standard.

Mesoscale Characteristics Analysis of a Fog Case with Complete Weather Information Derived from FengYun-4A Data

Currently,there is a lack of sufficient ocean meteorological data required for mesoscale weather predictions and fog characteristics analysis in the North China Sea.This study presents a methodology to supplement deficiencies in wind information in retrieval data from the Geostationary Interferometric Infrared Sounder(GIIRS)onboard the FengYun-4A(FY4A)satellite and analyze mesoscale weather characteristics.Atmospheric semi-geostrophic wind data were derived from semi-geostrophic theory to complete the weather elements in FY4AGIIRS retrieval data.First,the retrieval data accuracy was analyzed between L-band radiosonde data from seven stations and retrieval data from FY4AGIIRS.The errors in the temperature,humidity,and geopotential height from 850 to 400 hPa were smaller than those of other atmospheric layers.Subsequently,the mesoscale weather characteristics of a fog event were analyzed by creating a mesoscale weather map with derived weather information between 875 and 500 hPa.The analyses showed that the derived weather information might provide a new means for fog mesoscale characteristics analysis,which can help forecasters understand the spatial inhomogeneity in the visibility of fog events.

Analysis of Causes of Haze Weather in Winter in Zhangzhou City

From December 3 to 12,2017,Zhangzhou experienced a haze weather process lasting for 10 days.In this paper,based on surface meteorological observation and environmental monitoring data,statistical comparison,Eta correlation coefficient,clustering analysis and other methods were adopted to analyze the causes of haze weather in the whole process from clean air (December 2) to haze generation,maintenance (December 3-12) and dissipation (December 13).The results showed that two blasts of strong cold air invaded the city during the haze formation and maintenance,and regional pollution transport and static and stable weather were the main reasons for the continuous high concentration of particulate matter,the occurrence of mild pollution from PM 10 and PM 2.5 in some periods and mild-heavy haze weather lasting for 10 days.In this process,PM concentration had a strong negative correlation with air temperature and visibility,and the absolute values of the correlation coefficients were between 0.6 and 0.8.PM concentration correlated with relative humidity positively and with wind speed weakly.Regional transport of particulate matter and ozone was conducted in the form of northeast wind and southeast wind backflow.At night and in the morning,under the influence of static and stable weather and long-term sea and land breeze (6 d),average wind speed was less than 1.5 m/s,and the frequency of static wind and small wind exceeded 50%,while there was no precipitation.At 08:00,in the middle and low altitudes,the inversion layer appeared in one week,and cloud cover was large,while the height of mixed layer was below 600 m.In the whole process,it was in the weak divergence field under cold high pressure,and the overall diffusion,dilution and cleaning ability of the atmosphere were poor.

Cause Analysis on the Extreme Fog-haze Event in East China in January 2013

Characteristics and cause of the fog-haze event in East China in January 2013 were analyzed with the meteorological conventional observation data and atmospheric composition observation data. Results showed that fog or haze days in east area of Southwest China and most areas of central east China were more than 20 days in this month, especially in east of North China, Huanghuai and Jianghuai regions,that were 10 -15 days more than in the same period of normal years. 500 hPa circulation presented zonal type, cold air wasn＇t active, south-branch trough was weaker, and precipitation amounts was small, which was the weather background of the extreme fog and haze. Northwest airflow at upper layer of East Asia mid-high latitude,less cloud,ground temperature reduction at night, and warm dry air coverd at 850 hPa that led to temperature inversion near surface layer,which was the key thermal factor of fog and haze formation. High humidity near the ground ,weak horizontal wind speed, and weak ascending motion ,which were not favorable for horizontal diffusion and vertical exchange of water vapor and pollutant but were the dynamic factors of maintaining fog and haze. Whether there was a water vapor saturated layer performance in relative humidity /〉90% below 925 hPa or not can be looked as a basis of distinguishing between fog and haze.

Weather Typing and Dissipation Forecast of Fog in Haizhou Bay

[ Objective] The research aimed to study weather typing and dissipation forecast of the fog in Haizhou Bay. [ Method] Based on the me- teorological observation data of three representative stations in Lianyungang, we analyzed weather situation before fog occurrence as well as the meteorological elements of coastal fog in Haizhou Bay, and established dissipation rating forecast equation of the fog. [ Result] From the surface weather chart, the fog in Haizhou Bay was divided into four types： low-pressure inverted trough type, prefrontal warm-zone type, high-pressure rear type and high-pressure bottom type. FOg formation was closely related to stratification stability, temperature, relative humidity, wind direction and wind velocity. By using multiple linear regression method, dissipation rating prediction equation of the fog was established. Via test, prediction was correct basically, and it reached 77% that forecast rating error was below level 0.5.[Conclusion] The research could provide favorable reference for forecast and warninq of the fo_q in Haizhou Bay.

Changing Trend and Mutation Analysis of Number of Fog and Haze Days in Baoji City during 1981-2013

Based on data of number of fog and haze days in Baoji City from 1981 to 2013,the changing trends and mutation of number of fog and haze days in Baoji over the past 33 years were analyzed by using trend coefficient,tendency rate,linear regression analysis,anomaly percentage,Mann-Kendall mutation test and sliding t test.The results showed that during the 33 years,the number of fog and haze days in Baoji declined by 16.253d/10 a,and there was a cyclical turbulence every 6,15 or 28years.The frequency of fog and haze weather was the highest in winter,followed by spring and autumn,while it was the lowest in summer.According to the anomaly percentage of the number of fog and haze days in 12 months during 1981-2013,the anomaly percentage changed most greatly in July,followed by September,October,April,May,June,August,February and March,but it fluctuated less greatly in January.The number of fog and haze days from 1981 to 2013had obvious mutation trends in a single year and a single season,and mutation types are different.

Analysis of a Haze Weather Process in Eastern China from November 11th to 17th, 2020

This study mainly introduces a large-scale heavy haze weather process in northern China from November 11 to 17, 2020, and analyzes the weather process. Methods such as comparative analysis and data analysis were used in this study. The main reasons for the formation of smog are as follows. First, the relative humidity is high and the water vapor content is relatively high. Second, the atmosphere is in a static and stable state, and suspended particulate matter in the atmosphere is not easy to diffuse and dilute, so it will gradually accumulate in urban areas and suburban areas. Third, there is a temperature inversion in the vertical direction, and the suspended particles in the air are difficult to drift to high altitudes and are blocked at low altitudes and near the ground. Fourth, there must be cooling conditions. Meteorological factors are the external causes for the formation of smog. And inversion intensity has a negative correlation with visibility, which has some indicating importance in fog and haze predictions. Large-scale haze weather mainly occurs in the large-scale atmospheric circulation with weak cold air and good water vapor conditions, and wind near the ground is small. Due to the high humidity in haze weather, fog droplets provide adsorption and reaction sites, accelerating the conversion of gaseous pollutants to liquid particles. At the same time, particles are also easy to act as condensation nucleus to accelerate the generation of haze. When the two interact, the pollutants are not easy to diffuse outward, resulting in agglomeration effect, and the pollution is getting heavier.

A Brief Analysis of the Causes and Countermeasures of Fog-Haze in Beijing-Tianjin-Hebei Region

Since China broke the blockade and opened the country to the outside world, many township enterprises develop quickly. Together with the pollution caused by China’s coal-burning as the main source of national energy, the pollution caused by small and medium-sized enterprises in towns and villages due to their small investment, low technology level and weak environmental awareness, and the pollution caused by a sharp increase in motor vehicle emissions lead to the fact that fog-haze has been rampant in China’s cities and urban agglomerations for nearly two decades, especially in the Beijing-Tianjin-Hebei region. This paper sorted out the current situation of fog-haze and analyzed the causes of fog-haze from the two aspects of natural and man-made causes, discussed the harms of fog-haze to human body, environment and life, and put forward the concrete measures to solve the fog-haze problem.

Economy, Environment and Government: Study on the Path of Supply-Side Reform Forced by the Fog-Haze

Unbalanced development in term as industrial structure and the efficiency use of energy have aggravated environmental pollution to different degrees resulting in the increase of range, time and degree of fog-haze. This, in turn, forced the government to carry out supply-side reforms, to improve energy efficiency and optimize the industrial structure to weaken the environmental pollution. To tackle these problems, this work provides an index system for the issues related to fog-haze, uses a non-linear ST-SVAR model to reflect the effects of industrial structure and energy use efficiency on fog-haze. Results indicated that: First, current industrial structure and energy use efficiency have greater impact on the comprehensive equation of fog-haze risk than itself. With the passage of time, this influence is still gradually expanding. Second, the equations of industrial structure and energy use efficiency are strongly influenced by themselves, and other variables as the current period have less impact on them. Finally, the non-linear or asymmetric relationship is shown among industrial structure, energy use efficiency, and the fog-haze comprehensive risk equation.

基于数值模式与客观方法的辽宁地区空气质量预报检验分析

为检验数值模式和客观方法的空气质量产品预报能力,基于中国气象科学研究院(简称气科院,下同)CUACE模式、中国气象局沈阳大气环境研究所(简称沈阳大气所,下同)CUACE模式和中央气象台(简称中央台,下同)空气质量客观预报方法的产品,利用辽宁地区14个地市大气污染物质量浓度地面观测资料,对2019年1月至2021年4月各家预报产品在辽宁地区的预报效果进行检验。结果表明:中央台的环境空气质量指数(Air Quality Index,AQI)预报偏大,气科院和沈阳大气所偏小;各家的PM_(2.5)和PM_(10)预报均偏小,但中央台的误差最小;各家的O_(3)预报均偏大,气科院的预报误差最小。各家产品对PM_(2.5)和O_(3)浓度变化趋势的预报能力较高,对AQI范围的预报能力是强于AQI等级的。各家产品预报的PM_(2.5)质量浓度离散度和预报偏差最小,TS评分最高;大气污染物浓度和AQI在辽宁东南部的预报可靠性最高、中部地区最差。三家产品相比,中央台在辽宁地区的预报能力最强,对AQI、大气污染物浓度和首要污染物的预报TS评分均为最高,特别是在有(或无明显首要污染物)特定大气污染物对应的季节,预报更具有指导性。沈阳大气所的本地化CUACE模式对于大气污染物浓度和AQI的预报能力显著提高。

测风激光雷达在青岛低能见度天气下的适用性

利用2021年4月—2022年12月青岛国家基本气象站多普勒测风激光雷达和L波段探空系统低空风场观测数据,对比非降水时低能见度天气下测风激光雷达的探测高度和精度。结果表明:测风激光雷达在青岛地区具有良好的适用性,在能见度大于10000 m的非降水天气,其平均最大探测高度稳定在约1200 m,水平风速均方根误差约为1.2 m·s^(-1),水平风向均方根误差约为25°。在能见度小于10000 m的低能见度天气下,测风激光雷达在不同能见度和相对湿度范围内的探测高度和精度受干扰程度存在差异。在能见度为1000~10000 m、相对湿度小于90%的霾天,此时大气能见度降低主要是气溶胶粒子含量增加所致,测风激光雷达的探测能力与高能见度天气下相当。当相对湿度高于95%时,此时大气能见度降低是空气中水汽含量的增加所致,严重干扰了激光在大气中的传输,测风激光雷达的探测高度和精度均有所降低,尤其在能见度小于1000 m的雾天,需谨慎使用其风速和风向数据。

雾霾天气下泰州市环境空气中二噁英类物质浓度研究

针对泰州市雾霾天气下不同功能区域环境空气样品中二噁英类物质进行检测,结果表明:冬季雾霾周期内二噁英类物质毒性当量浓度范围为0.006~0.841 pgTEQ/m 3,不同功能区域的浓度高低为垃圾焚烧企业周边>工业区>商业交通居民混合区。二噁英类物质浓度先升高再降低,与环境空气中二氧化氮、二氧化硫的变化趋势相符。17种氯代二噁英单体浓度结果显示,环境空气样品中多氯代二苯并呋喃(PCDFs)浓度明显高于多氯代二苯并对二噁英(PCDDs)浓度,其中2,3,4,7,8-五氯代呋喃(2,3,4,7,8-PCDF)浓度最高。垃圾焚烧、燃煤等工业活动是该市环境空气中二噁英类物质的主要来源。

雾天网联车辆跟驰模型构建及行为影响分析

网联车辆(Connected Vehicle,CV)已从微观驾驶行为方面被证实其能有效改善雾天交通安全,但鲜有建立微观跟驰模型来模拟CV车辆在雾天的跟驰轨迹。本文根据雾天CV车辆的交通信息获取模式和跟驰行为特征,在雾天智能驾驶人模型的基础上,构建考虑车头时距因子、遵守因子和权重因子的雾天网联车辆智能驾驶人模型(Fog-related Intelligent Driver Model of Connected Vehicle,FIDMCV)。为评价FIDMCV模型的有效性及评估CV车辆在雾天的交通影响,选取累计碰撞时间倒数和交通量作为分析指标,并建立不同CV车辆渗透率和领车减速度的数值仿真场景。在进行数值仿真前,针对关键参数遵守因子和车头时距因子的取值进行敏感性分析。仿真结果表明:随着CV车辆渗透率的增加,混合交通流能更有效地改善雾天交通安全,但会导致雾天车辆跟驰间距增加,从而减少道路交通量,降低交通效率。CV车辆在高风险场景下(6 m·s^(-2)减速度)的碰撞时间倒数值减少比例为14.3%,在中低风险(4 m·s^(-2)和2 m·s^(-2)减速度)场景中为5.6%和6.3%,因此CV车辆在高风险场景下的交通安全改善作用更显著。本文提出的FIDMCV模型能有效再现雾天CV车辆的交通安全改善作用和跟驰间距增加特征,可用作雾天CV车辆的微观仿真工具。

滁州区域性浓雾特征统计分析

为提高对滁州浓雾基本特征和形成机制的认识,利用常规地面观测资料、探空资料、风云2号卫星云图资料和ERA5再分析资料,统计分析了2005—2021年滁州地区区域性辐射雾、平流雾和锋面雾的时空特点、地面和高空关键气象要素特点,并依据中低层天气形势对浓雾进行分型研究。结果表明:1)滁州区域性浓雾呈西部多、东部和南部少的特征,每年10月至次年3月为高发期,5—8月为低发期。2)浓雾主要分为辐射雾、平流雾和锋面雾,低层逆温是成雾的必要条件,其1000 hPa层相对湿度均大于等于80%,地面风速主要集中在2.5 m/s以下;辐射雾、平流雾低空呈“上干下湿”特点,而锋面雾不明显,辐射雾1000 hPa层风速小于等于4.0 m/s,而平流雾大于等于4.0 m/s,锋面雾风速变化范围较大。3)辐射雾的500 hPa层天气形势可分为西北气流型、西南气流型和偏西气流型,低空850 hPa层及以下呈反气旋环流形势且至少有一层受暖温度脊影响,边界层风力小,地面一般以弱高压区和均压控制;平流雾的925 hPa层天气形势分为低槽前、高压后部或底部和暖式切变线顶端三类,地面以偏东风(包括东南风)为主,局部时段风力较大,少数样本伴有弱降水;锋面雾主要由冷锋、暖锋和静止锋等锋面系统引发,冷锋引发的锋面雾占79%,以秋冬季居多。