Haze Weather Research Articles

Ultra-Short-Term Forecast of Photovoltaic Output Power under Fog and Haze Weather

Fog and haze (F-H) weather has been occurring frequently in China since 2012, which affects the output power of photovoltaic (PV) generation dramatically by directly weakening solar irradiance and aggravating dust deposition on PV panels. The ultra-short-term forecast method presented in this study would help to fully reflect the dual effects of F-H on PV output power. Aiming at the weakening effect on solar irradiance, estimation models of atmospheric aerosol optical depth (AOD) based on particle matter (PM) concentration were established with machine learning (ML) method, and the total irradiance received by PV panels was calculated based on simplified REST2 model. Aiming at the aggravating effect on dust deposition on PV panels, sample set of “cumulative PM concentration—efficiency reduction” was constructed through special measurement experiments, then the efficiency reduction under certain dust deposition state was estimated with similar-day choosing method. Based on photoelectric conversion model, PM concentration prediction and weather forecast information, ultra-short-term forecast of PV output power was realized. Experimental results proved the validity and feasibility of the presented forecast method.

Enhancement Method of Video Image in Haze Weather

In order to enhance the visual quality of video image collected by the internet monitoring equipment in the haze weather, the enhancement algorithm combine dark channel prior and Gamma correction was proposed. This method can improve the quality of the image and enhance the contrast of the image.

The characteristics of atmospheric phthalates in Shanghai: A haze case study and human exposure assessment

While phthalates in indoor environments are extensively studied, reports on phthalates in outdoor air, particularly their associations with haze weather events are rare. Phthalates, especially dimethyl phthalate, are known to react with criteria air pollutants contributing to the formation of secondary organic aerosols. This study investigated phthalates levels in the atmosphere in Shanghai with a focus on their associations with different air quality weather events. The air quality during the study period was classified into three levels: non-haze, light pollution and moderate pollution. Phthalates levels were found to be lower in non-haze weather events (236 ng/m3) and higher in moderate pollution weather events (up to 700 ng/m3). Meteorological factors of relative humidity and wind speed had an inverse relationship with phthalates levels. Particulate matter had a positive correlation with phthalates levels. Hydroxyl radical initiated photo-reaction of dimethyl phthalate was evident by its inverse relationship with total atmospheric oxidant (O3 + NO2), indicating that dimethyl phthalate could be one of the precursors of secondary organic aerosol causing haze weather events. Daily intake of phthalates through exposure to outdoor air is estimated to be relatively minor; children intake remains higher on a body weight basis. This is the first study demonstrating the relationship of phthalates and different air quality conditions in haze weather events. The knowledge contributes to our understanding on the cause of haze weather events in China and elsewhere.

The influence of PM2.5 coal power plant emissions on environment PM2.5 in Jilin Province, China

In recent years, in the Northeast of China, the heating period comes with large range of haze weather. All the units of coal power plants in Jilin Province have completed the cogeneration reformation; they provide local city heat energy. Many people believe that coal power plants heating caused the heavy haze. In is paper, by compared concentration of PM2.5 in environment in heating period and non heating period, meanwhile the capacity of local coal power plants, conclude that the PM2.5 emission of coal power plants not directly cause the heavy haze in Changchun and Jilin in the end of October and early November. In addition, the water-soluble iron composition of PM2.5 coal power plant emissions is compared with environment, which further proves that the heating supply in coal power plants is not the cause of high concentration of PM2.5 in Jilin province.

Severe haze in Hangzhou in winter 2013/14 and associated meteorological anomalies

Aerosol pollution over eastern China has worsened considerably in recent years, resulting in heavy haze weather with low visibility and poor air quality. The present study investigates the characteristics of haze weather in Hangzhou city, and aims to unravel the meteorological anomalies associated with the heavy haze that occurred over Hangzhou in winter 2013/14.On the interannual timescale, because of the neutral condition of tropical sea surface temperature anomalies during winter 2013/14, no significant circulation and convection anomalies were induced over East Asia, leading to a stable atmospheric condition favorable for haze weather in Hangzhou. Besides, the shift of the polar vortex, caused by changes in surface temperature and ice cover at high latitudes, induced a barotropic anomalous circulation dipole pattern. The southerly anomaly associated with this anomalous dipole pattern hindered the transportation of cold/clear air mass from Siberia to central-eastern China, leading to abnormal haze during winter 2013/14 in Hangzhou.On the intraseasonal timescale, an eastward-propagating mid-latitude Rossby wave train altered the meridional wind anomaly over East Asia, causing the intraseasonal variability of haze weather during 2013/14 in Hangzhou.

Natural Silicon Isotopic Signatures Reveal the Sources of Airborne Fine Particulate Matter.

Airborne particulate pollution is a critical environmental problem affecting human health and sustainable development. Understanding of the sources of aerosol particles is of extreme importance for regional air pollution control. Here we show that natural Si isotopic signature can be used as a new tool to elucidate the sources of fine particulate matter (PM2.5). Through the analysis of Si isotopic composition (δ30Si) of PM2.5 and its primary sources collected in a typical pollution region - Beijing, we recognized the direct source tracing ability of Si isotopes for PM2.5. The different primary sources of PM2.5 had different Si isotopic signatures. The δ30Si value of PM2.5 ranged from -1.99‰ to -0.01‰ and showed a distinct seasonal trend (isotopically lighter in spring/winter and heavier in summer/autumn). The variations in δ30Si of PM2.5 revealed that Si-isotopically light sources were important sources for Beijing's severe haze pollution and that coal burning was a major cause for the aggregating haze weather in spring/winter in Beijing. We also analyzed several typical haze events by using Si isotopic signatures. As the first study on the natural Si isotopes in the atmospheric environment, this study may reveal an important tool to advance the particulate pollution research and control.

Image dehazing based on dark channel prior and brightness enhancement for agricultural monitoring

Obtaining clear and true images is a basic requirement for agricultural monitoring. However, under the influence of fog, haze and other adverse weather conditions, captured images are usually blurred and distorted, resulting in the difficulty of target extraction. Traditional image dehazing methods based on image enhancement technology can cause the loss of image information and image distortion. In order to address the above-mentioned problems caused by traditional image dehazing methods, an improved image dehazing method based on dark channel prior (DCP) was proposed. By enhancing the brightness of the hazed image and processing the sky area, the dim and un-natural problems caused by traditional image dehazing algorithms were resolved. Ten different test groups were selected from different weather conditions to verify the effectiveness of the proposed algorithm, and the algorithm was compared with the commonly-used histogram equalization algorithm and the DCP method. Three image evaluation indicators including mean square error (MSE), peak signal to noise ratio (PSNR), and entropy were used to evaluate the dehazing performance. Results showed that the PSNR and entropy with the proposed method increased by 21.81% and 5.71%, and MSE decreased by 40.07% compared with the original DCP method. It performed much better than the histogram equalization dehazing method with an increase of PSNR by 38.95% and entropy by 2.04% and a decrease of MSE by 84.78%. The results from this study can provide a reference for agricultural field monitoring. Keywords: agricultural monitoring, image dehazing, monitoring image, dark channel prior (DCP), brightness promoting DOI: 10.25165/j.ijabe.20181102.3357 Citation: Wang X Y, Yang C H, Zhang J, Song H B. Image dehazing based on dark channel prior and brightness enhancement for agricultural monitoring. Int J Agric & Biol Eng, 2018; 11(2): 170–176.

Image Dehazing Using Residual-Based Deep CNN

There is a series of image degradation in the image acquired in haze and other weather. The single image dehazing is a challenging and ill-posed problem. Using deep neural network methods, it solves the drawbacks of manually designing haze-related features. This paper proposes a dehazing algorithm using residual-based deep CNN. The network model is divided into two phases: in the first stage, a haze image is input, and the transmission map is estimated by network; in the second stage, the ratio of foggy image and transmission map is used as input, and the residual network is used to remove haze. It avoids the estimation of atmospheric light and improves the efficiency of dehazing. To train the proposed network, we use the NYU2 depth dataset as the training set. In the full-reference metric peak signal to noise ratio, structural similarity, and feature similarity and no-reference metric Spatial–Spectral Entropy-based Quality, Blind/Referenceless Image Spatial Quality Evaluator, and Natural Image Quality Evaluator aspect, the experimental results confirm the efficiency and robustness of the proposed method.

Standardized Statistical Dataset of Haze Weather in Hubei Province, China (1961-2013)

Standardized Statistical Dataset of Haze Weather in Hubei Province, China (1961-2013)

Network governance of haze in Shenyang

Aim: This paper aims to study how governors cooperate with citizens and enterprises to solve haze in Shenyang based on network governance theory. By demonstrating the roles of different collaborative subjects, this paper will explain each subjectâA Zs separate and mutual responsibilities in haze governance.Methodology: This study adopted a qualitative methodology and data is obtained through rigorous literature review and analysis.Findings: The main outcome of this endeavour is a call for a view on what network governance can achieve in environmental governance for the Shenyang government. The positive aspects of network governance are its ability to mobilize actors from different backgrounds and sectors to put air pollution issues on top of the political agenda; its potential to create and nurture sustainable development through cooperation between public and private actors at the differentiated regional levels.Implications: This article applies the network governance theory to a concerned public issue haze weather, leading to a new public administrative method on environmental governance for the government. Compared to the top-down and bottom-up methods, the network governance allows the public to be engaged amidst the whole process and strengthens the unity of the whole society simultaneously by breaking the social hierarchy into a planar network where equal opportunities for dialogue can be achieved amongst stakeholders related to the social problem.

Relay-assisted WDM-FSO System: A Better Solution for Communication under Rain and Haze Weather Conditions

Among various conventional wireless communication systems, Free Space Optics (FSO) may be distinguished as well, which provides a good level security, high data rates, an enormous bandwidth and negligible susceptibility to electromagnetic interference. The main problem arises with unfavorable weather conditions, which affect the system’s parameters and require an aversion to other paths. The weather conditions discussed are rain and haze. Elimination of their adverse effects is essential for establishing a better communication system. The routing path is a major issue, as its decreased parameters lead to the diversion of the transmitted signal or to its total loss. In this article, increased system path length and proficiency levels are demonstrated by using relays, which are assisted by Wavelength Division Multiplexing (WDM).

Field study on indoor air quality of urban apartments in severe cold region in China

An investigation on indoor air quality was carried out in urban apartments in Harbin, China. The indoor and outdoor concentrations of PM2.5, PM10, CO, CO2, SO2, NOX, TVOC, HCHO and NH3 were monitored. Simultaneously, questionnaire surveys on the indoor perception of air quality among occupants were conducted. In addition, a continuous measure on indoor air pollutants was performed during cooking period and the indoor air quality in newly-decorated urban apartments was also studied.The results showed that the indoor PM2.5 and PM10 during the space heating period, especially the haze weather period caused by heavy smog, were polluted seriously. Good linear relationships between indoor and outdoor concentrations of PM were identified in the condition of terrible outdoor air quality. In contrast, the concentrations of HCHO, CO, CO2, NOX and SO2 approximately satisfied the requirements of national standard unless the serious haze weather occurred. According to the subjective surveys, occupants could evaluate the indoor ventilation correctly, but the indoor air quality was always overestimated. Moreover, the factor of illness history of the occupants had an obvious influence on the evaluation of indoor air quality. Furthermore, cooking increased the indoor concentrations of HCHO, CO and TVOC significantly, and the indoor air quality in newly-decorated urban apartments was heavily polluted by HCHO, NH3 and TVOC.

Study on the influence mechanism of air quality on stock market yield and Volatility: Empirical test from China based on GARCH model

The recent haze weather in China not only influenced people's health, but also had various impacts on stock market. This paper promotes three hypotheses of influence mechanism of air quality on the stock market. National AQI (Air Quality Index) is constructed based on the distribution of shareholders and investor sentiment that is collected from online comments. GARCH model is used for empirical test. The result demonstrates that air quality and investor sentiment can separately or jointly influence stock market, while only investor sentiment can directly influence stock market volatility. Further, Air quality has tremendous impact on investor sentiment.

Research on the Clean Energy Heating Systems in Rural Beijing

Fog and haze weather has seriously affected many important aspects of human life and physical fitness. In order to improve air quality, local government has transformed coal-fired heating into clean energy heating in Beijing rural areas. This paper introduces three typical clean energy heating systems which are low temperature air source heat pump (LTASHP), thermal storage heater (TSH) and wall-mounted gas furnace (WGF), researches and tests the practical operation situation of three heating systems in the field. To compare technical and economic feasibility of three heating systems, the paper takes such residence where energy-saving standard of building palisade structure is approximately 50% as the research object, and establishes technical and economic mathematical analysis models, compares primary energy consumption and carbon dioxide emissions of three heating systems. This paper adopts annual cost approach, comprehensively takes into account power capacity increasing tariff and gas pipe network construction fee, and compares initial investment, operation cost and annual cost of three heating systems respectively from the perspective of users and government. The results show that LTASHP is the most energy-saving and its annual cost is lowest in the three heating systems. LTASHP is the most suitable alternative solutions to coal-fired heating in the three heating systems in rural Beijing.

Heating energy saving potential from building envelope design and operation optimization in residential buildings: A case study in northern China

Residential building heating plays a critical role in building energy conservation in China as it consumes a large proportion of the total primary energy use. Heating energy consumption in China is much larger than that in leading countries. This study investigated the energy saving potential from the building envelope design and actual operation optimization. Results showed that the heating energy consumption target specified in latest forth-step energy efficiency standard in Tianjin still leads to 30.9% higher energy consumption than German building energy efficiency standard EnEv'2009 and 49.7% higher than Passivhaus standard used in Germany. Via field measurement and questionnaire survey during operation, major findings are: (1) high indoor air temperature and window opening for ventilation are accountable for the high heating energy consumption during the operation; (2) radiator heating consumes less energy than radiant floor heating system; (3) temperature-type thermostatic valve and compartment automatic control mode have the best control performance; (4) ventilation device with purifying air unit helps to improve the indoor air quality in the terrible haze weather and to reduce the window opening demand of occupants; (5) heat metering and occupants' energy saving awareness should be encouraged.

Experimental study on the contamination deposition characteristics of insulators in a fog–haze environment

In recent years, the frequent occurrence of fog and haze in China has attracted increasing attention in the field of electrical insulation. Fog–haze weather is an extreme weather condition with high humidity, high concentrations of suspended particulate matter, and sometimes high conductivity. This exacerbates insulator surface contamination and moistens the contamination layer, which may lead to flashover incidents. Here, an experimental system was established to simulate the fog–haze environment under controlled and tunable conditions. Simulated contamination tests were then conducted using three typical insulators. The influence of insulator type and environmental parameters was investigated. Test results showed that higher humidity led to faster pollution accumulation for all three insulators. Moreover, equivalent salt deposit density (ESDD) on the surface increased linearly with increasing fog conductivity, and that on the upper surface rose faster. The ESDD increased significantly under AC voltage, especially on the lower surface. Finally, insulator contamination was studied in a real-world fog–haze environment with periodic measurement of the ESDD and environmental parameters. The ESDD showed a good correlation with the PM2.5 and PM10 concentrations. This work should have relevance for the external insulation of the power grid to resist the effects of fog and haze.

Climatology of the meteorological factors associated with haze events over northern China and their potential response to the Quasi-Biannual Oscillation

An upswing in haze weather during autumn and winter has been observed over North and Northeast China in recent years, imposing adverse impacts upon local socioeconomic development and human health. However, such an increase in the occurrence of haze events and its association with natural climate variability and climate change are not well understood. To investigate the climatology of the meteorological factors associated with haze events and their natural variability, this study uses a meteorological pollution index called PLAM (Parameter Linking Air-quality to Meteorological conditions) and ERA-Interim reanalysis data. The results suggest that high PLAM values tend to occur over southern parts of northern China, implying the weather conditions over this area are favorable for the occurrence of haze weather. For the period 1979–2014, the regional mean PLAM shows an overall increase across Beijing, Tianjin, and Hebei Province, and parts of Shanxi Province. Also, a periodicity of 28–34 months is found in the temporal variation of PLAM, which implies a potential association of PLAM with the stratospheric Quasi-Biannual Oscillation (QBO). By using the QBO index during the autumn and winter seasons in the preceding year, an increase in PLAM is found for the westerly phases of the QBO, relative to the easterly phases. An upper-tropospheric warming is also found in the westerly phases, which can induce a stable stratification that favors the increase in PLAM across the midlatitudes. The modulations of large-scale environmental factors, including moist static stability, vertical velocity, and temperature advection, also act to enhance PLAM in the westerly phases. However, the baroclinic term of moist potential vorticity at 700 hPa tends to decrease over the south, and an increase in low-level ascent is found over the north. These factors can reduce PLAM and possibly limit the statistical significance of the increased PLAM in the westerly phases of the QBO.

Variations in the water vapor distribution and the associated effects on fog and haze events over Xi'an based on Raman lidar data and back trajectories.

A combination of more than two years of water vapor lidar data with back trajectory analysis using the hybrid single-particle Lagrangian integrated trajectory (HYSPLIT) model was used to study the long-range transport of air masses and the water vapor distribution characteristics and variations over Xi'an, China (34.233° N, 108.911° E), which is a typical city in Northwest China. High-quality profiles of the water vapor density were derived from a multifunction Raman lidar system built in Xi'an, and more than 2000 sets of profiles with >400 nighttime observations from October 2013 to July 2016 were collected and used for statistical and quantitative analyses. The vertical variations in the water vapor content were discussed. A mutation height of the water vapor exists at 2-4km with a high occurrence rate of ∼60% during the autumn and winter seasons. This height reflects a distinct stratification in the water vapor content. Additionally, the atmospheric water vapor content was mainly concentrated in the lower troposphere, and the proportion of the water vapor content at 0.5-5km accounted for 80%-90% of the total water vapor below 10km. Obvious seasonal variations were observed, including large water vapor content during the spring and summer and small content during the autumn and winter. Combined with back trajectory analysis, the results showed that markedly different water vapor transport pathways contribute to seasonal variations in the water vapor content. South and southeast airflows dominated during the summer, with 30% of the 84 trajectories originating from these areas; however, the air masses during the winter originated from the north and local regions (64.3%) and from the northwest (27%). In addition, we discussed variations in the water vapor during fog and haze weather conditions during the winter. A considerable enhancement in the mean water vapor density at 0.5-3km exhibited a clear positive correlation (correlation coefficient >0.8) with the PM2.5 and PM10 concentrations. The results indicate that local airflow trajectories mainly affect water vapor transport below the boundary layer, and that these flows are closely related to the formation of fog and haze events in the Xi'an area.

Atmospheric extinction coefficient retrieval and validation for the single-band Mie-scattering Scheimpflug lidar technique

An 808 nm single-band Mie scattering Scheimpflug lidar system is developed in Dalian, Northern China, for real-time, large-area atmospheric aerosol/particle remote sensing. Atmospheric measurement has been performed in urban area during a typical haze weather condition, and time-range distribution of atmospheric backscattering signal is recorded from March 18th to 22nd, 2017, by employing the Scheimpflug lidar system. Atmospheric extinction coefficient is then retrieved according to the Klett-inversion algorithm, while the boundary value is obtained by the slope-method in the far end where the atmosphere is homogeneous in a subinterval region. The correlation between the extinction coefficients retrieved from the Scheimpflug lidar technique and the PM10/PM2.5 concentrations measured by a conventional air pollution monitoring station is also studied. The good agreement between the measurement results, i.e., a correlation coefficient of 0.85, successfully demonstrates the feasibility and great potential of the Scheimpflug lidar technique for atmospheric studies and applications.

Application of VUV-PIMS coupled with GC-MS in chemical characterization, identification and comparative analysis of organic components in both vehicular-derived SOA and haze particles

Gasoline vehicle exhaust is a significant source of volatile organic compounds (VOCs) in megacities. In this study, chemical characterization of secondary aerosol particles from the oxidation of gasoline vehicular exhaust by O3, OH, and NO3 radicals and the airborne aerosol particles collected during a heavy haze episode (23–25 December 2015) in Beijing were elaborately investigated. The secondary organic aerosols (SOAs) collected from the exhaust and airborne aerosol particles were characterized with a newly built vacuum ultraviolet photoionization mass spectrometer (VUV-PIMS) after thermal desorption, and identified by gas chromatography mass spectrometry (GC-MS). The obtained photoionization mass spectra revealed that the SOAs from the oxidation of gasoline vehicular exhaust and airborne aerosol particles possess a series of common characteristic mass peaks at m/z 98, 112, 126, and 140. The components at m/z 98, 112, 126, 140 were further identified to be carbonyl species after PFBHA derivatization followed by GC-MS analyses. The carbonyl species from exhaust SOAs were found to be responsible for 51.7%, 57.5%, 36.3%, and 27.9% of the chemical components in haze particles at m/z 98, 112, 126, and 140, respectively, which indicates that these SOA components from the oxidation of gasoline vehicular exhaust are a major factor that affects the air quality in Beijing. Among the exhaust SOAs, the carbonyl species detected simultaneously in two (P(O3/OH)) or three kinds of exhaust oxidation reactions (P(O3/NO3/OH)) make a significant contributions to these carbonyl species in haze particles (10.6% for m/z 98, 18.3% for m/z 112, 23.4% for m/z 126, and 20.5% for m/z 140). These results implies that the unsaturated VOCs (i.e. alkenes) from exhaust may be one kind of important SOA precursor and that their chemical degradation in the atmosphere may have an important impact on urban air quality in heavy polluted cities such as Beijing, especially during severe winter haze weather.