Indoor Air Quality Measurements Research Articles

A seasonal investigation of indoor air quality in relation to architectural features in government office buildings in Enugu, Nigeria

Indoor air quality (IAQ) is crucial to environmental health significantly impacting on the well-being and productivity of building occupants. Several studies have explored various aspects of IAQ in non-tropical regions but there is limited information on how seasonal variations affect IAQ in hot-humid climates like Enugu, Nigeria. This study investigated seasonal changes in key indoor air parameters including CO, CO2, HCHO, TVOC, temperature, RH, PM2.5, and AQI across rainy and dry seasons in 58 government offices in Enugu, and evaluated how these fluctuations relate to architectural features of the offices. Using a mixed-methods approach, data collection involved qualitative assessments of building design attributes alongside quantitative IAQ measurements taken with the BOSEAN T-Z01Pro detector. Seasonal variations were analyzed using paired T-tests, ANOVA, and regression models. The results revealed a marked increase in pollutant concentrations during the dry season (p < 0.001–0.005), resulting in a poorer air quality index compared to the rainy season. Architectural features accounted for 68.5% of the variability in AQI (R2 = 0.685, p = 0.000), with casement windows being significantly associated with better air quality (Exp B = -4.217, p = 0.013) These shows that the dry season poses a greater risk to IAQ which is worsened in offices where projecting windows were used, potentially impacting health and productivity. The study emphasizes the need to address seasonal IAQ differences when designing office buildings in tropical regions. Design architects can help reduce seasonal air quality challenges and support healthier, more productive indoor environments by incorporating ventilation strategies, such as the use of casement windows. Further research should include long-term monitoring across various settings and additional IAQ parameters for better understanding of IAQ dynamics.

IAQ and ventilation measurements at the “ZEB Laboratory” office building in Norway

This study aims to assess indoor environmental quality (IEQ) within a Zero Emission Building (ZEB) office in Norway, focusing on occupant impact (CO2, temperature, humidity) and materials/substances influence (formaldehyde, particulate matter (PM2.5), total volatile organic compounds (TVOC)). It presents a detailed data collection spanning 14 months from March 30th, 2022, to June 1st, 2023.Occupancy varied significantly, affecting measured indoor air quality (IAQ) parameters, with the lowest temperatures recorded on the second floor and specific areas like the canteen experiencing temperature drops during low usage times. Relative humidity levels remained over 20% in winter despite the building's low occupancy, a notable aspect given Norway's dry winters. PM2.5 levels stayed below World Health Organization (WHO) guidelines, indicating effective pollution management.The study also evaluates the impact of reducing the ventilation rates on IAQ, noting no significant IAQ compromise. An analysis correlating IAQ measurements with building occupants' satisfaction post-intervention revealed that temperature is the most significant factor affecting satisfaction levels, excluding acoustic satisfaction. Occupants generally reported satisfaction with the indoor environmental quality (IEQ), with specific dissatisfaction tied to thermal environment and IAQ, suggesting the importance of temperature control in occupant perception.This research not only provides valuable insights into IEQ management in Zero Energy and Zero Emission office buildings but also emphasizes the critical role of indoor temperature and the potential of wooden structures to stabilize humidity levels, contributing to occupant comfort and satisfaction.

Energy retrofits: Factors affecting a just transition to better indoor air quality

In comparison with other European countries, Ireland has a disproportionately high number of poorly performing energy-inefficient buildings. Consequently, Ireland has one of the most ambitious energy retrofit programmes in Europe. The aim of this study was to evaluate the impact of deep energy renovation measures i.e. (replacement of heating system and upgrade to building envelope) on indoor air quality, thermal comfort and ventilation in a sample of primarily social housing in Ireland. A mixed methods approach including measurement of indoor air quality and a thermal comfort questionnaire survey was employed. Indoor concentration measurements of PM2.5, carbon dioxide, formaldehyde, and radon along with measurements of air temperature and relative humidity were made (N=14). Occupants (n=56) completed a thermal comfort questionnaire survey pre- and post-retrofit. Data collection ran from autumn 2020 until autumn 2023.Thermal comfort improved post-retrofit along with occupant satisfaction with the indoor thermal environment and heating-systems. Post-retrofit, higher bedroom CO2, and higher PM2.5 concentrations were recorded in both living areas and bedrooms. Occupant behaviours e.g. blocking wall vents were significant predictors of poorer ventilation while smoking indoors was related to higher concentrations of PM2.5. In general, homes that had mechanical ventilation systems installed were better ventilated. Underventilation, as indicated by visible condensation or mould was observed in half of the social homes surveyed and reported by questionnaire respondents (26 %). Tailored communications to occupants regarding the important role of ventilation and indoor air quality is required as part of retrofit to optimise impacts on IEQ.

Evaluation of Sick Building Syndrome (SBS) Symptoms and Measurement of Indoor Air Quality (IAQ) Parameter in One of Hospital Building in Johor

This study assesses Sick Building Syndrome (SBS) symptoms and Indoor Air Quality (IAQ) parameters among hospital ward staff. Utilizing a thorough methodology, a questionnaire survey and IAQ monitoring were conducted, aligning with Department of Occupational Safety and Health (DOSH) guidelines. IAQ parameters are generally within limits, except for relative humidity which recorded values of 73.09-75.23% for Ward 16 and 62.33-71.13% for Ward 18. Respondents expressed concerns about room conditions, including temperature variations, unpleasant odours, and noise. Fatigue, difficulties concentrating, and various respiratory symptoms were prevalent, suggesting potential health issues linked to indoor pollutants. The findings underscore the urgency of addressing IAQ concerns to improve the well-being of patients and healthcare workers.

Seasonal indoor air quality, self-reported health and comfort amongst tenants living at Danish multi-family social housing sites

Studies have identified seasonal differences between the indoor environment and residents’ comfort, as well as an association between indoor air quality (IAQ) and residents’ overall health. Furthermore, measured IAQ is not always aligned with perceived IAQ. The HOME-Health study is a cross-sectional study with seasonal measurements of IAQ amongst residents living in social housing. The aim is to describe and analyse measured and perceived IAQ, and residents’ health symptoms. We found a lower relative humidity, temperature (TP) and air change level (h−1) level, and a higher carbon dioxide (CO2) level during winter compared to summer. In general, higher IAQ levels were measured in apartments with increased crowdedness. The inability to be able to create cross ventilation increased TP, and a larger number of rooms decreased TP. Overall, there was no clear alignment between measured and perceived IAQ, but we found a trend that higher CO2-levels led to a perception of poor IAQ especially during summer. Overall, draught and thermal discomfort were the most common complaints. Self-reported humidity was increased during winter and was associated with nasal and respiratory symptoms, whereas self-reported humidity during summer was associated with fatigue and dermal symptoms. Findings show challenges with IAQ in Danish social housing that are associated with negative health issues.

Groundwater and indoor air quality of urban village housing: study in Janturan, Warungboto, Yogyakarta

Water and air are important elements for life. The presence of pathogenic bacteria in the surrounding environment can cause health problems resulting from the low quality of water and air. The purpose of this study is to measure the quality of groundwater and air based on microbiological parameters in urban village housing. This research was conducted in a descriptive survey, and a purposive sampling technique was carried out. Groundwater and air samples were taken from six residents' houses located in the Janturan area. The water quality test used the most probable number (MPN) method and the air quality test used the agar filter method using a microbiological air sampler (MAS) to trap microbes. The results of the MPN test for total coliform bacteria from six samples of groundwater showed that three samples were positive for coliform bacteria which exceeded the threshold according to Indonesian standard&amp;lt;50 MPN/100 ml. Assay of &lt;em&gt;E. coli&lt;/em&gt; bacteria showed that all samples of groundwater positively contained &lt;em&gt;E. coli&lt;/em&gt; bacteria which exceeded the threshold of 0 MPN/100 ml. The results of indoor air quality measurements from 6 residents' houses showed that five houses have air quality did not meet the standard for indoor air germ numbers based on Indonesian standard, less than 700 CFU/m3 (colony forming units per metres cubic) and 1 house that got the number of airborne germs, in the normal range, namely 356 CFU/m3. It was concluded that the water quality and air quality in the urban village did not meet health requirements.

How do occupants experience the onset and triggering of building-related symptoms in damp Australian housing? An inductive-deductive content analysis

In recent years, occupants’ time spent in dwellings has increased concurrently with an increase in the duration and intensity of extreme weather events and the worsening of housing conditions. Indoor dampness and or mould (D/M) are risk factors for building-related symptoms (BRS), yet little is known about how symptoms start, thus hindering where to focus indoor air quality measurements and improvements in occupant safety. This study describes perceived symptom initiators, triggers and coinciding factors that explain what and how symptoms occurred from the perspectives of occupants living with indoor D/M. This study uses an inductive/deductive qualitative analysis, with purposive sampling (n = 154) from data collected via an online survey. Deductive content analysis utilises a framework driven by the Determinants of Health (DoH). Themes that emerged from the inductive analysis include: 1) when occupants or others interact with D/M; 2) when indoor D/M conditions change; and 3) a home full of D/M problems. From the deductive analysis, perceived exposure relating to D/M conditions differed between the initial onset of symptoms and the later triggering of symptoms. Additional coinciding factors relating to climate, socioeconomic, policy and individual factors along with a lack of knowledge, attitudes and beliefs, emerged. This study highlights the need to raise occupant awareness, enhance housing and occupancy regulations, and introduce safe work practices to address the lack of health awareness and health significance regarding indoor D/M housing conditions. It also outlines the need for targeted research measuring bioaerosol exposure related to actions, proximity-based exposure, and wet and repeatedly wet conditions.

Health at Home: Investigating Low-Income Housing Quality on Colfax Avenue

Abstract: Addressing housing insecurity contributes to health care programs as stable housing has positive health benefits. Home environmental hazards may reduce these potential health benefits and could increase morbidity for conditions such as asthma. This study examined housing and indoor air quality among urban low-income households in Colorado to inform housing-insecurity interventions. We conducted a community-engaged study among residents of motels, mobile homes, apartments, and single-family homes that included a survey on the home environment, health, and sociodemographic factors, spirometry, and indoor air quality measurement. We enrolled 60 households: 50% single-family homes, 37% apartments, and 13% residential motels. Perceived stress and depression were higher among motel residents compared with other housing types. We did not find differences in lung function by housing type. Indoor fine particulate matter (PM2.5) and black carbon concentrations were higher in motels than in other housing types. The differential health impacts of housing type support housing programs that jointly address security and quality.

Systematic framework for quantitative assessment of Indoor Air Quality under future climate scenarios; 2100s Projection of a Belgian case study

Alteration of Indoor Air Quality (IAQ) levels in the context of changing climate is correlated with shifting air pollutant emissions, variations in ambient climate, and the mitigation/adaptation strategies applied in buildings to deal with increasing extreme weather events and energy demands. In this study, firstly, a systematic modeling-based framework for the quantitative assessment of the impacts of future building retrofit and climate scenarios on IAQ is presented. After describing the framework, its practical implementation in a demonstrative case study is presented. The proposed framework includes three main parts: i) IAQ measurements, ii) IAQ model design, and iii) future IAQ state evaluation. Regarding the case study, fabricated indoor monitoring devices (O3, CO, NO, NO2, PM2.5, PM10, VOCs, air temperature, relative humidity, and air pressure) based on Low-Cost Sensors were developed, and calibrated with reference analyzers. An indoor measurement campaign was conducted in a naturally ventilated residential building (+2 exhaust fans) in the Wallonia region, south of Belgium (summer of 2021). An IAQ model was designed in the multizone IAQ and ventilation software, CONTAM. The validation and calibration processes were carried out with the aid of experimental data from the indoor measurement campaign. The calibrated IAQ model showed a total conformity of +95 % from the average concentration perspective. Finally, predicted future outdoor air pollution and indoor and outdoor climate data of the case study were fed to the IAQ model (basis-year 2021), and indoor contaminant levels under different climate scenarios were quantitatively assessed till 2100.

Indoor air quality and sick-building syndrome at a metro station in Tianjin, China

Metro systems play a crucial role in public transportation worldwide. Given that metro stations are unique built environments with a significant volume of daily commuters, ensuring a satisfactory air quality in these spaces becomes paramount. This study involved measurements of indoor air quality (IAQ), staff satisfaction, particulate matter (PM) chemical composition, and heavy metal health risks at a typical metro station in Tianjin over two seasons. Although the air exchange rate was sufficient to maintain a CO2 concentration less than 1000 ppm, the proportion of staff reporting no sick-building symptoms decreased from 83 % in spring to 25 % in winter. An average mass concentration of PM with an aerodynamic diameter smaller than 2.5 μm (PM2.5) of 68.0 ± 42.2 μg/m3 and an average PM1 mass concentration of 51.8 ± 33.3 μg/m3 were observed on the platform in winter. PM2.5 contained more metal in winter than in spring. PM2.5 in winter contained more metal in winter than in spring. With a lower relative humidity in winter, the coefficient of friction between railway wheels and rails increased, thus increasing particle emission. The carcinogenic risk of Cr on the platform was unacceptable. Moreover, the health risks induced by Ba should be investigated. The findings indicate that PM control at metro stationss, particularly on platforms in winter, should be emphasized.

COVID-19 Mitigation in a K-12 School Setting: A Case Study of Avenues: The World School in New York City.

In this case study, we describe a well-resourced private school in New York City that implemented COVID-19 mitigation measures based on public health expert guidance and the lessons learned from this process. Avenues opened in New York City in 2012 and has since expanded, becoming Avenues: The World School, with campuses in São Paulo, Brazil; Shenzhen, China; the Silicon Valley, California; and online. It offers education at 16 grade levels: 2 early learning years, followed by a prekindergarten through grade 12. We describe the mitigation measures that Avenues implemented on its New York campus. We compare COVID-19 case prevalence at the school with COVID-19 case positivity in New York City, as reported by the New York State Department of Health. We also compare the school's indoor air quality to ambient indoor air quality measures reported in the literature. The school's mitigation measures successfully reduced the prevalence of COVID-19 among its students, staff, and faculty. The school also established a consistently high level of indoor air quality safety through various ventilation mechanisms, designed to reduce common indoor air pollutants. The school received positive parent and community feedback on the policies and procedures it established, with many parents commenting on the high level of trust and quality of communication established by the school. The successful reopening provides useful data for school closure and reopening standards to prepare for future pandemic and epidemic events.

Indoor Air Quality Measurements in Enclosed Spaces Combining Activities with Different Intensity and Environmental Conditions

The impact of the COVID-19 pandemic has caused an increase in knowledge in certain fields such as human breathing and respiratory diseases. In the current study, enclosed-space characteristics were assessed due to the great debate generated because of the pandemic. Temperature, relative humidity, carbon dioxide (CO2) concentration, particulate matter (PM) concentration and cumulative particle concentration percentage per size fraction were measured in three buildings under the occurrence of activities with different intensity levels. For the measurements, Arduino UNO, Sensiron SCD30 and APS-3321 devices were used. Natural ventilation was controlled via windows and/or doors, and the influence of air conditioning was studied in one of these rooms, in which medium- to high-intensity activities were conducted. All experiments revealed a decrease in temperature associated with an increase in the relative humidity when CO2 decreased. As a consequence, drastic decreases occurred a few minutes after windows and doors were opened. In no-ventilation intervals, the observed linear increase changed into an asymptotic trend below the 1000 ppm limit recommended by Sinphonie guidelines. Additionally, the opposite behavior was observed between particles above and below a certain size. This experiment is of interest to further investigate critical ventilation rate versus volume of air per individual.

A review of the indoor air quality in residential Passive House dwellings

The Passive House (PH) Standard is a voluntary building energy performance standard focused upon reducing space heating demand to a very low level and therefore considered a viable climate change mitigation technology. Besides comfort and energy requirements, the PH standard also defines criteria with respect to ventilation. However, the question remains, how well do PH dwellings perform when they are occupied? Does the PH approach provide good indoor air quality (IAQ) for its occupants and how does IAQ compare to non-PH homes, in particular, naturally ventilated homes? Additionally, can PH certification improve the quality of installed ventilation systems? This paper summarizes indoor air quality relevant aspects of the PH standard and presents results from measurements examining in-use IAQ in more than 600 PH or PH-like, newly built or retrofitted dwellings. The results reveal that pollutant and carbon dioxide concentration are generally lower compared to naturally ventilated homes, presumably due to the requirement to install a balanced Mechanical Ventilation with Heat Recovery (MVHR) system. Results also suggest that the quality assurance measures of PH certification are capable of improving ventilation and IAQ performance. However, the lack of cooking fume capture requirements in the PH standard, in combination with efforts to avoid energy losses associated with a possible extraction kitchen hood, may lead to elevated particulate matter concentration in PHs. Future research on cooking induced IAQ impairment is encouraged to assess the effectiveness of recently published PH-specific recommendations. Future efforts in empirical IAQ research should also address the lack of high quality IAQ measurement data and the standardisation of IAQ assessment methods and protocols.

The first test of indoor air quality in kindergartens of the Republic of Srpska

The first experimental results of the indoor air quality in two kindergartens located in the Republic of Srpska are presented in this paper. Kindergarten representatives for the year of construction (old and new), building materials, and energy efficiency have been chosen. Indoor air quality measurements (air temperature, relative humidity, ventilation rate, CO2, and radon concentration) were performed during the winter of 2015/2016. Measured indoor air quality parameters are discussed and compared to the international standards BAS EN 16798-1, ASHRAE 62.1, and ISO 7730. The average measured radon concentrations for both buildings have not exceeded the level of 200 Bq/m3, but for reliable results, long-term measurement needs to be performed. The CO2 concentration in the old kindergarten fulfills the BAS EN 16798-1 requirement for Category I during 62.43% of total occupancy time, while for the new kindergarten, it is only 5.79% of full occupancy time. Results of CO2 concentration confirm that good sealing of the envelope of new buildings and user behavior (number of users and natural ventilation) does affect air quality. Furthermore, a high correlation between CO2 concentration and relative humidity in both buildings and a more considerable correlation for the new building have been observed.

Association Between Air Microbiological Exposure With Sick Building Syndrome (SBS) among College Dormitory Students in Public University

Introduction: Microbiological pollutants in indoor air can lead to sick building syndrome (SBS). A conducive academic environment in university dormitories requires healthy indoor air quality to enhance student performance. This study aimed to determine the association between indoor air microbiological exposure and SBS among college dormitory students at a public university. Methods: A cross-sectional study was conducted among 112 male and female college dormitory students who stayed in the public university dormitory for more than three months. Respondents were given a self-administered questionnaire-based NIOSH Indoor Environmental Quality Survey. 14 houses were selected for the measurement of indoor air quality which included PM2.5, PM10, relative humidity (%), temperature (°C), air velocity (m/s), indoor bacterial concentration (cfu/m3), and indoor mould concentration (cfu/m3). Results: Higher percentages of SBS symptoms were reported among female (94.6%) college dormitory students compared to male (82.1%). A significant difference in itching symptom on the arms and forearms was found among individuals of different genders (p&lt;0.05). Indoor air parameters such as temperature (OR = 2.56, 95% CI = 2.66-9.87), relative humidity (OR = 1.77, 95% CI = 1.54 – 5.79), indoor bacteria concentration (OR=2.28, 95% CI = 2.48 – 10.93), and indoor mould concentration (OR=2.59, 95% CI = 1.75 – 8.98) were significantly associated with the recent SBS symptoms. Multiple logistic regression showed that the most significant predictor of SBS was indoor mould concentration. Conclusion: Exposure to high concentrations of indoor bacteria and mould, high temperatures, and high relative humidity influenced the prevalence of SBS among college dormitory students. Further assessment and preventive action need to be taken to reduce the exposure of indoor air microbiological to the students.

Impact of industrial pollution on children's lungs: A comparative analysis of pulmonary function in critically polluted and non-polluted areas in western India

BackgroundAir pollution is a pressing global health concern, particularly in low- and middle-income countries like India. Children living near industrialized and critically polluted areas (CPAs) face heightened health risks due to their developing respiratory systems. This study aimed to assess the impact of industrial pollution on children's lung function in a CPA in western India. MethodologyThe study evaluated 362 children studying in 5th to 7th standard from both a CPA and a relatively non-polluted area (NPA) for comparison. Ambient and indoor air quality measurements were taken, and pulmonary function tests were conducted to assess lung health. Group difference and regression analysis were performed with SPSS 26.0. ResultsThe CPA group showed significantly higher air pollution levels and a higher prevalence of obstructive and restrictive patterns in pulmonary function compared to the NPA group. The findings also revealed that children residing in CPA exhibited a significant decline of 530 ml forced expiratory flow rate (FEF 25–75%), and a reduction of 3.9% FEV1/FVC ratio when compared to children residing in relatively NPA. ConclusionWhile this study's cross-sectional design has limitations, it provides valuable evidence of the impact of air pollution on children's lungs in a semi-urban industrialized area. To mitigate these health risks, integrating respiratory health check-ups, including pulmonary function tests, in existing health programs, like Rastriya Bal Swasthya Karyakram (RBSK), is recommended for early detection and intervention. Implementing initiatives such as enhancing green belts around schools and continuous air quality monitoring will be crucial.

Systematically omitting indoor air quality: sub-standard guidance for shelters, group homes and long-term care in Ontario during the COVID-19 pandemic

ABSTRACT Public Health Ontario (PHO) is mandated by legislation to share scientific advice during infectious disease outbreaks and help reduce health inequities in Ontario, Canada. PHO was founded in part to address the failures of Ontario’s public health system during the 2003 outbreak of SARS-CoV-1, which included the failure to address airborne transmission. By January 2021, public health authorities had access to a body of literature suggesting SARS-CoV-2 was airborne, and had received urgent warnings from scientists. We set out to document how PHO responded to the likelihood – and, eventually, the certainty – of airborne transmission in the context of its guidance for congregate settings such as long-term care and shelters. In October 2021, we reviewed PHO’s public, written COVID-19 guidance for these settings, with a focus on indoor air quality (IAQ) measures that mitigate airborne transmission, such as ventilation. We identified 11 PHO documents for congregate settings. They contained no references to IAQ measures. We did, however, find references to IAQ measures in parallel documents for schools, summer camps, and clinical offices. Our findings demonstrate PHO omitted key infection prevention measures from its COVID-19 guidance for congregate settings, putting workers and residents at greater risk of exposure, illness and death, and exacerbating health inequities.

A novel low sampling rate and cost-efficient active sampler for medium/long-term monitoring of gaseous pollutants

Active sampling is a dependable approach for gaseous pollutants monitoring, offering high accuracy and precision that is unaffected by environmental factors such as wind and temperature in comparison to passive sampling. To measure long-term average concentrations while minimizing the use of materials, a reduced sampling rate is necessary. Thus, this study aims to develop a novel low sampling rate (down to 1 mL/min) and cost-efficient active sampler (LASP) for medium/long-term monitoring of gaseous pollutants. The LASP mainly consisted of a syringe pump, a Y-shaped fitting with two one-way valves, and a control unit for intermittent operation. Results showed that LASP can obtain a sampling rate of less than 1 mL/min and sampling rate exhibited a high level of stability. Daily average concentrations measurements for nitrogen dioxide and formaldehyde by LASP had normalized mean biases of 2.8% and 5.2%, respectively. These numbers were − 5.8% and 6.1% for weekly-average samplings. This study demonstrated applications of LASP in real outdoor (daily-average) and indoor (weekly-average) air quality measurements. It worked well with low noise levels, and without interfering with occupants' daily activities. LASP can assist in improving our ability to monitor air quality and pollutants emissions, thereby supporting health research and policy development. Environmental implicationGaseous air pollution is an important hazardous factor threatening human health. Medium/long-term air quality monitoring is essential for outdoor and indoor air quality assessment and control. However, air sampler for medium/long-term sampling is lacking. This study developed a novel low sampling rate and cost-efficient active sampler and applied it to medium/long-term air sampling. The sampler can work at a sampling rate of less than 1 mL/min. This technology provides a feasible strategy for medium/long-term monitoring of gaseous air pollutants in both environments and emission hotspots.

Internet of Things (IoT) in Buildings: A Learning Factory

Advances towards smart ecosystems showcase Internet of Things (IoT) as a transversal strategy to improve energy efficiency in buildings, enhance their comfort and environmental conditions, and increase knowledge about building behavior, its relationships with users and the interconnections among themselves and the environmental and ecological context. EU estimates that 75% of the building stock is inefficient and more than 40 years old. Although many buildings have some type of system for regulating the indoor temperature, only a small subset provides integrated heating, ventilation, and air conditioning (HVAC) systems. Within that subset, only a small percentage includes smart sensors, and only a slight portion of that percentage integrates those sensors into IoT ecosystems. This work pursues two objectives. The first is to understand the built environment as a set of interconnected systems constituting a complex framework in which IoT ecosystems are key enabling technologies for improving energy efficiency and indoor air quality (IAQ) by filling the gap between theoretical simulations and real measurements. The second is to understand IoT ecosystems as cost-effective solutions for acquiring data through connected sensors, analyzing information in real time, and building knowledge to make data-driven decisions. The dataset is publicly available for third-party use to assist the scientific community in its research studies. This paper details the functional scheme of the IoT ecosystem following a three-level methodology for (1) identifying buildings (with regard to their use patterns, thermal variation, geographical orientation, etc.) to analyze their performance; (2) selecting representative spaces (according to their location, orientation, use, size, occupancy, etc.) to monitor their behavior; and (3) deploying and configuring an infrastructure with +200 geolocated wireless sensors in +100 representative spaces, collecting a dataset of +10,000 measurements every hour. The results obtained through real installations with IoT as a learning factory include several learned lessons about building complexity, energy consumption, costs, savings, IAQ and health improvement. A proof of concept of building performance prediction based on neural networks (applied to CO2 and temperature) is proposed. This first learning shows that IAQ measurements meet recommended levels around 90% of the time and that an IoT-managed HVAC system can achieve energy-consumption savings of between 10 and 15%. In summary, in a real context involving economic restrictions, complexity, high energy costs, social vulnerability, and climate change, IoT-based strategies, as proposed in this work, offer a modular and interoperable approach, moving towards smart communities (buildings, cities, regions, etc.) by improving energy efficiency and environmental quality (indoor and outdoor) at low cost, with quick implementation, and low impact on users. Great challenges remain for growth and interconnection in IoT use, especially challenges posed by climate change and sustainability.

Suitability of Low-Cost Sensors for Submicron Aerosol Particle Measurement

The measurement and assessment of indoor air quality in terms of respirable particulate constituents is relevant, especially in light of the COVID-19 pandemic and associated infection events. To analyze indoor infectious potential and to develop customized hygiene concepts, the measurement monitoring of the anthropogenic aerosol spreading is necessary. For indoor aerosol measurements usually standard lab equipment is used. However, these devices are time-consuming, expensive and unwieldy. The idea is to replace this standard laboratory equipment with low-cost sensors widely used for monitoring fine dust (particulate matter—PM). Due to the low acquisition costs, many sensors can be used to determine the aerosol load, even in large rooms. Thus, the aim of this work is to verify the measurement capability of low-cost sensors. For this purpose, two different models of low-cost sensors are compared with established laboratory measuring instruments. The study was performed with artificially prepared NaCl aerosols with a well-defined size and morphology. In addition, the influence of the relative humidity, which can vary significantly indoors, on the measurement capability of the low-cost sensors is investigated. For this purpose, a heating stage was developed and tested. The results show a discrepancy in measurement capability between low-cost sensors and laboratory measuring instruments. This difference can be attributed to the partially different measuring method, as well as the different measuring particle size ranges. The determined measurement accuracy is nevertheless good, considering the compactness and the acquisition price of the low-cost sensors.