US Environmental Protection Agency Research Articles

Exploratory Data Analysis of the Groundwater Contaminants at the Former Panna Maria Uranium Recovery Facility.

The former Panna Maria mill was a uranium recovery facility that operated from 1979 to December 1992. Sulfuric acid leach was used to process several tons of ore daily. Therefore, the groundwater was sampled at the site to monitor the concentration of background chemical pollutants. The purpose of this study was to perform exploratory data analysis to evaluate whether the arsenic, nickel, selenium, sulfate, and uranium concentrations were in accord with state-regulated groundwater drinking standards at the site. To accomplish this, a substitution method was used to replace concentration values that were below measurable ranges of well monitoring units. Additionally, random forest regression was employed to account for missing not-at-random values in the dataset. Groundwater samples collected in wells before the facility began operations were used to determine an upper bound on background pollutants consistent with US Environmental Protection Agency Standards. The upper tolerance limit comprising 90% of the groundwater sample at a confidence coefficient of 95% was used to establish alternate concentration limits for each chemical based on well data from the National Uranium Resource Hydrogeochemical and Stream Sediment Reconnaissance program. Results obtained in this analysis establish a baseline on the chemical concentrations in the background groundwater at the former Panna Maria mill.

Polycyclic Aromatic Hydrocarbons (PAHs) in paddy soil around Nam Son landfill area, Ha Noi, Viet Nam

The paddy soils were collected in the rice growing fields and the uncultivated lands around the Nam Son domestic waste landfill in Hanoi. The average concentration of 16 US EPA priority PAHs in dry soil was 61.61 ng/g, with a range of 22.15-115.1 ng/g. The higher levels of PAHs in soil samples were observed in cultivated paddy fields near the landfill in comparison with the fields far from the landfill. On the other hand, there was no difference in PAHs levels in cultivated paddy fields near the landfill and along the irrigation water canal. Concentrations of 16 PAHs in paddy soils decreased in the order: 5 rings > 3 rings > 4 rings > 2 rings > 6 rings in this area. The PAH isomeric diagnostic ratios including Fluth/(Fluth+Pyr) ratio (Ave 0.43, a range of 0.17-0.61), BaA/(BaA+Chr) ratio (Ave 0.51, a range of 0.26-0.63), IcdP/(IcdP+BghiP) ratio (Ave 0.71, a range of 0.51-0.90) indicated that the potential main sources emitted PAHs in paddy soils from pyrogenic biomass combustion and coal burning. Compared with the risk threshold causing adverse impacts on the ecological environment from different countries in the world, concentrations of PAHs in the soil surrounding the Nam Son landfill area were still below the affected limit. However, environmental quality around the landfill area still needs to be regularly monitored to take timely measures to protect the environment in this area.

The rationale behind updates to ambient ozone guidelines and standards.

Although air quality has gradually improved in recent years, as shown by the decrease in PM2.5 concentration, the problem of rising ambient ozone has become increasingly serious. To reduce hazards to human health and environmental welfare exposure to ozone, scientists and government regulators have developed ozone guidelines and standards. These answer the questions of which levels of exposure are hazardous to human health and the environment, and how can ambient ozone exposure be guaranteed, respectively. So what are the basis for the ozone guidelines and standards? This paper reviews in detail the process of revising ozone guidelines and standards by the World Health Organization (WHO) and the United States Environmental Protection Agency (EPA). The present study attempts to explore and analyze the scientific basis and empirical methods for updating guidelines and standards, in a view to guide the future revision process and provide directions for further scientific research. We found many epidemiological and toxicological studies and exposure-response relationships provided strong support for developing and revising the ozone guidelines. When setting standards, ozone exposure has been effectively considered, and the economic costs, health, and indirect economic benefits of standard compliance were reasonably estimated. Accordingly, epidemiological and toxicological studies and the establishment of exposure-response relationships, as well as exposure and risk assessment and benefit-cost estimates of standards compliance should be strengthened for the further update of guidelines and standards. In addition, with the increasing prominence of combined air pollution led by ozone and PM2.5, more joint exposure scientific research related to ozone guidelines and standards should be undertaken.

Environmental persistence, bioaccumulation, and hazards of chemicals in e-cigarette e-liquids: short-listing chemicals for risk assessments

Background/MethodsIncreased use and sales of e-cigarettes raises concerns about the potential environmental impacts throughout their life-cycle. However, few available research studies focus on the environmental impacts and ecotoxicity of e-cigarettes....

Predicting Monthly Community-Level Radon Concentrations with Spatial Random Forest in the Northeastern and Midwestern United States.

In 1987, the United States Environmental Protection Agency recommended installing a mitigation system when the indoor concentration of radon, a well-known carcinogenic radioactive gas, is at or above 148 Bq/m3. In response, tens of millions of short-term radon measurements have been conducted in residential buildings over the past three decades either for disclosure or to initially evaluate the need for mitigation. These measurements, however, are currently underutilized to assess population radon exposure in epidemiological studies. Based on two relatively small radon surveys, Lawrence Berkeley National Laboratory developed a state-of-the-art national radon model. However, this model only provides coarse and invariant radon estimations, which limits the ability of epidemiological studies to accurately investigate the health effects of radon, particularly the effects of acute exposure. This study involved obtaining over 2.8 million historical short-term radon measurements from independent laboratories. With the use of these measurements, an innovative spatial random forest (SRF) model was developed based on geological, architectural, socioeconomical, and meteorological predictors. The model was used to estimate monthly community-level radon concentrations for ZIP Code Tabulation Areas (ZCTAs) in the northeastern and midwestern regions of the United States from 2001 to 2020. Via cross-validation, we found that our ZCTA-level predictions were highly correlated with observations. The prediction errors declined quickly as the number of radon measurements in a ZCTA increased. When ≥15 measurements existed, the mean absolute error was 24.6 Bq/m3, or 26.5% of the observed concentrations (R2 = 0.70). Our study demonstrates the potential of the large amount of historical short-term radon measurements that have been obtained to accurately estimate longitudinal ZCTA-level radon exposures at unprecedented levels of resolutions and accuracy.

Flow-based compact microfluidic electrochemical cell with Parafilm® channels

A planar interdigitated microelectrodes-based microfluidic electrochemical cell (P-μFEC) with channels made by Parafilm® sheets was conceptualized with the application as a sensor for detecting heavy metal ions. Herein, we first-timely proposed a new strategy for creating Parafilm® microchannels using a Plotter cutter and Hot bonding self-sealing method for solid Microfluidic devices (PPHM). For the prepared novel P-µFEC by the PPHM protocol, which operated in the laminar regime, its electrochemical performance was well-studied using the well-known electrochemical reporter potassium Ferri/Ferrocyanide (K3/K4[Fe(CN)6]). A reference electrode (RE) layer deposited at the top silica glass substrate was embedded within the device to minimize the ohmic drop (iRcell) between the working electrode (WE) and RE. The experimental and virtualized computational COMSOL results demonstrated: (i) The changes in the RE's placements had negligible influences on the P-µFEC's electrochemical performance. (ii) The laminar flow's influence on the P-µFEC's electrochemical performance was quite prominent, which was due to the changes in the mass transfer process from diffusion (stationary) to diffusion + convection (hydrodynamic). (iii) A direct virtualized demonstration of laminar flow's influences on the mass transfer process from diffusion (stationary) to diffusion + convection (hydrodynamic) was first timely validated by finite element analysis simulation using COMSOL Multiphysics. (iv) Finally, the proposed P-µFEC showed promise as a sensitive electrochemical sensor for different heavy metal ion substrate (model analytes) detection. The IUPAC detection limits for Cu2+, Pb2+, [Fe(CN)6]3- and Hg2+ is ∼318.6±3.55 μg/L, ∼191±5.4 4 μg/L, ∼113.5±9.9 μg/L, and 8.21±0.88 μg/L, respectively. Among them, the detection limit for Cu2+ and Hg2+ meets the US Environmental Protection Agency (EPA)'s water contamination level for Cu (1300 μg/L) and is close to the EPA level for Hg (2 μg/L), respectively. These findings demonstrate the potential of using the Parafilm® sheet as the microfluidic channel for a flow-based P-μFEC as a novel analytical tool.

Advancing the community health vulnerability index for wildland fire smoke exposure

Wildland fire smoke risks are not uniformly distributed across people and places, and the most vulnerable communities are often disproportionately impacted. This study develops a county level community health vulnerability index (CHVI) for the Contiguous United States (CONUS) using three major vulnerability components: adaptive capacity, sensitivity, and exposure at the national and regional level. We first calculated sensitivity and adaptive capacity sub-indices using nine sensitivity and twenty adaptive capacity variables. These sub-indices were then combined with an exposure sub-index, which is based on the Community Multiscale Air Quality data (2008–2018), to develop CHVI. Finally, we conducted several analyses with the derived indices to: 1) explore associations between the level of fine particulate matter from wildland fires (fire-PM2.5) and the sub-indices/CHVI; 2) measure the impact of fire-PM2.5 on the increase in the annual number of days with 12-35 μg/m3 (moderate) and >35 μg/m3 (at or above unhealthy for sensitive groups) based on the US EPA Air Quality Index categories, and 3) calculate population size in different deciles of the sub-indices/CHVI. This study has three main findings. First, we showed that the counties with higher daily fire-PM2.5 concentration tend to have lower adaptive capacity and higher sensitivity and vulnerability. Relatedly, the counties at high risk tended to experience a greater increase in the annual number of days with 12-35 μg/m3 and >35 μg/m3 than their counterparts. Second, we found that 16.1, 12.0, and 17.6 million people out of 332 million in CONUS reside in the counties in the lowest adaptive capacity decile, highest sensitivity decile, and highest vulnerability decile, respectively. Third, we identified that the US Northwest, California, and Southern regions tended to have higher vulnerability than others. Accurately identifying a community's vulnerability to wildfire smoke can help individuals, researchers, and policymakers better understand, prepare for, and respond to future wildland fire events.

Increased Endocrine Activity of Xenobiotic Chemicals as Mediated by Metabolic Activation.

The US Environmental Protection Agency (USEPA) is faced with long lists of chemicals that require hazard assessment. The present study is part of a larger effort to develop in vitro assays and quantitative structure-activity relationships applicable to untested chemicals on USEPA inventories through study of estrogen receptor (ER) binding and estrogen-mediated gene expression in fish. The present effort investigates metabolic activation of chemicals resulting in increased estrogenicity. Phenolphthalin (PLIN) was shown not to bind rainbow trout (Oncorhynchus mykiss) ER (rtER) in a competitive binding assay, but vitellogenin (Vtg) expression was induced in trout liver slices exposed to 10-4 and 10-3.7 M PLIN. Phenolphthalein (PLEIN), a metabolite of PLIN, was subsequently determined to be formed when slices were exposed to PLIN. It binds rtER with a relative binding affinity to 17β-estradiol of 0.020%. Slices exposed to PLEIN expressed Vtg messenger RNA (mRNA) at 10-4.3 , 10-4 , and 10-3.7 M, with no detectable PLIN present. Thus, Vtg expression noted in PLIN slice exposures was explained by metabolism to PLEIN in trout liver slices. A second model chemical, 4,4'-methylenedianiline (MDA), was not shown to bind rtER but did induce Vtg mRNA production in tissue slices at 10-4.3 , 10-4 , and 10-3.7 M in amounts nearly equal to reference estradiol induction, thus indicating metabolic activation of MDA. A series of experiments were performed to identify a potential metabolite responsible for the observed increase in activity. Potential metabolites hydroxylamine-MDA, nitroso-MDA, azo-MDA, and azoxy-MDA were not observed. However, acetylated MDA was observed and tested in both ER-binding and tissue slice Vtg induction assays. Environ Toxicol Chem 2023;42:2747-2757. © 2023 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Assessment of heavy metals' pollutions and potential risks associated to the rocks of Pouma subdivision-Cameroon.

The present study aimed to assess the ecological and health risks of the Pouma rock samples. Twenty-three (23) trace element concentrations were evaluated. The concentrations of these trace elements were compared with those of quartzite from other countries and with global reported values. When compared with the world values, the concentrations of trace metals were below the world average values except that of Barium. The ecological risk assessment was carried out using the geo-accumulation index, contamination factors and the potential ecological risk index. The geo-accumulation index and contamination factors showed that the quartzite of Pouma subdivision are not polluted and not contaminated by the investigated metal except for Barium and Mercury. The health risk assessment using the USEPA (United States Environmental Protection Agency) method showed that there is a possible non-carcinogenic risk from Al2O3 (for children and adults) and from Cr for Children. However, there is a tolerable and high carcinogenic risk due to Cr for adults and children, respectively. It was found independently for non-carcinogenic and carcinogenic risk that the exposure via the ingestion route is the most dangerous for adults and children.

The Birth of Green Chemistry: A Political History

Few authors have investigated the origins of green chemistry (GC). Most literature relies on a narrative of its birth at the US Environmental Protection Agency in the 1990s through the original work by Paul Anastas and John Warner and the successful networking and institutionalizing activities that followed. However, this perspective has two drawbacks: it fails to consider the Environmental Protection Agency’s (EPA) political background (without which individual action would not have been possible), and it highlights a contradiction between the revolutionary theoretical message of the founders of GC and their strategy of promotion, which is uncritical of “brown” chemistry and excludes participation by civil society and the public. I argue that GC is not only the success of enthusiastic individuals who took advantage of existing political resources to promote a new vision of greening research and innovation but is also an expression of major political changes and a tool for managing chemical risks at the EPA in the 1990s. Using the concept of “design,” I argue that GC is a tool illustrating the EPA’s comanagement approach with the regulated industry. The paper sheds light on how authorities react to the difficulties of regulating chemical risks.

Evaluation of in vitro SARS-CoV-2 inactivation by a new quaternary ammonium compound: Bromiphen bromide.

The pneumonia (COVID-19) outbreak caused by the novel coronavirus namedsevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which unpredictably exploded in late December of 2019 has stressed the importance of being able to control potential pathogens with the aim of limiting their spread. Althoughvaccines are well known as a powerful tool for ensuring public health and controlling the pandemic, disinfection and hygiene habits remain crucial to prevent infection from spreading and maintain the barrier, especially when the microorganism can persist and survive on textiles, surfaces, and medical devices. During the coronavirus disease pandemic, around half of the disinfectants authorized by the US Environmental Protection Agency contained quaternary ammonium compounds (QACs);their effectiveness had not been proven. Herein, the in vitro SARS-CoV-2 inactivation by p-bromodomiphen bromide, namely bromiphen (BRO), a new, potent, and fast-acting QACis reported. This study demonstrates that BRO,with a dose as low as 0.02%, can completely inhibit SARS-CoV-2 replication in just 30 s. Its virucidal activity was 10- and 100-fold more robust compared to other commercially available QACs, namely domiphen bromide and benzalkonium chloride. The critical micellar concentration and the molecular lipophilicity potential surface area support the relevance of the lipophilic nature of these molecules for their activity.

Assessment of Elemental Composition of Kaolin from Kankara and Dutsinma Mine Sites, Katsina State, Nigeria

This research aimed to assess the health hazards associated with heavy metals contamination around Kankara and Dutsinma Kaolin mining sites. The analysis was done by using Energy Dispersive X-ray Fluorescence (EDXRF) at the Central Laboratory, Umaru Musa Yar-adua University, Katsina. In which health hazards were evaluated. using numerous Statistical and United States Environmental Protection Agency (USEPA) models. Thirty nine (39) different elements were analyzed using the most associated environmental and health risk of priority in which seven (07) of them are heavy metals of interest; Among them are: Nickel (Ni), Copper (Cu), Zink (Zn), Thallium (Ti), Chromium (Cr), Lead (Pb), and Arsenic (As), with an average concentrations of 20.02, 12.59, 54.03, 1344.4, 21.94, 140.00, and Not Available Value (NA) in the studied area. The Values obtained for overall hazard index (HI) are within the accepted values by (USEPA) which indicates no cancer risk for both adults and Children. While the overall excess lifetime cancer risk for a heavy metal was 8.5555E-06 (a maximum of 9 people per 1 million may be affected) for children and 7.5773E-05 (a maximum of 8 people per 1 million may be affected) for adults.

Bioavailability and Toxicity Models of Copper to Freshwater Life: The State of Regulatory Science.

Efforts to incorporate bioavailability adjustments into regulatory water quality criteria in the United States have included four major procedures: hardness-based single-linear regression equations, water-effect ratios (WERs), biotic ligand models (BLMs), and multiple-linear regression models (MLRs) that use dissolved organic carbon, hardness, and pH. The performance of each with copper (Cu) is evaluated, emphasizing the relative performance of hardness-based versus MLR-based criteria equations. The WER approach was shown to be inherently highly biased. The hardness-based model is in widest use, and the MLR approach is the US Environmental Protection Agency's (USEPA's) present recommended approach for developing aquatic life criteria for metals. The performance of criteria versions was evaluated with numerous toxicity datasets that were independent of those used to develop the MLR models, including olfactory and behavioral toxicity, and field and ecosystem studies. Within the range of water conditions used to develop the Cu MLR criteria equations, the MLR performed well in terms of predicting toxicity and protecting sensitive species and ecosystems. In soft waters, the MLR outperformed both the BLM and hardness models. In atypical waters with pH <5.5 or >9, neither the MLR nor BLM predictions were reliable, suggesting that site-specific testing would be needed to determine reliable Cu criteria for such settings. The hardness-based criteria performed poorly with all toxicity datasets, showing no or weak ability to predict observed toxicity. In natural waters, MLR and BLM criteria versions were strongly correlated. In contrast, the hardness-criteria version was often out of phase with the MLR and, depending on waterbody and season, could be either strongly overprotective or underprotective. The MLR-based USEPA-style chronic criterion appears to be more generally protective of ecosystems than other models. Environ Toxicol Chem 2023;42:2529-2563. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Phytochemical and Heavy Metal Screening of Fura da Nono, Ciklavit®, Katoka Mixtures®, and Yoyo Bitters®

Background: Evaluation of the phytochemicals and heavy metals contained in four commonly consumed beverage and herbal products in Nigeria, was investigated. This was to ascertain the health benefits as well as potential for toxicity that may be associated with the consumption of these products. Methods: The samples studied are Fura da Nono, Ciklavit®, Katoka Mixtures® and Yoyo Bitters®. The phytochemical screening of each product was done using standard procedures. The heavy metals screening was done using Agilent®720 Inductively Coupled Plasma -Optical Emission Spectroscopy machine (ICP-OES). The Hazard quotient and Index were assessed using appropriate equations in line with United States Environmental ProtectionAgency (USEPA). Results: All phytochemicals tested were found in Fura da Nono except Steroids and Terpenoids.Also, all the tested phytochemicals were detected in Ciklavit® except Alkaloids and Phlobatannins. Both Katoka Mixtures® and Yoyo Bitters® contained all other phytochemicals except Phlobatannins. Quantitatively, Fura da Nono was high in Cardiac glycosides, and Ciklavit® was found to be high in Flavonoid content. Both Katoka Mixtures® and Yoyo Bitters® are high in Phenols. The results of the heavy metal analysis revealed different concentrations (ppm) of arsenic, mercury, lead, cadmium, zinc, manganese, copper and nickel in the four products. Arsenic was not detected only in Fura da Nono. The heavy metal concentrations obtained were all within WHO maximum permissible limits. Further analysis for potential non-carcinogenic health risk using Hazard quotient on each of the four toxic heavy metals (arsenic, mercury, lead and cadmium) and Hazard Index (HI) on the same toxic heavy metals revealed that by the United States Environmental ProtectionAgency (USEPA) threshold value of HI ≤1, Yoyo Bitters® (0.4684) and Ciklavit® (0.7870) had the lower and safer values for combined heavy metal risk while Katoka Mixtures® (0.9908) and Fura da Nono (1.4144) had the highest. Conclusion: The phytochemical screening of the investigated products showed that the commonly consumed food drink and herbal products, are rich in phytochemicals. Even though the heavy metal screening indicates a fairly positive safety margin for three of the products. Caution should therefore be exercised in the use of these products.

Effect of crude oil spillage on some soil physical properties within Ovia North East Local Government in Edo State.

The release of crude oil into the environment by oil spill is currently receiving a worldwide attention due to the high risk it portends to the health of the environment. The purpose of this study was to determine the effect of crude oil spillage on some soil physical properties. Eight (8) soil samples were collected from eight sampling locations around the flow station at Gelegele River, Edo State. The total petroleum hydrocarbon (TPH) recorded were above the 1,000 mg/kg permissible limit by World Health Organization (WHO) and United States Environmental Protection Agency (USEPA) for hydrocarbon contaminated soil. The physiochemical studies were carried out according to the methods of Association of Official Analytical Chemist (A.O.A.C) for the determination of the soil physicochemical parameters. The physiochemical parameters obtained were pH (6.01 ± 0.02 – 6.49 ± 0.07), Electrical Conductivity (EC) (416.00 ± 10.70 – 656.45 ± 11.65) mS/m, Carbon (2.13 ± 0.03 – 3.70 ± 0.01a) %, Nitrogen (0.04 ± 0.01 – 1.67 ± 0.02ab) %, Phosphorus (1.33 ± 0.06 – 2.91 ± 0.04ab)%, Water holding capacity (WHC) (82.48 ± 0.82 – 92.48 ± 0.82) %, Bulk density (0.70 ± 0.02ab – 2.79 ± 0.05) %. There is a current concern of environmental pollution and this study showed that the area of study currently of concern that needs to be monitored.

A Semi-Automatic Environmental Monitoring Device for Mercury and Cobalt Ion Detection.

A syringe-based, semi-automatic environmental monitoring device is developed for on-site detection of harmful heavy metal ions in water. This portable device consists of a spring-embedded syringe and a polydimethylsiloxane (PDMS) membrane-based flow regulator for semi-automatic fix-and-release fluidic valve actuation, and a paper-based analytical device (PAD) with two kinds of gold nanoclusters (AuNCs) for sensitive Hg2+ and Co2+ ion detection, respectively. The thickness of the elastic PDMS membrane can be adjusted to stabilize and modulate the flow rates generated by the pushing force provided by the spring attached to the plunger. Also, different spring constants can drastically alter the response time. People of all ages can extract the fix-volume sample solutions and then release them to automatically complete the detection process, ensuring high reliability and repeatability. The PAD comprises two layers of modified paper, and each layer is immobilized with bovine serum albumin-capped gold nanoclusters (R-AuNCs) and glutathione-capped gold clusters (G-AuNCs), respectively. The ligands functionalized on the surface of the AuNCs not only can fine-tune the optical properties of the nanoclusters but also enable specific and simultaneous detection of Hg2+ and Co2+ ions via metallophilic Au+ -Hg2+ interaction and the Co2+ -thiol complexation effect, respectively. The feasibility of the device for detecting heavy metal ions at low concentrations in various environmental water samples is demonstrated. The Hg2+ and Co2+ ions can be seen simultaneously within 20 min with detection limits as low as 1.76 nm and 0.27 µm, respectively, lower than those of the regulatory restrictions on water by the US Environmental Protection Agency and the European Union. we expect this sensitive, selective, portable, and easy-to-use device to be valid for on-site multiple heavy metal ion pollution screenings in resource-constrained settings.

Use of plant viruses as bioherbicides: The first virus-based bioherbicide and future opportunities.

Until recently, only a few plant viruses had been studied for use as biological control agents for weeds, but none was developed into a registered bioherbicide. This position changed in 2015 when the U.S. Environmental Protection Agency (EPA) granted an unrestricted Section 3 registration for tobacco mild green mosaic virus (TMGMV) strain U2 as an herbicide active ingredient (a.i.) for a commercial bioherbicide (SolviNix LC). It is approved for the control of tropical soda apple (TSA, Solanum viarum), an invasive 'noxious weed' in the United States. TSA is a problematic weed in cattle pastures and natural areas in Florida. The TMGMV-U2 product kills TSA consistently, completely, and within a few weeks after its application. It is part of the TSA integrated best management practice (BMP) in Florida along with approved chemical herbicides and a classical biocontrol agent, Gratiana boliviana (Coleoptera: Chrysomelidae). TMGMV is nonpathogenic and nontoxic to humans, animals, and other fauna, environmentally safe, and as effective as chemical herbicides. Unlike the insect biocontrol agent, TMGMV kills and eliminates the weed from fields and helps recycle the dead biomass in the soil. Here the discovery, proof of concept, mode of action, risk analyses, application methods and tools, field testing, and development of the virus as the commercial product are reviewed. Also reviewed here are the data and scientific justifications advanced to answer the concerns raised about the use of the virus as a herbicide. The prospects for discovery and development of other plant-virus-based bioherbicides are discussed. This article is protected by copyright. All rights reserved.

Carbon monoxide formation from total volatile organic compounds from the use of household spray products

Introduction: Air pollutants emitted from household spray products used in our homes and offices have adverse effects on human health. The quantification and identification of emission sources of air pollutants forms a foundation for an effective indoor exposure control. This study presents the results of a fundamental study conducted to evaluate the kinetics and emission trends Total Volatile Organic Compounds (TVOCs) and Carbon Monoxide (CO) from household spray products.&#x0D; Materials and methods: Fortyfive (45) commonly used household spray products were selected for this study. The experiment was conducted in an isolated empty room of dimension (2.72×2.82×2.00) m3 with no known/ significant indoor emission source(s). CO and TVOCs concentrations were measured with Aeroqual® 500 series monitor with CO and TVOCs head at 15 min, 1 h, 3 h, and 24 h, for all 45 samples of household spray products.&#x0D; Results: Spontaneous second – order conversion of TVOCs to CO was observed for most of the spray products in the indoor environment. For the insecticides samples, TVOCs initial concentrations were 7.2–73±19.76 ppm which after one hour the concentrations became 1.8 – 17±7.20 ppm. CO measured initial concentration were 0 – 4±1.08 ppm which the concentration levels reduced to 0–7±2.16 ppm. TVOCs concentration was above the permissible limit set by USEPA and CO concentration for some of the air fresheners, perfume, shoe impregnation spray and hair sprays fall short the limit of 40,081.89 and 25,562.37 µg/m3 set by United States Environmental Protection Agency (USEPA) and World Health Organization (WHO), respectively.&#x0D; Conclusion: As the concentration of TVOCs decreased as the concentration the concentration, CO increased following a second order kinetics. The result obtained will help in the development of safer products and a proper guide on how to use them in a way it will not cause harm to both the user of the product and the environment.

The Landscape Urban Planning Approach for Improving Urban Air Quality, Case Study of Algiers, Algeria

Gardens and urban parks are areas of great importance for the support of the urban ecosystem, in addition to their psychological and therapeutic values; they provide the urban environment with a large amount of oxygen. Trees produce oxygen through the operation of photosynthesis; one hectare of eucalyptus tree annually produces oxygen for 37 to 80 people, and absorbs 25, 000 kg of carbon dioxide for the same period of time. Wooded zone in urban areas significantly improve and purify the quality of the air that we breathe and make living environments healthier. A recent study carried out by the World Health Organization (WHO) revealed that the MENA region (Middle East and North Africa) is one of the most polluted in the world, air polluted by particulate matter smaller than 2.5µm (PM2.5). For the case of Algiers, measurements were taken during the first two months of the year 2023 by the station of the United States Embassy in Algiers, showed that daily average of 14 µm/m3 for particulate matter less than 2.5 µm/m3 and a daily average of 50 for the IQA, air quality index. According to the US EPA's NAAQS, any measurement above 12.0 μg/m 3 (US AQI 50) may be hazardous to human health. Several factors of an exogenous and endogenous nature act directly on the quality of the air in large urban concentrations, CO2 emissions, modes and nature of urban mobility, uncontrolled urban sprawl. High population densities, urban forms, morphology, the size of cities, which getting larger and larger, the choice of urbanization models, and the surface of wooded areas, all are, factors responsible for air quality. This study will be particularly interested in the contribution of gardens, parks and wooded areas in improving air quality, and consequently on the quality of the living environment in urban areas. In this respect, and to understand the situation, we take the city of Algiers as a case study. The field work will allow us to understand in a qualitative and quantitative way the contribution of the tree and the choice of tree species, understanding co-relation between landscape architecture decision and results obtained on the urban air quality, and try to research on how it would possible to improve air quality in urban areas by using trees new essence.

Computational Thinking for Science: Positioning coding as a tool for doing science

AbstractThe role of computation in science is ever‐expanding and is enabling scientists to investigate complex phenomena in more powerful ways and tackle previously intractable problems. The growing role of computation has prompted calls to integrate computational thinking (CT) into science instruction in order to more authentically mirror contemporary science practice and to support inclusive engagement in science pathways. In this multimethods study, we present evidence for the Computational Thinking for Science (CT+S) instructional model designed to support broader participation in science, technology, engineering, and mathematics (STEM) pathways by (1) providing opportunities for students to learn CT within the regular school day, in core science classrooms; and (2) by reframing coding as a tool for developing solutions to compelling real‐world problems. We present core pedagogical strategies employed in the CT+S instructional model and describe its implementation into two 10‐lesson instructional units for middle‐school science classrooms. In the first unit, students create computational models of a coral reef ecosystem. In the second unit, students write code to create, analyze, and interpret data visualizations using a large air quality dataset from the United States Environmental Protection Agency to understand, communicate, and evaluate solutions for air quality concerns. In our investigation of the model's implementation through these two units, we found that participating students demonstrated statistically significant advancements in CT, competency beliefs for computation in STEM, and value assigned to computation in STEM. We also examine evidence for how the CT+S model's core pedagogical strategies may be contributing to observed outcomes. We discuss the implications of these findings and propose a testable theory of action for the model that can serve future researchers, evaluators, educators, and instructional designers.