Dry Fog Research Articles

Decontamination Effect of Hypochlorous Acid Dry Mist on Selected Bacteria, Viruses, Spores, and Fungi as Well as on Components of Electronic Systems.

This publication presents the effect of hypochlorous acid dry mist as a disinfectant on selected bacteria, viruses, spores, and fungi as well as on portable Microlife OXY 300 finger pulse oximeters and electronic systems of Raspberry Pi Zero microcomputers. The impact of hypochlorous acid on microbiological agents was assessed at concentrations of 300, 500, and 2000 ppm of HClO according to PN-EN 17272 (Variant I). Studies of the impact of hypochlorous acid fog on electronic components were carried out in an aerosol chamber at concentrations of 500 ppm and 2000 ppm according to two models consisting of 30 (Variant II) and 90 fogging cycles (Variant III). Each cycle included the process of generating a dry mist of hypochlorous acid (25 mL/m3), decontamination of the test elements, as well as cleaning the chamber of the disinfectant agent. The exposure of the materials examined on hypochlorous acid dry mist in all variants resulted in a decrease in the number of viruses, bacteria, spores, and fungi tested. In addition, the research showed that in the variants of hypochlorous acid fogging cycles analyzed, no changes in performance parameters and no penetration of dry fog of hypochlorous acid into the interior of the tested medical devices and electronic systems were observed.

The HOCl dry fog-is it safe for human cells?

This study aims to investigate if high-concentration HOCl fogging disinfection causes cytotoxicity and genotoxicity to cultured primary human skin fibroblasts. The cells were exposed to a dry fog of HOCl produced from solutions with a concentration of 300 ppm (5.72 mM) or 500 ppm (9.53 mM). After four times when fibroblasts were exposed to aerosolized HOCl at a concentration of 500 ppm for 9 minutes, significant cytotoxicity and genotoxicity effects were observed. Significant changes in the morphology of fibroblasts and cell death due to membrane disruption were observed, independent of the number of exposures. Flow cytometry analyses performed under these experimental conditions indicated a decrease in the number of cells with an intact cell membrane in the exposed samples compared to the sham samples, dropping to 49.1% of the total cells. Additionally, under the same conditions, the neutral comet assay results demonstrated significant DNA damage in the exposed cells. However, no analogous damages were found when the cells were exposed to aerosolized HOCl generated from a 300-ppm solution for 3 minutes, whether once or four times. Therefore, we have concluded that aerosolized HOCl in dry fog, with a concentration exceeding 300 ppm, can cause cytotoxic and genotoxic effects on human skin fibroblasts.

Design and Analysis of Fugitive Dust Emission Collector

This creative project explores the design and analysis of a novel fugitive dust emission collector, with a focus on its application in stone crusher units and crematorium facilities. Recognizing the detrimental health and environmental impacts of dust emissions, this project proposes a multifaceted approach. The core solution involves a combined system, this captures and removes larger dust particles through established methods like cyclones or bag houses. Dry fog dust suppression system, this technology utilizes atomized water droplets to suppress smaller fugitive dust particles, preventing their airborne spread. This project delves into the specific needs of stone crusher units and crematorium facilities. Utilizing CAD software, 3D models of the emission collector will be created, incorporating considerations like material selection, efficiency and airflow optimization, integration with existing infrastructure. Computational fluid dynamics (CFD) analysis by Simulating airflow patterns and dust capture efficiency within the collector. Assessing the collector's ability to withstand operational loads and environmental factors. This project aims to achieve, reduced fugitive dust emissions, enhanced environmental compliance, improved operational efficiency. Overall, this creative project showcases an innovative approach to fugitive dust control, potentially leading to improved environmental and public health outcomes in diverse industrial settings

Assessment of the Spraying System Impact at the Preparation Stage of Iron Ore Concentrate Products

Introduction. Harmful components of ore dust, formed during the unloading of products in the preparation of iron ore concentrate (PPIOC) at the mixing stage, cause damage to both workers and equipment. To address this issue, liquid aerosol spraying using nozzles with large diameters (>20 μm) is used. However, this method proves ineffective in capturing fine-dust particles. Therefore, enhancing the efficiency of the dust deposition method through PPIOC dust spraying becomes a pressing challenge. The aim of this study is to investigate the impact of the Dry Fog technology, generating liquid droplets up to 20 μm in size, during the unloading stage of PPIOC at a mining and metallurgical enterprise in the precipitation of suspended fine-dust particles. The primary goal of this research was to assess the effectiveness and potential advantages of applying the Dry Fog technology for dust spraying with subsequent precipitation, as this technology has not been previously applied to PPIOC dust.Materials and Methods. The experiment on the PPIOC dust deposition was conducted in a specially designed laboratory setup. Through physical modeling in the laboratory setup, parameters of the precipitation process were obtained. Subsequently, the results were analyzed to understand the dependence of dust precipitation over time, taking into account the influence of the Dry Fog technology. An experiment program was developed for physical modeling. According to the devised program, dust was uniformly loaded into the interior of the laboratory setup (from the top), distributed in the air stream throughout the volume of the setup by a fan, and an instrument located at the bottom recorded changes in concentration over time. Experiments on dust precipitation were then conducted using liquid spraying (filtered water as the liquid) introduced into the setup through nozzles generating droplets with sizes of 10 and 15 μm, concurrently with the loading of dust into the laboratory setup. The effectiveness of the Dry Fog technology in the deposition of PPIOC dust was determined visually and further analyzed based on a comparison of graphs. The dynamics of changes in the average dust concentrations depending on time was studied both during precipitation without spraying and using the Dry Fog technology. During the experiment, the characteristics of the microclimate inside the laboratory setup (humidity, temperature and air velocity) and the parameters of two nozzles — their operating pressure and the supplied liquid spraying time — were recorded.Results. The comparison of the results showed a reduction in the dust precipitation time by 40 % and 75 % when using nozzles with sizes of 10 μm and 15 μm, respectively.Discussion and Conclusion. The experiment results confirm the effectiveness of the Dry Fog technology for PPIOC dust precipitation during unloading at the mixing stage. Fundamental findings have been obtained, providing a basis for further assessment of the efficiency of dust precipitation with the additional application of pulsating ventilation. In such a combination, an additional 20–25 % increase in precipitation efficiency is anticipated compared to the results presented in this article. The obtained results will support the justification of rational parameters and the implementation of the described method in production to enhance dust precipitation efficiency. Additionally, they will aid in developing a methodology to accelerate the PPIOC dust precipitation using the pulsating ventilation method.

Design and Testing of Apparatus for Producing Dry Fog

Dry fog is a specific form of aerosol that is used in many branches of industry and many aspects of everyday life. It can be used, inter alia, to disinfect rooms or to control the level of humidity. One of its greatest advantages is undoubtedly its ability to work in the vicinity of electrical devices. Although the process of its formation and the very phenomenon of its occurrence are extremely simple things to describe, there are still many aspects that can be discovered, which are the focus of research by scientists around the world. One of the main parameters that influence the production process of dry fog is the pressure of the supplied gas, as well as the environmental conditions in which the aerosol is formed. This work focuses on the production of dry fog with the use of the designed and constructed apparatus, the structure of which is based on a jet nebulizer. The test and measurement stand is equipped with a compressor with a built-in pressure gauge for reading air pressure, a valve that allows the flow to be regulated, and an air supply and heating device that operates at various power values. The aim of this research was to check the impact of the power that is supplied to the system, as well as the impact of changing selected parameters such as gas pressure (which is one of the required media), on the liquid spraying process. The analysis of the results obtained during the experimental tests was based on the photographic method and allowed the mean Sauter volume–surface diameters of the obtained droplets to be compared. The analysis also showed that an increase in the power of the air supply and heating device translates directly into an increase in the ambient temperature in which the dry fog is formed, and contributes to the reduction of the diameter of the generated droplets. Changing the pressure of the atomized gas has a direct impact on the size of droplets in the generated aerosol—the higher the pressure, the smaller the droplets.

Active Volcanoes, Active Imaginations: Fire-Spitting Mountains and Subterraneous Roars in the German Territories in the Summer of 1783

Abstract In the summer of 1783, a sulphuric, dry fog that lasted for several weeks covered much of Europe. As a result, the sun, moon and other celestial objects appeared 'blood-red'. Speculation in Europe was rife as to the cause of this unusual weather. In Iceland, the Laki fissure had erupted; from June 1783 to February 1784, it released the greatest volume of lava of any eruption on planet Earth in the last millennium. The ejected gases travelled to Europe and beyond via the jet stream. Unaware of the Icelandic eruption, some contemporaries from the German Territories hypothesised that the dry fog emanated from a local source, namely one or more supposed German volcanoes. This paper traces the reports of these 'eruptions' from the perspective of environmental history and presents translations of pertinent newspaper articles that have, for the most part, remained unstudied, in order to evaluate the possible reasons for the emergence of this idea.

High relative humidity enhances chilling tolerance of zucchini fruit by regulating sugar and ethanol metabolisms during cold storage

High relative humidity (RH) cold room (RH: 98 ± 2%) controlled by a ‘dry fog’ system and normal cold room (RH: 74 ± 2%) were used to store zucchini fruit to investigate the regulation of high RH on chilling tolerance and sugar and ethanol metabolisms under cold stress. High RH storage inhibited chilling injury (CI) and maintained higher activities of sucrose synthase-synthesis and sucrose phosphate synthase and contents of glucose, fructose and sucrose in zucchini fruit. Meanwhile, high RH-stored fruit exhibited lower activities of hexokinase, phosphofructokinase, and pyruvate kinase as compared with the control. Besides, the accumulation of acetaldehyde and ethanol under cold stress was decreased by high RH storage together with the inhibition of the increase in activities of alcohol dehydrogenase, pyruvate decarboxylase and expressions of related genes. Taken together, high RH storage enhanced chilling tolerance in zucchini fruit by maintaining high levels of soluble sugars and inhibiting ethanol production.

Is Peracetic Acid Fumigation Effective in Public Transportation?

The COVID-19 pandemic made more people aware of the danger of viruses and bacteria, which is why disinfection began to be used more and more often. Epidemiological safety must be ensured not only in gathering places, but also in home and work environments. It is especially challenging in public transportation, which is a perfect environment for the spread of infectious disease. Therefore, the aim of the study was the identification of bacteria in crowded places and the evaluation of the effect of fumigation with peracetic acid (PAA) in public transportation. Inactivation of microorganisms in buses and long-distance coaches was carried out using an automatic commercial fogging device filled with a solution of peracetic acid stabilized with acetic acid (AA) and hydrogen peroxide (H2O2). Before and after disinfection, samples were taken for microbiological tests. The most prevalent bacteria were Micrococcus luteus and Bacillus licheniformis. Staphylococcus epidermidis was only present in buses, whereas Staphylococcus hominis and Exiguobacterium acetylicum were only present in coaches. Statistical analysis showed a significant reduction in the number of microorganisms in samples taken from different surfaces after disinfection in vehicles. The overall effectiveness of disinfection was 81.7% in buses and 66.5% in coaches. Dry fog fumigation with peracetic acid is an effective method of disinfecting public transport vehicles.

Hybrid modeling method of dust suppression efficiency for dry fog dust suppression process

The original mechanism model of dust suppression efficiency for dry fog dust suppression could not guide the actual process. In order to accurately predict the dust suppression efficiency in the process, a new mechanism model was established by my analysis of the process. But there were some factors that I could not establish the model. So a hybrid model combining mechanism model and support vector machine (SVM) was proposed. Using the data of dry fog dust suppression oval process, the hybrid model was simulated. The simulation results show that the hybrid model can accurately predict the dry fog dust suppression.

New trends in application of the fumigation method in medical and non-medical fields.

In the twentieth century, fumigation became a very popular method of disinfection, although in the same century many agents used as fumigants were withdrawn for ecological reasons. Fogging (fumigation) is a relatively new disinfection technology using dry fog, which behaves more like a gas and easily fills the sanitized space, reaching all surfaces in the room. The undoubted advantage of fumigation is the possibility of disinfecting difficult to clean areas. Fumigation has become particularly important in the twenty-first century due to procedures related to combating and preventing the spread of the coronavirus that causes COVID-19. The aim of this review article is to summarize the current state of knowledge in the field of fumigation on the basis of past results of original research, taking into account new trends and possibilities of its application. Due to the fact that fumigation is safe for apparatus, equipment, and electronics, while simultaneously enabling the highest possible bactericidal and virucidal levels, this method is widely used in various areas, both medical and non-medical. Fogging technology is used in the medical, pharmaceutical, and food industries, as well as in transportation, for air fumigation or surface disinfection in closed spaces, such as hospital and laboratory rooms, incubators, refrigerators, ships, trucks, railway containers, and aircraft, to name only a few. The most common fumigants are hydrogen peroxide and peracetic acid, and their mechanism of action is related to their oxidizing properties. Hydrogen peroxide and peracetic acid are highly effective and non-toxic fumigants that can be safely used for fogging laboratory and medical equipment, pharmaceutical facilities, hospital rooms, and animal breeding rooms.

Dry-fog decontamination of microbiological safety cabinets after activities with SARS-CoV-2: cycle development and process validation for dry fogging with peroxyacetic acid.

Background: Technical protection measures for laboratory activities involving biological agents include biological safety cabinets (BSC) that may be contaminated. In the case of diagnostic activities with SARS-CoV-2, this may also affect BSC that are operated at protection level 2; therefore, decontamination of all contaminated surfaces of the BSC may be required. In addition to fumigation with hydrogen peroxide (H2O2), dry fogging of H2O2-stabilized peroxyacetic acid (PAA) represents another alternative to fumigation with formalin. However, to prove their efficacy, these alternatives need to be validated for each model of BSC.Methods: The validation study was performed on 4 different BSCs of Class II A2 using the “Mini Dry Fog” system.Results: An aerosol concentration of 0.03% PAA and 0.15% H2O2 during a 30 min exposure was sufficient to inactivate SARS-CoV-2. Effective concentrations of 1.0% PAA and 5% H2O2 were required to decontaminate the custom-prepared biological indicators loaded with spores of G. stearothermophilus and deployed at 9 different positions in the BSC. Commercial spore carriers were easier to inactivate by a factor of 4, which corresponded to a reduction of 106 in all localizations.Conclusions: Dry fogging with PAA is an inexpensive, robust, and highly effective decontamination method for BSCs for enveloped viruses such as SARS-CoV-2. The good material compatibility, lack of a requirement for neutralization, low pH – which increases the range of efficacy compared to H2O2 fumigation – the significantly shorter processing time, and the lower costs argue in favor of this method.

Fugitive dust emission control study for a developed smart dry fog system

Air pollution due to dust emission is continuously increasing day by day in mining and allied industrial areas. Mining operations contribute a substantial amount of dust emission at the crushing, screening, and bulk material handling in loading areas. The ambient suspended dust particles create a severe nuisance to workers and local dwellers. For effective controlling of positive dust emission, an innovative automated dry fog dust suppression system (DFDSS) has been developed using hybrid nozzles, sensors, actuators, controllers, screw compressors, air receivers, pumps, motors, and water arrangement with filtration facility. The DFDSS was installed in a crushing and screening plant of an iron ore mine in India. Performance study indicted fugitive dust emission concentration values ranged from 354 to 7040 μg m−3, which was reduced to 91–300 μg m−3 after installation of DFDSS. The reduced values were within the permissible limit of 1200 μg m−3 at a distance of 25 ± 2 m in the predominant downwind direction. The installed DFDSS added a meager addition of moisture content of 0.032% in the handling iron ore material, which was below the acceptable limit of 0.1%. The DFDSS precisely regulated fugitive dust emission from various mining activities without affecting the minerals processing performance. Thus, the DFDSS can be implemented effectively in different mining and allied industries where there is a dust emission problem.

Decontamination of common healthcare facility surfaces contaminated with SARS-CoV-2 using peracetic acid dry fogging

BackgroundThe SARS-CoV-2 pandemic has highlighted the urgent need for safe and effective surface decontamination methods, particularly in healthcare settings.AimTo evaluate the effectiveness of peracetic acid (PAA) dry fogging in decontaminating healthcare facility surfaces experimentally contaminated with SARS-CoV-2.MethodsNine materials (stainless steel, latex painted wood, unsealed hardwood, melamine countertop, vinyl flooring, clear plastic, faux leather, computer keyboard button, and smartphone touch screen) were surface contaminated with >106 median tissue culture infectious dose (TCID50) of SARS-CoV-2, and allowed to dry before exposing to PAA dry fogging.FindingsWhen fumigated with PAA dry fog for 1 h, no infectious SARS-CoV-2 virus was recovered from any of the experimentally inoculated surface types. By contrast, high titres of infectious virus were recovered from corresponding untreated drying controls of the same materials.ConclusionStandard surface decontamination processes, including sprays and wipes, are laborious and frequently cannot completely decontaminate sensitive electronic equipment. The ease of use, low cost, and overall effectiveness of a PAA dry fogging suggest that it should be considered for decontaminating healthcare settings, particularly intensive care units where severely ill SARS-CoV-2 patients are cared for.

Intelligent dry fog dust suppression system: an efficient technique for controlling air pollution in the mineral processing plant

Dust suppression system plays a significant role in mining and allied industries. It has become an integral part of the environmental management system. Dust emission from mining and mineral processing industries poses environmental and health problems to workers and surrounding people. Dust creates a reliability issue in machinery and ventilation systems, causing infrastructural damage and the industry’s financial losses. This paper deals with a smart dry fog dust suppression system which has been developed for effectively controlling dust emission from mining and mineral processing activities. The system has been implemented in an iron ore crushing and screening plant in India, and its efficacy has been evaluated for controlling dust emission. The installed dry fog system reduced dust concentration to 0.10–0.17 mg m−3 from the prevailing dust concentration of 0.62–1.73 mg m−3 in work zone areas, which was much below the permissible limit below 1 mg m−3 where silica content in the dust was less than 5%. Percentage of free silica in the work zone dust reduced to traces from 3.61 to 4.80%. Similarly, PM10 and PM2.5 concentrations in the ambient air were decreased to 90–99 μg m−3 and 49–58 μg m−3 from 185 to 250 μg m−3 and 148–200 μg m−3, respectively. Further, concentrations of PM10 and PM2.5 were drastically reduced by 51.35–60.4% and 69.69–71.0%, respectively. The reduced dust concentrations in the ambient air were within the prescribed limit of PM10 (100 μg m−3) and PM2.5 (60 μg m−3). The system significantly reduces dust and free silica concentration in the work zone areas below the permissible limit. The system controls dust emission with an increase in production as it has been found that the number of nozzles is directly correlated with a reduction in dust. Furthermore, the system does not change the raw material’s mass as water added to dust is less than 0.01% of the raw material. The system is designed to give the best results within the closed environment of the plant. The system helps in eco-friendly and clean mining. The system reduces the breakdown and maintenance cost of mining equipment, thereby decreasing overall operating costs. Further, the system minimizes mine workers’ health problems, like silicosis and severe other occupation diseases. The system is automatic, cost-effective, energy efficient, and easy to maintain. Further, the system is capable of handling dust problems in the closed environment of crushing and screening plants. These properties make the system techno-economically feasible for installation in mineral processing plants.

Modelling for Air Quality Estimation for a Planned Coal Washery to Control Air Pollution

Tasra coal washery has been planned in Tasra block which is located in Jharia coalfield of Jharkhand state in India. In order to predict air pollution impact because of the proposed washery, modelling has been done using fugitive dust model. Dust levels (PM10 and PM2.5) have been assessed both for conditions of controlled and uncontrolled emissions from various sources of the washery. Baseline site specific air quality data (PM10 and PM2.5) of winter season and maximum coal washing capacity of 700 t h−1 have been considered for prediction of air quality in case of worst-case scenario. Based on modelling exercise, it has been predicted that PM10 concentration may increase from 0.058–51.333 and 0.039–17.485 μg m−3 under the conditions of uncontrolled and controlled emissions respectively at the air quality monitoring sites and the selected receptor locations in the nearby vicinity of the proposed washery. Similarly, PM2.5 concentrations may rise from 0.044–16.636 and 0.022–7.219 μg m−3 due to the uncontrolled and controlled emissions respectively. In order to minimize the fugitive dust levels from the washery site, installation of dry fog dust suppression system has been recommended at different dust generating sources in addition to implementation of other dust control measures in and around the coal washery.

Fine Dust Monitoring and Removal Method in Urban Construction Sites Using Autonomous Mobile Vehicle and Dry Fog System

Fine Dust Monitoring and Removal Method in Urban Construction Sites Using Autonomous Mobile Vehicle and Dry Fog System

Microbial composition in seasonal time series of free tropospheric air and precipitation reveals community separation

Primary biological aerosols are transported over large distances, are traveling in various media such as dry air masses, clouds or fog, and eventually deposited with dry deposition, especially for larger particles, or precipitation like rain, hail or snow. To investigate relative abundance and diversity of airborne bacterial and fungal communities, samples have been collected with a liquid impinger (Coriolis µ) from the top of Mount Sonnblick (3106 m asl, Austrian Alps) from the respective sources under a temporal aspect over four seasons over the year to include all climatic conditions. Bacterial and fungal samples (16S rRNA and ITS) were sequenced using Illumina MiSeq paired-end sequencing, investigated for relative abundance by qPCR(16S rRNA and 18S rRNA) and ice nucleation activity. Results show that there is no stable free tropospheric air microbial community and air mass origin was different for the four sampling periods which exerted influence on the microbial composition of the atmosphere although a core microbiome could be identified consisting of 61 bacterial OTUs and eight fungal genera. Differentiation between seasons was stronger pronounced in air than in precipitation, with rain being most different and variable of precipitation types, indicating distinct forces driving microbial fate in the air. Microorganisms precipitated with snow, hail or rain or being transported by clouds differ in their species composition from free tropospheric air masses and do not mirror the air community structure. They were more diverse, distinct in composition, 16S:18S ratio and abundance from free-floating PBA. Hence, snow or cloud samples are not suitable proxies for free tropospheric air microbiome composition, since separation processes in aerosolization, transport and scavenging occur. The microbial composition of arriving precipitation or clouds represents only a part of the microbial air composition communities of the cumulative sources of origin. Relative abundance and composition of ice nucleation-active bacteria showed a higher share of relative % reads of known ice nucleation-active bacteria present in all wet phases compared to air. Results propose a separation of IN-active reads with higher shares occurring in precipitation. This study presents the first comparison of free tropospheric bacterial and fungal abundance and diversity in time series of air over several seasons in contrast to various precipitation forms in the free troposphere.

Effects of dry fog humidification on pericarp browning and quality of litchi fruit stored at low temperature

Pericarp browning is the major cause of deterioration of harvested litchi fruit. Water loss plays a role in pericarp browning of litchi fruit. This study investigated the effects of humidification with dry fog on pericarp browning and quality of litchi fruit stored at low temperature. Litchi fruit were stored in a non-humidified cold chamber (control) or in a humidified cold room using Tabor atomizer system that generated 95% relative humidity (RH) without depositing water on the fruit surface at 4°C. Control fruit stored in cold room without added humidity underwent rapid weight loss, accompanied by severe pericarp browning after 25 d of storage. However, slight weight loss and no obvious pericarp browning were found in humidified-fruit. Moreover, humidification maintained well the integrity of cell membrane and inhibited polyphenol oxidase activity during early storage. In addition, respiration rate was obviously inhibited in humidified-fruit compared with control fruit. This study might provide a convenient approach to reduce pericarp browning of harvested litchi fruit by humidifying the fruit using the Tabor atomizer at low temperature instead of packaging with film. Keywords: litchi, pericarp browning, dry fog, high relative humidity, cold storage DOI: 10.25165/j.ijabe.20191204.4420 Citation: Xiao L, Li T T, Jiang G X, John A, Zhang D D, Jin W Y, et al. Effects of dry fog humidification on pericarp browning and quality of litchi fruit stored at low temperature. Int J Agric & Biol Eng, 2019; 12(4): 192–196.

Assessment of Ambient Air Quality at Joda Iron Ore Mines, Jharkhand (India)

Opencast mining is the major source of air pollution in respect of fines and dust. Maintenance of energy demand, opencast mining is required at a phenomenal rate. The natural resources like land, water, air are heavily affected by exploration, excavation and mineral processes. The use of explosives creates airborne pressure variations (air blast). Particulate matter (Dust) of various sizes, gas is the major air pollutant from mining. The study aimed to assess the impact of mining and mining processes on ambient air quality in Joda iron ore mines, which comes under OMQ Noamundi, TATA Steel Ltd., West Singhbhum, and Jharkhand covering an area of 6.708 sq. km. It is a mechanized open cast mine, and its production capacity is 6.00 million tons per annum. Samples were collected from four sampling points by residential and sensitive zone to analyse the PM10, PM2.5, SPM, SO2, and NOX on 24 hourly bases twice in a week. The concentration of PM10, PM2.5, SPM, SO2 and NOX varies between 59.0-27.0 μg/m3, 39.0-9.5 μg/m3, 183-109 μg/m3, 9.9-8.0 μg/m3 and 10.2-8.2 μg/m3 respectively. Due to the presence of pollution control equipment and techniques as sprinklers, dry fog system, and dust extractor, etc., air pollutants are within the permissible limit of National Ambient Air quality standards (2009). Dust was the single largest air pollutant observed in the study area.

Effects of dry fog humidification on pericarp browning and quality of litchi fruit stored at low temperature

Pericarp browning is the major cause of deterioration of harvested litchi fruit. Water loss plays a role in pericarp browning of litchi fruit. This study investigated the effects of humidification with dry fog on pericarp browning and quality of litchi fruit stored at low temperature. Litchi fruit were stored in a non-humidified cold chamber (control) or in a humidified cold room using Tabor atomizer system that generated 95% relative humidity (RH) without depositing water on the fruit surface at 4°C. Control fruit stored in cold room without added humidity underwent rapid weight loss, accompanied by severe pericarp browning after 25 d of storage. However, slight weight loss and no obvious pericarp browning were found in humidified-fruit. Moreover, humidification maintained well the integrity of cell membrane and inhibited polyphenol oxidase activity during early storage. In addition, respiration rate was obviously inhibited in humidified-fruit compared with control fruit. This study might provide a convenient approach to reduce pericarp browning of harvested litchi fruit by humidifying the fruit using the Tabor atomizer at low temperature instead of packaging with film. Keywords: litchi, pericarp browning, dry fog, high relative humidity, cold storage DOI: 10.25165/j.ijabe.20191204.4420 Citation: Xiao L, Li T T, Jiang G X, John A, Zhang D D, Jin W Y, et al. Effects of dry fog humidification on pericarp browning and quality of litchi fruit stored at low temperature. Int J Agric & Biol Eng, 2019; 12(4): 192–196.