Validity of Mobility-Based Exposure Assessment of Air Pollution: A Comparative Analysis with Home-Based Exposure Assessment.

Air pollution exposure is typically assessed at the front door where people live in large-scale epidemiological studies, overlooking individuals' daily mobility out-of-home. However, there is limited evidence that incorporating mobility data into personal air pollution assessment improves exposure assessment compared to home-based assessments. This study aimed to compare the agreement between mobility-based and home-based assessments with personal exposure measurements. We measured repeatedly particulate matter (PM2.5) and black carbon (BC) using a sample of 41 older adults in the Netherlands. In total, 104 valid 24 h average personal measurements were collected. Home-based exposures were estimated by combining participants' home locations and temporal-adjusted air pollution maps. Mobility-based estimates of air pollution were computed based on smartphone-based tracking data, temporal-adjusted air pollution maps, indoor-outdoor penetration, and travel mode adjustment. Intraclass correlation coefficients (ICC) revealed that mobility-based estimates significantly improved agreement with personal measurements compared to home-based assessments. For PM2.5, agreement increased by 64% (ICC: 0.39-0.64), and for BC, it increased by 21% (ICC: 0.43-0.52). Our findings suggest that adjusting for indoor-outdoor pollutant ratios in mobility-based assessments can provide more valid estimates of air pollution than the commonly used home-based assessments, with no added value observed from travel mode adjustments.

Personal exposure to radiofrequency electromagnetic fields: A comparative analysis of international, national, and regional guidelines.

A worldwide overview and analysis for the existing limits of human exposure to Radiofrequency Electromagnetic Fields (RF-EMF) is given in this paper. These reference levels have been established by different national and even regional governments, which can be based on the guidelines provided by the recommendations of the International Commission on Non-Ionizing Radiation Protection (ICNIRP), the International Committee on Electromagnetic Safety of the Institute of Electrical and Electronics Engineers (IEEE), and even in the United States of the Federal Communications Commission (FCC), as well as, are based on the so-called precautionary principle. Explicit reference is made to the exposure limits adopted in countries or regions, such as Canada, Italy, Poland, Switzerland, China, Russia, France, and regions of Belgium (Brussels, Flanders, Wallonia), where the limits are much lower than the international standards. The limits are compared to a selected set of in-situ measurements. This clearly shows that the measured values are typically very small compared to the international standards but could be somewhat higher compared to the reduced limits. Based on this observation and the reasonable assumption that the sensitivity of people to Electromagnetic Fields (EMF) is the same everywhere (whole-body), we propose the idea to establish a worldwide reference limit for the general public, thus applicable in all countries, if the ICNIRP considers it appropriate. Research must continue to generate measurement data that demonstrate the levels of exposure to which we are really exposed, and with this, provide arguments to the organizations that established the guidelines, especially the ICNIRP, to evaluate whether the current limits are too much. High and can be modified when considered pertinent. To the best of our knowledge, at no time has the reference level for the general public been exceeded.

A comprehensive review of 5G NR RF-EMF exposure assessment technologies: fundamentals, advancements, challenges, niches, and implications.

This review offers a detailed examination of the current landscape of radio frequency (RF) electromagnetic field (EMF) assessment tools, ranging from spectrum analyzers and broadband field meters to area monitors and custom-built devices. The discussion encompasses both standardized and non-standardized measurement protocols, shedding light on the various methods employed in this domain. Furthermore, the review highlights the prevalent use of mobile apps for characterizing 5G NR radio network data. A growing need for low-cost measurement devices is observed, commonly referred to as "sensors" or "sensor nodes", that are capable of enduring diverse environmental conditions. These sensors play a crucial role in both microenvironmental surveys and individual exposures, enabling stationary, mobile, and personal exposure assessments based on body-worn sensors, across wider geographical areas. This review revealed a notable need for cost-effective and long-lasting sensors, whether for individual exposure assessments, mobile (vehicle-integrated) measurements, or incorporation into distributed sensor networks. However, there is a lack of comprehensive information on existing custom-developed RF-EMF measurement tools, especially in terms of measuring uncertainty. Additionally, there is a need for real-time, fast-sampling solutions to understand the highly irregular temporal variations EMF distribution in next-generation networks. Given the diversity of tools and methods, a comprehensive comparison is crucial to determine the necessary statistical tools for aggregating the available measurement data.

Characterization of airborne endotoxin in personal exposure to fine particulate matter (PM2.5) and bioreactivity for elderly residents in Hong Kong.

The heavy metals and bioreactivity properties of endotoxin in personal exposure to fine particulate matter (PM2.5) were characterized in the analysis. The average personal exposure concentrations to PM2.5 were ranged from 6.8 to 96.6 µg/m3. The mean personal PM2.5 concentrations in spring, summer, autumn, and winter were 32.1±15.8, 22.4±11.8, 35.3±11.9, and 50.2±19.9 µg/m3, respectively. There were 85 % of study targets exceeded the World Health Organization (WHO) PM2.5 threshold (24 hours). The mean endotoxin concentrations ranged from 1.086 ± 0.384-1.912 ± 0.419 EU/m3, with a geometric mean (GM) varied from 1.034 to 1.869. The concentration of iron (Fe) (0.008-1.16 µg/m3) was one of the most abundant transition metals in the samples that could affect endotoxin toxicity under Toll-Like Receptor 4 (TLR4) stimulation. In summer, the interleukin 6 (IL-6) levels showed statistically significant differences compared to other seasons. Spearman correlation analysis showed endotoxin concentrations were positively correlated with chromium (Cr) and nickel (Ni), implying possible roles as nutrients and further transport via adhering to the surface of fine inorganic particles. Mixed-effects model analysis demonstrated that Tumor necrosis factor-α (TNF-α) production was positively associated with endotoxin concentration and Cr as a combined exposure factor. The Cr contained the highest combined effect (0.205-0.262), suggesting that Cr can potentially exacerbate the effect of endotoxin on inflammation and oxidative stress. The findings will be useful for practical policies for mitigating air pollution to protect the public health of the citizens.

Assessment of PM2.5 Concentration at University Transit Bus Stops Using Low-Cost Aerosol Monitors by Student Commuters.

Particulate matter of 2.5 µm and smaller (PM2.5) is known to cause many respiratory health problems, such as asthma and heart disease. A primary source of PM2.5 is emissions from cars, trucks, and buses. Emissions from university transit bus systems could create zones of high PM2.5 concentration at their bus stops. This work recruited seven university students who regularly utilized the transit system to use a low-cost personal aerosol monitor (AirBeam) each time they arrived at a campus bus stop. Each participant measured PM2.5 concentrations every time they were at a transit-served bus stop over four weeks. PM2.5 concentration data from the AirBeam were compared with an ADR-1500 high-cost monitor and EPA PM2.5 reference measurements. This methodology allowed for identifying higher-than-average concentration zones at the transit bus stops compared to average measurements for the county. By increasing access to microenvironmental data, this project can contribute to public health efforts of personal protection and prevention by allowing individuals to measure and understand their exposure to PM2.5 at the bus stop. This work can also aid commuters, especially those with pre-existing conditions who use public transportation, in making more informed health decisions and better protecting themselves against new or worsening respiratory conditions.

[Personal nitrogen oxides exposure levels and related influencing factors in adults over 35 years old in Tianjin and Shanghai].

OBJECTIVE: To investigate personal exposures to nitrogen oxides (NOX) and nitrogen di-oxide (NO2) and the influence of baseline personal characteristics, living environment and daily activity patterns of the participants on the exposures among adults over 35 in Tianjin and Shanghai. METHODS: In this panel study, 91 healthy nonsmoking adults aged over 35 from Tianjin and Shanghai participated in our study. The study was conducted in summer and winter. The participants were followed for three times with an interval of at least two weeks. Only participants in Shanghai were followed once in winter because of the COVID-19 pandemic. Twenty-seven participants completed follow-up visits in both seasons. We measured their 24 h personal exposures to NOX and NO2and collected their baseline and time-activity information through questionnaire/diary. The linear mixed model was used to analyze the associations between potential influencing factors and personal NOX and NO2 exposure levels. RESULTS: There were 349 follow-up visits with valid 24 h personal NO2 and NOX exposure measurements in the two cities. The ave-rage 24 h personal exposures to NO2 and NOX (volume fraction) in Tianjin participants were 18.0×10-9 and 26.2×10-9 in summer, and 31.0×10-9 and 54.9×10-9 in winter, respectively; and the average 24 h personal exposures to NO2 and NOX in Shanghai participants were 38.7×10-9 and 100.0×10-9 in summer, and 45.5×10-9 and 139.2×10-9 in winter, respectively. The results of univariate regression analysis showed that their personal NOX exposure levels were significantly associated with city, season, gender, average daily cooking times, and ambient NO2 concentrations measured at fixed-site monitoring stations. In addition to the above factors, the personal NOX exposure levels were also significantly associated with educational level and the personal NO2 exposure levels were also significantly associated with passive smoking, average daily home time, cooking energy type, residential distance from main traffic road, and use of kitchen ventilators. Multivariate regression analysis showed that the personal exposure levels of NO2 and NOX were significantly lower in Tianjin than that in Shanghai, were significantly lower in summer than that in winter, and were significantly and positively associated with ambient NO2 concentrations measured at fixed-site monitoring stations. In addition, personal NOX exposure levels were significantly lower in females than in males, and personal NO2 exposure levels were significantly positively associated with average daily cooking times and significantly inversely associated with average daily home time. For every interquartile range (IQR) increase (12.7×10-9) in ambient NO2, the personal NO2 exposure levels increased by 27.5% (95%CI: 17.0%-38.9%), and personal NOX exposure levels increased by 16.1% (95%CI: 7.1%-25.8%). CONCLUSION: Season, city and ambient NO2 concentrations are significant influencing factors of personal exposure levels of NO2and NOX. At the same time, the personal exposures levels of NO2are also affected by lifestyle factors. Our study provides scientific evidence for making precise air pollution control decisions and reducing the exposure levels of NOX in the population.

AirPen: A Wearable Monitor for Characterizing Exposures to Particulate Matter and Volatile Organic Compounds.

Exposure to air pollution is a leading risk factor for disease and premature death, but technologies for assessing personal exposure to particulate and gaseous air pollutants, including the timing and location of such exposures, are limited. We developed a small, quiet, wearable monitor, called the AirPen, to quantify personal exposures to fine particulate matter (PM2.5) and volatile organic compounds (VOCs). The AirPen combines physical sample collection (PM onto a filter and VOCs onto a sorbent tube) with a suite of low-cost sensors (for PM, VOCs, temperature, pressure, humidity, light intensity, location, and motion). We validated the AirPen against conventional personal sampling equipment in the laboratory and then conducted a field study to measure at-work and away-from-work exposures to PM2.5 and VOCs among employees at an agricultural facility in Colorado, USA. The resultant sampling and sensor data indicated that personal exposures to benzene, toluene, ethylbenzene, and xylenes were dominated by a specific workplace location. These results illustrate how the AirPen can be used to advance our understanding of personal exposure to air pollution as a function of time, location, source, and activity, even in the absence of detailed activity diary data.

A Comparison of Measured Airborne and Self-Reported Secondhand Smoke Exposure in the MADRES Pregnancy Cohort Study.

INTRODUCTION: Secondhand smoke (SHS) exposure during pregnancy is linked to adverse birth outcomes, such as low birth weight and preterm birth. While questionnaires are commonly used to assess SHS exposure, their ability to capture true exposure can vary, making it difficult for researchers to harmonize SHS measures. This study aimed to compare self-reported SHS exposure with measurements of airborne SHS in personal samples of pregnant women. METHODS: SHS was measured on 48-hour integrated personal PM2.5 Teflon filters collected from 204 pregnant women, and self-reported SHS exposure measures were obtained via questionnaires. Descriptive statistics were calculated for airborne SHS measures, and analysis of variance tests assessed group differences in airborne SHS concentrations by self-reported SHS exposure. RESULTS: Participants were 81% Hispanic, with a mean (SD) age of 28.2 (6.0) years. Geometric mean (SD) personal airborne SHS concentrations were 0.14 (9.41) µg/m3. Participants reporting lower education have significantly higher airborne SHS exposure (p=0.015). Mean airborne SHS concentrations were greater in those reporting longer duration with windows open in the home. There was no association between airborne SHS and self-reported SHS exposure; however, asking about the number of smokers nearby in the 48-hour monitoring period was most correlated with measured airborne SHS (Two+ smokers: 0.30µg/m3 vs. One: 0.12µg/m3 and Zero: 0.15µg/m3; p=0.230). CONCLUSIONS: Self-reported SHS exposure was not associated with measured airborne SHS in personal PM2.5 samples. This suggests exposure misclassification using SHS questionnaires and the need for harmonized and validated questions to characterize this exposure in health studies. IMPLICATIONS: This study adds to the growing body of evidence that measurement error is a major concern in pregnancy research, particularly in studies that rely on self-report questionnaires to measure secondhand smoke (SHS) exposure. The study introduces an alternative method of SHS exposure assessment using objective optical measurements, which can help improve the accuracy of exposure assessment. The findings emphasize the importance of using harmonized and validated SHS questionnaires in pregnancy health research to avoid biased effect estimates. This study can inform future research, practice, and policy development to reduce SHS exposure and its adverse health effects.

Pre-natal exposure to NO2 and PM2.5 and newborn lung function: An approach based on repeated personal exposure measurements.

CONTEXT: While strong evidence supports adverse effects of pre-natal air pollution on child's lung function, previous studies rarely considered fine particulate matter (PM2.5) or the potential role of offspring sex and no study examined the effects of pre-natal PM2.5 on the lung function of the newborn. AIM: We examined overall and sex-specific associations of personal pre-natal exposure to PM2.5 and nitrogen (NO2) with newborn lung function measurements. METHODS: This study relied on 391 mother-child pairs from the French SEPAGES cohort. PM2.5 and NO2 exposure was estimated by the average concentration of pollutants measured by sensors carried by the pregnant women during repeated periods of one week. Lung function was assessed with tidal breathing analysis (TBFVL) and nitrogen multiple breath washout (N2MBW) test, performed at 7 weeks. Associations between pre-natal exposure to air pollutants and lung function indicators were estimated by linear regression models adjusted for potential confounders, and then stratified by sex. RESULTS: Mean exposure to NO2 and PM2.5 during pregnancy was 20.2 µg/m3 and 14.3 µg/m3, respectively. A 10 µg/m3 increase in PM2.5 maternal personal exposure during pregnancy was associated with an adjusted 2.5 ml (2.3%) decrease in the functional residual capacity of the newborn (p-value = 0.11). In females, functional residual capacity was decreased by 5.2 ml (5.0%) (p = 0.02) and tidal volume by 1.6 ml (p = 0.08) for each 10 µg/m3 increase in PM2.5. No association was found between maternal NO2 exposure and newborns lung function. CONCLUSIONS: Personal pre-natal PM2.5 exposure was associated with lower lung volumes in female newborns, but not in males. Our results provide evidence that pulmonary effects of air pollution exposure can be initiated in utero. These findings have long term implications for respiratory health and may provide insights into the underlying mechanisms of PM2.5 effects.

Characteristics and determinants of personal exposure to typical air pollutants: A pilot study in Beijing and Baoding, China.

Personal exposure to fine particulate matter (PM2.5), nitrogen oxides (NOx, NO2 and NO), ozone (O3) and sulfur dioxide (SO2) was repeatedly measured among fourteen office workers in Beijing and Baoding, China in summer, autumn and winter of 2019. Time-activity patterns were simultaneously recorded. Determinants of personal air pollution exposure were investigated for each pollutant via a linear mixed effect model. The personal concentrations of PM2.5, NO2, NO and O3 were higher in autumn and winter than those in summer. A decreasing trend was found in the personal PM2.5 level for a typical indoor population in Beijing, indicating that particulate pollution was effectively controlled in Beijing and its surrounding area. The personal levels of PM2.5, NO2, and O3 were weakly correlated with those monitored at ambient stations and were lower than the respective ambient levels except for PM2.5 in summer and NO2 in winter. This pilot study showed that the indoor air environment, ambient pollution, traffic-related variables and temperature were significant exposure sources for office workers. Our study highlighted the significance of controlling traffic emissions and improving the workplace air quality to protect the health of office workers. More importantly, we demonstrated the feasibility of model development for personal air pollution exposure prediction.

Measurement studies of personal exposure to radiofrequency electromagnetic fields: A systematic review.

The last 25 years have seen an increase in the number of radiofrequency sources with the global adoption of smartphones as primary connectivity devices. The objective of this work was to review and evaluate the measured studies of personal exposure to Radiofrequency Electromagnetic Fields (RF-RMF) and meet the basic quality criteria eligible for inclusion in this Review, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, following the eligibility criteria of the PECO (Population, Exposure, Comparator, and Outcome) methodology, and the instrument for critical reading Critical Appraisal Skills Programme Español (CASPe). We systematically reviewed the works published between January 1, 1998, and December 31, 2021, yielding 56 publications. Of the different types of studies in which personal exposure to RF-EMF has been measured with two measurement methodologies can be highlighted: Personal measurements with volunteers and Personal measurements with a trained researcher (touring a specific area, one or several microenvironments, an entire city, walking or in some means of transport). Personal exposimeters were used in 83% of the studies. The lowest mean was measured in Egypt with a value of 0.00100 µW/m2 (1.00 nW/m2) in 2007 and the highest mean was measured in Belgium with a value of 285000 µW/m2 (0.285 W/m2) in 2019. The results of our study confirm that RF-EMF exposure levels are well below the maximum levels established by the ICNIRP guidelines.

Assessment of silicone wristbands for monitoring personal exposure to chlorinated paraffins (C8-36): A pilot study.

Chlorinated paraffins (CPs) are a major environmental concern due to their ubiquitous presence in the environment. Since human exposure to CPs can significantly differ among individuals, it is essential to have an effective tool for monitoring personal exposure to CPs. In this pilot study, silicone wristbands (SWBs) were employed as a personal passive sampler to measure time-weighted average exposure to CPs. Twelve participants were asked to wear a pre-cleaned wristband for a week during the summer of 2022, and three field samplers (FSs) in different micro-environments were also deployed. The samples were then analyzed for CP homologs by LC-Q-TOFMS. In worn SWBs, the median concentrations of quantifiable CP classes were 19 ng/g wb, 110 ng/g wb, and 13 ng/g wb for ∑SCCPs, ∑MCCPs, and ∑LCCPs (C18-20), respectively. For the first time, lipid content is reported in worn SWBs, which could be a potential impact factor in the kinetics of the accumulation process for CPs. Results showed that micro-environments were key contributors to dermal exposure to CPs, while a few outliers suggested other sources of exposure. CP exposure via dermal contact showed an increased contribution and thus poses a nonnegligible potential risk to humans in daily life. Results presented here provide proof of concept of the use of SWBs as a cheap and non-invasive personal sampler in exposure studies.

The association between real-life markers of phone use and cognitive performance, health-related quality of life and sleep.

INTRODUCTION: The real-life short-term implications of electromagnetic fields (RF-EMF) on cognitive performance and health-related quality of life have not been well studied. The SPUTNIC study (Study Panel on Upcoming Technologies to study Non-Ionizing radiation and Cognition) aimed to investigate possible correlations between mobile phone radiation and human health, including cognition, health-related quality of life and sleep. METHODS: Adult participants tracked various daily markers of RF-EMF exposures (cordless calls, mobile calls, and mobile screen time 4 h prior to each assessment) as well as three health outcomes over ten study days: 1) cognitive performance, 2) health-related quality of life (HRQoL), and 3) sleep duration and quality. Cognitive performance was measured through six "game-like" tests, assessing verbal and visuo-spatial performance repeatedly. HRQoL was assessed as fatigue, mood and stress on a Likert-scale (1-10). Sleep duration and efficiency was measured using activity trackers. We fitted mixed models with random intercepts per participant on cognitive, HRQoL and sleep scores. Possible time-varying confounders were assessed at daily intervals by questionnaire and used for model adjustment. RESULTS: A total of 121 participants ultimately took part in the SPUTNIC study, including 63 from Besancon and 58 from Basel. Self-reported wireless phone use and screen time were sporadically associated with visuo-spatial and verbal cognitive performance, compatible with chance findings. We found a small but robust significant increase in stress 0.03 (0.00-0.06; on a 1-10 Likert-scale) in relation to a 10-min increase in mobile phone screen time. Sleep duration and quality were not associated with either cordless or mobile phone calls, or with screen time. DISCUSSION: The study did not find associations between short-term RF-EMF markers and cognitive performance, HRQoL, or sleep duration and quality. The most consistent finding was increased stress in relation to more screen time, but no association with cordless or mobile phone call time.

Long-Term Thermal Comfort Monitoring via Wearable Sensing Techniques: Correlation between Environmental Metrics and Subjective Perception.

The improvement of comfort monitoring resources is pivotal for a better understanding of personal perception in indoor and outdoor environments and thus developing personalized comfort models maximizing occupants' well-being while minimizing energy consumption. Different daily routines and their relation to the thermal sensation remain a challenge in long-term monitoring campaigns. This paper presents a new methodology to investigate the correlation between individuals' daily Thermal Sensation Vote (TSV) and environmental exposure. Participants engaged in the long-term campaign were instructed to answer a daily survey about thermal comfort perception and wore a device continuously monitoring temperature and relative humidity in their surroundings. Normalized daily profiles of monitored variables and calculated heat index were clustered to identify common exposure profiles for each participant. The correlation between each cluster and expressed TSV was evaluated through the Kendall tau-b test. Most of the significant correlations were related to the heat index profiles, i.e., 49% of cases, suggesting that a more detailed description of physical boundaries better approximates expressed comfort. This research represents the first step towards personalized comfort models accounting for individual long-term environmental exposure. A longer campaign involving more participants should be organized in future studies, involving also physiological variables for energy-saving purposes.

Response Surface Modeling of the Steady-State Impedance Responses of Gas Sensor Arrays Comprising Functionalized Carbon Nanotubes to Detect Ozone and Nitrogen Dioxide.

Carbon nanotube (CNT) sensors provide a versatile chemical platform for ambient monitoring of ozone (O3) and nitrogen dioxide (NO2), two important airborne pollutants known to cause acute respiratory and cardiovascular health problems. CNTs have shown great potential for use as sensing layers due to their unique properties, including high surface to volume ratio, numerous active sites and crystal facets with high surface reactivity, and high thermal and electrical conductivity. With operational advantages such as compactness, low-power operation, and easy integration with electronics devices, nanotechnology is expected to have a significant impact on portable low-cost environmental sensors. Enhanced sensitivity is feasible by functionalizing the CNTs with polymers, metals, and metal oxides. This paper focuses on the design and performance of a two-element array of O3 and NO2 sensors comprising single-walled CNTs functionalized by covalent modification with organic functional groups. Unlike the conventional chemiresistor in which the change in DC resistance across the sensor terminals is measured, we characterize the sensor array response by measuring both the magnitude and phase of the AC impedance. Multivariate response provides higher degrees of freedom in sensor array data processing. The complex impedance of each sensor is measured at 5 kHz in a controlled gas-flow chamber using gas mixtures with O3 in the 60-120 ppb range and NO2 between 20 and 80 ppb. The measured data reveal response change in the 26-36% range for the O3 sensor and 5-31% for the NO2 sensor. Multivariate optimization is used to fit the laboratory measurements to a response surface mathematical model, from which sensitivity and selectivity are calculated. The ozone sensor exhibits high sensitivity (e.g., 5 to 6 MΩ/ppb for the impedance magnitude) and high selectivity (0.8 to 0.9) for interferent (NO2) levels below 30 ppb. However, the NO2 sensor is not selective.

Human personal air pollution clouds in a naturally ventilated office during the COVID-19 pandemic.

Personal cloud, termed as the difference in air pollutant concentrations between breathing zone and room sites, represents the bias in approximating personal inhalation exposure that is linked to accuracy of health risk assessment. This study performed a two-week field experiment in a naturally ventilated office during the COVID-19 pandemic to assess occupants' exposure to common air pollutants and to determine factors contributing to the personal cloud effect. During occupied periods, indoor average concentrations of endotoxin (0.09 EU/m3), TVOC (231 µg/m3), CO2 (630 ppm), and PM10 (14 µg/m3) were below the recommended limits, except for formaldehyde (58 µg/m3). Personal exposure concentrations, however, were significantly different from, and mostly higher than, concentrations measured at room stationary sampling sites. Although three participants shared the same office, their personal air pollution clouds were mutually distinct. The mean personal cloud magnitude ranged within 0-0.05 EU/m3, 35-192 µg/m3, 32-120 ppm, and 4-9 µg/m3 for endotoxin, TVOC, CO2, and PM10, respectively, and was independent from room concentrations. The use of hand sanitizer was strongly associated with an elevated personal cloud of endotoxin and alcohol-based VOCs. Reduced occupancy density in the office resulted in more pronounced personal CO2 clouds. The representativeness of room stationary sampling for capturing dynamic personal exposures was as low as 28% and 5% for CO2 and PM10, respectively. The findings of our study highlight the necessity of considering the personal cloud effect when assessing personal exposure in offices.

Health risk assessment of workers' exposure to BTEX and PM during refueling in an urban fuel station.

The proximity of fuel stations to the roads and the activities inside the station can contribute to PM and VOCs and impose health risks on station workers. The study presents the exposure and health risk assessment of the fuel station personnel to total volatile organic compounds (TVOCs) and particulate matter (PM) during refueling operations. TVOCs and PM monitoring were carried out at a fuel station in Chennai, India, for 1 week in March 2021, covering both weekdays and weekends. The health risks were assessed using EPA's health impact assessment methodology. Exposure to TVOCs (3177.39 ± 5450.32 µg/m3) exceeded the EPA standard of 5 µg/m3, by more than 500 times, peaking during refueling operations. The average concentrations of PM10, PM2.5, and PM1 were 76.55 ± 23.08 µg/m3, 41.81 ± 9 µg/m3, and 30.38 ± 7.56 µg/m3, respectively. The concentrations were observed to be high during morning and evening hours due to the increased traffic on the adjacent road and inside the fuel station. The synergistic health risks linked with long-term exposure to high concentrations of BTEX and PM were also estimated. At the fuel station, a significant contribution to the SOA formation potential was shown by toluene, followed by m-xylene, p-xylene, o-xylene, ethylbenzene, and benzene. Furthermore, the deposition of airborne particles in the workers' respiratory tract was calculated using the Multiple Path Particle Dosimetry model while considering the daily average exposure duration of 12 h. The results showed that 59% of PM10 particles were deposited in the head region, whereas 11% and 10% of PM2.5 and PM1 particles were deposited in the pulmonary region. Hence, the health risk assessment indicated no non-cancer risk of exposure to PM (hazard quotient = 0.13) to station personnel exposed regularly for 1 year. However, prolonged exposure to VOCs for more than 1 year can result in both carcinogenic and non-carcinogenic risk (hazard quotient = 0.045 and cancer risk > 10-6) in workers.

Determination of subpicogram levels of airborne polycyclic aromatic hydrocarbons for personal exposure monitoring assessment.

A method based on the use of GC coupled to Q-exactive Orbitrap mass spectrometry (GC-Orbitrap-MS) has been developed for the analysis of polycyclic aromatic hydrocarbons (PAHs) at sub-picogram levels. Outdoor ambient air particulate matter (PM2.5) and standard reference materials (SRM2260a) were analyzed in full scan mode showing low instrumental uncertainties (1-22%) and high linearity over a wide concentration range (0.5 pg and 500 pg/µL). Good reproducibility was obtained compared to the use of conventional single quadrupole GC-MS of PM samples. The quantification limit of the GC-Orbitrap-MS method for full scan analysis of PAHs in outdoor ambient air PM samples was 0.5 pg/µL. This low limit allowed the analysis of PAHs in samples collected with low volumes (< 0.5 m3), such as punch samples from whole filters or filter strips from personal exposure monitoring equipment. PAHs were successfully analyzed in filter strips from real-time Aethalometer AE51 equivalent black carbon (eBC) analyzers used in urban and rural sites, and in personal exposure monitors of firefighters during prescribed burns. The correlations between PAHs and eBC in these analyses were very strong (r2 ≥ 0.93). However, the equations obtained reflected the dominance of different emission sources, such as traffic in urban areas, wood burning for domestic heating, or wildfires. The method reported here affords the analyses of PAHs in high precision studies of atmospheric PM samples, e.g., high frequency sampling of low volumes, affording personal exposure monitoring assessments.

Personal PM2.5-bound PAH exposure and lung function in healthy office workers: A pilot study in Beijing and Baoding, China.

The effect of short-term exposure to polycyclic aromatic hydrocarbons (PAHs) on the respiratory system among healthy residents is unclear. Beijing and Baoding are typical polluted cities in China, and there is little research on PAH exposure and its health effects at the individual level. Fourteen healthy female office workers were recruited in urban Beijing and Baoding, China, in 2019. The personal exposure to fine particulate matter (PM2.5)-bound PAHs and lung function were seasonally monitored. The relationships between PAH exposure and lung function were determined by a generalized mixed linear model. Subjects were exposed to high levels of PAH, in which the benzo[a]pyrene (BaP) level (1.26 ng/m3) was over than Chinese national indoor standard (1 ng/m3). All PAHs concentration was higher in winter than that in summer and autumn. Only benz[a]anthracene (BaA) and chrysene (Chr) exposure showed weak relations with decreased lung function, i.e., a 0.58% and 0.73% decrease in peak expiratory flow at lag 2 day, respectively (p < 0.05). PAHs may not be suitable exposure indicators for short-term change in lung function. Our findings highlight the importance of reducing PAH pollution for public respiratory health protection in heavy-polluted cities of China. This pilot study also provides experience on personal PAH assessment such as estimation of the number of repeated measurements required, which is helpful to determine the relationship between PAH exposure and health effect.

Associations between Individual Exposure to Fine Particulate Matter Elemental Constituent Mixtures and Blood Lipid Profiles: A Panel Study in Chinese People Aged 60-69 Years.

Dyslipidemia may be a potential mechanism linking fine particulate matter (PM2.5) to adverse cardiovascular outcomes. However, inconsistent associations between PM2.5 and blood lipids have resulted from the existing research, and the joint effect of PM2.5 elemental constituents on blood lipid profiles remains unclear. We aimed to explore the overall associations between PM2.5 elemental constituents and blood lipid profiles and to identify the significant PM2.5 elemental constituents in this association. Sixty-nine elderly people were recruited between September 2018 and January 2019. Each participant completed a survey questionnaire, 3 days of individual exposure monitoring, health examination, and biological sample collection at each follow-up visit. Bayesian kernel machine regression (BKMR) models were used to identify the joint effects of the 17 elemental constituents on blood lipid profiles. Total cholesterol, low-density lipoprotein cholesterol (LDL-C), and non-high-density lipoprotein cholesterol (non-HDL-C) levels were significantly increased in older adults when exposed to the mixture of PM2.5 elemental constituents. Copper and titanium had higher posterior inclusion probabilities than other constituents, ranging from 0.76 to 0.90 (Cu) and 0.74 to 0.94 (Ti). Copper and titanium in the PM2.5 elemental constituent mixture played an essential role in changes to blood lipid levels. This study highlights the importance of identifying critical hazardous PM2.5 constituents that may cause adverse cardiovascular outcomes in the future.