Individual Exposure Assessment Research Articles

Unveiling the potential of a novel portable air quality platform for assessment of fine and coarse particulate matter: in-field testing, calibration, and machine learning insights.

Although low-cost air quality sensors facilitate the implementation of denser air quality monitoring networks, enabling a more realistic assessment of individual exposure to airborne pollutants, their sensitivity to multifaceted field conditions is often overlooked in laboratory testing. This gap was addressed by introducing an in-field calibration and validation of three PAQMON 1.0 mobile sensing low-cost platforms developed at the Mining and Metallurgy Institute in Bor, Republic of Serbia. A configuration tailored for monitoring PM2.5 and PM10 mass concentrations along with meteorological parameters was employed for outdoor measurement campaigns in Bor, spanning heating (HS) and non-heating (NHS) seasons. A statistically significant positive linear correlation between raw PM2.5 and PM10 measurements during both campaigns (R > 0.90, p ≤ 0.001) was observed. Measurements obtained from the uncalibrated NOVA SDS011 sensors integrated into the PAQMON 1.0 platforms exhibited a substantial and statistically significant correlation with the GRIMM EDM180 monitor (R > 0.60, p ≤ 0.001). The calibration models based on linear and Random Forest (RF) regression were compared. RF models provided more accurate descriptions of air quality, with average adjR2 values for air quality variables in the range of 0.70 to 0.80 and average NRMSE values between 0.35 and 0.77. RF-calibrated PAQMON 1.0 platforms displayed divergent levels of accuracy across different pollutant concentration ranges, achieving a data quality objective of 50% during both measurement campaigns. For PM2.5, uncertainty ( ) was below 50% for concentrations between 9.06 and 34.99μg/m3 in HS and 5.75 and 17.58μg/m3 in NHS, while for PM10, it stayed below 50% from 19.11 to 51.13μg/m3 in HS and 11.72 to 38.86μg/m3 in NHS.

Biochemical and gene expression alterations due to individual exposure of atrazine, dichlorvos, and imidacloprid and their combination in zebrafish.

In environmental toxicology, combined toxicity has emerged as an important concern. Atrazine (ATZ), dichlorvos (DIC), and imidacloprid (IMD) are the major pesticides, extensively used to control insect, flies, mosquitoes, and weed. Here, we investigate whether the exposure to three different types of pesticides individually and in combination for 24h alters antioxidant enzyme responses in zebrafish (Danio rerio). Oxidative stress parameters (biochemical and mRNA expression), acetylcholinesterase (AChE) activity, and Metallothionein-II (MT-II) mRNA expression levels were measured. Present work includes toxicological assessment of individual and combined (CMD) exposure of ATZ (185.4µM), DIC (181µM), IMD (97.8 µ), and CMD (ATZ 92.7µM + DIC 90.5µM + IMD 48.9µM), in the liver, kidney, and brain of adult zebrafish. Lipid peroxidation (LPO), glutathione (GSH) content, AChE, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) activity along with mRNA expression of SOD, CAT, GPx, and MT-II were evaluated. Briefly, LPO, GSH content, the activity of AChE, and all antioxidant enzymes enhanced significantly in individual exposure, which was further altered in the CMD group. The mRNA expression of SOD, CAT, GPx, and MT-II in the liver and kidney showed significant down-regulation in all exposed groups. In the brain, significant upregulation in mRNA expression of SOD, CAT, GPx, and MT-II was observed in DIC and IMD groups, while ATZ and CMD showed significant downregulation except for GPx. Findings postulate that the CMD group exhibits synergistic toxic manifestation. The present study provides the baseline data on the combined toxic effects of pesticides and suggests regulating the use of pesticides.

A Spatial Network-Based Assessment of Individual Exposure to COVID-19

This study seeks to examine the possible impacts of sociodemographic factors, individual mobility patterns, and daily activities on individual exposure to COVID-19 risk when assessed by different risk measures. Taking Hong Kong as the study area, we first model the risk of COVID-19 using a density-based approach and a network-based approach and reveal the differences in the spatial distributions of COVID-19 transmission risk they obtained. Then, using two-day individual Global Positioning System trajectory data and travel diaries collected from individuals in two communities, we measure individual exposure to COVID-19 transmission risk based on their mobility patterns and reveal the disparities in COVID-19 risk exposure among residents of different demographic groups and neighborhoods when conducting different activities. This study reveals the differences in the spatial patterns of COVID-19 transmission risk when the risk is conceptualized by density and network. It demonstrates the power of a spatial network approach in enhancing our understanding of individual exposure to infectious diseases. This study also advances the existing literature by exploring COVID-19 risk exposure, considering individual daily mobility and addressing the uncertain geographic context problem in analyzing individual COVID-19 risk exposure.

Association between respiratory tract deposited inhaled dose of PM0.25-10 mass-count and airway inflammation based on individual exposure assessment

Association between respiratory tract deposited inhaled dose of PM0.25-10 mass-count and airway inflammation based on individual exposure assessment

Integrating participant feedback and concerns to improve community and individual level chemical exposure assessment reports

BackgroundAs exposure assessment has shifted towards community-engaged research there has been an increasing trend towards reporting results to participants. Reports aim to increase environmental health literacy, but this can be challenging due to the many unknowns regarding chemical exposure and human health effects. This includes when reports encompass a wide-range of chemicals, limited reference or health standards exist for those chemicals, and/or incompatibility of data generated from exposure assessment tools with published reference values (e.g., comparing a wristband concentration to an oral reference dose).MethodsHouston Hurricane Harvey Health (Houston-3H) participants wore silicone wristbands that were analyzed for 1,530 organic compounds at two time-points surrounding Hurricane Harvey. Three focus groups were conducted in separate neighborhoods in the Houston metropolitan area to evaluate response to prototype community and individual level report-backs. Participants (n = 31) evaluated prototype drafts using Likert scales and discussion prompts. Focus groups were audio-recorded, and transcripts were analyzed using a qualitative data analysis program for common themes, and quantitative data (ranking, Likert scales) were statistically analyzed.ResultsFour main themes emerged from analysis of the transcripts: (1) views on the report layout; (2) expression of concern over how chemicals might impact their individual or community health; (3) participants emotional response towards the researchers; and (4) participants ability to comprehend and evaluate environmental health information. Evaluation of the report and key concerns differed across the three focus groups. However, there was agreement amongst the focus groups about the desire to obtain personal exposure results despite the uncertainty of what the participant results meant.ConclusionsThe report-back of research results (RBRR) for community and individual level exposure assessment data should keep the following key principles in mind: materials should be accessible (language level, data visualization options, graph literacy), identify known information vs unknown (e.g., provide context for what exposure assessment data means, acknowledge lack of current health standards or guidelines), recognize and respect community knowledge and history, and set participant expectations for what they can expect from the report.

Calibration methodology of low-cost sensors for high-quality monitoring of fine particulate matter

Low concentrations of pollutants may already be associated with significant health effects. An accurate assessment of individual exposure to pollutants therefore requires measuring pollutant concentrations at the finest possible spatial and temporal scales. Low-cost sensors (LCS) of particulate matter (PM) meet this need so well that their use is constantly growing worldwide. However, everyone agrees that LCS must be calibrated before use. Several calibration studies have already been published, but there is not yet a standardized and well-established methodology for PM sensors. In this work, we develop a method combining an adaptation of an approach developed for gas-phase pollutants with a dust event preprocessing to calibrate PM LCS (PMS7003) commonly used in urban environments. From the selection of outliers to model tuning and error estimation, the developed protocol allows to analyze, process and calibrate LCS data using multilinear (MLR) and random forest (RFR) regressions for comparison with a reference instrument. We demonstrate that the calibration performance was very good for PM1 and PM2.5 but turns out less good for PM10 (R2 = 0.94, RMSE = 0.55 μg/m3, NRMSE = 12 % for PM1 with MLR, R2 = 0.92, RMSE = 0.70 μg/m3, NRMSE = 12 % for PM2.5 with RFR and R2 = 0.54, RMSE = 2.98 μg/m3, NRMSE = 27 % for PM10 with RFR). Dust events removal significantly improved LCS accuracy for PM2.5 (11 % increase of R2 and 49 % decrease of RMSE) but no significant changes for PM1. Best calibration models included internal relative humidity and temperature for PM2.5 and only internal relative humidity for PM1. It turns out that PM10 cannot be properly measured and calibrated because of technical limitations of the PMS7003 sensor. This work therefore provides guidelines for PM LCS calibration. This represents a first step toward standardizing calibration protocols and facilitating collaborative research.

Individual Exposure to Microplastics through the Inhalation Route: Comparison of Microplastics in Inhaled Indoor Aerosol and Exhaled Breath Air

Human exposure to microplastics (MPs), especially from indoor air, has aroused growing public concern, but very little is known about the assessment of individual MPs inhalation exposure. In this study, a total of 30 volunteers were recruited from Shanghai, China. Both human inhaled indoor aerosol (HIA) and human exhaled breath (HEB) samples were pairwise collected for each participant and analyzed through micro-Raman imaging spectroscopy. MPs were detected in all samples, averaging 43 ± 16 (range of 11–92) items/m3 for HIA and 12 ± 5 (range of 3–28) items/m3 for HEB. Moreover, the dominant components in all samples were small fragment- and fiber-shaped MPs. It is estimated that the daily intake of HIA was roughly 704 ± 254 MPs items, most of which would deposited in the airway with 526 ± 203 MPs items, whereas 178 ± 75 MPs items could be daily discharged via HEB. The actual daily inhalation exposure of MPs could be overestimated by 1.33 times with the HIA-based approach and by 1.40 times for smaller MPs (<10 μm). These results suggest that integration of HIA and HEB should be considered when evaluating individual MPs exposure via respiration.

The variability of arsenic in blood and urine of humans

BackgroundHumans are exposed to inorganic and organic arsenic. The total arsenic (As) concentration in urine is a commonly used biomarker of exposure. However, little is known about variability of As in biological fluids and the diurnal variation of As excretion. ObjectivesMain objectives were to assess the variability of As in urine, plasma (P-As), whole blood (B-As), and the blood cell fraction (C-As), and to assess diurnal variation of As excretion. MethodsSix urine samples were collected at fixed times during 24 h on two different days around one week apart among 29 men and 31 women. Blood samples were collected when the morning urine samples were delivered. The intra-class correlation coefficient (ICC) was calculated as the ratio of the between-individuals variance to the total observed variance. ResultsGeometric mean (GM) 24 h urinary excretions of As (U-As24 h) were 41 and 39 µg/24 h on the two days of sampling. Concentrations of B-As, P-As and C-As were highly correlated with U-As24 h and As in first void morning urine. No statistically significant differences were observed for the urinary As excretion rate between the different sampling times. A high ICC was observed for As in the cellular blood fraction (0.803), while ICC for first morning urine corrected for creatine was low (0.316). ConclusionsThe study suggests that C-As is the most reliable biomarker for use in exposure assessment of individual exposure. Morning urine samples have low reliability for such use. No apparent diurnal variation was observed in the urinary As excretion rate.

New perspectives in application of kidney biomarkers in mycotoxin induced nephrotoxicity, with a particular focus on domestic pigs.

The gradual spread of Aspergilli worldwide is adding to the global shortage of food and is affecting its safe consumption. Aspergillus-derived mycotoxins, including aflatoxins and ochratoxin A, and fumonisins (members of the fusariotoxin group) can cause pathological damage to vital organs, including the kidney or liver. Although the kidney functions as the major excretory system in mammals, monitoring and screening for mycotoxin induced nephrotoxicity is only now a developmental area in the field of livestock feed toxicology. Currently the assessment of individual exposure to mycotoxins in man and animals is usually based on the analysis of toxin and/or metabolite contamination in the blood or urine. However, this requires selective and sensitive analytical methods (e.g., HPLC-MS/MS), which are time consuming and expensive. The toxicokinetic of mycotoxin metabolites is becoming better understood. Several kidney biomarkers are used successfully in drug development, however cost-efficient, and reliable kidney biomarkers are urgently needed for monitoring farm animals for early signs of kidney disease. β2-microglobulin (β2-MG) and N-acetyl-β-D-glucosaminidase (NAG) are the dominant biomarkers employed routinely in environmental toxicology research, while kidney injury molecule 1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL) are also emerging as effective markers to identify mycotoxin induced nephropathy. Pigs are exposed to mycotoxins due to their cereal-based diet and are particularly susceptible to Aspergillus mycotoxins. In addition to commonly used diagnostic markers for nephrotoxicity including plasma creatinine, NAG, KIM-1 and NGAL can be used in pigs. In this review, the currently available techniques are summarized, which are used for screening mycotoxin induced nephrotoxicity in farm animals. Possible approaches are considered, which could be used to detect mycotoxin induced nephropathy.

A life course approach to asthma and wheezing among young children caused by ozone: A prospective birth cohort in northern China

BackgroundGiven differences in vulnerability of children in early life, a life course approach to asthma and wheezing (AW) in young children caused by ozone (O3) is not fully understood. MethodsWe conducted a birth cohort in Jinan, China from 2018 to 2021 to elucidate the onset model of childhood AW due to O3 exposure. An inverse distance weighted model was used for individual exposure assessment. The time-dependent Cox proportional-hazard model and logistic model were used to investigate the effects of O3 exposure on AW. Principal component analysis, interaction analysis, and distributed lag model were used to analyze the life course approach. ResultsThe cumulative incidence rate for AW among 6501 children aged 2 was 1.4%. A high level of O3 was related to AW (HR: 2.10, 95% CI: 1.31, 3.37). Only O3 exposure after birth was associated with AW, with an OR of 1.82 (1.08, 3.12), after adjusting for the effect before birth. Furthermore, adjusting for other air pollutants, the HR for the individual effect of high O3 exposure on AW was 2.44 (1.53, 3.89). Interestingly, P values for interactions for O3 and the principal components of other pollutants, as well as the characteristic variable of open windows were less than 0.1. Moreover, an increase in the IQR of O3 exposure at the 31st to 37th weeks before birth and the 1st to 105th weeks after birth was associated with an increase in the HRs for AW. ConclusionsHigh-level of O3 exposure after birth could lead to AW among young children. Importantly, the AW onset model may include the risk factors accumulation and the sensitive period model. Specifically, there are two sensitive windows in early life, and the correlated insults between the high level of O3 and other pollutants as well as open windows in the asthma-inducing effect.

PFAS exposures in Veneto, Italy: the role of biomonitoring in addressing a serious public health threat

Background and Aim In 2013, high levels of perfluoroalkyl substances (PFAS) were identified in the drinking water of the Veneto region, Italy, primarily due to industrial emissions from a nearby PFAS manufacturer. For decades, the factory released wastewater into the ground, contaminating both surface water bodies and groundwater, mainly by perfluorooctanoic acid (PFOA), before charcoal filters were introduced. The groundwater contamination plume extends over 190 km2 and reached public waterworks serving 30 municipalities (roughly 130,000 inhabitants). This presentation will provide an overview of the Veneto health surveillance program and its impact. Methods The health surveillance program started in January 2017 and continues for the prevention, early diagnosis and treatment of chronic disorders possibly associated with PFAS. The target population included 105,000 residents of the contaminated area born between 1951 and 2014. Data are collected through a structured interview on socio-demographic characteristics, personal health history and lifestyle habits; routine blood and urine tests; and the measurements of 12 PFAS. The population is being recruited for a second round, which started in September 2020. Results By February 2022 55,597 individuals were recruited (60,5% of invited) in the 1st round, and 2,623 in the 2nd round. The PFAS with the highest serum concentrations was PFOA (median 36.8 ng/mL), about 20 times higher than in the Italian population with background exposures, followed by perfluorooctanesulfonic acid (PFOS) (median 3.8 ng/mL) and perfluorohexanesulfonic acid (PFHxS) (median 3.7 ng/mL). Conclusions This population is unique in that biomonitoring has been offered to the entire highly exposed population. The program includes a thorough assessment of individual exposure as well as behavioural and clinical risk factors for cardiometabolic disorders, providing tailored counselling for exposure and risk reduction, and the referral of subjects with altered biomarkers for subsequent diagnostic and therapeutic evaluation. Keywords: PFAS, biomonitoring, health surveillance program, PFOA contamination

Simultaneous determination of eight β-adrenergic agonists in human urine by an isotope dilution-online clean-up system coupled with liquid chromatography-tandem mass spectrometry.

β-Adrenergic agonist compounds are medicines that open up the lung's medium and large airways. β-Adrenergic agonist compounds have been illegally or legally used to increase lean muscle mass in meat animals, bodybuilding, weight-loss programs, and athletes. Developing a rapid analytical approach for determining β-adrenergic agonist compounds in biological samples is crucial for individual exposure assessment. This study established an analytical method for simultaneously measuring eight β-adrenergic agonist compounds in human urine, including clenbuterol, terbutaline, salbutamol, ractopamine, zilpaterol, cimaterol, tulobuterol, and fenoterol. Two hundred microliters of a urine sample were added to eight deuterium-labeled internal standard mixtures and glucuronidase/arylsulfatase for enzymatic hydrolysis, and were then analyzed using an online clean-up system coupled with a liquid chromatography-tandem mass spectrometry system (LC-MS/MS). The limit of quantification ranged from 0.03 to 0.12ng/mL urine for the eight β-adrenergic agonist compounds. The relative standard deviations (RSD) of the within-run and between-run precisions were less than 10%, and the relative accuracy errors were less than 17% in the three-level spiked artificial urine samples. Two hundred eighty human urine samples collected from the general population in Taiwan were assessed to demonstrate the capability and feasibility of this method. The detection frequencies were 33% for clenbuterol, 5% for ractopamine, and less than 5% for the others. We concluded that the isotope dilution-online clean-up system coupled with LC-MS/MS method is a valuable analytical method for investigating urinary β-adrenergic agonist compounds in humans and is valuable for human biomonitoring studies.

Short-term effects of air pollution on respiratory diseases among young children in Wuhan city, China

BackgroundThe high risks for childhood respiratory diseases are associated with exposure to ambient air pollution. However, there are few studies that have explored the association between air pollution exposure and respiratory diseases among young children (particularly aged 0–2 years) based on the entire population in a megalopolis.MethodsDaily hospital admission records were obtained from 54 municipal hospitals in Wuhan city, China. We included all children (aged 0–2 years) hospitalized with respiratory diseases between January 2017 and December 2018. Individual air pollution exposure assessment was used in Land Use Regression model and inverse distance weighted. Case-crossover design and conditional logistic regression models were adopted to estimate the hospitalization risk associated with air pollutants.ResultsWe identified 62,425 hospitalizations due to respiratory diseases, of which 36,295 were pneumonia. Particulate matter with an aerodynamic diameter less than 2.5 μm (PM2.5) and nitrogen dioxide (NO2) were significantly associated with respiratory diseases and pneumonia. ORs of pneumonia were 1.0179 (95% CI 1.0097–1.0260) for PM2.5 and 1.0131 (95% CI 1.0042–1.0220) for NO2 at lag 0–7 days. Subgroup analysis suggested that NO2, Ozone (O3) and sulfur dioxide (SO2) only showed effects on pneumonia hospitalizations on male patients, but PM2.5 had effects on patients of both genders. Except O3, all pollutants were strongly associated with pneumonia in cold season. In addition, children who aged elder months and who were in central urban areas had a higher hospitalization risk.ConclusionsAir pollution is associated with higher hospitalization risk for respiratory diseases, especially pneumonia, among young children, and the risk is related to gender, month age, season and residential location.

Research on occupational diseases in the absence of occupational data: a mixed-method study among cancer registries of Western Switzerland.

The contribution of occupation-related diseases to the global burden of disease is greatly underestimated, mainly due to a shortage of occupational exposure data. This problem is particularly salient in Switzerland, where no estimates of occupation-related disease burden exist, even for the well-recognised occupational cancers, such as malignant pleural mesothelioma and lung cancer. To overcome this situation, we launched a research project "Examining Cancers and Labour Indicators to assess the Burden" (ExCaLIBur). Within this project, we aimed to assess the need for and quality (i.e., completeness, accuracy and precision) of occupation registration in all cancer registries of Western Switzerland. We also aimed to find a relevant and feasible strategy to collect this information in the future. We applied a mixed research method. We observed that, independently of the level of precision (5-3-2-1-digit aggregation level), the accuracy was lesser in the registries that were able to actively search and verify occupational information. Overall, the distinction of occupations based on the 3-digit code presents an acceptable compromise in terms of precision. Having such occupations registered in all, or most, Swiss cancer registries routinely would obviously be valuable for epidemiological surveillance of occupational cancers in Switzerland. However, it seems less obvious how these data could fulfill the research objectives, since a better precision than 3-digit occupational coding is challenging to achieve. Currently, the collection of occupational data by the Swiss cancer registries remains feasible in the frame of specific research projects on occupational cancers. However, available data sources, as well as lack of financial and human resources, will continue to affect quality of the collected occupation data. Therefore, the usage of the standardised questionnaire retracing the individual occupational history to enable further assessment of individual exposure to potential occupational hazards is recommended. However, this approach will disable the Swiss registries to insuring their epidemiological surveillance mission with respect to occupational cancers in Switzerland, for which national statistics remain limited.

Determination of Parabens, Bisphenol A and Its Analogs, Triclosan, and Benzophenone-3 Levels in Human Urine by Isotope-Dilution-UPLC-MS/MS Method Followed by Supported Liquid Extraction.

The development of a rapid analytical approach for determining levels of antibacterial agents, plasticizers, and ultraviolet filters in biosamples is crucial for individual exposure assessment. We developed an analytical method to determine the levels of four parabens—bisphenols A (BPA) and its analogs, triclosan (TCS), triclocarban, and benzophenone-3 (BP-3)—in human urine. We further measured the levels of these chemicals in children and adolescents. We used a supported liquid extraction (SLE) technique coupled with an isotope-dilution ultraperformance liquid chromatography-tandem mass spectrometry (ID-UPLC-MS/MS) method to assess the detection performance for these chemicals. Forty-one urine samples from 13 children and 28 adolescents were assessed to demonstrate the capability and feasibility of our method. An acceptable recovery (75.6–102.4%) and matrix effect (precision < 14.2%) in the three-level spiked artificial urine samples were achieved, and good performance of the validated ID-UPLC-MS/MS method regarding linearity, limits of detection, and quantitation was achieved. The within-run and between-run accuracy and precision also demonstrated the sensitivity and stability of this analytical method, applied after SLE. We concluded that the ID-UPLC-MS/MS method with SLE pretreatment is a valuable analytical method for the investigation of urinary antibacterial agents, plasticizers, and ultraviolet filters in humans, useful for human biomonitoring.

Interactive effects of cold spell and air pollution on outpatient visits for anxiety in three subtropical Chinese cities

BackgroundAlthough low temperature and air pollution exposures have been associated with the risk of anxiety, their combined effects remain unclear. ObjectiveTo investigate the independent and interactive effects of low temperature and air pollution exposures on anxiety. MethodUsing a case-crossover study design, the authors collected data from 101,636 outpatient visits due to anxiety in three subtropical Chinese cities during the cold season (November to April in 2013 through 2018), and then built conditional logistic regression models based on individual exposure assessments [temperature, relative humidity, particulate matter (PM2.5, PM10), sulfur dioxide (SO2), and nitrogen dioxide (NO2)] and twelve cold spell definitions. Additive-scale interactions were assessed using the relative excess risk due to interaction (RERI). ResultsBoth cold spell and air pollution were significantly associated with outpatients for anxiety. The effects of cold spell increased with its intensity, ranging from 8.98% (95% CI: 2.02%, 16.41%) to 15.24% (95% CI: 6.75%, 24.39%) in Huizhou. Additionally, each 10 μg/m3 increase of PM2.5, PM10, NO2 and SO2 was associated with a 1.51% (95% CI: 0.61%, 2.43%), 1.58% (95% CI: 0.89%, 2.28%), 13.95% (9.98%, 18.05%) and 11.84% (95% CI: 8.25%, 15.55%) increase in outpatient visits for anxiety. Synergistic interactions (RERI >0) of cold spell with all four air pollutants on anxiety were observed, especially for more intense cold spells. For particulate matters, these interactions were found even under mild cold spell definitions [RERI: 0.11 (95% CI: 0.02, 0.21) for PM2.5, and 0.24 (95% CI: 0.14, 0.33) for PM10]. Stratified analyses yielded a pronounced results in people aged 18–65 years. ConclusionsThese findings indicate that both cold spell and air pollution are important drivers of the occurrence of anxiety, and simultaneous exposure to these two factors might have synergistic effects on anxiety. These findings highlight the importance of controlling air pollution and improving cold-warning systems.

High spatiotemporal resolution mapping of PM2.5 concentrations under a pollution scene assumption

Accurate individual exposure assessment to particulates in complex urban environments requires maps of PM2.5 concentration at high spatiotemporal resolution. Previous empirical researches of PM2.5 mapping usually have ignored the contextual influences of associated factors on pollution variation. This study presents a new thinking about spatial prediction of PM2.5 pollution based on the pollution scene assumption. Methodologically, pollution scenes are areas exert contextual influences on the spatiotemporal variety of air pollution and can be expressed by urban microenvironment dependence and temporal nonstationarity. Taking Changsha, China as a case, a two-stage modelling strategy of geographically weighted regression kriging (GWRK) was developed to validate the assumption based on a high-density sampling campaign and a fine-scale, manually interpreted urban microenvironment map. Our results confirm the potential existence of urban air pollution scene. PM2.5 concentration varies between urban microenvironments; pollution scene based GWRK is effective for high resolution mapping of PM2.5 concentration at the hourly scale and depicts more detailed spatial variations than traditional GWR in this study. This assumption and modelling strategy provide a promising way for mapping urban air pollution at high resolution which will further benefits works on exposure assessment and risk avoidance at fine scales.

An Integrated Individual Environmental Exposure Assessment System for Real-Time Mobile Sensing in Environmental Health Studies.

The effects of environmental exposure on human health have been widely explored by scholars in health geography for decades. However, recent advances in geospatial technologies, especially the development of mobile approaches to collecting real-time and high-resolution individual data, have enabled sophisticated methods for assessing people’s environmental exposure. This study proposes an individual environmental exposure assessment system (IEEAS) that integrates objective real-time monitoring devices and subjective sensing tools to provide a composite way for individual-based environmental exposure data collection. With field test data collected in Chicago and Beijing, we illustrate and discuss the advantages of the proposed IEEAS and the composite analysis that could be applied. Data collected with the proposed IEEAS yield relatively accurate measurements of individual exposure in a composite way, and offer new opportunities for developing more sophisticated ways to measure individual environmental exposure. With the capability to consider both the variations in environmental risks and human mobility in high spatial and temporal resolutions, the IEEAS also helps mitigate some uncertainties in environmental exposure assessment and thus enables a better understanding of the relationship between individual environmental exposure and health outcomes.

Occupational Exposures and Environmental Health Hazards of Military Personnel.

Background: Military personnel are frequently exposed to environmental pollutants that can cause a variety of diseases. Methods: This review analyzed publications regarding epidemiological and biomonitoring studies on occupationally-exposed military personnel. Results: The exposures include sulfur mustard, organ chlorines, combustion products, fuel vapors, and ionizing and exciting radiations. Important factors to be considered are the lengths and intensities of exposures, its proximity to the sources of environmental pollutants, as well as confounding factors (cigarette smoke, diet, photo-type, healthy warrior effect, etc.). Assessment of environmental and individual exposures to pollutants is crucial, although often omitted, because soldiers have often been evaluated based on reported health problems rather than on excessive exposure to pollutants. Biomarkers of exposures and effects are tools to explore relationships between exposures and diseases in military personnel. Another observation from this review is a major problem from the lack of suitable control groups. Conclusions: This review indicates that only studies which analyzed epidemiological and molecular biomarkers in both exposed and control groups would provide evidence-based conclusions on exposure and disease risk in military personnel.

Do Individuals' Activity Structures Influence Their PM2.5 Exposure Levels? Evidence from Human Trajectory Data in Wuhan City.

Severe air pollution has become a major risk to human health from a global environmental perspective. It has been recognized that human mobility is an essential component in individual exposure assessment. Activity structure reflects the characteristics of human mobility. Thus, a better understanding of the relationship between human activity structure and individual exposure level is of crucial relevance. This study examines this relationship using a large cell-phone GPS dataset in Wuhan, China. The results indicate that there is a strong linear relationship between people’s activity structures and exposures to PM2.5. Inter-group comparisons based on the four activity structure groups obtained with K-means clustering found that groups with different activity structures do experience different levels of PM2.5 exposure. Furthermore, differences in detailed characteristics of activity structure were also found at different exposure levels at the intra-group level. These results show that people’s activity structures do influence their exposure levels. The paper provides a new perspective for understanding individual exposure through human activity structure, which helps move the perspective of research on individual exposure from the semantic of physical location to the semantic of human activity pattern.