Children exposure to indoor ultrafine particles in urban and rural school environments

Assessment of indoor environmental quality and seasonal well-being of students in a combined historic technical school building in Slovakia

One of the major present challenges in the building sector is to construct sustainable and low-energy buildings with a healthy, safe, and comfortable environment. This study is designed to explore long-term impacts of indoor environmental quality (IEQ) parameters in a historic technical school building on the health and comfort of students. The main objective is to identify environmental problems in schools and to direct public policy towards the enhancement of in-service historic buildings. The collected data on five consecutive days in various seasons from five different classrooms indicate allergy in 45% and asthma in 10% of students. Environmental factors, such as temperature, draught, noise, or light, affected 51% of students' attention. Low temperature, unpleasant air, noise, and draught were found to be the most frequent concerns for students. The lowest temperature was measured during spring at 17.6 °C, the lowest humidity of 21.1% in winter, the largest CO2 amount in the air in autumn at 2041 ppm level, and the greatest total volatile organic compounds (TVOC) as 514 µg/m3. The experimental and statistical analysis results suggest the necessity of a comprehensive restoration of the building with a focus on enhancement of IEQ as well as replacement of old non-standard materials. An effective ventilation system is also necessary. The building requires major renovations to preserve its historic features while safeguarding the well-being and comfort of students and staff. Further research is needed on acoustics, lighting, and energy factors as well as the health effects of old building materials.

Indoor environmental quality in households of families with infant twins under 1 year of age living in Porto

Exposure to air pollution in early years can exacerbate the risk of noncommunicable diseases throughout childhood and the entire life course. This study aimed to assess temperature, relative humidity (RH), carbon dioxide (CO₂) and monoxide (CO), particulate matter (PM_2.5, PM₁₀), ultrafine particles, nitrogen dioxide (NO₂), ozone (O₃), formaldehyde, acetaldehyde and volatile organic compounds (VOC) levels in the two rooms where infant twins spend more time at home (30 dwellings, Northern Portugal). Findings showed that, in general, the worst indoor environmental quality (IEQ) settings were found in bedrooms. In fact, although most of the bedrooms surveyed presented adequate comfort conditions in terms of temperature and RH, several children are sleeping in a bedroom with improper ventilation and/or with a significant degree of air pollution. In particular, mean concentrations higher than recommended limits were found for CO₂, PM_2.5, PM₁₀ and total VOC. Additionally, terpenes and decamethylcyclopentasiloxane were identified as main components of emissions from indoor sources. Overall, findings revealed that factors related to behaviors of the occupants, namely related to a conscientious use of cleaning products, tobacco and other consumer products (air-fresheners, incenses/candles and insecticides) and promotion of ventilation are essential for the improvement of air quality in households and for the promotion of children's health.

Assessment of indoor air exposure among newborns and their mothers: Levels and sources of PM10, PM2.5 and ultrafine particles at 65 home environments

Significant efforts have been directed towards addressing the adverse health effects of atmospheric particles, emphasizing the relevance of indoor exposure. Homes represent an indoor environment where human spend the majority of their time. Thus, the objective of this work was to concurrently assess different matrix of indoor particles considering both mass (PM₁₀, PM_2.5) and number (N_20-1000) concentrations in indoor and outdoor air of homes (n = 65). Real-time measurements (PM₁₀, PM_2.5, UFP) were conducted simultaneously during 48 h in dwellings situated in Oporto, Portugal. In 75% of homes, indoor PM_2.5 (mean = 53 μg m^-3) exceeded limit of 25 μg m^-3, for PM₁₀ (mean = 57 μg m^-3) 41% of homes demonstrated average levels higher than 50 μg m^-3, thus indicating potential risks. Indoor PM₁₀ was mostly (82-99%) composed of PM_2.5, both PM were highly correlated (|rs|>0.9655), thus suggesting the similar origin. Indoor PM originated from infiltrations of outdoor emissions; ∼70% of homes exhibited indoor to outdoor (I/O) ratio < 1. On the contrary, UFP indoors (mean = 13.3 × 10³ # cm^-3) were higher than outdoors (mean = 10.0 × 10³ # cm^-3). Indoor UFP spatially varied as follows: kitchens > living rooms > bedrooms. UFP indoors were poorly correlated (|rs| = 0.456) with outdoor concentrations, I/O ratios showed that indoor UFP predominantly originated from indoor emission sources (combustions). Therefore, in order to reduce exposure to UFP and protect public health, the primary concerns should be focused on controlling emissions from indoor sources.

Comprehensive assessment of the indoor air quality in a chlorinated Olympic-size swimming pool

Elite swimmers and swimming pool employees are likely to be at greater health risk due to their regular and intense exposure to air stressors in the indoor swimming pool environment. Since data on the real long-term exposure is limited, a long-term monitoring and sampling plan (22 non-consecutive days, from March to July 2017) was carried out in an indoor Olympic-size pool with a chlorine-based disinfection method to characterize indoor environments to which people involved in elite swimming and maintenance staff may be exposed to. A comprehensive set of parameters related with comfort and environmental conditions (temperature, relative humidity (RH), carbon dioxide (CO₂) and monoxide and ultrafine particles (UFP)) were monitored both indoors and outdoors in order to determine indoor-to-outdoor (I/O) ratios. Additionally, an analysis of volatile organic compounds (VOC) concentration and its dynamics was implemented in three 1-hr periods: early morning, evening elite swimmers training session and late evening. Samplings were simultaneously carried out in the air layer above the water surface and in the air surrounding the pool, selected to be representative of swimmers and coaches/employees' breathing zones, respectively. The results of this work showed that the indoor climate was very stable in terms of air temperature, RH and CO₂. In terms of the other measured parameters, mean indoor UFP number concentrations (5158 pt/cm³) were about 50% of those measured outdoors whereas chloroform was the predominant substance detected in all samples collected indoors (13.0-369.3 µg/m³), among a varied list of chemical compounds. An I/O non-trihalomethanes (THM) VOC concentration ratio of 2.7 was also found, suggesting that, beyond THM, other potentially hazardous VOC have also their source(s) indoors. THM and non-THM VOC concentration were found to increase consistently during the evening training session and exhibited a significant seasonal pattern. Compared to their coaches, elite swimmers seemed to be exposed via inhalation to significantly higher total THM levels, but to similar concentrations of non-THM VOC, during routine training activities. Regarding swimming employees, the exposure to THM and other VOC appeared to be significantly minimized during the early morning period. The air/water temperature ratio and RH were identified as important parameters that are likely to trigger the transfer processes of volatile substances from water to air and of their accumulation in the indoor environment of the swimming pool, respectively.

Exposure to ultrafine particles in children until 18 years of age: A systematic review

Airborne ultrafine particles (UFP) have been related to adverse health effects, but exposure in vulnerable population groups such as children is still not well understood. We aim to review the scientific literature regarding personal exposure to UFP in different microenvironments in populations until 18 years of age. The bibliographical search was carried out in July 2019 using the online database PubMed and was completed with references in articles found in the search. We selected the studies that used continuous counters and measured UFP levels in both specific microenvironment (houses, schools, transport, etc) and personal exposure. Finally, 32 studies fulfilled the criteria: of these, 10 analyzed personal exposure and 22 examined UFP levels in the microenvironment (especially in schools or nurseries (18/22)) and five in various microenvironments (including dwellings and means of transport, where exposure levels were higher). The characteristics of the microenvironments with the greatest levels of UFP were being close to heavy traffic or near cooking and cleaning activities. This review revealed the wide differences in exposure assessment methodologies that could lead to a lack of uniform and comparable information about the real UFP exposure in children.

Assessment of the air quality in 20 public indoor swimming pools located in the Northern Region of Portugal

Air exposures occurring in indoor swimming pools are an important public health issue due to their popularity and regular use by the general population, including vulnerable groups such as children and elderly people. More comprehensive information on indoor air quality (IAQ) in swimming pools is thus needed in order to understand health risks, establish appropriate protective limits and provide evidence-based opportunities for improvement of IAQ in these facilities. In this context, twenty public indoor swimming pools located in the Northern Region of Portugal were examined in two sampling campaigns: January-March and May-July 2018. For each campaign, a comprehensive set of environmental parameters was monitored during the entire period of the facilities' operating hours of a weekday, both indoors and outdoors. In addition, four air (1-h samplings) and water samples were collected. Findings show that comfort conditions, ultrafine particles number concentrations and exposure to substances in the indoor air (concentration and composition) is likely to vary greatly from one public indoor swimming pool to another. Trihalomethanes (THM) and dichloroacetonitrile were the predominant disinfection by-products identified in the indoor air but other potentially hazardous volatile organic compounds, such as limonene, 1,2,4-trimethylbenzene, 2,2,4,4,6,8,8-heptamethylnonane, 2- and 3-methylbutanenitrile, acetophenone, benzonitrile, and isobutyronitrile were found to have relevant putative emission sources in the environment of the swimming pools analyzed. Furthermore, indicators of poor ventilation conditions (namely carbon dioxide, relative humidity and existence of signs of condensation in windows) and some water-related parameters (THM levels, conductivity and salinity) were found to be determining factors of the measured airborne THM concentrations that appeared to significantly potentiate the exposure. In summary, this work provides evidence for the need to establish adequate standards for the comprehensive evaluation of IAQ in public swimming pools, in order to guide further development of evidence-based prevention/remediation strategies for promoting healthy environments in swimming pools.

Assessment of ultrafine particles in primary schools: Emphasis on different indoor microenvironments

Due to the negative health impacts, significant efforts have been directed towards investigating ultrafine particle (UFP) exposure in various indoor environments. As children spend approximately one third of their time in schools, educatory environments deserve particular attention; however, majority of past research has focused on UFP assessment in classrooms. Thus, this work aims to expand the characterization of UFP in primary schools by considering different indoor and outdoor school microenvironments and estimating inhalation doses for the respective students (6-11yrs old). Real-time UFP measurements were daily conducted (9:00-17:30) in 20 primary schools in Oporto (January-April 2014; October-February 2015) in classrooms, canteens, gyms, libraries, and concurrently outdoors. Overall, UFP concentrations showed large temporal and spatial variations. For classrooms (n = 73), median UFP (1.56 × 10³-16.8 × 10³ # cm^-3) were lower than the corresponding levels in ambient air of schools (1.79 × 10³-24.1 × 10³ # cm^-3). Outdoor emissions contributed to indoor UFP (indoor-to-outdoor ratios I/O of 0.0.30-0.85), but ventilation, room characteristics and its occupancy were identified as important parameters contributing to overall indoor UFP levels. Considering specific indoor school microenvironments, canteens were the microenvironment with the highest UFP levels (5.47 × 10³-36.4 × 10³ # cm^-3), cooking conducted directly on school grounds resulted in significantly elevated UFP in the respective classrooms (p < 0.05); the lowest UFP were found in libraries (4.45 × 10³-8.50 × 10³ # cm^-3) mostly due to the limited occupancies. Although students spend majority of their school time in classrooms (66-71%), classroom exposure was not consistently the predominant contributor to school total UFP inhalation dose (29-75%). Outdoor exposure contributed 23-70% of school dose (depending on UFP levels in ambient levels and/or conducted activities) whereas short periods of lunch break accounted for 8-40%. Therefore, when evaluating UFP exposure in educatory settings other microenvironments beyond classrooms should be an integral part of the study.

Indoor air quality in health clubs: Impact of occupancy and type of performed activities on exposure levels

Associations between indoor air quality (IAQ) and health in sport practise environments are not well understood due to limited knowledge of magnitude of inhaled pollutants. Thus, this study assessed IAQ in four health clubs (HC1-HC4) and estimated inhaled doses during different types of activities. Gaseous (TVOCs, CO, O₃, CO₂) and particulate pollutants (PM₁, PM₄) were continuously collected during 40 days. IAQ was influenced both by human occupancy and the intensity of the performed exercises. Levels of all pollutants were higher when clubs were occupied (p < 0.05) than for vacant periods, with higher medians in main workout areas rather than in spaces/studios for group activities. In all spaces, TVOCs highly exceeded legislative limit (600 μg/m³), even when unoccupied, indicating possible risks for the respective occupants. CO₂ levels were well correlated with relative humidity (r_s 0.534-0.625) and occupancy due to human exhalation and perspiration during exercising. Clubs with natural ventilations exhibited twice higher PM, with PM₁ accounting for 93-96% of PM₄; both PM were highly correlated (r_s 0.936-0.995) and originated from the same sources. Finally, cardio classes resulted in higher inhalation doses than other types of exercising (1.7-2.6).

Indoor particulate pollution in fitness centres with emphasis on ultrafine particles

Fitness centres (FC) represent a unique indoor microenvironment. Exercising on regular basis provides countless health benefits and improves overall well-being, but if these facilities have poor indoor air quality, the respective exercisers might be subjected to some adverse risks. Considering the limited existent data, this work aimed to evaluate particulate pollution (PM_10, PM_2.5, and ultrafine particles - UFP) in indoor air of FC and to estimate the respective risks for occupants (both staff and exercising subjects). Sampling was conducted during 40 consecutive days of May-June 2014 in general fitness areas, studios and classrooms (for group activities) of four different fitness centres (FC1-FC4) situated within Oporto metropolitan area, Portugal. The results showed that across the four FC, PM₁₀ ranged between 5 and 1080 μg m^-3 with median concentrations (15-43 μg m^-3) fulfilling the limit (50 μg m^-3) of Portuguese legislation in all FC. PM_2.5 (medians 5-37 μg m^-3; range 5-777 μg m^-3) exceeded thresholds of 25 μg m^-3 at some FC, indicating potential risks for the respective occupants; naturally ventilated FC exhibited significantly higher PM ranges (p < 0.05). Similarly, UFPs (range 0.5-88.6 × 10³ # cm^-3) median concentrations were higher (2-3 times) at FC without controlled ventilation systems. UFP were approximately twice higher (p < 0.05) during the occupied periods (mean of 9.7 × 10³vs. 4.8 × 10³ # cm^-3) with larger temporal variations of UFP levels observed in general fitness areas than in classrooms and studios. Cardio activities (conducted in studios and classrooms) led to approximately twice the UFPs intakes than other types of exercising. These results indicate that even short-term physical activity (or more specifically its intensity) might strongly influence the daily inhalation dose. Finally, women exhibited 1.2 times higher UFPs intake than men thus suggesting the need for future gender-specific studies assessing UFP exposure.

Urinary trans-trans muconic acid (exposure biomarker to benzene) and hippuric acid (exposure biomarker to toluene) concentrations in Mexican women living in high-risk scenarios of air pollution

This study aimed to determine t,t-muconic acid (t,t-MA; exposure biomarker for benzene) and hippuric acid (HA; exposure biomarker for toluene) concentrations in the urine of women living in Mexico. In a cross-sectional study, apparently healthy women (n = 104) were voluntarily recruited from localities with a high risk of air pollution; t,t-MA and HA in urine were quantified using a high-performance liquid chromatography (HPLC) technique. Mean urinary levels of t,t-MA ranged from 680 to 1,310 μg/g creatinine. Mean values of HA ranged from 0.38 to 0.87 g/g creatinine. In conclusion, compared to data recently reported in literature, we found high urinary levels of t,t-MA and HA in assessed women participating in this study. We therefore deem the implementation of a strategy aimed at the reduction of exposure as a necessary measure for the evaluated communities.

Ultrafine particles and black carbon personal exposures in asthmatic and non-asthmatic children at school age

Traffic-related air pollution (TRAP) exposure during childhood is associated with asthma; however, the contribution of the different TRAP pollutants in each microenvironment (home, school, transportation, others) in asthmatic and non-asthmatic children is unknown. Daily (24-h) personal black carbon (BC), ultrafine particle (UFP), and alveolar lung-deposited surface area (LDSA) individual exposure measurements were obtained from 100 children (29 past and 21 current asthmatics, 50 non-asthmatics) aged 9±0.7 years from the INMA-Sabadell cohort (Catalonia, Spain). Time spent in each microenvironment was derived by the geolocation provided by the smartphone and a new spatiotemporal map-matching algorithm. Asthmatics and non-asthmatics spent the same amount of time at home (60% and 61%, respectively), at school (20% and 23%), on transportation (8% and 7%), and in other microenvironments (7% and 5%). The highest concentrations of all TRAPs were attributed to transportation. No differences in TRAP concentrations were found overall or by type of microenvironment between asthmatics and non-asthmatics, nor when considering past and current asthmatics, separately. In conclusion, asthmatic and non-asthmatic children had a similar time-activity pattern and similar average exposures to BC, UFP, and LDSA concentrations. This suggests that interventions should be tailored to general population, rather than to subgroups defined by disease.