Environmental Factors and Deactivation Mechanism of Au/α-Fe2O3 Catalyst during Storage in Ambient Air

2011 ◽  
Vol 31 (12) ◽  
pp. 1489-1495 ◽  
Author(s):  
Jiying WEI ◽  
Guifang FAN ◽  
Feng JIANG ◽  
Zhenzhong ZHANG ◽  
Lan ZHANG
Keyword(s):  
Environmental Factors ◽  
Ambient Air ◽  
Deactivation Mechanism

Evaluation of the influence of ambient air temperature and air velocity on mortar cement durability using a forced convection solar dryer

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Younes Bahammou ◽  
Mounir Kouhila ◽  
Haytem Moussaoui ◽  
Hamza Lamsyehe ◽  
Zakaria Tagnamas ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Forced Convection ◽  
Air Temperature ◽  
Building Materials ◽  
Ambient Air ◽  
Physical Significance ◽  
Drying Process ◽  
Air Velocity ◽  
Content Type ◽  
Ambient Air Temperature

PurposeThis work aims to study the hydrothermal behavior of mortar cement toward certain environmental factors (ambient air temperature and air velocity) based on its drying kinetics data. The objective is to provide a better understanding and controlling the stability of mortar structures, which integrate the sorption phenomenon, drying process, air pressure and intrinsic characteristics. This leads to predict the comportment of mortar structures in relation with main environmental factors and minimize the risk of cracking mortar structures at an early age.Design/methodology/approachThermokinetic study was carried out in natural and forced convection solar drying at three temperatures 20, 30 and 40°C and three air velocities (1, 3 and 5 m.s-1). The empirical and semiempirical models tested successfully describe the drying kinetics of mortar. These models simulate the drying process of water absorbed by capillarity, which is the most common humidity transfer mechanism in building materials and contain parameters with physical significance, which integrate the effect of several environmental factors and intrinsic characteristics of mortar structures.FindingsThe models simulate the drying process of water absorbed by capillarity, which is the most common humidity transfer mechanism in building materials and contain parameters with physical significance, which integrate the effect of several environmental factors and intrinsic characteristics of mortar structures. The average activation energy obtained expressed the temperature effect on the mortar diffusivity. The drying constant and the diffusion coefficient can be used to predict the influence of these environmental factors on the drying behavior of various building materials and therefore on their durability.Originality/valueEvaluation of the effect of several environmental factors and intrinsic characteristics of mortar structures on their durability.

scholarly journals Droplet and Aerosol Suspension Times in Ambient Air in Confined Spaces and Transmission of COVID-19: Influence of Environmental Factors

2021 ◽  
Vol 13 (2) ◽  
pp. 495-506
Author(s):  
M. R. Islam ◽  
S. H. Naqib
Keyword(s):  
Relative Humidity ◽  
Environmental Factors ◽  
Ambient Air ◽  
Confined Space ◽  
Natural Processes ◽  
Confined Spaces ◽  
Potential Source ◽  
Aerosol Droplet ◽  
Exhaled Air ◽  
Mode Of Transmission

The COVID‑19 pandemic, alternatively known as the coronavirus pandemic, is an unfolding pandemic of coronavirus disease 2019 (COVID‑19) across the entire globe in an unprecedented proportion. COVID-19 is caused by severe acute respiratory syndrome coronavirus 2. The mode of transmission of COVID-19 is a subject of intense research. The airborne transmission is one prime possibility. Breathing and talking are natural processes which generate exhaled particles. The exhaled air is an aerosol/droplet composed of naturally produced particulates of varying size. The duration over which the aerosols/droplets are suspended in the air is an important factor. Long suspended aerosols/droplets are potential source of transmission, particularly in confined spaces. We have calculated times of suspension by considering various environmental factors, namely, the ambient temperature and relative humidity in a confined space, in this work. Both temperature and relative humidity affect the suspension time of the exhaled aerosols/droplets with varying degree. The effects of environmental factors are significant for aerosols, particularly for those with small radii. We have discussed the possible implications of our findings in this paper.

scholarly journals Application of quantile regression in environmental epidemiology

2019 ◽  
Vol 129 (3) ◽  
pp. 72-74
Author(s):  
Mieczysław Szyszkowicz
Keyword(s):  
Air Pollution ◽  
Environmental Factors ◽  
Quantile Regression ◽  
Negative Relationship ◽  
Environmental Epidemiology ◽  
Ambient Air ◽  
Emergency Department Visits ◽  
Ambient Air Pollution ◽  
Mortality Data ◽  
Weather Factors

Abstract Introduction. Among many problems present in studies evaluating associations between health conditions and exposure to ambient air pollution, there is the correlation between environmental factors. These issues are usually resolved by providing a correlation matrix for the parameters of interest. Aim. To explore correlations between environmental factors. Material and methods. As sample data we use environmental factors presented in Milan mortality data (Italy, 1980-1989) and emergency department visits for asthma in Windsor (Canada, 2004-2010). Here, we propose to use a series of quantile regression evaluations to emphasize and identify dependency among environmental factors. Results. This presentation outlines an important role to investigate the potential correlations among ambient air pollutants, weather factors, and the values of the Canadian Air Quality Health Index (AQHI). In environmental epidemiology studies, these components are usually used in a common statistical model. Their correlations affect the values of the estimated relative risks, odds ratios or other estimated health effects. The presented approach examines associations among the factors as well as changes in correlations along quantiles. The examples used in this study explain various environmental phenomena; for example, the negative relationship between ambient ozone and nitrogen dioxide. Conclusions. By a consequence, this work can aid in further developing policies aimed at reducing the health impacts of air pollution as it allows to identify highly correlated factors in the constructed models.

scholarly journals Seasonal Volatile Emission Patterns of the Endemic New Zealand Shrub Dracophyllum subulatum on the North Island Central Plateau

2021 ◽  
Vol 12 ◽  
Author(s):  
Evans Effah ◽  
D. Paul Barrett ◽  
Paul G. Peterson ◽  
Murray A. Potter ◽  
Jarmo K. Holopainen ◽  
...  
Keyword(s):  
Soil Moisture ◽  
New Zealand ◽  
Environmental Factors ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Ambient Air ◽  
Sampling Occasion ◽  
Central Plateau ◽  
Volatile Emissions ◽  
The North

Volatile organic compounds (VOCs) produced by plants are essential indicators of their physiological response to environmental conditions. But evidence of natural variation in VOC emissions and their contributing factors is still limited, especially for non-cultivated species. Here we explored the natural volatile emissions of Dracophyllum subulatum Hook.f., an endemic shrub to the North Island Central Plateau of New Zealand, and determined some environmental factors driving the plant’s emissions. Volatile emissions of D. subulatum were measured on four separate occasions from December 2017 to September 2018 using the “push-pull” headspace sampling technique and analyzed using gas chromatography-mass spectrometry (GC-MS). D. subulatum was classified based on the volatiles measured on each sampling occasion using linear discriminant analysis (LDA). On each sampling occasion, we also recorded and compared ambient air temperature, herbivory damage, total soil nitrogen (N), available phosphorus (P), potassium (K), and soil moisture content. The relationship between environmental variables that differed significantly between sampling occasions and volatile emissions were estimated using generalized linear models (GLMs). Based on VOCs measured on each sampling occasion, we were able to distinguish different chemical profiles. Overall, we found that total emission and the relative proportions of all major chemical classes released by D. subulatum were significantly higher during summer. The GLMs reveal that differences in environmental factors between the four sampling occasions are highly associated with changing emissions. Higher temperatures in summer had a consistently strong positive relationship with emissions, while the impacts of soil moisture content, P and K were variable and depended on the chemical class. These results are discussed, particularly how high temperature (warming) may shape volatile emissions and plants’ ecology.

scholarly journals Health risk assessment for adolescents depending on environmental factors and lifestyle

2016 ◽  
Vol 97 (5) ◽  
pp. 771-777 ◽  
Author(s):  
N V Efimova ◽  
I V Myl’nikova
Keyword(s):  
Relative Risk ◽  
Environmental Factors ◽  
Indoor Air ◽  
Suspended Solids ◽  
Ambient Air ◽  
Lifestyle Factors ◽  
Ambient Air Pollution ◽  
Upper Respiratory Tract ◽  
Flat Feet ◽  
The Impact

Aim. To assess the risk of developing non-carcinogenic health disorders in adolescents depending on environmental factors and lifestyle.Methods. Calculation of daily doses in inhalation exposure of substances was performed according to the monitoring data of The Federal Service for Hydrometeorology and Environmental Monitoring of Russia (ambient air of Angarsk) in 2003-2014 and the results of the control of impurity levels (formaldehyde, carbon monoxide, nitrogen dioxide, suspended solids) in ambient air, as well as in the air of study rooms and living accommodations, conducted in the laboratory of physical and chemical methods of investigation. The study of the impact of lifestyle factors was performed according to the results social hygienic survey of adolescents. Health problems in adolescents were identified as a result of the medical examination conducted with the participation of the pediatrician, ophthalmologist, otolaryngologist, neurologist, orthopedist, endocrinologist.Results. It has been established that the risk of non-carcinogenic effects for adolescents of industrial city and suburban villages was caused by the presence of formaldehyde and suspended solids, mainly in indoor air. For adolescents living in areas with low exposure, the health risks were associated with the concentration of suspended solids in ambient air and indoor air. The adverse impact of lifestyle factors was observed only in urban adolescents. High relative risk of scoliosis, valgus feet, and flat feet was found for adolescents with insufficient physical activity, myopia - for those with long-term working at a computer.Conclusion. The results are indicative of the specificity of the effects of combined factors (ambient air pollution and lifestyle) on the developing body; adolescents living in the city have higher relative risk of diseases of the upper respiratory tract, musculoskeletal system, visual organs, and autonomic dysfunction syndrome.

scholarly journals Lag Effects of Ozone, PM2.5, and Meteorological Factors on COVID-19 New Cases at the Disease Epicenter in Queens, New York

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 357
Author(s):  
Atin Adhikari ◽  
Jingjing Yin
Keyword(s):  
New York ◽  
Environmental Factors ◽  
Air Pollutants ◽  
Negative Binomial ◽  
Meteorological Factors ◽  
Absolute Humidity ◽  
Negative Binomial Regression ◽  
Ambient Air ◽  
Reproductive Number ◽  
Lag Effects

The influences of environmental factors on COVID-19 may not be immediate and could be lagged for days to weeks. This study investigated the choice of lag days for calculating cumulative lag effects of ozone, PM2.5, and five meteorological factors (wind speed, temperature, relative humidity, absolute humidity, and cloud percentages) on COVID-19 new cases at the epicenter of Queens County, New York, before the governor’s executive order on wearing of masks in public places (1 March to 11 April 2020). Daily data for selected air pollutants and meteorological factors were collected from the US EPA Air Quality System, weather observation station of the NOAA National Centers for Environmental Information at John F. Kennedy Airport, and World Weather Online. Negative binomial regression models were applied, including the autocorrelations and trend of the time series, as well as the effective reproductive number as confounders. The effects of ozone, PM2.5, and five meteorological factors were significant on COVID-19 new cases with lag9-lag13 days. Incidence rate ratios (IRRs) were consistent for any lag day choice between lag0 and lag14 days and started fluctuating after lag15 days. Considering moving averages >14 days yielded less reliable variables for summarizing the cumulative lag effects of environmental factors on COVID-19 new cases and considering lag days from 9 to 13 would yield significant findings. Future studies should consider this approach of lag day checks concerning the modeling of COVID-19 progression in relation to meteorological factors and ambient air pollutants.

scholarly journals Typologization of russian regions as per environmental factors, factors related to educational process and schoolchildren’s health

2021 ◽  
pp. 82-91
Author(s):  
S.V. Kleyn ◽  
◽  
D.A. Eisfeld ◽  
N.V. Nikiforova ◽  
◽  
...  
Keyword(s):  
Environmental Factors ◽  
Eating Habits ◽  
Medical Personnel ◽  
Ambient Air ◽  
Integral Characteristic ◽  
Educational Process ◽  
Living Standard ◽  
Road Map ◽  
Demographic Processes

The structure of children population determined as per health groups is an integral characteristic of population health in this age group; it can be used as a criterion in creating medical and preventive programs aimed at managing demographic processes and assessing their efficiency. Health disorders among children occur due to many reasons including influence by socioeconomic and sanitary-epidemiological factors, peculiarities of the educational process, eating habits, lifestyle, etc. Our research aim was to determine types of regions in Russia as per environmental factors, the educational process and schoolchildren’s health. Determining different types of regions was considered to be an information basis for developing common strategies and mechanisms for improving schoolchildren’s health. Typologization of regions as per health groups revealed that the most favorable situation was in 31 regions; the last favorable, only in 2. The most favorable situation as per the educational process was in 55 regions where schools operated in one shift; the least favorable situation was observed in two RF regions where schools had to operate in two or even three shifts. Relative sanitary-epidemiological welfare was found in 20 regions and the situation in 21 regions was the least favorable as per several markers that characterized quality of drinking water, ambient air, and soils. Socioeconomic situations in the regions were analyzed to reveal that only 3 regions could be considered the most favorable and 28 regions were the least favorable; the latter were combined into one cluster with the lower values of the relevant markers including gross regional products per capita, living standard, provision with qualified medical personnel and in-patient hospital beds. A situation in each particular region is a reflection of regularities related to influence exerted by a set of aforementioned factors on children’s health; this proves the necessity to create a road map for each region in the RF with feasible mechanisms aimed at improving the existing situation as per specific aspects.

scholarly journals Experimental Study of Steel Shot and Lead Shot Transformation Under the Environmental Factors

2022 ◽  
Author(s):  
Vladimir Lisin ◽  
Valentina Chizhikova ◽  
Tatiana Lubkova ◽  
Daria Yablonskaya
Keyword(s):  
Experimental Study ◽  
Environmental Factors ◽  
Organic Acids ◽  
Natural Waters ◽  
Atmospheric Precipitation ◽  
Ambient Air ◽  
Lead Shot ◽  
Transformation Rate ◽  
Steel Shot ◽  
The Impact

This paper presents the results of an experimental study of the patterns of steel and lead shot transformation under the impact of environmental factors (two types of shot exposed alone and in combination with each other). The analyzed environmental factors include atmospheric precipitation of various acidity and soil solutions with a higher content of organic acids. This research demonstrated that steel shot is characterized by a high transformation rate that is an order of magnitude higher on average than the transformation rate of lead under the same conditions. The prevalence of the suspended iron form (excluding the interaction with organic acids) presents risks for such environmental components as soils and sediments and may be hazardous to the ambient air and natural waters in case of wind erosion and surface runoff from the catchment area. Furthermore, the joint presence of steel and lead shot mutually accelerates the corrosion of both metals, thus increasing the environmental risks.

scholarly journals Fine Particulate Matter-Induced Oxidative Stress Mediated by UVA-Visible Light Leads to Keratinocyte Damage

2021 ◽  
Vol 22 (19) ◽  
pp. 10645
Author(s):  
Krystian Mokrzyński ◽  
Olga Krzysztyńska-Kuleta ◽  
Marcin Zawrotniak ◽  
Michał Sarna ◽  
Tadeusz Sarna
Keyword(s):  
Oxidative Stress ◽  
Free Radicals ◽  
Particulate Matter ◽  
Environmental Factors ◽  
Singlet Oxygen ◽  
Air Pollutants ◽  
Ambient Air ◽  
Skin Tissue ◽  
Dependent Manner ◽  
Ambient Air Pollutants

The human skin is exposed to various environmental factors including solar radiation and ambient air pollutants. Although, due to its physical and biological properties, the skin efficiently protects the body against the harm of environmental factors, their excessive levels and possible synergistic action may lead to harmful effects. Among particulate matter present in ambient air pollutants, PM2.5 is of particular importance for it can penetrate both disrupted and intact skin, causing adverse effects to skin tissue. Although certain components of PM2.5 can exhibit photochemical activity, only a limited amount of data regarding the interaction of PM2.5 with light and its effect on skin tissue are available. This study focused on light-induced toxicity in cultured human keratinocytes, which was mediated by PM2.5 obtained in different seasons. Dynamic Light Scattering (DLS) and Atomic Force Microscopy (AFM) were employed to determine sizes of the particles. The ability of PM2.5 to photogenerate free radicals and singlet oxygen was studied using EPR spin-trapping and time-resolved singlet oxygen phosphorescence, respectively. Solar simulator with selected filters was used as light source for cell treatment to model environmental lightning conditions. Cytotoxicity of photoexcited PM2.5 was analyzed using MTT assay, PI staining and flow cytometry, and the apoptotic pathway was further examined using Caspase-3/7 assay and RT-PCR. Iodometric assay and JC-10 assay were used to investigate damage to cell lipids and mitochondria. Light-excited PM2.5 were found to generate free radicals and singlet oxygen in season-dependent manner. HaCaT cells containing PM2.5 and irradiated with UV-Vis exhibited oxidative stress features–increased peroxidation of intracellular lipids, decrease of mitochondrial membrane potential, enhanced expression of oxidative stress related genes and apoptotic cell death. The data indicate that sunlight can significantly increase PM2.5-mediated toxicity in skin cells.

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