Indoor Residential Environment Research Articles

Eco-Friendly Sanitization of Indoor Environments: Effectiveness of Thyme Essential Oil in Controlling Bioaerosol Levels and Disinfecting Surfaces.

Bioaerosols and pathogens in indoor workplaces and residential environments are the primary culprits of several infections. Techniques for sanitizing air and surfaces typically involve the use of UV rays or chemical sanitizers, which may release chemical residues harmful to human health. Essential oils, natural substances derived from plants, which exhibit broad antimicrobial properties, could be a viable alternative for air and surface sanitation. The objective of this study has been to investigate the efficacy of thyme essential oil (TEO) in environmental sanitation processes. In Vitro assays through agar well diffusion, disk volatilization and tube dilution methods revealed significant antimicrobial activity of TEO 100% against foodborne and environmental isolates, with both bacteriostatic/fungistatic and bactericidal/fungicidal effects. Therefore, aqueous solutions of TEO 2.5% and 5% were formulated for air sanitation through nebulization and surface disinfection via direct contact. Bioaerosol samples and surface swabs were analyzed before and after sanitation, demonstrating the efficacy of aqueous solutions of TEO in reducing mesophilic and psychrophilic bacteria and environmental fungi levels in both air and on surfaces. The obtained results prove the antimicrobial potential of aqueous solutions of TEO in improving indoor air quality and surface cleanliness, suggesting thyme essential oil as an effective and safe natural sanitizer with minimal environmental impact compared to dangerous chemical disinfectants.

Microplastics suspended in dust from different indoor environments in Barranquilla, Colombia: Predominant microparticles?

Considering that microplastics (MPs) are classified as ubiquitous pollutants, that air quality affects human health, and that people remain indoors most of the time, the need has arisen to evaluate the exposure to MPs within the suspended dust in indoor environments. With this objective, the present study carried out passive sampling to analyze the precipitation of microparticles in some indoor residential environments (2 apartments) and workplaces (an office, a pastry shop, a gift shop, and a paint shop) in Barranquilla, Colombia. The quantification and physical characterization of microparticles were carried out under a stereomicroscope, and the chemical characterization was carried out by infrared microspectroscopy (μFTIR). The highest average concentration of MPs in the apartments was found in the air-conditioned rooms (1.1 × 104 MP/m2/day), and concerning the workplaces, the gift shop and the paint shop were the spaces with a higher proportion of MPs (6.0–6.1 × 103 MP/m2/day), with polyesters being the main synthetic polymers, but being semi-synthetic particles the predominant among the samples. Regarding its morphology, fibers were the most abundant shape (>90%), grouping mainly in the 1000–5000 μm range, while the few fragments found were mostly grouped below 50 μm. Exposure by inhalation of MPs in adults was estimated between 1.7 × 102–1.6 × 103 MP/kg/day, while by ingestion it ranged between 2.7 × 102–2.4 × 103 MPs/kg/day. On the other hand, within our research, a significant presence of non-plastic microparticles was found, which reached up to 69% in analyzed samples, corresponding mainly to cotton and cellulose, so we suggest that these should also be included in future studies that aim to estimate potential health implications from exposure to suspended micropollutants.

Observationally constrained mass balance box model analysis of aerosol mitigation potential using fan powered filters

Indoor air pollution contributes significantly as a world-wide environmental issue, impacting health and livelihood. To quantify benefits of filtration on indoor air quality, it is essential to understand the relationships between the various factors impacting the concentrations of indoor air pollutants. This work uses a mass-conserving 2-box model, high-frequency observations of aerosol number concentration, and a home-made, low-cost, 3-layer non-woven fabric filter, powered by a standard ventilation fan to quantify the effectiveness aerosol reduction in multiple indoor environments. The data shows that aerosol loading is effectively reduced under both steady-state and extreme event conditions, although there are significant and important differences between simultaneous observations both indoor and outside. To obtain a proper accounting, the following must be considered: the usage or not of the fan filter, whether windows are opened or closed, the state of outdoor air is pollution, and the strength and duration of indoor emissions. The experiments are applied in residential indoor environments in four cities in eastern (Xuzhou), central (Zhoukou), and southern (Zhuhai and Shunde) China. Photographic evidence of the altered fan filter state under both conditions show that while usually dark/black aerosols dominate, there are conditions when yellow aerosols also dominate. The observations are based on multiple, independent, continuous low-cost sensors which have been calibrated against a GRIMM-180 over the number concentration range from 0.3 to 1.0 microns, and yield a removal rate due to the fan-filter of 46%, 80%, 81%, and 36% respectively across the four cities. A corresponding rate to return from an extreme event to steady-state, is computed outdoors and indoors respectively from: 14.−44. minutes, 6.6–21. minutes, 16.−33. minutes, and 24.−58. minutes. The most important factors contributing to the removal efficiency and decay gradient are observed as keeping windows closed and reducing leakiness, the apartment/classroom size, and the outdoor air pollution loading.

Analysis of Indoor Residential Environment Satisfaction among Social Housing Households in Seoul

Social housing in Seoul has been provided since 2015 via collaboration between the city and the private sector to address the increasing housing burden for single-person households and the younger generation. Despite the eight years since the implementation of this initiative, there remains a lack of research regarding the satisfaction of residents with respect to indoor social housing environments. The aim of this study is two-fold: (1) to explore household characteristics, such as floor area and living room, bathroom, and kitchen issues; and (2) to examine the factors that affect indoor residential environment satisfaction. In May and June of 2022, 57 households from 22 social housing projects participated in the survey, and data were analyzed using frequency and descriptive methods. The results indicated that the interior layout of the house affected and influenced residential satisfaction. This was followed by accessibility to major facilities, interactions with the community, accessibility to transportation, and facility maintenance. The implications of these findings were discussed.

The effect of housework, psychosocial stress and residential environment on musculoskeletal disorders for Chinese women

Historically, discussions of work-related musculoskeletal disorders (MSDs) have focused on paid work factors. However, the relation between housework (unpaid work) and MSDs for women is important. Little is known about the relationship between housework and MSDs and how this relationship can be influenced by physical environment factors and psychosocial stress, as well as other individual characteristics. Therefore, this study proposed a model to disentangle interactions between housework, residential indoor environment, psychosocial stress and MSDs for women, using the structural equation modeling approach, based on the cross-sectional data in the Central Plain of China. Model results showed housework (0.23) and psychosocial stress (0.44) were risk factors for the development of MSDs, while indoor environmental satisfaction (−0.27) was the protective factor for MSDs. Moreover, housework had a significant effect on psychosocial stress (0.20) while indoor environment satisfaction showed negative effect on psychosocial stress (−0.22). Furthermore, multiple group analysis suggested individual characteristics, including age, BMI, education, length of residence, household size and floor area, could change the strength of relationships in the model. This paper formulated and validated a model to define interactions between housework, residential indoor environment, psychosocial stress and MSDs for women, which would help improve knowledge on impact of housework on MSDs.

Exposure to different residential indoor characteristics during childhood and asthma in adolescence: a latent class analysis of the Danish National Birth Cohort

BackgroundMany residential indoor environments may have an impact on children’s respiratory health.ObjectivesThe aims of this study were to identify latent classes of children from the Danish National Birth Cohort (DNBC) who share similar patterns of exposure to indoor home characteristics, and to examine the association between membership in the latent classes and asthma in adolescence.MethodsWe included data on residential indoor characteristics of offspring from the DNBC whose mothers had responded to the child’s 11-year follow-up and who had data on asthma from the 18-year follow-up. Number of classes and associations were estimated using latent class analysis. To account for sample selection, we applied inverse probability weighting.ResultsOur final model included five latent classes. The probability of current asthma at 18 years was highest among individuals in class one with higher clustering on household dampness (9, 95%CI 0.06–0.13). Individuals in class four (with higher clustering on pets ownership and living in a farm) had a lower risk of current asthma at age 18 compared to individuals in class one (with higher clustering on household dampness) (OR 0.53 (95%CI 0.32–0.88), p = .01).ConclusionOur findings suggest that, in a high-income country such as Denmark, groups of adolescents growing up in homes with mold and moisture during mid-childhood might be at increased risk of current asthma at age 18. Adolescents who grew-up in a farmhouse and who were exposed to pets seem less likely to suffer from asthma by age 18.

Size-resolved inhalation intake fractions for particles released from human activities in residential indoor environments

Inhalation exposure to elevated concentrations of airborne particulate matter is a public health concern. Assessment of exposure can be enhanced through better knowledge of source-receptor relationships, which can be characterized through the inhalation intake fraction metric. This case study provides new insights on variations in particle inhalation intake fractions for indoor sources associated with common human activities in residential buildings. In a controlled climate chamber (air temperature: 24 ± 1 °C, relative humidity: 50 ± 5%), we investigated size-resolved intake fractions for particles in relation to four scripted activities performed by a human volunteer: sitting, walking, cooking, and vacuuming. We measured size- and time-resolved particle number concentrations at the volunteer's breathing zone to characterize intake fractions. In addition, we measured particles at four different stationary locations across the climate chamber to assess the degree of spatial heterogeneity in particulate matter concentrations. The results show that particles released from human skin and clothing during sitting were associated with the highest total inhalation intake fraction (13‰), followed by cooking (9‰), vacuuming (5.7‰), and walking (3.9‰). These results highlight how breathing zone proximity to localized emission sources and low indoor air mixing can enhance inhalation exposure to particles. Sitting and cooking caused a maximum inhalation intake fraction in the size range of 1–3 μm. Findings also show that the assumption of a perfectly mixed environment could lead to an underestimation of the inhalation intake of particles by up to 3.2-fold. The results of this case study provide a basis for achieving more accurate personal inhalation exposure assessment and improved indoor air quality management.

Derivation and application of indoor air screening values for inhalation exposure to semi-volatile organic compounds

Semi-volatile organic compounds (SVOCs) are being increasingly studied in indoor air. The absence of health-based inhalation exposure guidelines for most SVOCs impedes the interpretation of indoor air concentrations from a health risk context. To accelerate the derivation of screening values for a large number of SVOCs, a tiered framework was developed to evaluate and adjust published hazard assessments for SVOCs to calculate benchmarks relevant for evaluation of inhalation risk. Inhalation screening values were derived for 43 SVOCs considered in this study, most of which required extrapolation from oral exposure guidelines. The screening values were compared to published SVOC concentrations in homes in Canada to evaluate the potential health risks of chronic exposure to SVOCs in indoor residential environments. SVOCs that could be prioritized for further evaluation were dibutyl phthalates (DBP), di(2-ethylhexyl) phthalate (DEHP) and polybrominated diphenyl ethers (PBDEs). The framework could be applied more broadly in the future to derive screening values for other non-traditional indoor air contaminants with limited inhalation hazard data or assessments.

Molecular Characteristics, Sources, and Health Risk Assessment of Gaseous Carbonyl Compounds in Residential Indoor and Outdoor Environments in a Megacity of Northwest China

Carbonyl compounds (CCs) in indoor air pose a significant threat to residents’ health and have garnered considerable attention in recent years. However, most studies have focused on low-molecular-weight carbonyl compounds (LMW-CCs) and have underestimated the impact of high-molecular-weight ones (HMW-CCs), causing a failure to comprehensively understand their effects on health. In this study, we analyzed twenty carbonyls in the indoor and outdoor air at typical residential communities in a megacity in Northwest China by using high-performance liquid chromatography (HPLC) coupled with a photodiode array detector (DAD). The total concentration of indoor carbonyls was 1.4-3.4 times that of outdoor carbonyls. In addition, the concentration of indoor carbonyls was much higher during the heating season than that during the nonheating season. Conversely, the concentration of outdoor carbonyls was higher during the nonheating season than that during the heating season. The principal component analysis (PCA) revealed that indoor carbonyl pollution was primarily influenced by building materials, cooking fume, and wooden furniture. Formaldehyde exposure in indoor environments posed a greater health risk to children than acetaldehyde exposure. HMW-CCs were the primary contributors to indoor odor pollution, which was considered a significant cause of sick building syndrome (SBS). Our findings underscore the crucial role of HMW-CCs in indoor environments in exerting adverse impacts on health.

Can air handling equipment be beneficial to children’s health? Results from a cross-sectional survey in 2010 and 2019 in China

A growing number of studies have shown that the indoor residential environment is associated with respiratory and allergic diseases in children. This study aimed to investigate the prevalence of respiratory and allergic diseases among children in China and its correlation with using air handling equipment, based on the cross-sectional survey results of the China Children Homes Health Project in 2010 and 2019. The binary logistic regression model was used to explore the association between asthma, rhinitis, eczema and pneumonia and the use of air handling equipment in children. The prevalence of children’s respiratory and allergic diseases has decreased, and the usage rate of portable air purifiers and split air conditioners has increased in 2019 compared to 2010. The results showed that using a fresh air system with filters was negatively correlated with children’s pneumonia (adjusted odds ratio (aOR): 0.767, 95% confidence interval (95% CI): 0.704–0.835). The use of portable air purifiers was positively correlated with most diseases’ symptoms in two undertaken surveys. In 2019, the positive correlation between using split air conditioners and asthma-related symptoms decreased compared with 2010, while it was positively correlated with rhinitis, eczema and pneumonia. To avoid children’s allergic diseases and reduce respiratory symptoms, parents should choose appropriate air handling equipment.

Effects of residential indoor environments on occupant satisfaction and performance

ABSTRACT With vast influences of Chinese industrial transformation, also largely impacted by the global challenges, such as climate change and pandemic, the home becomes as a place for occupants to perform their work tasks. To that end, this study concentrates on the effects of residential indoor environments, especially the factor of indoor environment quality (IEQ) and indoor greenery (IG), on occupants’ residential satisfaction and performance. By conducting a post-occupancy evaluation (POE) survey with the perspective of user experience (UX), 764 samples were collected, of which 528 are valid for statistical analysis. The method of structural equation modeling (SEM) was adopted to test the hypotheses. The results show that both indoor environment quality and indoor greenery have a positive effect on residential satisfaction and occupant performance, however, the former is more influential. In addition, residential satisfaction is a partial mediator, which demonstrates the mechanism: residential indoor environment mainly affects satisfaction, then occupant performance. The findings of this study provide important evidence from China in the period of the post-pandemic era that combines the unique characteristics of urbanization, gaining more insight for researchers to understand the relationship between the built environment of homes and their occupants, revealing specific design implications for practitioners.

Indoor Environmental Comfort Assessment of Traditional Folk Houses: A Case Study in Southern Anhui, China.

Due to the unique geographical location and historical culture, the traditional houses in the southern region of Anhui Province, China (South Anhui) have different indoor environments. In summer and winter, this study adopted a field survey, questionnaire survey, and statistical analysis to carry out a comprehensive field survey on Xixinan Village in South Anhui, and selected a typical traditional residence in the village to evaluate its indoor environment status. The final results show that the overall indoor environment of the traditional houses in South Anhui was awful, including the indoor thermal environment, with high temperature and humidity in summer and cold and humidity in winter. Additionally, the indoor light environment with dim light still had much room for improvement, while the indoor air quality and sound environment were relatively excellent. In addition, this study determined that the neutral temperatures of residents are 15.5 °C and 28.7 °C in winter and summer, respectively, and the comfort range of indoor light intensity is 752.6-1252.5 lx, which determines the adjustment range of indoor environmental parameters for residents' comfort needs. This paper's research methods and results provide a reference for the study of residential indoor environments in other regions with similar climatic conditions as South Anhui, and a theoretical basis for architects and engineers to enhance the indoor environment of traditional houses in this region.

The impact of automated control of indoor air pollutants on cardiopulmonary health, environmental comfort, sleep quality in a simulated apartment: A crossover experiment protocol

Air pollution makes an impact on cardio-pulmonary health. Since people spend over 90% of their time indoors, exposures to the indoor environment make the most significant impact on health. Among indoor sources, cooking emits the most particles that disperse through the residential indoor environment and expose occupants. We use fully controlled simulated residential modules to conduct exposure experiments. In the pilot study, participants stayed in modules for 1 week, and in the main study, 14 participants will stay in the module for 4 weeks. One module is operated as a classical US house air supply recommendation. The second module has an advanced control system that, alongside the standard air supply, activates air quality interventions: stove hood, portable air cleaners, bathroom exhaust and air flush (increasing air supply ∼3 times) as a function of the PM2.5 levels in the space. Environmental sensors based on Internet of Things technology simultaneously monitored Particulate Matter (PM2.5), CO2, Total Volatile Organic Compounds Relative Humidity and air temperature in all spaces and operated air quality interventions. Participant’s scheduled activities include morning and evening tasks, Monday through Friday. Participants may leave the module during the day. They will be asked to cook breakfast and dinner using lab-provided recipes. We measured each participant’s blood pressure, heart rate, and heart rate variability. Blood and urine samples were collected 3 times per participant in the pilot and will be collected 2 times a week in the main study. Up to 20 ml of blood and a minimum of 30 ml of urine will be sampled per collection. Analysis of blood and urine was performed for 8-hydroxy-2-deoxyguanosine (8-OHdG, urine), von Willebrand Factor (vWF, blood plasma), high sensitivity C-Reactive Protein (hsCRP, blood serum), Interleukin-6 (blood plasma), CD11b (blood), Fibrinogen (blood plasma), and Myeloperoxidase (blood serum). We conducted a Pilot for 2 weeks with 3 participants to test the study protocol and data collection. We adjusted the protocol for the main study based on the pilot results. Results showed that the proposed study protocol could be completed, and the methodology adopted in this study will provide valuable insights into the relationship between exposure to cooking particles and occupants' health.Trial registration: Mayo Clinic IRB 20-007908.

Influence of residential indoor environment on quality of life in China

The residential indoor environment has been acknowledged as one of the main settings affecting quality of life. However, complex relationships exist between residential indoor environment and quality of life. Most studies frequently tend to address a narrow range of residential environmental factors and associated quality of life. Therefore, this study is to identify the relationships between overall residential indoor environment and quality of life, and how relationships can be influenced by potential confounding factors, based on the Pan-China residential environment and health survey data. Results showed that the prominent residential environmental issues reported by participants were thermal problems. There was a statistically significant association between the increase in physical/mental health conditions and the reduction in reported frequency of residential environmental problems, including thermal, indoor air quality, lighting, acoustic, hygiene, safe and security environment, even after adjustment for age, sex, education, smoking status, drinking status, and number of residents per household. Furthermore, the significant combined effects on physical/mental health were found for paired residential environmental problems, including temperature and humidity, thermal environment and air quality/noise/mold, air quality and noise, and fall risks and wet problems, after adjustment for confounders. This paper attempted to disentangle complex relationships between residential indoor environment and quality of life, which will provide a basis to develop strategies for improving quality of life.

Formation pathways of aldehydes from heated cooking oils.

Cooking emissions account for a major fraction of urban volatile organic compounds and organic aerosol. Aldehyde species, in particular, are important exposure hazards in indoor residential and occupational environments, and precursors to particulate matter and ozone formation in outdoor air. Formation pathways of aldehydes from oils that lead to their emissions are not well understood. In this work, we investigate the underlying mechanisms involved in the formation of aldehydes from heated cooking oil emissions, through studying how antioxidants and oil composition modulate oxidation chemistry. Our results demonstrate that gaseous emissions are driven by radical-mediated autoxidation reactions in cooking oil, and the composition of cooking oils strongly influences the reaction mechanisms. Antioxidants have a dual effect on aldehyde emissions depending on the rates of radical propagation reactions. We propose a mechanistic framework that can be used to understand and predict cooking emissions under different cooking conditions. Our results highlight the need to understand the rates and mechanisms of autoxidation and other reactions in cooking oils in order to accurately predict the gas- and particle-phase emissions from food cooking in urban atmospheres.

Sex-differences in the effects of indoor air pollutants and household environment on preschool child cognitive development

Air pollution, outdoor residential environment, indoor household characteristics, and parental mental health are potential factors associated with child development. However, few studies have simultaneously analyzed the association between the aforementioned factors and preschool child (aged 2–5 years) development. This study investigated the effects of those factors on child development and their potential modifying effects. A total of 142 participants were recruited from a birth cohort study in the Greater Taipei Area, and the evaluation was conducted at each participant's home from 2017 to 2020. Child cognitive development was assessed by psychologists using the Bayley Scales of Infant and Toddler Development and the Wechsler Preschool & Primary Scale of Intelligence. Household air pollutants, outdoor residential environment, indoor household characteristics, parental mental health, and other covariates were evaluated. Multiple regressions were used to examine the relationships between child development and covariates. Stratified analysis by child sex and parental mental health was conducted. Average indoor air pollutant levels were below Taiwan's Indoor Air Quality Standards. After adjustment for covariates, the indoor total volatile organic compounds (TVOCs) level was significantly associated with poor child development (per interquartile range increase in the TVOC level was associated with a 5.1 percentile decrease in child cognitive development). Sex difference was observed for the association between TVOC exposure and child development. Living near schools, burning incense at home, purchasing new furniture, and parental anxiety were related to child development. Indoor TVOC level was associated with poor child cognitive development, specifically with the girls. Indoor and outdoor residential environment and parental anxiety interfered with child development. TVOCs should be used cautiously at home to minimize child exposure. A low-pollution living environment should be provided to ensure children's healthy development.

Older Adults' Response to Color Visibility in Indoor Residential Environment Using Eye-Tracking Technology.

Older adults spend relatively more time in indoor residential environments than young people. As their visual and cognitive abilities decline, they experience a high risk of accidents in indoor environments; thus, understanding their gaze behavior while considering cognitive capacity is essential in preventing potential accidents and planning for aging-friendly environments. The purpose of this study was to examine whether the use of color in living environments affects the visual attention of older adults. The following two experiments were conducted using eye-tracking technology: Experiment 1: Older adults' gaze behaviors were measured while viewing four images consisting of nine sets of door-door frames with different color combinations of safety colors, black and white; and Experiment 2: Based on results from Experiment 1, images of simulated living environments were created, and older adults' gaze behaviors were measured while viewing eight images in which two door colors were applied to verify spatial color visibility. Their cognitive state represented by the Mini-Mental State Examination (MMSE) was then compared with their gaze behavior. The results show that: (a) participants paid more attention to doors with color combinations including red (red-black and white-red) and remained longer on the red-black combination; (b) older adults looked at red-black doors faster than white doors in the same position; (c) the dwell time on a red-black door was longer than on that of the corresponding position of a white door; and (d) based on participants' MMSE values, the gaze behaviors of the group with low cognition were less focused and observable than those of the group with normal cognition. The results of this study are significant in that they reveal that indoor color can improve the visibility of elements that can impact safety in the living environments of older adults and enhance their quality of life.

Partition of phthalates among air, PM2 .5 , house dust and skin in residential indoor environments.

As a group of typical endocrine disrupters, phthalates are simultaneously present in a variety of environmental media and enter human body through multiple exposure pathways. In this study, field monitoring data were used to characterize the skin-air (Klg ), dust-air (Kd ), and PM2.5 -air (Kp ) partition coefficients of DiBP, DnBP, and DEHP. The median values of log(Klg ) in the summer and winter were 7.654 and 7.932, 7.265 and 7.902, 9.419 and 9.015 for DiBP, DnBP, and DEHP, respectively, and Klg was significantly higher in the winter. The median Kd (m3 /mg) in the summer (0.036-0.151 for DiBP, 0.021-0.036 for DnBP and 1.479-4.069 for DEHP) were significantly higher than the counterparts in the winter (0.027-0.065 for DiBP, 0.022-0.245 for DnBP, and 0.140-3.250 for DEHP). In addition, Kd was associated with material of surface and residence time of dust. The Kp values (m3 /μg) of DiBP, DnBP, and DEHP in the summer (0.053, 0.015, and 0.021) were also significantly higher than the counterparts in the winter (0.011, 0.004, and 0.025). The partition of phthalates was influenced by built environment, such as temperature, humidity, ventilation, indoor chemistry, smoking, and building age. Except Klg , there was substantial discrepancy between the estimates of K with empirical equations and the values of K based on field monitoring data in our study.

Association between levels of radon and bioaerosols (bacteria and fungi) by living conditions

ABSTRACT This study aimed to measure the levels of airborne radon Rn and bioaerosols – culturable airborne bacteria (CAB) and culturable airborne fungi (CAF)—in South Korea’s residential environments, considering living conditions such as the number of ventilations, number of windows, floors, temperature, and relative humidity. . The range of Rn levels was 0.43–7.439 pCi/L with a median of 0.70 pCi/L. The CAB levels were 239–488 colony-forming unit (CFU)/m3 with a median of 309 CFU/m3, and CAF levels were 174–366 CFU/m3 with a median of 233 CFU/m3. Thus, this study found that semi-basement residential indoor environments negatively affected Rn and bioaerosol levels, and living in such residences resulted in high health condition scores on the bad side. Given the correlation between airborne Rn and bioaerosol levels, further large-scale studies are needed to identify more reliable and representative of research.

PM2.5 elemental composition in indoor residential environments and co-exposure effects on respiratory health in an industrial area

This study aimed to identify and characterise indoor sources of particulate matter (PM) in domestic environments. 74 inhabited apartments located in the urban area of Gela (Sicily, Italy), close to a refinery, and in three villages of the hinterland were evaluated, in real-world conditions, for the elemental composition of PM2.5. The samples were collected simultaneously inside and outside each apartment for 48 h. In addition, two of the apartments were simultaneously studied for four weeks.The elemental composition of PM2.5 was determined by applying a chemical fractionation procedure followed by inductively-coupled plasma spectrometry analysis, with both optical emission and mass detection. The extractable, more bio-accessible fraction (ext), and the mineralised residual fraction (res) of each element were determined, thus increasing the selectivity of elements as source tracers.Indoor air in the considered apartments was affected by both outdoor pollution and specific indoor emission sources. The behaviour of each source was studied in detail, identifying a reliable tracer: Tires for soil, Asext for industrial sources, Vext for heavy oil combustion, Ce for cigarette smoking and Mo for the use of vacuum dust cleaners. Asext and Vext showed an excellent infiltration capacity, while the concentration of Tires was affected by a low infiltration capacity and by the contribution of particles re-suspension caused by the residents' movements. In the case of Ce and Mo, indoor concentrations were much higher than outdoor with a high variability among the apartments, due to the inhabitants’ habits concerning cigarette smoke and use of electric appliances. To test the overall effect of the concomitant exposure to the identified sources on Wh12 M and on DDA, a WQS analysis was conducted. Cigarette smoking and heavily oil combustion driven the Wh12 M odds increase, while the DDA odds increase was mainly driven by heavily oil combustion and the use of vacuum dust cleaners.