Indoor Air Particulate Matter Research Articles

Advancing Methodologies for Investigating PM2.5 Removal Using Green Wall System.

Combustion processes are the primary source of fine particulate matter in indoor air. Since the 1970s, plants have been extensively studied for their potential to reduce indoor air pollution. Leaves can retain particles on their surfaces, influenced by factors such as wax content and the presence of hairs. This study introduces an innovative experimental approach using metal oxide particles in an office-like environment to evaluate the depolluting effect of plant walls. Two plant walls were installed in a controlled room, housing three plant species: Aglaonema commutatum 'Silver Bay', Dracaena fragrans, and Epipremnum aureum. Metal oxide particles were introduced via a compressed air blower positioned between the two walls. The concentration of these particles was monitored using PM2.5 sensors, and the deposition of iron (Fe) on the leaves was quantified through Inductively Coupled Plasma Mass Spectrometry (ICP-MS). This novel methodology effectively demonstrated the utility of both real-time sensors and ICP-MS in quantifying airborne particle concentrations and leaf deposition, respectively. The results revealed that Dracaena fragrans had a 44% higher Fe particle retention rate compared to the control (wallpaper). However, further validation through methodological replication is necessary to confirm the reproducibility of these findings.

Mitigation strategies to reduce particulate matter concentrations in civil engineering laboratories

In the departments of civil engineering, many experiments are conducted in laboratories for educational and research purposes. Varying degrees of respirable dust are generated as the outcome of these experiments, which could cause harm to instructors’ and students’ health. This study is devised to highlight the importance of indoor air quality in university laboratories. As part of the research, four different particulate matter (PM) sizes (PM1.0, PM2.5, PM4.0, and PM10) were measured during specific experiments—sieve analysis, preparation of the concrete mixture, crushing aggregate by jaw crusher, dynamic triaxial compression test, sieve analysis of silt specimen, cleaning sieve by an air compressor, and proctor compaction test—being conducted periodically in the laboratories of civil engineering departments. The measured values are mainly high compared to indoor air quality standards. Mitigation strategies were applied to reduce indoor air PM levels in the three experiments that contained the highest PM levels. The results have shown that mitigation strategies applied as control measures could make a remarkable difference in protecting instructors and civil engineering students.

Dichotomy of predictor variables of indoor air quality and prevailing public perception of green living space – A preliminary assessment

Indoor environmental quality has a profound effect on human health and productivity. In this respect, this study evaluates indoor air quality in terms of its various parameters in sustainably built homes in three different locations. A supplementary study to examine the formaldehyde emission levels from furniture with three different finishes was also undertaken. A questionnaire-based survey was then conducted to evaluate the general public perception of the prevailing indoor air quality in the three locations. The results revealed that temperature, relative humidity, indoor air speed, particulate matter (PM10), CO2, NO2, and total volatile organic compounds (TVOC) and formaldehyde (HCHO) readings were not significantly different between the three locations and were below the existing limit allowed for indoor environmental quality. However, the HCHO emission was the highest from furniture with the two-layer coatings, followed by single layer coating, and finally the furniture with the veneer overlay. It was noteworthy that the general public’s awareness and knowledge of indoor air quality was relatively poor, except for the tertiary level educated respondents. In this regard, policymakers need to increase the awareness and knowledge of indoor environmental quality among the general public, if non-compliance is to be detected and promptly addressed.

Indoor Air Factors Affecting the Growth of Microorganism in an Indonesian Gas Company’s Dormitory

Introduction: Mold may affect the Indoor Air Quality (IAQ) in workplace dormitories. This study aims to investigate indoor air factors that affect molds growth in a dormitory of an LNG Company in Indonesia. Several indoor air determinant factors, including relative humidity, general temperature, wet temperature, dry temperature, air velocity, illumination, particulate matter, and carbon dioxide concentration were assessed against the growth of microorganism colonies. Methods: This study was a cross-sectional study using a 2 (two)-stage Andersen sampler based on NIOSH 0800 Bioaerosol Sampling Method for Indoor Air Quality for viable bioaerosol sampling. Bioaerosol samples were collected from 50 indoor, corridor, and outdoor sampling points. The total colony count for bioaerosols (TCC) was then determined (CFU/m3). Ten indoor air quality parameters, i.e., relative humidity, general temperature, wet temperature, dry temperature, air velocity, illumination, particulate matter, and carbon dioxide concentration, were measured. Results: The average mold colony concentration in the dormitory rooms was higher (703.1 CFU/m3) than the maximum standard issued by the Ministry of Health of the Republic of Indonesia (< 700 CFU/m3) while the relative humidity was very high (84.4% RH on average), with a direct relation between the humidity and the mold colony concentration. A significant correlation was also identified between mold colony concentration, wet temperature, and CO2 concentration. Conclusion: Significant correlations between bioaerosols, relative humidity, wet temperature, and indoor CO2 concentration indicate insufficient ventilation and poor indoor air quality in the dormitory.

Can data reliability of low-cost sensor devices for indoor air particulate matter monitoring be improved? – An approach using machine learning

Poor indoor air quality has adverse health impacts. Children are considered a risk group, and they spend a significant time indoors at home and in schools. Air quality monitoring has traditionally been limited due to the cost and size of the monitoring stations. Recent advancements in low-cost sensors technology allow for economical, scalable and real-time monitoring, which is especially helpful in monitoring air quality in indoor environments, as they are prone to sudden peaks in pollutant concentrations. However, data reliability is still a considerable challenge to overcome in low-cost sensors technology. Thus, following a monitoring campaign in a nursery and primary school in Porto urban area, the present study analyzed the performance of three commercially available low-cost IoT devices for indoor air quality monitoring in real-world against a research-grade device used as a reference and developed regression models to improve their reliability. This paper also presents the developed on-field calibration models via machine learning technique using multiple linear regression, support vector regression, and gradient boosting regression algorithms and focuses on particulate matter (PM1, PM2.5, PM10) data collected by the devices. The performance evaluation results showed poor detection of particulates in classrooms by the low-cost devices compared to the reference. The on-field calibration algorithms showed a considerable improvement in all three devices' accuracy (reaching up to R2 > 0.9) for the light scattering technology based particulate matter sensors. The results also show the different performance of low-cost devices in the lunchroom compared to the classrooms of the same school building, indicating the need for calibration in different microenvironments.

Laboratory Determination of Gravimetric Correction Factors for Real-time Area Measurements of Electronic Cigarette Aerosols.

Research on secondhand electronic cigarette (ECIG) aerosol exposure using aerosol monitors has demonstrated that ECIG use can generate high concentrations of particulate matter (PM) and impact indoor air quality. However, quantifying indoor air PM concentrations using real-time optical monitors with on-site calibration specifically for different PM exposures has not been established. Therefore, the ECIG aerosol filter correction factors were calculated for different PM sizes (PM1, PM2.5, and PM10) and different aerosol optical monitors, the MiniWRAS, pDR, and SidePak. ECIG aerosol generation was achieved using five ECIGs representing three ECIG types, disposable, pod-mod, and box mod. The aerosol size distribution by mass was measured for the five ECIGs during PM generation. Compared to the discrete filter measurements, the MiniWRAS performed the best when the concentrations were low, followed by the pDR and SidePak. The average PM concentrations and correction factor ranges for the different ECIGs were 323-1,775 μg/m3 and 0.64-6.01 for the MiniWRAS, 1,388-13,365 μg/m3 and 0.41-0.80 for the pDR, and 4,632-55,339 μg/m3 and 0.13-0.20 for the SidePak, respectively. The mass median diameter ranged from 0.41 and 0.62 μm, and most particles generated from the ECIGs were smaller than 1 μm. This study demonstrates that aerosol size distribution varies between ECIGs. Likewise, the correction factors developed for the real-time aerosol monitors are specific to the ECIG used. Thus, these data can help improve ECIG aerosol exposure measurement accuracy.

Toxicological transcriptome of human airway constructs after exposure to indoor air particulate matter: In search of relevant pathways of moisture damage-associated health effects.

Multiple health effects are associated with moisture damage in buildings. Studies explaining these associations and cell-level mechanisms behind the observed health effects are urgently called for. We focused on characterizing gene expression in human airway epithelium after exposure to indoor air particulate matter (PM) sampled from houses with and without moisture damage, alongside determination of general toxicological markers. We performed detailed technical building inspections in 25 residential houses and categorized them based on the detection of moisture damages and the probability of occupant exposure. PM sampling was complemented by microbiological and volatile organic compound assessment. We exposed human airway constructs to three dilutions (1:16, 1:8, 1:4) of collected PM from moisture-damaged (index) and non-moisture-damaged (reference) houses and imaged selected constructs with electron microscopy. We analyzed general toxicological markers and the RNA of exposed constructs was sequenced targeting genes associated with toxicological pathways. We did groupwise comparisons between index and reference houses and pairwise comparisons in matched index/reference houses. In groupwise comparison, gene Cytochrome P450 Family 1 Subfamily A Member 1 (CYP1A1) was statistically significantly over-expressed in index houses at all dilutions of collected PM and Nuclear Factor Kappa B Subunit 1 (NFKB1) at dilution 1:4 of collected PM. In pairwise index/reference house comparison, several genes related to multiple toxicological pathways were activated, largest expression differences seen for CYP1A1. However, none of the genes was consistently expressed in all the matched pairs, and general toxicological markers did not differentiate index and reference houses. The exposure to PM from index houses activated toxicology -related genes in airway constructs. Differential expression was not consistent among all the index/reference pairs, possibly due to compositional differences of bioactive particles. Our study highlights CYP1A1 and NFKB1 as potential targets in moisture damage -associated cellular responses.

Genotoxic and inflammatory effects of spruce and brown coal briquettes combustion aerosols on lung cells at the air-liquid interface

Solid fuel usage in residential heating and cooking is one of the largest sources of ambient and indoor air particulate matter, which causes adverse effects on the health of millions of peoples worldwide. Emissions from solid fuel combustion, such as biomass or coal, are detrimental to health, but toxicological responses are largely unknown. In the present study, we compared the toxicological responses regarding cytotoxicity, inflammation and genotoxicity of spruce (SPR) and brown coal briquette (BCB) combustion aerosols on human alveolar epithelial cells (A549) as well as a coculture of A549 and differentiated human monocytic cells (THP-1) into macrophages exposed at the air-liquid interface (ALI). We included both the high emissions from the first hour and moderate emissions from the third hour of the batch combustion experiment in one ALI system, whereas, in the second ALI system, we exposed the cells during the whole 4-hour combustion experiment, including all combustion phases. Physico-chemical properties of the combustion aerosol were analysed both online and offline. Both SPR and BCB combustion aerosols caused mild cytotoxic but notable genotoxic effects in co-cultured A549 cells after one-hour exposure. Inflammatory response analysis revealed BCB combustion aerosols to cause a mild increase in CXCL1 and CXCL8 levels, but in the case of SPR combustion aerosol, a decrease compared to control was observed.

Effect of Seasonal Variation on the Relationship of Indoor Air Particulate Matter with Measures of Obesity and Blood Pressure in Children.

Background.Particulate matter (PM) air pollution is an important environmental health risk factor. Although some studies have shown PM to be associated with obesity and hypertension, very few studies have assessed the association of indoor PM specifically with obesity and blood pressure measures in children with respect to seasonal variation.Objectives.The present study investigated the relationship of PM with obesity and blood pressure variables in children across the winter and summer seasons.Methods.A comparative descriptive approach was adopted and school children from 10–14 years of age from selected rural and urban localities of the Eastern Cape Province of South Africa were assessed in winter and summer. Anthropometric measurements were taken, including height, weight, waist circumference, body mass index (BMI), and total fat mass (TFM), while blood pressure variables including systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR) were measured. Indoor air PM concentrations were measured in the classrooms in the presence of children.Results.The prevalence of obesity and hypertension in children were 13.4% and 5.1% in winter and 12.9% and 1.0% in summer, respectively. High blood pressure was more prevalent in children in rural areas, while the prevalence of obesity in children was higher in urban areas. Particulate matter was significantly (p<0.05) higher in rural areas compared to urban areas. Obese children in summer had a greater than 3-fold association (AOR: 3.681, p=0.005) with 4th interquartile range (IQR) of PM5 and a greater than 3- and 4-fold association (AOR: 3.08; 4.407; p<0.05) with 2nd and 4th IQR of PM10, respectively, than their overweight, normal weight or underweight counterparts. High blood pressure was not associated (p< 0.05) with PM.Conclusions.High concentrations of indoor PM were positively associated with obesity in children in summer, particularly among rural children. This association could be accounted for by location and seasonal differences.Participant Consent.ObtainedEthics Approval.Ethics approval was obtained from the Health Sciences Ethics Committee of Walter Sisulu University, South Africa (Ref No: CHI011SCHU01).Competing Interests.The authors declare no competing financial interests.

Real-time air monitoring of occupational exposures to particulate matter among hairdressers in Maryland: A pilot study.

Hairdressers are exposed to particulate matter (PM), a known air pollutant linked to adverse health effects. Still, studies on occupational PM exposures in hair salons are sparse. We characterized indoor air PM concentrations in three salons primarily serving an African/African American (AA) clientele, and three Dominican salons primarily serving a Latino clientele. We also assessed the performance of low-cost sensors (uRAD, Flow, AirVisual) by comparing them to high-end sensors (DustTrak) to conduct air monitoring in each salon over 3days to quantify work shift concentrations of PM2.5 , respirable PM (RPM), and PM10 . We observed high spatial and temporal variability in 30-min time-weighted average (TWA) RPM concentrations (0.18-5518μg/m3 ). Readings for the uRAD and AirVisual sensors were highly correlated with the DustTrak (R2 =0.90-0.99). RPM 8-hour TWAs ranged from 18 to 383µg/m3 for AA salons, and 9-2115µg/m3 for Dominican salons. Upper 95th percentiles of daily RPM exposures ranged from 439 to 2669µg/m3 . The overall range of 30-min TWA PM2.5 and PM10 concentrations was 0.13-5497 and 0.36-,541μg/m3 , respectively. Findings suggest that hairdressers could be overexposed to RPM during an 8-hour shift. Additional comprehensive monitoring studies are warranted to further characterize temporal and spatial variability of PM exposures in this understudied occupational population.

Detailed Analysis of Thermal Comfort and Indoor Air Quality Using Real-Time Multiple Environmental Monitoring Data for a Childcare Center

Thermal comfort, indoor air quality (IAQ), and energy use are closely related, even though these have different aspects with respect to building performance. We analyzed thermal comfort and IAQ using real-time multiple environmental data, which include indoor air temperature, relative humidity, carbon dioxide (CO2), and particulate matter (e.g., PM10 and PM2.5), as well as electricity use from an energy recovery ventilation (ERV) system for a childcare center. Thermal comfort frequency and time-series analyses were conducted in detail to thoroughly observe real-time thermal comfort and IAQ conditions with and without ERV operation, and to identify energy savings opportunities during occupied and unoccupied hours. The results show that the highest CO2 and PM10 concentrations were reduced by 51.4% and 29.5%, respectively, during the occupied hours when the ERV system was operating. However, it was also identified that comfort frequencies occurred during unoccupied hours and discomfort frequencies during occupied hours. By analyzing and communicating the three different types of real-time monitoring data, it is concluded that the ERV system should be controlled by considering not only IAQ (e.g., CO2 and PM2.5) but also thermal comfort and energy use to enhance indoor environmental quality and save energy based on real-time multiple monitoring data.

Experimental Study on Purification of Indoor Air Particulate Matter by Household Air Conditioner

The most common indoor air pollutants are particulate matter. However, existing indoor air purification techniques have many drawbacks. Admittedly, the low-temperature condensation method can be regarded as an effective method to remove particulate matter. In this paper, experiments are designed to examine the concentration reduction efficiency of PM2.5 and PM10 in the room by using air conditioner. The experimental results showed that household air conditioners have a purification effect on particulate matter. Under the refrigeration mode of maximum air volume, the concentration reduction efficiency of PM2.5 and PM10 reaches 60.99% and 57.47% respectively. The greater the volume of the air, the higher the concentration reduction efficiency of particulate matter. In the purification of PM2.5 and PM10 by household air conditioner, low-temperature condensation plays an important role. It can be suggested that the amount of condensed water affects the concentration reduction efficiency of PM2.5 and PM10 in the room.

Polycyclic aromatic compounds in particulate matter and indoor dust at preschools in Stockholm, Sweden: Occurrence, sources and genotoxic potential in vitro

Children spend a significant amount of their day in preschool; thus, environmental quality at preschools may have an impact on children's health. In the present study, we analyzed polycyclic aromatic compounds (PACs), including PAHs, alkylated PAHs and oxygenated PAHs (OPAHs), in indoor and outdoor air particulate matter (PM10) and indoor dust at preschools in Stockholm, Sweden. There were significant correlations between PAC levels in outdoor and indoor PM10, with in general higher PAC levels outdoors. Fluoranthene and pyrene were detected at highest levels in all sample types, although phenanthrene and methylated phenanthrene derivatives also were found at high levels in indoor dust. In addition, the highly carcinogenic PAHs 7H-benzo[c]fluorene, 7,12-dimethylbenz[a]anthracene, benz[j]aceanthrylene, and dibenzo[a,l]pyrene were detected in some samples. Benzanthrone was the most prevalent OPAH in PM10 samples and 9,10-anthraquinone in indoor dust. Based on diagnostic ratios and Positive Matrix Factorization we identified vehicle emission and biomass burning as important PAC sources for all samples analyzed. However, poor correlation between PAC levels in indoor PM10 and indoor dust suggested additional sources for the latter. Measuring activation of DNA damage signaling in human cells exposed to organic extracts of the samples indicated substantial genotoxic potential of outdoor PM10 and indoor dust. Determination of benzo[a]pyrene equivalents demonstrated that the highly potent PAHs benz[j]aceanthrylene and dibenz[a,h]anthracene contributed more than 20% to the total carcinogenic potency of the samples. We conclude that PAC levels at Stockholm preschools are relatively low but that outdoor air quality may impact on the indoor environment.

Comprehensive Evaluation on the Removal Performance of Air Cleaners for Indoor Air Pollution

Portable air cleaners (PACs) are widely used as the most effective strategies to improve indoor environment. However, with the indoor air components have become more complicated, the current studies focusing on the removal performance for composite pollutants have been inadequate. Therefore, it is necessary to evaluate the comprehensive removal performance of PACs by mixture that is mainly existed in indoor air. In this study, the initial clean air delivery rates (CADRs) of several best-selling sorption-based air cleaners in Chinese market were calculated with a mixing model. The results indicated that the PACs displayed a reliable performance in improving indoor air quality, especially in terms of particulate matter purification. Furthermore, the removal performance of volatile organic compounds (VOCs) by air cleaners was found to be negatively correlated with molecular weight and polarity of pollutant, and the PACs removal performance for most VOCs was improved by reducing the concentration of particulate matter in indoor air.

Assessment of Ventilation Efficiency in School Classrooms Based on Indoor–Outdoor Particulate Matter and Carbon Dioxide Measurements

The concentration of indoor suspended particulate matter is considered to be one of the main factors that affect health and quality of life. In Poland, in response to the pressure of public opinion, a few thousand air purifiers have been installed in public buildings where children spend time. However, another factor that also impacts upon the quality of indoor air, namely increased CO2 mixing ratios, is frequently overlooked. The only way to remove CO2 excess from interiors is through intensive ventilation. This is often an action at odds with the need to maintain low concentrations of particulate matter in indoor air. Two methods are presented to assess the rate of air exchange using CO2 or particulate matter as a tracer. One of the methods using indoor/outdoor PM (particulate matter) concentrations is based on the use of box models for analysis. The second one uses indoor CO2 concentration change analysis. At the tested locations, they showed large deviations of the determined values of the air exchange coefficients from its limits. Both methods showed consistent ventilation parameters estimation.

Metabolic linkages between indoor negative air ions, particulate matter and cardiorespiratory function: A randomized, double-blind crossover study among children

BackgroundIonization air purifiers, which purify particulate matter (PM) by producing vast number of negative air ions (NAI), are widely used. Recent study implied that ionization air purification could bring respiratory benefits but deterioration of heart rate variability (HRV). However, its underlying molecular mechanisms remain unclear. ObjectivesTo explore the molecular linkages between indoor NAI, decreased PM and the cardiorespiratory effect after purification. MethodsUrine samples were collected from 44 healthy children three times of each study period (real and sham purification) in an existing randomized, double-blind crossover study. Ultra-high performance liquid chromatography/mass spectrometry was conducted in metabolomics analysis, the associations between indoor NAI, decreased PM and the cardiorespiratory function were investigated via the meet-in-metabolite approach (MIMA) based on statistical and metabolic pathway analysis. Mixed-effect models were used to establish associations between exposure, health parameters and metabolites. ResultsTwenty-eight and fourteen metabolites were identified with significant correlations to NAI and PM, respectively. Besides, eight and eighteen metabolites were separately associated with respiratory function and HRV. The increased NAI and decreased PM improved respiratory function mainly with eight pathways, promoting energy production, anti-inflammation and anti-oxidation capacity. Decreased PM ameliorated HRV with six main pathways, increasing energy production and anti-inflammation capacity while increased NAI deteriorated HRV with five main pathways, lowering energy generation and anti-oxidation capacity. ConclusionsIncreased NAI and decreased PM ameliorated respiratory function by increasing energy production, improving anti-inflammation and anti-oxidation capacity. Decreased PM improved cardiac autonomic function by increasing energy production and anti-inflammation capacity, while these benefits were overcast by massive NAI via lowering energy generation and anti-oxidation capacity with different metabolic pathways.

Characterization and pro-inflammatory potential of indoor mold particles.

A number of epidemiological studies find an association between indoor air dampness and respiratory health effects. This is often suggested to be linked to enhanced mold growth. However, the role of mold is obviously difficult to disentangle from other dampness-related exposure including microbes as well as non-biological particles and chemical pollutants. The association may partly be due to visible mycelial growth and a characteristic musty smell of mold. Thus, the potential role of mold exposure should be further explored by evaluating information from experimental studies elucidating possible mechanistic links. Such studies show that exposure to spores and hyphal fragments may act as allergens and pro-inflammatory mediators and that they may damage airways by the production of toxins, enzymes, and volatile organic compounds. In the present review, we hypothesize that continuous exposure to mold particles may result in chronic low-grade pro-inflammatory responses contributing to respiratory diseases. We summarize some of the main methods for detection and characterization of fungal aerosols and highlight in vitro research elucidating how molds may induce toxicity and pro-inflammatory reactions in human cell models relevant for airway exposure. Data suggest that the fraction of fungal hyphal fragments in indoor air is much higher than that of airborne spores, and the hyphal fragments often have a higher pro-inflammatory potential. Thus, hyphal fragments of prevalent mold species with strong pro-inflammatory potential may be particularly relevant candidates for respiratory diseases associated with damp/mold-contaminated indoor air. Future studies linking of indoor air dampness with health effects should assess the toxicity and pro-inflammatory potential of indoor air particulate matter and combined this information with a better characterization of biological components including hyphal fragments from both pathogenic and non-pathogenic mold species. Such studies may increase our understanding of the potential role of mold exposure.

Indoor Particulate Matter From Smoker Homes Induces Bacterial Growth, Biofilm Formation, and Impairs Airway Antimicrobial Activity. A Pilot Study.

Background: Particulate matter (PM) air pollution causes deleterious health effects; however, less is known about health effects of indoor air particulate matter (IAP).Objective: To understand whether IAP influences distinct mechanisms in the development of respiratory tract infections, including bacterial growth, biofilm formation, and innate immunity. Additionally, we tested whether IAP from Iowa houses of subjects with and without recent respiratory exacerbations recapitulated the National Institute of Standards and Technology (NIST) IAP findings.Methods: To test the effect of NIST and Iowa IAP on bacterial growth and biofilm formation, we assessed Staphylococcus aureus growth and Pseudomonas aeruginosa biofilm formation with and without the presence of IAP. To assess the effect of IAP on innate immunity, we exposed primary human airway surface liquid (ASL) to NIST, and Iowa IAP. Lastly, we tested whether specific metals may be responsible for effects on airway innate immunity.Results: NIST and Iowa IAP significantly enhanced bacterial growth and biofilm formation. NIST IAP (whole particle and the soluble portion) impaired ASL antimicrobial activity. IAP from one Iowa home significantly impaired ASL antimicrobial activity (p < 0.05), and five other homes demonstrated a trend (p ≤ 0.18) of impaired ASL antimicrobial activity. IAP from homes of subjects with a recent history of respiratory exacerbation tended (p = 0.09) to impair ASL antimicrobial activity more than IAP from homes of those without a history respiratory exacerbation. Aluminum and Magnesium impaired ASL antimicrobial activity, while copper was bactericidal. Combining metals varied their effect on ASL antimicrobial activity.Conclusions: NIST IAP and Iowa IAP enhanced bacterial growth and biofilm formation. ASL antimicrobial activity was impaired by NIST IAP, and Iowa house IAP from subjects with recent respiratory exacerbation tended to impair ASL antimicrobial activity. Individual metals may explain impaired ASL antimicrobial activity; however, antimicrobial activity in the presence of multiple metals warrants further study.

Human airway construct model is suitable for studying transcriptome changes associated with indoor air particulate matter toxicity.

In vitro models mimicking the human respiratory system are essential when investigating the toxicological effects of inhaled indoor air particulate matter (PM). We present a pulmonary cell culture model for studying indoor air PM toxicity. We exposed normal human bronchial epithelial cells, grown on semi‐permeable cell culture membranes, to four doses of indoor air PM in the air‐liquid interface. We analyzed the chemokine interleukin‐8 concentration from the cell culture medium, protein concentration from the apical wash, measured tissue electrical resistance, and imaged airway constructs using light and transmission electron microscopy. We sequenced RNA using a targeted RNA toxicology panel for 386 genes associated with toxicological responses. PM was collected from a non‐complaint residential environment over 1 week. Sample collection was concomitant with monitoring size‐segregated PM counts and determination of microbial levels and diversity. PM exposure was not acutely toxic for the cells, and we observed up‐regulation of 34 genes and down‐regulation of 17 genes when compared to blank sampler control exposure. The five most up‐regulated genes were related to immunotoxicity. Despite indications of incomplete cell differentiation, this model enabled the comparison of a toxicological transcriptome associated with indoor air PM exposure.

Real-time Monitoring of Suspended Particulate Matter in Indoor Air: Validation and Application of a Light-scattering Sensor

ABSTRACT Since the 1950s, awareness of the impact of air pollution on human health has been growing. Of the many recognized air pollutants, suspended particulate matter has received the most attention, as both PM2.5 and PM10 can affect humans upon inhalation. Consequently, PM monitoring is critical to linking indoor pollution and exposure, and a validated measuring instrument is essential. Portable monitors, which track temporal changes in the aerosol mass concentration in real time, are a faster alternative to offline gravimetric techniques, which provide only averaged values. Hence, this study evaluated the performance of the DustTrak DRX aerosol monitor in assessing indoor air quality and validated its ability to measure complex aerosols. Three DustTrak units were used to measure different aerosols, e.g., ambient air, polystyrene latex (PSL) spheres, and environmental tobacco smoke (ETS), and the results were compared to those obtained with the standard gravimetric method. Notably, the bias of the DustTrak relative to the gravimetric method for ETS measurements ranged from 2% to 15% when a photometric calibration factor (PCF) of 0.38 was applied. Additionally, the working range of the tested units was established, and the limits of detection and quantification were found to be 5 and 15 µg m–3, respectively. Finally, in order to serve as an alternative to the gravimetric method, these instruments must be accredited for PM measurement in accordance with standards such as ISO 17025.