Air Samples Research Articles

Urban green spaces with high connectivity and complex vegetation promote occupancy and richness of birds in a tropical megacity

Urban growth often leads to land-use changes that result in biodiversity loss and reduced human benefits. In urban zones, green areas facilitate physicochemical processes (such as carbon capture, reducing environmental temperature and noise pollution), offer multiple benefits to human beings (e.g., water filtration and purification), and support numerous vertebrate populations, including birds. In the tropics, the capacity of green spaces to maintain bird populations is regulated by characteristics of these areas (e.g., vegetation structure) and environmental seasonality. In order to generate ecological knowledge to help conserve bird diversity in large urban settlements, this study aimed to (1) identify the most influential variables on the distribution of bird species in green areas of a tropical megacity, and (2) assess how bird richness varies between the dry and rainy seasons. Across two dry and rainy seasons between 2021 and 2022, detection records of 108 bird species were obtained from 101 green areas. Air temperature and sampling time were the primary factors influencing bird detection. Bird occupancy and richness were higher in parks near other green areas in first dry and increased with tree richness during the rainy seasons. Floral abundance explained the occupancy and richness in the second dry season. In 2021, the highest richness was observed during the dry season, while in 2022, the highest richness was estimated during the rainy season. These findings highlight the importance of resource availability and spatial arrangement in urban green areas for bird diversity, offering insights for conservation and maintaining ecosystem benefits in urban environments.

The soil-air interfacial migration process of volatile PFAS at the contaminated sites: Evidence from stable carbon isotopes with CSIA

Volatile per- and polyfluoroalkyl substances (PFAS) are prone to transport among various environmental media, with the soil-air interfacial migration process being an important pathway that significantly influences their environmental fate. To assess the migration and transformations of target volatile PFAS at contaminated site using compound-specific stable isotope analysis (CSIA), it is necessary to understand the isotopic fractionation that occurs during their transfer from soil to air. We have established methods for pre-treatment and GC/CSIA analysis methods of target volatile PFAS in soil and air samples and ensured the accuracy of carbon isotope analysis. GC/IRMS δ13C measurements showed optimal precision at instrumental response above 1.35–2.75 Vs, with recommended minimum on-column C levels of 1.67–5.00 nmol for target volatile PFAS. Stable carbon isotope fractionation factors related to the soil-air interfacial migration process for target volatile PFAS were determined by performing laboratory simulations. The observed εsoil-air values are all negative, suggesting that the soil-air interfacial migration process for target volatile PFAS is kinetic fractionation, the removal of molecules containing lighter isotopes. By comparing the simulated and experimentally observed δ13C (‰) values of target volatile PFAS, we found consistent trends in the soil and inverse trends in the air. These δ13C (‰) values and the related isotope fractionation model provide valuable insights into the isotopic behavior of target volatile PFAS during soil-air interfacial migration process, aiding in the assessment of their environmental fate.

The Determination of the Rapid and Effective Activity of an Air Sanitizer against Aerosolized Bacteria Using a Room-Sized Aerobiology Chamber.

Air sanitization is an important non-pharmaceutical intervention for mitigating the risk of indoor pathogen spreading. A dipropylene glycol-containing air sanitizer was tested against aerosolized Staphylococcus aureus and Klebsiella pneumoniae. The bacteria, suspended in a soil load, were aerosolized using a six-jet Collison nebulizer with pressurized air. The 25-m3 (~900 ft3) aerobiology chamber was maintained at 22 ± 2 °C and 50 ± 5% relative humidity per the U.S. Environmental Protection Agency's 2012 Guidelines on air sanitizers. An initial 2-min air sample was collected from the chamber using a slit-to-agar sampler containing 150-mm Petri plates, with Trypticase soy agar (TSA) containing neutralizers to quench the microbicidal activity of the air sanitizer, to determine the initial bacterial challenge in the air. The air sanitizer was sprayed into the chamber from pressurized cans. Additional air samples were collected from the chamber over 10 min to detect surviving bacteria. The TSA plates were then incubated aerobically at 36 ± 1 °C for 90 ± 4 h and scored for bacterial colony-forming units. A 30-s spray of the air sanitizer reduced infectious S. aureus and K. pneumoniae titers by 3.0 log10 (99.9%) in 3.2 ± 0.3 min and 1.2 ± 0.0 min, respectively. Based on these findings, the EPA granted registration of the air sanitizer as the first product of its kind for indoor air sanitization.

Potential health risks of inhaling hazardous chemical exposures at fuel stations: a pilot study in a hot, arid environment

In recent years, there has been a growing focus on the issue of exposure to hazardous chemical compounds and the potential health risks associated with them. Fuel stations play a critical role in society, supporting the transportation industry and serving the general public. However, the routine activities at these stations expose workers and customers to dangerous chemical compounds, posing potential health risks. As part of a pilot study, the exposure of workers and customers to hazardous chemical compounds at fuel stations in Kuwait, characterized by its hot and arid environment, was investigated. The study specifically looked at volatile organic compounds (VOC) concentration and their effects on human health. Three hundred-eight air samples were collected in a hot, arid environment, focusing on fuel stations. Two sampling methods were used in this pilot study: personal inhalation exposure using active sampling and workplace air sampling using passive sampling. Samples were collected in fuel filling areas, indoor control rooms, and through personal exposures, adhering to ISO procedures (EPA TO-17). The study also assessed the non-carcinogenic and carcinogenic risks to human health to potential exposure to hazardous hazardous chemicals. The findings revealed that hazardous chemicals levels in the pump area were lower than those in the indoor control rooms. Workers’ inhalation exposure to hazardous chemicals remained below the international occupational exposure limit (OEL). However, the study identified unsafe inhalation exposure levels to Benzene, which could have adverse carcinogenic effects. In contrast, exposure to ethylbenzene was found to be within safe limits, with no associated carcinogenic effects. This study underscores the importance of identifying the risks associated with exposure to hazardous chemical compounds to minimize human health risks and promote a safe working environment.

Indoor moss biomonitoring proving construction-related pollution load from outdoors

Indoor pollution load in an office environment was investigated during ongoing construction works in the vicinity using the wet moss biomonitoring technique. Monitoring boxes were placed inside eight offices with mechanical ventilation located on three floors and with four different orientations to outdoor construction works for 8 weeks. Samples were collected every two weeks for two months, and the concentrations of selected elements: Al, As, Ca, Cd, Cr, Cu, Fe, Mg, Mn, Pb, Si and Zn were determined. Total deposition (composition, number and size of particles) was determined in the samples too. Correlation analysis complemented by Principle Component Analysis (PCA) was performed using a compositional approach. Concentrations correlated significantly among crustal elements and among road dust elements. PCA identified three groups of elements – representing construction dust, traffic origin and indoor origin, while those associated with construction dust had the highest contribution. The elevation (floor) affected the composition of the samples the most, the orientation to the pollution sources was secondary. Construction dust was most dominant on the 1st floor; samples from the sheltered sites were negatively associated with construction dust elements; here, the finest particles were also observed. Starting at 6 weeks of exposure, construction dust elements started to dominate in samples. Construction dust is a serious pollution problem, and its infiltration from the outdoors is apparent even in mechanical-ventilated indoor environments. Moss indoor monitoring technique was proven to be a suitable cost-effective alternative to automatic air samplers in determining the outdoor-originating pollution loads indoors.

Archetypes of Spatial Concentration Variability of Organic Contaminants in the Atmosphere: Implications for Identifying Sources and Mapping the Gaseous Outdoor Inhalation Exposome.

Whereas inhalation exposure to organic contaminants can negatively impact human health, knowledge of their spatial variability in the ambient atmosphere remains limited. We analyzed the extracts of passive air samplers deployed at 119 unique sites in Southern Canada between 2019 and 2022 for 353 organic vapors. Hierarchical clustering of the obtained data set revealed four archetypes of spatial concentration variability in the outdoor atmosphere, which are indicative of common sources and similar atmospheric dispersion behavior. "Point Source" signatures are characterized by elevated concentration in the vicinity of major release locations. A "Population" signature applies to compounds whose air concentrations are highly correlated with population density, and is associated with emissions from consumer products. The "Water Source" signature applies to substances with elevated levels in the vicinity of water bodies from which they evaporate. Another group of compounds displays a "Uniform" signature, indicative of a lack of major sources within the study area. We illustrate how such a data set, and the derived spatial patterns, can be applied to support the identification of sources, the quantification of atmospheric emissions, the modeling of air quality, and the investigation of potential inequities in inhalation exposure.

Microplastic levels in the indoor air of buildings based on plastic waste recycling in Indonesia

Introduction: Microplastics are a new type of contamination in the environment caused by plastic fragmentation and degradation. The generation of plastic waste increases every year, therefore efforts are made to recycle it into building materials. It is unclear how building use resulting from recycling plastic waste affects the development of microplastics in the atmosphere. The purpose of this study is to determine the airborne concentrations of microplastics in buildings constructed from recycled plastic waste. Materials and methods: The study measured microplastic levels in the air for 30 days in a miniature building made from plastic waste. Samples taken during the dry season in Indonesia in 2023. Air sampling is carried out by passive method. Visual observation of the shape, and amount of microplastics using a microscope. Results: Microplastics are found in the air of building spaces made from recycled plastic waste with varying levels every day. The average level of microplasty in the air for 30 days was 30,8 particles/m2/day. Maximum microplastic rate of 63 particles/m2/day, and minimum rate of 18 particles/m2/ day. The average air temperature when sampling is 25,48 ºC, air humidity is 68,37 % and ultraviolet intensity is 860 mwatt/cm2. Conclusions: Microplastic levels in the air of building spaces made from recycled plastic waste that can not be identified can be identified whether they are still within safe limits or not. This is because there is no regulation in Indonesia even in the world that regulates the safe limit of microplastic levels in the environment.

Surgical Face Mask as an Air Sampling Device for Assessing Personal Exposure to Airborne Antimicrobial Resistance Gene-Bearing Bacteria.

In this study, we assessed the feasibility of using a surgical face mask as a sampling device to collect airborne antimicrobial resistance genes (ARGs). The method entails collection of ARG-bearing microbes on face masks, followed by their DNA extraction and quantification by qPCR analysis. Analysis of masks worn by volunteers showed an apparent mask wearing time-dependent accumulation of 16S rRNA gene and select ARGs trapped on masks, highlighting the applicability of the method in monitoring personal ARG exposure through inhalation. The sampling method was then validated for reproducibility and compared with a filter-based sampling method before application in different environmental settings to further assess personal exposure to ARGs. In comparison with the filter-based method, our new sampling method does not require a sampling pump and is more user-friendly. More importantly, it records ARG exposure down to the personalized level; thus, it may be used in routine monitoring of occupational exposure and surveillance of ARG concentrations in indoor environments.

Organophosphate esters (OPEs) in the air and dust of new vehicle cabins: Concentrations, sources and contributions

Vehicles cabin represents unique indoor environment characterized by its limited space and multiple interior materials. For the first time, OPEs levels in vehicles and OPEs content in cabin materials were measured, and the material contributions were also analyzed. Between May and July in 2023, air, dust and materials samples were collected from 32 new vehicles. The detection rates were as high as 71%–100 % in dust and 100 % in selected cabin materials. The median of ∑OPEs in air-phase (both gas and particles) was significantly higher at 589.26 ng/m3 compared to those in other vehicle investigations. Material content analysis revealed that the top three were cushion textile, mat and lubricant, with ∑OPEs ranging from 85.94 μg/g to 1406.04 μg/g, which were three orders of magnitude higher than those in toys. Chlorinated forms such as TCIPP and TDCIPP were predominant among all air, dust and material samples analyzed. Particle-phase OPEs provided statistic diversity on manufactures and seat materials. Positive Matrix Factorization (PMF) analysis found that the combination of cushion textile, seat leather, and carpet substrate textile contributed significantly, accounting for 68 % of cabin OPEs.

Are the postmortem concentration changes of the synthetic cannabinoid cumyl-5F-P7AICA and its N-pentanoic acid metabolite dependent on the environmental conditions? – A systematic study following pulmonary administration to pigs

The number of fatal cases involving synthetic cannabinoids (SCs) is increasing. However, interpretation of postmortem (PM) toxicological findings is challenging, due to unknown PM intervals and possible redistribution processes or instabilities. Only sparse data on SCs are available. Therefore, a controlled pig study was performed to determine the PM stability of cumyl-5F-P7AICA under different environmental conditions. Ten pigs inhalatively received 200 µg/kg body weight cumyl-5F-P7AICA each. Six hours later, they were euthanized and biopsies of the main tissues and body fluids were taken. Animals were stored in air or water (n=5 each) and samples were repeatedly taken for three days. Quantification of cumyl-5F-P7AICA and its N-pentanoic acid metabolite (NPA) was performed using standard addition or a fully validated method (blood) followed by LC-MS/MS. Time-dependent concentration changes of cumyl-5F-P7AICA were observed in liver, bile fluid and muscle specimens at both conditions. Concentrations of NPA only changed considerably in duodenum content of animals stored in air. Environment-dependent concentrations changes were only observed for cumyl-5F-P7AICA in kidney and the NPA metabolite in duodenum content. Overall, cumyl-5F-P7AICA and its metabolite seem to be quite stable in PM specimens. Hence, also central blood might be analyzed, if no peripheral blood is available.

Detection and characterization of Campylobacter in air samples from poultry houses using shot-gun metagenomics – a pilot study

BackgroundFoodborne pathogens such as Campylobacter jejuni are responsible for a large proportion of the gastrointestinal infections worldwide associated with poultry meat. Campylobacter spp. can be found in the chicken fecal microbiome and can contaminate poultry meat during the slaughter process. Commonly used sampling methods to detect Campylobacter spp. at poultry farms use fecal droppings or boot swabs in combination with conventional culture techniques or PCR. In this pilot study, we have used air filtering and filters spiked with mock communities in combination with shotgun metagenomics to detect Campylobacter and test the applicability of this approach for the detection and characterization of foodborne pathogens. To the best of our knowledge is this the first study that combines air filtering with shotgun metagenomic sequencing for detection and characterization of Campylobacter.ResultsAnalysis of air filters spiked with different levels of Campylobacter, into a background of mock or poultry house communities, indicated that we could detect as little as 200 colony forming units (CFU) Campylobacter per sample using our protocols. The results indicate that even with limited sequencing effort we could detect Campylobacter in the samples analysed in this study. We observed significant amounts of Campylobacter in real-life samples from poultry houses using both real-time PCR as well as shotgun metagenomics, suggesting that the flocks in both houses were infected with Campylobacter spp. Interestingly, in both houses we find diverse microbial communities present in the indoor air which reflect the fecal microbiome of poultry. Some of the identified genera such as Staphylococcus, Escherichia and Pseudomonas are known to contain opportunistic pathogenic species.ConclusionsThese results show that air sampling of poultry houses in combination with shotgun metagenomics can detect and identify Campylobacter spp. present at low levels. This is important since early detection of Campylobacter enables measures to be put in place to ensure the safety of broiler products, animal health and public health. This approach has the potential to detect any pathogen present in poultry house air.

Measurement and health risks assessment of BTEX compounds exposure in beauty Lahijan City salons

The presence of BTEX (Benzene, Toluene, Ethylbenzene, and Xylene) compounds in beauty salons has raised concerns about potential health risks. This study aimed to measure the levels of BTEX compounds in the air of beauty salons in Lahijan, Iran and assess the associated health risks. Air samples were collected from 15 beauty salons, and the concentrations of BTEX compounds were measured according to 1501 NIOSH standard method. The results showed that the mean concentrations of benzene (20.62 µg/m3), toluene (18.3 µg/m3), ethylbenzene (38.36 µg/m3), and O and P-xylene (27.35, 23.6 µg/m3) were above the recommended levels. The indoor to outdoor ratios for benzene, toluene, ethylbenzene, O and P-xylene were 3.04, 2.36, 3.75, 4.89, and 6.54, respectively. Also, the toluene/benzene (T/B) ratio in indoor and outdoor was 20.9 and 2.68 respectively. Almost half of the technicians (49.12%) reported adverse health effects, including joint pain, itchy eyes and nose, and respiratory allergies. The IARC guideline suggests that there is a potential risk of cancer development for individuals in all salons with LCR values exceeding 10−6, but the HQ index values indicate no non-carcinogenic risk. The findings suggest that beauty salon workers and customers are at risk of developing health problems from exposure to BTEX compounds. Effective risk management strategies, such as proper ventilation, use of personal protective equipment, and substitution of harmful chemicals with safer alternatives, to minimize exposure and protect the health of salon workers and customers recommended.

Assessment of VOCs emission inventory in Seoul through spatiotemporal observations using passive and online PAMS measurements

We have conducted a quantitative analysis of volatile organic compounds (VOCs) in Seoul from September 2022 to June 2023, employing passive air samplers (PAS) at 25 sites and continuous monitoring at five photochemical assessment monitoring stations (PAMS). Comparing VOCs concentrations and compositions from PAS and PAMS during the same time periods, we found that most VOCs showed no significant difference (p-value >0.05) between the methods, except for olefins, which were overestimated by 24 % in passive sampling, confirming PAS as an effective tool for assessing the spatial distribution of VOCs species over large areas. Throughout Seoul, median values of total volatile organic compounds (TVOCs) concentrations collected with passive samplers remained stable with a standard deviation of 1.22 ppbv, typically ranging from 11 to 13 ppbv, except for an increase during winter in the southwestern regions of the city, where intense industrial and vehicular emissions are reported in the current Clean Air Policy Support System (CAPSS) emissions inventory. Positive matrix factorization (PMF) analysis using the passive data revealed general consistency in the spatial distribution of area and road emissions when compared with CAPSS emission inventory, although localized discrepancies were observed. In quantitative assessments of TVOCs comparing PAS observations with emission-based models, modeled values were within 1.5 times the interquartile range of observed PAS concentrations over Seoul. However, the lack of detection of emission hotspots in southeastern Seoul in the PAS data, coupled with the omission of photochemical loss in our dispersion-only models, indicates that the current CAPSS emission inventory may significantly underestimate actual ambient VOCs levels, especially in summer.

COVID-19 detection from exhaled breath

The SARS-CoV-2 coronavirus emerged in 2019 causing a COVID-19 pandemic that resulted in 7 million deaths out of 770 million reported cases over the next 4 years. The global health emergency called for unprecedented efforts to monitor and reduce the rate of infection, pushing the study of new diagnostic methods. In this paper, we introduce a cheap, fast, and non-invasive COVID-19 detection system, which exploits only exhaled breath. Specifically, provided an air sample, the mass spectra in the 10–351 mass-to-charge range are measured using an original micro and nano-sampling device coupled with a high-precision spectrometer; then, the raw spectra are processed by custom software algorithms; the clean and augmented data are eventually classified using state-of-the-art machine-learning algorithms. An uncontrolled clinical trial was conducted between 2021 and 2022 on 302 subjects who were concerned about being infected, either due to exhibiting symptoms or having recently recovered from illness. Despite the simplicity of use, our system showed a performance comparable to the traditional polymerase-chain-reaction and antigen testing in identifying cases of COVID-19 (that is, 95% accuracy, 94% recall, 96% specificity, and 92% \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$F_1$$\\end{document}-score). In light of these outcomes, we think that the proposed system holds the potential for substantial contributions to routine screenings and expedited responses during future epidemics, as it yields results comparable to state-of-the-art methods, providing them in a more rapid and less invasive manner.

The sampling and removal of tritiated water vapor in Taiwan research reactor

The Taiwan Research Reactor (TRR) is a research facility in Taiwan. TRR is a heavy water reactor designed based on the National Research Experiment (NRX) with output thermal power 40 MW. On January 3, 1973, it reach criticality. TRR had been operated for 15 years and was permanently shut down in early 1988. TRR uses heavy water moderation and light water cooling. Hence, some tritium was created when deuterium captures a neutron. The inside of the Calandria has been washed with clean water after shutdown. After draining the water in the interior, it is inevitable that some residual water would remain at the bottom of the Calandria. Air sampling and analysis techniques were employed to detect and quantify tritiated water vapor. The investigation of tritiated water vapor in the TRR Calandria proved potential tritium contamination risks. Adopting the vapor condensation drying technique proved effective in removing tritiated water vapor from the TRR Calandria. After the removal of tritiated water vapor, the air in the Calandria no longer contains rich concentration of tritiated water vapor. That will help to ensure a safe environment for decommissioning operations.

Polychlorinated Biphenyl Levels and Associated Health Risks in Indoor Atmosphere of Beauty Salons

Exposure to high concentrations of Polychlorinated Biphenyl (PCBs) has negative impacts on human wellbeing and the climate. This study determined the concentration, sources and health risks of PCBs in selected beauty shops in Ilorin, Kwara state. Air samples from fourteen beauty salons were taken using Solvent-Impregnated Polyurethane Foam (SIP-PUF) passive samplers for 30 days. The concentration of PCBs was determined with Gas Chromatography-Mass Spectrometry (GC–MS) operated in a Selected Ionization Mode (SIM). The health risk assessment of the PCBs was estimated using the Toxicity Equivalence Quotient (TEQ), Incremental Life Cancer Risk (ILCR), and Hazard Quotient (HQ) prescribed by United State Environmental Protection Agency (USEPA). The Positive Matrix Factorization (PMF) method was used in the source apportionment study. The average concentration of the PCBs ranged from 0.11–3.32 µg/m3 . The average TEQs for the PCBs in the beauty salon ambient air ranged between 2.96 × 10−1 - 9.30 × 10−1 ng WHO-TEQ/m3 . ILCRs and HQs estimated for the beauty shops considered were lower than 10-6 and 1 (USEPA set limit) for both adults and children. Eight factors were identified to be associated with the PCB sources; the most predominant sources are combined paint and pigment and mixed sources, which accounted for 20.08 and 28.91% of the total PCBs, respectively.

Efficacy of sevoflurane flush out and activated charcoal filtration—a bench study

PurposeA bench study to assess the elimination of sevoflurane from an anesthetic workstation using three different processing methods.MethodsSevoflurane concentrations from samples of the inspiratory breathing hose and air samples from within the investigation room were assessed during predetermined flush out intervals using Gas Chromatography-Ion Mobility Spectrometry. The primary objective was to determine the time to reach concentrations below 5 ppmv.ResultsReduction of sevoflurane volume concentrations below a threshold of 5 ppmv was achieved within the first minute after removal of the vaporizer and the complete exchange of the soda and the breathing system and within the 15 min measurement interval after inclusion of two activated charcoal filters without a 90 s of flushing and without changing of the breathing hoses as required by the manufacturer.ConclusionsComplete removal of the vaporizer and an exchange of the soda and the ventilation unit most quickly reduced sevoflurane concentrations, but the total processing interval may exceed 30 min. Inserted activated charcoal filters without a previous 90 s of flushing and without changing the breathing hoses followed by flushing only with raised fresh gas flow allow ventilation below trigger threshold to be reached within due time.

The influence of phytoncidal properties of indoor plants on the air microflora of preschool educational organizations

BACKGROUND: The quality of indoor air is an important factor affecting health. AIM: To study the effect of phytoncidal properties of indoor plants on closed space under normal operating conditions of preschool educational institutions. MATERIAL AND METHODS: The dynamics of the microorganisms’ total number in the air of group rooms of preschool educational institutions was assessed according to current guidelines. The rooms were identical in area. The radius of phytoncidal action of indoor plants was determined. Air samples were taken after a week of exposure at different distances from a group of these plants in the breathing zone of children using an aspiration method with a sampling device. Statistical processing was carried out using the Statistica 10.0 and Microsoft Excel packages, ANOVA analysis of variance was applied. RESULTS: Plant species with phytoncidal activity were selected and designated (Chlorophytum comosum, Aspidistra elatior, Begonia ricinifolia, Hibiscus rosa-sinensis, Kalanchoe blossfeldiana, Plectranthus scutellarioides, Murraya exotica, Nephrolepis, Sansevieria trifasciata, Cyperus alternifolius). The total number of microorganisms in the air of group rooms before and after the installation of phytoncidal plants was compared (1201 and 584 CFU/m3). The maximum radius of plant placement at which bacterial contamination of the air decreased was determined. It was found that within a radius of 5 m from the placement of plants, the number of microorganisms was in the range of 380–481 CFU/m3, more than 5 m — 728–1101 CFU/m3. CONCLUSION: The use of indoor plants with phytoncidal activity in closed spaces of organized children's groups can serve as an additional way to improve the quality of the air environment.

Breath Analysis: Identification of Potential Volatile Biomarkers for Non-Invasive Diagnosis of Chronic Kidney Disease (CKD).

Recently, volatile organic compound (VOC) determination in exhaled breath has seen growing interest due to its promising potential in early diagnosis of several pathological conditions, including chronic kidney disease (CKD). Therefore, this study aimed to identify the breath VOC pattern providing an accurate, reproducible and fast CKD diagnosis at early stages of disease. A cross-sectional observational study was carried out, enrolling a total of 30 subjects matched for age and gender. More specifically, the breath samples were collected from (a) 10 patients with end-stage kidney disease (ESKD) before undergoing hemodialysis treatment (DIAL); (b) 10 patients with mild-moderate CKD (G) including 3 patients in stage G2 with mild albuminuria, and 7 patients in stage G3 and (c) 10 healthy controls (CTRL). For each volunteer, an end-tidal exhaled breath sample and an ambient air sample (AA) were collected at the same time on two sorbent tubes by an automated sampling system and analyzed by Thermal Desorption-Gas Chromatography-Mass Spectrometry. A total of 110 VOCs were detected in breath samples but only 42 showed significatively different levels with respect to AA. Nonparametric tests, such as Wilcoxon/Kruskal-Wallis tests, allowed us to identify the most weighting variables able to discriminate between AA, DIAL, G and CTRL breath samples. A promising multivariate data mining approach incorporating only selected variables (showing p-values lower than 0.05), such as nonanal, pentane, acetophenone, pentanone, undecane, butanedione, ethyl hexanol and benzene, was developed and cross-validated, providing a prediction accuracy equal to 87% and 100% in identifying patients with both mild-moderate CKD (G) and ESKD (DIAL), respectively.

Application of tree cores to investigate the historical pollution trends of atmospheric polycyclic aromatic compounds: A case study in a typical coal-contaminated region of China

In this study, 76 polycyclic aromatic compounds (PACs) were detected in air, soil, and tree core samples from Huainan, a typical coal-contaminated region of China. Concentrations of ΣPACs in soil and air samples were 2400 ± 5100 ng/g and 150 ± 63 ng/m3, respectively. Priority PAHs were predominant in both air and soil samples, contributing over 50 % of ΣPACs. Source analysis indicated that PAC contamination in Huainan primarily originated from local coal-related activities. The benzo[a]pyrene (BaP)-toxic equivalent concentrations (TEQBaP) of PACs in the air samples (5.6 ± 5.3 ng/m3) exceeded the threshold of 1 ng/m3. Some PACs, such as benzo[e]pyrene (BeP) and Alk-BaPs, demonstrated significant toxicity and are recommended for consideration as priority pollutants. The historical pollution trends of atmospheric PACs were obtained based on the tree core samples. PAC concentrations in tree core segments showed a strong correlation with atmospheric PM10 levels in Huainan. As air quality has improved in recent years, the PACs concentrations in tree core segments have also decreased. Historical fluctuations of atmospheric PACs were largely attributed to the changes in the gas treatment systems of a nearby coal-fired power plant and adjustments in environmental policies. By integrating trends observed in tree core segments with air concentrations, the historical atmospheric PAC concentrations were extrapolated. The extrapolated results showed similar concentration levels and trends when compared with historical data from other studies in China. Thus, tree cores can not only reflect the historical trends of atmospheric PACs with high temporal precision but also are feasible for extrapolating historical concentrations of airborne PACs.