Indoor air quality (IAQ) is a significant concern that affects comfort and health. It is well understood that hospitals are thermal environments in which comfort must be calibrated. This comparative study examined existing international standards of IAQ in Iranian health care facilities. A systematic review of studies on IAQ standards was conducted to test the hypothesis regarding which parameters, and at what level, can have an impact on hospital IAQ: EPA, ASHRAE, LEED, BREEAM, NIOSH, OSHA, WHO, ACGIH, Canadian, and OEL. The inclusion criteria were met by 34 of the 1886 studies that were screened from 2010-2021. The findings of the selected studies were classified into four categories for analysis: monitoring of IAQ according to standards (n=34), IAQ in healthcare facilities (n=1), impact of air pollution on human health (n=9), and interventions to improve IAQ (n=1). Based on these IAQ standards, the acceptable limit for CO2 6300 *10³ µg/m³, for CO 9000 µg/m³, for Formaldehyde 19 µg/m³, for NO2 37 µg/m³, for O3 98 µg/m³, for PM2.5 0.1 µg/m³, for PM10 10 µg/m, and for SO2 31 µg/m³ was suggested. The majority of studies conducted monitoring of pollutants in indoor environments used for homes and schools, with the majority of them relying on WHO IAQ standards. CO, PM, and NO2 concentrations have been the most studied and have the longest track record of research. The acceptable limit for IAQ parameters was proposed.

The objective of this study was to identify the correlation between NOx concentration and envi-ronmental variables at photocatalytic concrete pavements containing TiO2 by direct monitoring in field. In order to confirm the NOx concentration according to various environmental variables of the photocatalytic concrete pavements, humidity, temperature, light intensity, and NOx concen-tration were measured continuously for 3 days at photocatalytic pavement, concrete pavement, and atmospheric conditions, respectively. We identified the NOx concentration at all measurement sites and calculated the NOx removal efficiency of the photocatalytic pavements. As a result, the NOx concentration of the photocatalytic pavement was 0.086 ppm on the 1st day, 0.125 ppm on the 2nd day, and 0.106 ppm on the 3rd day, which was mostly lower than that of the concrete pavement and the atmospheric conditions. When the NOx removal efficiency of the photocatalytic pavement on days 1–3 was examined by time, the NOx removal efficiency was evidently higher in the order of 0–6 h > 18–24 h or 6–12 h > 12–18 h for all three measurement days. In addition, the relationship between NOx removal efficiency and environmental variables was analyzed. As a result of corre-lation analysis between NOx removal efficiency and environmental variables of the site, relative humidity showed a positive (+) correlation, while temperature and light intensity showed a negative (-) correlation. Based on our results, we summarize some considerations for evaluating the NOx removal performance of photocatalytic pavements applied in the field.

This study was conducted to assess air quality status in the selected cities of Pakistan through Air Quality Index (AQI) and Multi Pollutant Index (MPI) and their correlation. Secondary data on air pollutants’ concentrations for the year 2021 were used from the literature. For this investigation, major air pollutants including carbon monoxide, nitrogen dioxide, sulfur dioxide, and particulate matter were used and compared with Punjab Environmental Quality Standards. Air quality indices, Multi Pollutant Index (MPI) and the Air Quality Index (AQI) were used in the study. Overall condition of the air pollutants in the particular location was described using the Air Quality Index. For this formula, the average concentration of each pollutant across a range of time periods was first calculated. The concentration of each pollutant was then divided by the relevant standard value, which was then cumulatively averaged and represented as a percentage. Results showed that Lahore and Karachi are two of the cities with unhealthy to hazardous AQI values and poor air quality according to MPI values. Air quality is deteriorating in industrial and traffic-congested cities where pollution levels significantly exceeded the threshold values. Using the linear regression, the results confirmed the strong association between the AQI and MPI. There is a need for immediate action to be taken to lower pollutants’ concentrations and improve air quality in urban areas.

Two fly ashes from municipal solid waste incineration were selected to study their heavy metal leaching behavior. The main purpose of this research is to investigate the characteristics of fly ashes and compare the leaching of heavy metals in different leaching environment. pH and acid neutralization capacity analysis showed that fly ashes were highly alkaline. Fly ashes also contained a variety of heavy metals including Pb, Cu, Cr, Zn, Cd and Ni etc. Leaching studies showed that the alkalinity of fly ashes raised the pH of leaching solution from acidic to basic. Ni, Cu and Zn were strongly bound to ashes and manifested low leaching. In contrast, Cr and Cd had high mobility but their leaching was inhibited by the low solubility of carbonate Cr and Cd. Pb was highly leachable in the alkaline environment with concentration in the leaching solution reached as high as 9.74 mg/L. In addition, the presence of EDTA in the environment also increased leaching. Pb concentration was raised to 16.63 mg/L. This could be attributed to the chelating capacity of EDTA which means that the presence of organics in natural environment should be taken into consideration.

The study was conducted in Lake Rinconada, a glacial lake affected by artisanal and small-scale gold mining activities in the southern Andes in Peru. The objectives of the study were to investigate the spatial distribution of heavy metals (As, Cu, Hg, Pb and Zn) in water and sediments and to assess the degree of metal pollution and ecological risk using the geoaccumulation and potential ecological risk indexes. The concentrations of As and Hg in sediments from Lake Rinconada exceeded the Canadian sediment quality regulations, whereas the concentrations of As, Hg and Pb in water and sediments from the mining-affected tributary, Lunar de Oro River exceeded the Peruvian and Canadian guidelines for water and sediments quality respectively. According to the geoaccumulation and potential ecological risk indexes, Lake Rinconada is extremely polluted by As and Hg, and the pollution is mostly concentrated in the northern part of the lake, where the mining-affected Lunar de Oro River flows into the lake. Concentrations of Pb are also high in the northern part of the lake, suggesting that the nearby gold mining town is a source of pollution. The results of this study allows to report that Lake Rinconada is completely deteriorated.

During the COVID-19 pandemic large numbers of single-use, surgical style face masks were lost or discarded in public spaces, primarily in on public streets and car parking settings. Many of these masks were blown onto the road surfaces where they were subjected to degradation through the tire impact of passing vehicle traffic. As series of field observations as well as experimental simulations show that the three-ply polypropylene mask fabric is subjected to shear forces when compressed between the tire and the road surface. The mechanical action breaks the bonds between the fibers (both spunbonded and meltblown) leading to a continual shedding of microfibers. Wind disperses these into the environment along road sides, while surface water action moves them into stormwater drains and from there into the waterways. As the decay is rapid, municipal agencies only have a short window of time to remove stray face masks from the urban environment if micro-fiber pollution is to be reduced.

Air fresheners are the synthetic products, used to improve the quality of indoor air by removing unpleasant or disturbing odours, in addition they disinfect the air by removing allergens and in turn add pleasant odours. However, these fresheners since they contain varied chemicals, which on magnification in a closed environment may cause respiratory illness. Therefore, constant usage of these air fresheners would deteriorate the ambient quality of indoor air. Even air fresheners which claim to be “green”, since these lack regulatory norms, they too emit hazardous or chemically harmful compounds. Hence there is a dire need to use alternative products that substantiate the quality of indoor air.  The present study aimed at exploring the efficacy of medicinal plant extracts of Azadirachta indica, Menta piperita and Aloe barbadensis in controlling air borne fungi in indoor environments by creating a simulation of an indoor environment and checking the efficiency of these natural air fresheners. About 60-70% reduction in the vegetative structures (colony diameter) and 30% reduction in reproductive structures were observed after exposure for 11 days to environment containing Azadirachta indica and Menta piperita extracts. Thus this study has novelty in formulating herbal based air fresheners based on the proven antifungal activities of these medicinal plant extracts, thereby replacing the usage of commercial air fresheners in the near future in controlling indoor air borne fungi. Since these natural formulations undoubtedly disinfect the indoor air, has commercial prospects and are eco-friendly, cost-effective with no health implications.

Coronavirus (COVID-19) pandemic ushered in a new era that led to the adjustments of diverse ecosystems. The pandemic restructured the global socio-economic events which prompted several adaptation measures as a response mechanism to cushion the negative impact of the disease pandemic. Critical health safety actions were imperative to curtail the spread of the disease such as wearing personal protective equipment (PPEs), masks, goggles, and using sanitizers for disinfection purposes. The daily demands for the products by individuals and medical personnel heightened their production and consumption, leading to a corresponding increase of COVID-19 wastes in the environment following indiscriminate waste disposal and poor waste management. The persistent occurrence of COVID-19 wastes aggravated microplastics (MPs) contamination in the aquatic ecosystem following the breakdown of PPEs-based plastics via oxidation, fragmentation, and photo-degradation actions. These MPs are transported in the aquatic environment via surface runoff and wind action, apart from discrete sources. MPs' presence in the aquatic systems is not without repercussions. Ingestion of MPs by aquatic organisms can cause several diseases (e.g., poor growth, oxidative distress, neurotoxicity, developmental toxicity, reproductive toxicity, immunotoxicity, and organ toxicity). Humans are at high risk of MPs uptake. Apart from aerial and soil contamination sources, consumption of aquatic food products is a critical pathway of MPs into the human body. MP toxicities in humans include liver disorder, respiratory failure, infertility, hormonal imbalance, diarrhea, developmental disorder, and mortality. Measures to alleviate the effect of COVID-19 waste litters include effective waste management plans and the adoption of technologies to extract cum degrade MPs from the aquatic and terrestrial environment.

Evidence of the health impact of air pollution in Morocco is scarce. We aimed to test our hypothesis that exposure to air pollutants has a significant impact on the health of Moroccans. For this systematic review, we searched PubMed, ScienceDirect, LILACS, and ProQuest databases, Google Scholar, and forward and backward citations for studies published between the database inception and August 16, 2022. All studies and reports that measure air quality in Morocco and its health impact were included, without language restrictions. This study is registered on PROSPERO under number CRD42020163948. Studies were selected based on inclusion and exclusion criteria rather than their methods. The data was extracted, coded, and prepared for future examination. After that, descriptive and thematic analyses were carried out. Of 1230 records identified, 31 were eligible, all of which had annual air pollutant concentrations in excess of WHO Air Quality Guidelines. The health impact was demonstrated in five studies. The most studied pathologies were asthma, respiratory and cardiac infections in children under 12 years and adults. In addition to heavy metals, the most investigated pollutants were PM10, O3, SO2, and NOx. The significant association between exposure to air pollutants and health in the Moroccan population has been demonstrated, even if it is not causal. Future research should quantify the health impact of pollution in other Moroccan cities.

Nickel nitrate is a heavy metal known as an environmental contaminant due to its toxicity, long environmental half-lives, and capacity for bioaccumulation.  This study aims to determine chromosomal aberration, nuclear alteration, and cell death in Allium cepa var. aggregatum L. root caused by different nickel concentrations.  Roots of Allium cepa var. aggregatum were induced by soaking bulbs in water, then transferred to a solution containing nickel (Ni) at a concentration of 20 ppm, 30 ppm, and 40 ppm for 72 hours.  Root tip mitotic chromosome preparations were done by the squash method.  The chromosome was stained with aceto-orcein and chromosomal damages were observed under a microscope.  The results showed that the mitotic index decreased from 5.025% at control to 3.144%, 2.467%, and 2.181% at immersion with 20 ppm, 30 ppm 40 ppm nickel nitrate, respectively.  Anaphase and telophase indexes in roots with Ni treatments were lower than in control, suggesting that nickel inhibits cell division.  Nickel nitrate induced chromosomal damages and nuclear abnormalities, such as sticky chromosome, fragmented chromosome, chromosome bridge and chromosome laggard, micronuclei, binucleate and nuclear budding.  The percentage of chromosomal damage increases with a higher concentration of Ni.  In situ cell visualization showed that the higher the nickel concentration, the more coloured the root tips indicating high levels of cell death.