Human Breath Research Articles

Co3O4/CQDs composite for selective ammonia detection in exhaled human breath analysis

Co3O4 was synthesized using electrospinning method and different amounts of carbon quantum dots (CQDs) were subsequently doped into the Co3O4 matrix via grinding, resulting in Co3O4/CQDs composite materials with various ratios. Gas sensing tests revealed that the resulting composite Co3O4/CQDs sensors exhibited excellent performance at a low temperature of 50°C, with outstanding selectivity towards ammonia gas and rapid response and recovery characteristics. Specifically, response and recovery time for 50 ppm ammonia gas were 14 s and 164 s, respectively. The outcomes of the exhalation simulation test utilizing sensors composed of this material demonstrate that the sensor's response to simulated chronic kidney disease breath closely approximates that of pure biological samples (1.08), exceeding the average response value of healthy exhaled breath samples (1.0). This demonstrates the sensor's capability to differentiate between healthy individuals and chronic kidney disease patients despite significant water vapor and carbon dioxide interference. This study provides valuable insights for the development of more efficient ammonia sensors and their role in the early detection of chronic kidney disease.

Environmentally stable, Adhesive, Self-healing, Stretchable and Transparent Gelatin based Eutectogels for Self-Powered Humidity Sensors

Intrinsic environmental and stability limitations of hydrogels have inhibited their practical applications as a flexible wearable device due to water evaporation or freezing in complex environments such as low temperatures and arid environments. In this work, a multifunctional gelatin based ionic conductive eutectogel with double network structure is designed via ternary deep eutectic solvent (DES) (acrylic acid (AA), choline chloride (ChCl) and ethylene glycol (EG)). In this system, the introduction of ethylene glycol (EG) can be used to dissolve gelatin. The resulting DESG eutectogel exhibited excellent adhesion, mechanical robustness, anti-freeze, anti-drying, and self-healing. Interestingly, the DESG gels showed high humidity sensitivity in a wide humidity detection range (11 %–83 %), which can be assembled as a self-powdered humidity sensor to monitor human mouth and nose breathing. This work is expected to bring new prospect to construct high performance humidity sensors using gelatin based humidity-responsive materials for a wide range of potential applications in respiratory diagnostics, sleep monitoring, electronic skin and wearable electronics.

Portable and Hand-Held Ammonia Gas Sensor Enables Noninvasive Prediagnosis of Helicobacter pylori Infection.

Disease diagnosis of Helicobacter pylori (Hp) through human exhaled breath analysis has attracted considerable attention. However, conventional methods, such as carbon 13 (13C) breath test and infrared spectrometers, are facing the challenge of achieving portability and reliability synchronously. Herein, we report a portable and hand-held Hp analyzer using a bimetallic PtRu@SnO2-based gas sensor for the prediagnosis of Hp infection, which is based on detecting ammonia (NH3) as a potential biomarker in exhaled breath. Owing to the surface functionalization through highly catalytically active bimetallic PtRu nanoparticles (NPs) prepared by a photochemical reduction strategy, the PtRu@SnO2-based sensor exhibits high sensitivity and selectivity toward trace-level (200 ppb) NH3 even at high-humidity surroundings (80% RH). Consequently, the designed portable and hand-held Hp analyzer makes the accurate determination of NH3 at 800 ppb in exhaled breath. The tuning of energy band structure and electrical characteristics and the catalytic modulation of NH3 oxidation by PtRu NPs are proposed to be the reasons behind the enhanced NH3 gas-sensing performance, as confirmed by in situ analysis using an online MKS MultiGas 2030 FTIR gas analyzer. This work paves the way for the prediagnosis of Hp infection using a metal oxide gas sensor.

Accelerating the Diagnosis of Pandemic Infection Based on Rapid Sampling Algorithm for Fast-Response Breath Gas Analyzers.

This paper presents a novel technique for extracting the alveolar part of human breath. Gas exchange occurs between blood and inhaled air in the alveoli, which is helpful in medical diagnostics based on breath analysis. Consequently, the alveolar portion of the exhaled air contains specific concentrations of endogenous EVOC (exogenous volatile organic compound), which, among other factors, depend on the person's health condition. As this part of the breath enables the screening for diseases, accurate sample collection for testing is crucial. Inaccurate sampling can significantly alter the composition of the specimen, alter the concentration of EVOC (biomarkers) and adversely affect the diagnosis. Furthermore, the volume of alveolar air is minimal (usually <350 mL), especially in the case of people affected by respiratory system problems. For these reasons, precise sampling is a key factor in the effectiveness of medical diagnostic systems. A new technique ensuring high accuracy and repeatability is presented in the article. It is based on analyzing the changes in carbon dioxide concentration in human breath using a fast and compensated non-dispersive infrared (NDIR) sensor and the simple moving adjacent average (SMAA) algorithm. Research has shown that this method accurately identifies exhalation phases with an uncertainty as low as 20 ms. This provides around 350 ms of breath duration for carrying out additional stages of the diagnostic process using various types of analyzers.

Analysis of Exhaled Human Breaths using Graphene Gas Sensor Based on the Male Gender

Breath analysis is an intriguing method that has the potential to significantly improve non-implantable physical health management via the use of flexible sensors to monitor breathing behaviours. In comparison to other analytical techniques for detecting breath elements, non-invasive breathing diagnostics based on chemical sensors can provide numerous benefits, including nanotechnology, power efficiency, simplicity of structure, and cost-effectiveness, contributing to the flexibility of experimental studies. This paper presents the graphene-based human breath sensor. Graphene was prepared in a paste form by mixing the graphene powder with two types of the binder. Two binders were prepared to compare their performance to human breath. The graphene paste was deposited using screen-printing on different substrates, Kapton film, and glass. The sensing film was thermally annealed at 200°C for 30 minutes and characterized using SEM and FTIR. All graphene gas sensor samples responded well to collected male human breath samples: Bumiputera (Sarawak), Malay, Chinese, and Indian. The best graphene gas sensor for males was OG-T(G) and OG-T(K) with sensitivity, S=1.10415 and S=1.01629. Based on the comparison results of male human breath, the fastest response time and recovery time were 0.52s and 13s, respectively.

High-performance flexible humidity sensor based on B-TiO2/ SnS2 nanoflowers for non-contact sensing and respiration detection

The development of flexible humidity sensors is essential for the advancement of wearable devices and electronic skin. However, the process of preparing these sensors is typically complex, and they often suffer from poor stability and a limited sensing range, which fails to meet the requirements for practical applications. Here, we prepared SnS2 with nanoflower morphology by hydrothermal method, and successfully prepared a high-performance flexible humidity sensor with a high response range (20-95 %) by compositing it with B-TiO2 nanoparticles with oxygen defects after sodium borohydride reduction and coating it on a PET flexible substrate. This sensor demonstrates an exceptional response (753.2 at 90 % RH) in high humidity environments and exhibits rapid response (13 s) and recovery times (19 s). Moreover, the sensor accurately detects human breathing patterns and frequencies, making it suitable for non-contact sensing applications. This research offers valuable insights into the simplified preparation and advancement of flexible humidity sensors.

Dome structure nonwoven-based dual-mode pressure-humidity sensor: Enhancing sensitivity and breathability for human health monitoring

In the field of health monitoring and electronic skin, flexible wearable sensors have attracted considerable research interest. However, preparing a flexible multifunctional sensor that simultaneously possesses a rapid response time, stability, reliability, high breathability, as well as high sensitivity remains a significant challenge. Herein, a flexible pressure-humidity dual-mode sensor based on nonwoven fabrics is developed in this study, using hydroentangled nonwoven fabric with graphene oxide/carbon nanotube composite as the sensing layer and polyester plain nonwoven fabric with carbon nanotube printed interdigitated electrodes as the electrode layer. The sensor exhibits high permeability (649.2 mm/s), high sensitivity (2.72 kPa−1), wide sensing range (0–220 kPa), fast response/recovery time (24.4 /73.3 ms), and low detection limit (2.79 Pa). In addition, the sensor exhibits excellent cyclic stability (15,000 cycles) and can detect both weak body movements (pulses, swallowing) as well as large deformational movements (joint movements). Furthermore, the sensing layer of the sensor responds quickly to different humidity levels, which can be used to monitor humidity in real time, and human breathing and speech can be monitored by placing it inside a mask. This high-performance flexible pressure-humidity dual-mode sensor shows promising potential for applications in health monitoring and respiratory monitoring.

Deep-Learning-Based Blood Glucose Detection Device Using Acetone Exhaled Breath Sensing Features of α-Fe2O3-MWCNT Nanocomposites.

Owing to the correlation between acetone in human's exhaled breath (EB) and blood glucose, the development of EB acetone gas-sensing devices is important for early diagnosis of diabetes diseases. In this article, a noninvasive blood glucose detection device through acetone sensing in EB, based on an α-Fe2O3-multiwalled carbon nanotube (MWCNT) nanocomposite, was successfully developed. Different amounts of α-Fe2O3 were added to the MWCNTs by a simple solution method. The optimized acetone gas sensor showed a response of 5.15 to 10 ppm acetone gas at 200 °C. Also, the fabricated sensor showed very good sensing properties even in an atmosphere with high relative humidity. Since the EB has high humidity, the proposed sensor is a promising device to exactly detect the amount of acetone in EB with high humidity. The sensor was powered by a 3200 mAh battery with the possibility of charging using mains electricity. To increase the reliability and calibration of the sensing device, a practical test was taken to detect acetone EB from 50 volunteers, and a deep learning algorithm (DLA) was used to detect the effect of various factors on the amount of acetone in each person's acetone EB. The proposed device with ±15 errors had almost 85% correct responses. Also, the proposed device had excellent response, short response time, good selectivity, and good repeatability, leading it to be a suitable candidate for noninvasive blood glucose sensing.

A breath-based in vitro diagnostic assay for the detection of lower respiratory tract infections.

An accurate diagnosis is critical to reducing mortality in people with lower respiratory tract infections (LRTIs). Current microbiological culture is time-consuming, and nucleic acid amplification-based molecular technologies cannot distinguish between colonization and infection. Previously, we described developing a sampling system for effectively capturing biomolecules from human breath. We identified a new class of proteoform markers of protease activation, termed proteolytic products of infection, for detecting LRTIs in people with mechanical ventilation. Here, we further developed an in vitro assay by designing a specific substrate sensor for human neutrophil elastase (HNE) to detect LRTIs in breath samples. In the proof-of-concept study, we then applied this in vitro assay to breath samples collected from intubated patients and healthy volunteers. The findings revealed that the LRTI group demonstrated a significant mean differential, showing a 9.8-fold elevation in measured HNE activity compared with the non-LRTI group and a 9.2-fold compared with healthy volunteers. The in vitro assay's diagnostic potential was assessed by constructing a receiver operating characteristic curve, resulting in an area under the curve of 0.987. Using an optimal threshold for HNE at 0.2 pM, the sensitivity was determined to be 1.0 and the specificity to be 0.867. Further correlation analysis revealed a strong positive relationship between the measured HNE activity and the protein concentration in the breath samples. Our results demonstrate that this breath-based in vitro assay provides high diagnostic performance for LRTIs, suggesting that the technology may be useful in the near term for the accurate diagnosis of LRTIs.

Carbon-Nanotube-Based Optical Fiber Sensor With Rapid Response for Human Breath Monitoring and Voiceprint Recognition

Carbon-Nanotube-Based Optical Fiber Sensor With Rapid Response for Human Breath Monitoring and Voiceprint Recognition

The detection of acetone in exhaled breath using gas Pre-Concentrator by modified Metal-Organic framework nanoparticles

Volatile organic compounds (VOCs) from exhaled breath are promising indicators for the diagnostics of human health conditions. However, the composition of breath is rather complex, including water vapors and various tiny amounts of gases and biomarkers. Pre-concentrator plays a significant role in capturing and concentrating target gas in the gas mixture. In this work, the MIL-101 (Cr) nanoparticles are coated with polydimethylsiloxane (PDMS) through physical vapor deposition process to concentrate acetone under high humidity and room temperature. Experimentally, the newly developed material exhibits significant improvement in signal intensity that is 76.3 times greater than a commercial reference material under relative humility of 80 %. The detection range is also proven to be desirable (from 100 ppb to 2500 ppb), capturing the spectrum of acetone concentrations typically found in human exhaled breath. Moreover, following a thermal desorption process, the device demonstrates a high degree of linearity with a coefficient of 0.9956. The modified metal–organic framework materials are made into a flexible thin-film-shape device, that could be embedded in a facemask. The proposed device could meet the critical requirements for sampling, concentrating and detecting of exhaled breath biomarkers, thereby opening a new opportunity as part of the flexible electronic systems on face masks to facilitate quantitative breath analyses.

Assemble and validation of a simulated device of human exhaled breath aerosols for screening of illicit drug abuse by HPLC-TQ-MS/MS detection

Collecting exhaled breath aerosols (EBA) as a sample has a great potential to monitoring illicit drug abuse due to advantages of simple, non-invasiveness and unrestricted sampling. However, scarcity of positive samples has cramped development of more efficient techniques for monitoring illicit drug abuse in EBA. In this work, a simulated human exhaled breath aerosol (SHEBA) generating device based on Venturi jet principle was constructed by integrating nebulizing unit and collection unit to prepare positive EBAs. By means of ultra high-performance hyphenated with triple quadrupole tandem mass spectrometry (HPLC-TQ-MS/MS), using caffeine as a target drug, the device parameters were investigated by studying the effects of flow rates of nebulizing and auxiliary gases, drug concentration and etc., the performance was further validated by commonly abused drugs such as amphetamines (AMP, MAMP, MDA and MDMA). Electret material as adsorbent was used to collect SHEBAs generated by the device, achieving HPLC-TQ-MS/MS detection of the captured drugs at 40.0–2000.0 pg/filter. By this way, caffeine content in EBAs from six volunteers was successfully detected in the range of 51.6 ± 6.8–708 ± 51 pg/filter after drinking the caffeinated beverage. These validation experiments proved that SHEBA generating device could not only meet to the requirement of EBA analysis for illicit drug abuse at trace levels, but also provide the correction factors to calibrate the lower detection value caused by incomplete material adsorption.

Functionalized N95 Face Mask with a Chemical-Free Paper-Based Collector for Exhaled Breath Analysis: SARS-CoV-2 Detection with a Printed Immunosensor as a Case Study.

Exhaled breath electrochemical sensing is a promising biomedical technology owing to its portability, painlessness, cost-effectiveness, and user-friendliness. Here, we present a novel approach for target analysis in exhaled breath by integrating a comfortable paper-based collector into an N95 face mask, providing a universal solution for analyzing several biomarkers. As a model analyte, we detected SARS-CoV-2 spike protein from the exhaled breath by sampling the target analyte into the collector, followed by its detection out of the N95 face mask using a magnetic bead-based electrochemical immunosensor. This approach was designed to avoid any contact between humans and the chemicals. To simulate human exhaled breath, untreated saliva samples were nebulized on the paper collector, revealing a detection limit of 1 ng/mL and a wide linear range of 3.7-10,000 ng/mL. Additionally, the developed immunosensor exhibited high selectivity toward the SARS-CoV-2 spike protein, compared to other airborne microorganisms, and the SARS-CoV-2 nucleocapsid protein. Accuracy assessments were conducted by analyzing the simulated breath samples spiked with varying concentrations of SARS-CoV-2 spike protein, resulting in satisfactory recovery values (ranging from 97 ± 4 to 118 ± 1%). Finally, the paper-based hybrid immunosensor was successfully applied for the detection of SARS-CoV-2 in real human exhaled breath samples. The position of the collector in the N95 mask was evaluated as well as the ability of this paper-based analytical tool to identify the positive patient.

Flexible wearable fiber optic sensor for real-time human breath monitoring based on Fabry-Perot interferometer with agar film.

A flexible wearable sensor based on the Fabry-Perot (FP) structure for human breath monitoring is proposed and demonstrated. This sensor is constructed by fusing a single-mode optical fiber to a small section of capillary and coating the end with agar film. In high relative humidity (RH) environments, the agar film absorbs moisture from the air, which leads to a change in the length of the FP cavity to cause a shift in the interference spectrum. The sensor has a sensitivity of 0.95 nm/%RH for testing RH in the range of 60%RH to 85%RH. The temperature sensitivity of the sensor varies nonlinearly from 30°C to 90°C, averaging 0.34 nm/°C over the range of 30°C to 55°C and 0.06 nm/°C over the range of 60°C to 90°C. The temperature and RH crosstalk problems can be solved by using cascaded fiber Bragg grating followed by matrix operations to monitor temperature and RH parameters simultaneously. In addition, the sensor has a fast response time of 0.88 s and a recovery time of 1.17 s for human breathing. The normal and deep breathing of nine subjects are monitored using the sensor, demonstrating that the sensor is able to recognize normal and deep breathing accurately. The success of this sensor proves that it is feasible to develop sensors with good resistance to vibration interference, good repeatability and high stability for human breath monitoring, which is of great significance for research on human breath monitoring.

Systematic study of polymer gas sampling bags for offline analysis of exhaled breath

Polymeric bags are a widely applied, simple, and cost-effective method for the storage and offline analysis of gaseous samples. Various materials have been used as sampling bags, all known to contain impurities and differing in their cost, durability, and storage capabilities. Herein, we present a comparative study of several well-known bag materials, Tedlar (PVF), Kynar (PVDF), Teflon (PTFE), and Nalophan (PET), as well as a new material, ethylene vinyl copolymer (EVOH), commonly used for storing food. We investigated the influences of storage conditions, humidity, bag cleaning, and light exposure on volatile organic compound concentration (acetone, acetic acid, isoprene, benzene, limonene, among others) in samples of exhaled human breath stored in bags for up to 48 h. Specifically, we show high losses of short-chain fatty acids (SCFAs) in bags of all materials (for most SCFAs, less than 50% after 8 h of storage). We found that samples in Tedlar, Nalophan, and EVOH bags undergo changes in composition when exposed to UV radiation over a period of 48 h. We report high initial impurity levels in all the bags and their doubling after a period of 48 h. We compare secondary electrospray ionization and proton transfer reaction mass spectrometry in the context of offline analysis after storage in sampling bags. We provide an analytical perspective on the temporal evolution of bag contents by presenting the intensity changes of all significantm/zfeatures. We also present a simple, automated, and cost-effective offline sample introduction system, which enables controlled delivery of collected gaseous samples from polymeric bags into the mass spectrometer. Overall, our findings suggest that sampling bags exhibit high levels of impurities, are sensitive to several environmental factors (e.g. light exposure), and provide low recoveries for some classes of compounds, e.g. SCFAs.

Wearable Masks Integrated with Conducting Polymer and Carbon-Based Nanomaterials for VOC and Breath Monitoring

There has been considerable effort to develop wearable electronics from life-supporting devices for solders to fashion accessories such as smartwatches. The research of gas sensors has also attempted to adapt wearables with the power of nanotechnology. On the wearable platform, miniature gas sensors will provide real-time information about the atmosphere to protect each personnel from possible hazardous chemical attacks. In addition, wearable gas sensors can be facilitated to monitor human’s breath as medical applications. [1] Continuous monitoring of respiratory rate in real-time can act as a crucial benchmark for non-invasively detecting cardiac or arterial vascular function. Anomalies in respiratory rate serve as a significant indicator of a patient's health deterioration. Furthermore, it has been reported that aberrations in respiratory rate, as a physiological parameter, can be utilized to monitor common COVID-19 symptoms [2]. The analysis of breath through identifying biomarkers in exhaled breath proves to be an effective method for assessing metabolic disorders or dysfunctions in the human body. Conducting polymers (CPs) have generated significant interest in constructing flexible gas sensors. The inherent issue with pure CPs lies in their tendency to deprotonate in the presence of air, leading to a notable decline in long-term stability. Furthermore, limited gas response on diverse gaseous species demands the exploration of hybridizing CPs and other nanomaterials. When nanomaterials are hybridized with CPs, a synergistic effect, which comes from the benefits of each material, can improve sensing performance.In this study, polyaniline (PANI) conducting polymer and carbon-based nanomaterials, including carbon nanotubes (CNTs), graphene, or MXene were synthesized in a composite form and deposited into disposable masks. The developed gas sensor demonstrates remarkable stability attributed to the presence of van der Waals forces and π–π interactions between carbon-based nanomaterials and polyaniline (PANI). This stability is crucial for its reliable performance over time. The sensor's sensitivity is notably improved due to enhanced charge transfer channels and a porous structure that facilitates the adsorption of target gas. Additionally, the composite sensors detect breathing patterns in real-time, which demonstrates noninvasive human breath monitoring. A noteworthy aspect is that a significant portion of breath signals originates from the presence of target gases and moisture in exhaled breath. Although volatile sulfur compounds, CO2, and volatile organic compounds in the exhaled breath have a minimal influence on the sensing signals, the sensor remains highly responsive to the key components, particularly target gas by selecting carbon-based nanomaterials [3, 4]. The proposed gas sensing mechanism of the CP-based composites is discussed.

Evaluation of tetrachloroethylene (PCE) and its degradation products in human exhaled breath and indoor air in a community setting

Tetrachloroethylene (PCE) is a widely utilized volatile chemical in industrial applications, including dry cleaning and metal degreasing. Exposure to PCE potentially presents a significant health risk to workers as well as communities near contamination sites. Adverse health effects arise not only from PCE, but also from PCE degradation products, such as trichloroethylene (TCE) and vinyl chloride (VC). PCE, TCE, and VC can contaminate water, soil, and air, leading to exposure through multiple pathways, including inhalation, ingestion, and dermal contact. This study focused on a community setting in Martinsville, Indiana, a working-class Midwestern community in the United States, where extensive PCE contamination has occurred due to multiple contamination sites (referring to 'plumes'), including a Superfund site. Utilizing proton transfer reaction time-of-flight mass spectrometry (PTR-TOF-MS), PCE, TCE, and VC concentrations were measured in the exhaled breath of 73 residents from both within and outside the plume areas. PCE was detected in 66 samples, TCE in 26 samples, and VC in 68 samples. Our results revealed a significant positive correlation between the concentrations of these compounds in exhaled breath and indoor air (Pearson correlation coefficients: PCE = 0.75, TCE = 0.71, and VC = 0.89). This study confirms the presence of PCE and its degradation products in exhaled breath in a community exposure investigation, demonstrating the potential of using exhaled breath analysis in monitoring exposure to environmental contaminants. This study showed the feasibility of utilizing PTR-TOF-MS in community investigations to assess exposure to PCE and its degradation products by measuring these compounds in exhaled breath and indoor air.

Application of silicon nanowires in sensors of temperature, light and humidity

Resistive and capacitive types of sensors based on silicon nanowires (SiNWs) for measuring of physical quantities have been manufactured. Silicon nanowires were obtained through a two-step metal-assisted chemical etching (MACE) method. The surface morphology of the silicon nanowire array was investigated using atomic force microscopy (AFM) and scanning electron microscopy (SEM). The impact of SiNWs synthesis parameters on sensor sensitivity has been investigated. In particular, the influence of deposition time of AgNPs and etching time of silicon, as well as the content of H2O2 in the etchant, preliminary texturing of the substrate, and additional post-processing in isotropic/anisotropic etchant after the MACE process, on the characteristics of physical quantity sensors has been determined. Static and dynamic parameters were calculated for the obtained sensors. To compare the obtained sensors, physical sensors without SiNWs were manufactured. The highest response value for temperature sensors was 132, which is two orders of magnitude better than for sensors without SiNWs. The presence of SiNWs on the surface of the sensor led to an increase in the response value by about two orders of magnitude for all types of sensors. The speed of humidity sensors improved by 3–4 times, and for temperature and light sensors by an order of magnitude. Further device applications include of multi-parameter sensors, human breath sensors, and solar radiation power sensors.

Impact of human micro-movements on breathing zone and thermal plume formation

To enhance the realism and precision of indoor environment assessments and the evaluation of human health risks using computational fluid dynamics (CFD), it is crucial to accurately replicate human shape and physiological functions. This study investigates the influence of micro-movements resulting from posture control on the human breathing zone (BZ) using CFD analysis. A Computer-Simulated Person (CSP) incorporating a sophisticated nasal cavity model and multi-node thermoregulation was employed to precisely predict the microclimate around the human body, including the BZ. Two types of movements were considered to replicate micro-movements of a standing human body: angular and linear movements. The BZs were evaluated based on the Scale for Ventilation Efficiency (SVE) 4 and 5 for exhalation and inhalation modes, respectively. While the distribution of exhaled air remained generally consistent, distinct differences were observed in inhaled air distribution. In a representative case with a maximum angular velocity of 4°/s, the horizontal length increased by 12 cm, and the vertical distance of the SVE5>10 % distribution decreased by 14 cm compared to the stationary case. Linear movement, particularly in the mediolateral (ML) direction, led to a horizontal expansion of the inhaled air distribution. The findings of this study suggest that replicating human micro-movements has a minimal impact on general indoor climate analysis but significantly enhances the accuracy of predicting breathing air quality.

Correlation of Fine Particulates and Meteorological Parameters in Indoor Public Schools Environment within Benin City, Edo State, Nigeria

This study focused on the correlation of fine particulates and meteorological parameters in indoor public school environments, in Benin City, Edo State, Nigeria. Thirty public schools (17 primary and 13 secondary) were selected for the study. The PM2.5 samples were taken 1.5 – 2.0 meters within the human breathing zone. The sampling was done using an Apex 21 S Casella regular pump with a conical inhalable sampling (CIS) head for eight hours at a flow rate of 3.5L per minute (LPM). The 37-diameter quartz filters were processed in a muffle furnace for four hours at 450 – 500 oC before sampling and weighing afterward. The results obtained showed variations in the meteorological parameters with a range of temperature from 28.52 – 29.82°C. The relative humidity ranged from 84.22 – 427.78%; pressure was 1006.70 - 5052.87 mmHg; wind speed was 4.13 – 1660.88 Km/h and dew point was 24.7 – 3293.56%. The correlation coefficient showed a positive relationship exists in meteorological parameters between primary and secondary schools’ sources of enrichment. The PM2.5 mass concentration had the range of 135 – 785.31 µg/m3 which were above the stationary limits of 25 µg/m3 and 35 µg/m3 stipulated by the National Ambient Air Quality Standards and World Health Organization, respectively. These call for greater attention to alleviate all negative outcomes of environmental health issues.