Model misspecification, measurement error, and apparent supralinearity in the concentration-response relationship between PM2.5 and mortality.

A growing number of studies have produced results that suggest the shape of the concentration-response (C-R) relationship between PM2.5 exposure and mortality is "supralinear" such that incremental risk is higher at the lowest exposure levels than at the highest exposure levels. If the C-R function is in fact supralinear, then there may be significant health benefits associated with reductions in PM2.5 below the current US National Ambient Air Quality Standards (NAAQS), as each incremental tightening of the PM2.5 NAAQS would be expected to produce ever-greater reductions in mortality risk. In this paper we undertake a series of tests with simulated cohort data to examine whether there are alternative explanations for apparent supralinearity in PM2.5 C-R functions. Our results show that a linear C-R function for PM2.5 can falsely appear to be supralinear in a statistical estimation process for a variety of reasons, such as spatial variation in the composition of total PM2.5 mass, the presence of confounders that are correlated with PM2.5 exposure, and some types of measurement error in estimates of PM2.5 exposure. To the best of our knowledge, this is the first simulation-based study to examine alternative explanations for apparent supralinearity in C-R functions.

Urinary concentrations of phthalate metabolites in relation to preeclampsia and other hypertensive disorders of pregnancy in the environmental influences on child health outcomes (ECHO) program.

BACKGROUND: Phthalate exposure may contribute to hypertensive disorders of pregnancy (HDP), including preeclampsia/eclampsia (PE/E), but epidemiologic studies are lacking. OBJECTIVES: To evaluate associations of pregnancy phthalate exposure with development of PE/E and HDP. METHODS: Using data from 3,430 participants in eight Environmental influences on Child Health Outcomes (ECHO) Program cohorts (enrolled from 1999 to 2019), we quantified concentrations of 13 phthalate metabolites (8 measured in all cohorts, 13 in a subset of four cohorts) in urine samples collected at least once during pregnancy. We operationalized outcomes as PE/E and composite HDP (PE/E and/or gestational hypertension). After correcting phthalate metabolite concentrations for urinary dilution, we evaluated covariate-adjusted associations of individual phthalates with odds of PE/E or composite HDP via generalized estimating equations, and the phthalate mixture via quantile-based g-computation. We also explored effect measure modification by fetal sex using stratified models. Effect estimates are reported as odds ratios (OR) with 95% confidence intervals (95% CIs). RESULTS: In adjusted analyses, a doubling of mono-benzyl phthalate (MBzP) and of mono (3-carboxypropyl) phthalate (MCPP) concentrations was associated with higher odds of PE/E as well as composite HDP, with somewhat larger associations for PE/E. For example, a doubling of MCPP was associated with 1.12 times the odds of PE/E (95%CI 1.00, 1.24) and 1.02 times the odds of composite HDP (95%CI 1.00, 1.05). A quartile increase in the phthalate mixture was associated with 1.27 times the odds of PE/E (95%CI 0.94, 1.70). A doubling of mono-carboxy isononyl phthalate (MCiNP) and of mono-carboxy isooctyl phthalate (MCiOP) concentrations were associated with 1.08 (95%CI 1.00, 1.17) and 1.11 (95%CI 1.03, 1.19) times the odds of PE/E. Effect estimates for PE/E were generally larger among pregnancies carrying female fetuses. DISCUSSION: In this study, multiple phthalates were associated with higher odds of PE/E and HDP. Estimates were precise and some were low in magnitude. Interventions to reduce phthalate exposures during pregnancy may help mitigate risk of these conditions.

Long-term exposure to ambient air pollution and measures of central hemodynamics and arterial stiffness among multiethnic Chicago residents.

OBJECTIVES: To examine whether long-term air pollution exposure is associated with central hemodynamic and brachial artery stiffness parameters. METHODS: We assessed central hemodynamic parameters including central blood pressure, cardiac parameters, systemic vascular compliance and resistance, and brachial artery stiffness measures [including brachial artery distensibility (BAD), compliance (BAC), and resistance (BAR)] using waveform analysis of the arterial pressure signals obtained from a standard cuff sphygmomanometer (DynaPulse2000A, San Diego, CA). The long-term exposures to particles with an aerodynamic diameter < 2.5 µm (PM2.5) and nitrogen dioxide (NO2) for the 3-year periods prior to enrollment were estimated at residential addresses using fine-scale intra-urban spatiotemporal models. Linear mixed models adjusted for potential confounders were used to examine associations between air pollution exposures and health outcomes. RESULTS: The cross-sectional study included 2,387 Chicago residents (76% African Americans) enrolled in the ChicagO Multiethnic Prevention And Surveillance Study (COMPASS) during 2013-2018 with validated address information, PM2.5 or NO2, key covariates, and hemodynamics measurements. We observed long-term concentrations of PM2.5 and NO2 to be positively associated with central systolic, pulse pressure and BAR, and negatively associated with BAD, and BAC after adjusting for relevant covariates. A 1-µg/m3 increment in preceding 3-year exposures to PM2.5 was associated with 1.8 mmHg higher central systolic (95% CI: 0.98, 4.16), 1.0 mmHg higher central pulse pressure (95% CI: 0.42, 2.87), a 0.56%mmHg lower BAD (95% CI: -0.81, -0.30), and a 0.009 mL/mmHg lower BAC (95% CI: -0.01, -0.01). CONCLUSION: This population-based study provides evidence that long-term exposures to PM2.5 and NO2 is related to central BP and arterial stiffness parameters, especially among African Americans.

Accommodating detection limits of multiple exposures in environmental mixture analyses: an overview of statistical approaches.

BACKGROUND: Identifying the impact of environmental mixtures on human health is an important topic. However, such studies face challenges when exposure measurements lie below limit of detection (LOD). While various approaches for accommodating a single exposure subject to LOD have been used, their impact on mixture analysis has not been thoroughly investigated. Our study aims to understand the impact of five popular LOD accommodation approaches on mixture analysis results with multiple exposures subject to LOD, including omitting subjects with any exposures below LOD (complete case analysis); single imputations by LOD/ 2 , and by estimates from a censored accelerated failure time (AFT) model; and multiple imputation (MI) with or without truncation based on LOD. METHODS: In extensive simulation studies with high-dimensional and highly correlated exposures and a continuous health outcome, we examined the performance of each LOD approach on three mixture analysis methods: elastic net regression, weighted quantile sum regression (WQS) and Bayesian kernel machine regression (BKMR). We further analyzed data from the National Health and Nutrition Examination Survey (NHANES) on how persistent organic pollutants (POPs) influenced leukocyte telomere length (LTL). RESULTS: Complete case analysis was inefficient and could result in severe bias for some mixture methods. Imputation by LOD/ 2 showed unstable performance across mixture methods. Conventional MI was associated with consistent mild biases, which can be reduced by using a truncated distribution for imputation. Estimating censored values by AFT models had a minimal impact on the results. In the NHANES analysis, imputation by LOD/ 2 , truncated MI and censored AFT models performed similarly, with a positive overall effect of POPs on LTL while PCB126, PCB169 and furan 2,3,4,7,8-pncdf being the most important exposures. CONCLUSIONS: Our study favored using truncated MI and censored AFT models to accommodate values below LOD for the stability of downstream mixture analysis.

Limited exposure of captive Australian marsupials to plastics.

The global concern regarding the ubiquitous presence of plastics in the environment has led to intensified research on the impact of these materials on wildlife. In the Australian context, marsupials represent a unique and diverse group of mammals, yet little is known about their exposures to plastics. This study aimed to assess the contamination levels of seven common plastics (i.e., polystyrene (PS), polycarbonate (PC), poly-(methyl methacrylate) (PMMA), polypropylene (PP), polyethylene terephthalate (PET), polyethylene (PE), and polyvinyl chloride (PVC)) in both the diet and faeces of kangaroos, wallabies and koalas sampled from a sanctuary in Northeastern Australia. Quantitative analysis was performed by pressurized liquid extraction followed by double-shot microfurnace pyrolysis coupled to gas chromatography mass spectrometry. Interestingly, the analysis of the food and faeces samples revealed the absence of detectable plastic particles; with this preliminary finding suggesting a relatively limited exposure of captive Australian marsupials to plastics. This study contributes valuable insights into the current state of plastic contamination in Australian marsupials, shedding light on the limited exposures and potential risks, and highlighting the need for continued monitoring and conservation efforts. The results underscore the importance of proactive measures to mitigate plastic pollution and protect vulnerable wildlife populations in Australia's unique ecosystems.

Chemical uptake into silicone wristbands over a five day period.

Silicone wristbands are a noninvasive personal exposure assessment tool. However, despite their utility, questions remain about the rate at which chemicals accumulate on wristbands when worn, as validation studies utilizing wristbands worn by human participants are limited. This study evaluated the chemical uptake rates of 113 organic pollutants from several chemical classes (i.e., polychlorinated biphenyls (PCB), organophosphate esters (OPEs), alkyl OPEs, polybrominated diphenyl ethers (PBDEs), brominated flame retardants (BFR), phthalates, pesticides, and polycyclic aromatic hydrocarbons (PAHs) over a five-day period. Adult participants (n = 10) were asked to wear five silicone wristbands and then remove one wristband each day. Several compounds were detected in all participants' wristbands after only one day. The number of chemicals detected frequently (i.e. in at least seven participants wristbands) increased from 20% of target compounds to 26% after three days and more substantially increased to 34% of target compounds after four days of wear. Chemicals detected in at least seven participants' day five wristbands (n = 24 chemicals) underwent further statistical analysis, including estimating the chemical uptake rates over time. Some chemicals, including pesticides and phthalates, had postive and significant correlations between concentrations on wristbands worn five days and concentrations of wristbands worn fewer days suggesting chronic exposure. For 23 of the 24 compounds evaluated there was a statistically significant and positive linear association between the length of time wristbands were worn and chemical concentrations in wristbands. Despite the differences that exist between laboratory studies using polydimethylsiloxane (PDMS) environmental samplers and worn wristbands, these results indicate that worn wristbands are primarily acting as first-order kinetic samplers. These results suggest that studies using different deployment lengths should be comparable when results are normalized to the length of the deployment period. In addition, a shorter deployment period could be utilized for compounds that were commonly detected in as little as one day.

A prospective cohort study of exposure to household pesticide with cardiovascular diseases mortality in older adults.

OBJECTIVES: We examined the associations of self-reported exposures, and urinary metabolites related to household pesticide with cardiovascular disease (CVD) mortality in older adults based on the 2007 to 2014 waves of National Health and Nutrition Examination Survey (NHANES). METHODS: Information on application and urinary metabolites related to household pesticide exposure were collected. We estimated the risks of household pesticide exposure, urinary metabolites with subsequent incident CVD death using Cox proportional hazards regression models. The indirect effects of urinary metabolites and effect modifications were examined. RESULTS: The participants who reported exposure to household pesticide had a higher risk of incident CVD death (adjusted HR 1.40, 95% CI 1.08 to 1.81). Per 1-log10 increase in urinary N, N-diethyl-3-methylbenzamide (DEET) related to household insect repellents was associated with a higher risk of incident CVD death (adjusted HR 1.97, 95% CI 1.14 to 3.40). Urinary DEET explained 4.21% of the total association between household pesticide exposure and CVD death risk. The participants who persisted a low level of health diet exhibited pronounced CVD death risks with household pesticide exposures. CONCLUSIONS: Exposure to household pesticide, especially household insect repellents, was consistently associated with an elevated CVD death risk in older adults. A heatlhy diet could partly attenuate the associations.

A systematic review of global distribution, sources and exposure risk of phthalate esters (PAEs) in indoor dust.

Phthalate esters (PAEs) are a class of plasticizers that are readily released from plastic products, posing a potential exposure risk to human body. At present, much attention is paid on PAE concentrations in indoor dust with the understanding of PAEs toxicity. This study collected 8187 data on 10 PAEs concentrations in indoor dusts from 26 countries and comprehensively reviewed the worldwide distribution, influencing factors, and health risks of PAEs. Di-(2-ethylhexyl) phthalate (DEHP) is the predominant PAE with a median concentration of 316 µg·g-1 in indoor dust. Polyvinyl chloride wallpaper and flooring and personal care products are the main sources of PAEs indoor dust. The dust concentrations of DEHP show a downward trend over the past two decades, while high dust concentrations of DiNP are found from 2011 to 2016. The median dust contents of 8 PAEs in public places are higher than those in households. Moreover, the concentrations of 9 PAEs in indoor dusts from high-income countries are higher than those from upper-middle-income countries. DEHP in 69.8% and 77.8% of the dust samples may pose a potential carcinogenic risk for adults and children, respectively. Besides, DEHP in 16.9% of the dust samples may pose a non-carcinogenic risk to children. Nevertheless, a negligible risk was found for other PAEs in indoor dust worldwide. This review contributes to an in-depth understanding of the global distribution, sources and health risks of PAEs in indoor dust.

Factors impacting human exposure to legacy and emerging contaminants in residential dust in Beijing, China: Characteristics of indoor microenvironment.

Exposure to indoor dust is of concern since dust may be contaminated by various toxic chemicals and people spend considerable time indoors. Factors impacting human exposure risks to contaminants in indoor dust may differ from those affecting the loadings of contaminants, but the dominant factors have not yet been well clarified. In this study, the occurrence, human exposure, and related influencing factors of several classes of legacy and emerging contaminants in residential dust across Beijing were investigated, including per- and polyfluoroalkyl substances (PFASs) and three types of flame retardants (FRs), i.e., organophosphate esters (OPEs), polybrominated diphenyl ethers (PBDEs), and novel halogenated FRs (NHFRs). OPEs (median: 3847 ng/g) were the most abundant group, followed by PBDEs (1046 ng/g) and NHFRs (520 ng/g). PFASs (14.3 ng/g) were one to two orders of magnitude lower than FRs. The estimated daily intakes of these contaminants were relatively higher for toddlers than other age groups, with oral ingestion being the main exposure pathway compared with dermal contact. Higher human exposure risks were found in new buildings or newly finished homes due to the elevated intake of emerging contaminants (such as OPEs). Furthermore, higher risks were also found in homes with wooden floors, which were mainly associated with higher levels of PFASs, chloroalkyl and alkyl OPEs, compared with tile floors. Citizens in the urban area also showed higher exposure risks than those in the suburban area. The quantity of household appliances and finishing styles (simple or luxurious) showed an insignificant impact on overall human exposure risks despite their significant effect on the levels of some of the dust contaminants. Results in this study are of importance in understanding human exposure to the co-existence of multiple contaminants in indoor dust.

Probing the occurrence, sources and cancer risk assessment of polycyclic aromatic hydrocarbons in PM2.5 in a humid metropolitan city in China.

Fifty-two consecutive PM2.5 samples from December 2021 to February 2022 (the whole winter) were collected in the center of Chongqing, a humid metropolitan city in China. These samples were analysed for the 16 USEPA priority polycyclic aromatic hydrocarbons (16 PAHs) to explore their composition and sources, and to assess their cancer risks to humans. The total concentrations of the 16 PAHs (ng m-3) ranged from 16.45 to 174.15, with an average of 59.35 ± 21.45. Positive matrix factorization (PMF) indicated that traffic emissions were the major source (42.4%), followed by coal combustion/industrial emission (31.3%) and petroleum leakage/evaporation (26.3%). The contribution from traffic emission to the 16 PAHs increased from 40.0% in the non-episode days to as high as 46.2% in the air quality episode during the sampling period. The population attributable fraction (PAF) indicates that when the unit relative risk (URR) is 4.49, the number of lung cancer cases per million individuals under PAH exposure is 27 for adults and 38 for seniors, respectively. It was 5 for adults and 7 for seniors, when the URR is 1.3. The average incremental lifetime cancer risk (ILCR) for children, adolescents, adults and seniors was 0.25 × 10-6, 0.23 × 10-6, 0.71 × 10-6, and 1.26 × 10-6, respectively. The results of these two models complemented each other well, and both implied acceptable PAH exposure levels. Individual genetic susceptibility and exposure time were identified as the most sensitive parameters. The selection and use of parameters in risk assessment should be further deepened in subsequent studies to enhance the reliability of the assessment results.

Seasonal extreme temperatures and short-term fine particulate matter increases pediatric respiratory healthcare encounters in a sparsely populated region of the intermountain western United States.

BACKGROUND: Western Montana, USA, experiences complex air pollution patterns with predominant exposure sources from summer wildfire smoke and winter wood smoke. In addition, climate change related temperatures events are becoming more extreme and expected to contribute to increases in hospital admissions for a range of health outcomes. Evaluating while accounting for these exposures (air pollution and temperature) that often occur simultaneously and may act synergistically on health is becoming more important. METHODS: We explored short-term exposure to air pollution on children's respiratory health outcomes and how extreme temperature or seasonal period modify the risk of air pollution-associated healthcare events. The main outcome measure included individual-based address located respiratory-related healthcare visits for three categories: asthma, lower respiratory tract infections (LRTI), and upper respiratory tract infections (URTI) across western Montana for ages 0-17 from 2017-2020. We used a time-stratified, case-crossover analysis with distributed lag models to identify sensitive exposure windows of fine particulate matter (PM2.5) lagged from 0 (same-day) to 14 prior-days modified by temperature or season. RESULTS: For asthma, increases of 1 µg/m3 in PM2.5 exposure 7-13 days prior a healthcare visit date was associated with increased odds that were magnified during median to colder temperatures and winter periods. For LRTIs, 1 µg/m3 increases during 12 days of cumulative PM2.5 with peak exposure periods between 6-12 days before healthcare visit date was associated with elevated LRTI events, also heightened in median to colder temperatures but no seasonal effect was observed. For URTIs, 1 unit increases during 13 days of cumulative PM2.5 with peak exposure periods between 4-10 days prior event date was associated with greater risk for URTIs visits that were intensified during median to hotter temperatures and spring to summer periods. CONCLUSIONS: Delayed, short-term exposure increases of PM2.5 were associated with elevated odds of all three pediatric respiratory healthcare visit categories in a sparsely population area of the inter-Rocky Mountains, USA. PM2.5 in colder temperatures tended to increase instances of asthma and LRTIs, while PM2.5 during hotter periods increased URTIs.

Per- and polyfluoroalkyl substances (PFAS) in senior care facilities and older adult residents.

Per- and polyfluoroalkyl substances (PFAS) are fluorinated organic compounds used in a variety of consumer products and industrial applications that persist in the environment, bioaccumulate in biological tissues, and can have adverse effects on human health, especially in vulnerable populations. In this study, we focused on PFAS exposures in residents of senior care facilities. To investigate relationships between indoor, personal, and internal PFAS exposures, we analyzed 19 PFAS in matched samples of dust collected from the residents' bedrooms, and wristbands and serum collected from the residents. The median ∑PFAS concentrations (the sum of all PFAS detected in the samples) measured in dust, wristbands, and serum were 120 ng/g, 0.05 ng/g, and 4.0 ng/mL, respectively. The most abundant compounds in serum were linear- and branched-perfluorooctane sulfonic acid (L-PFOS and B-PFOS, respectively) at medians of 1.7 ng/mL and 0.83 ng/mL, respectively, followed by the linear perfluorooctanoic acid (L-PFOA) found at a median concentration of 0.59 ng/mL. Overall, these three PFAS comprised 80 % of the serum ∑PFAS concentrations. A similar pattern was observed in dust with L-PFOS and L-PFOA found as the most abundant PFAS (median concentrations of 13 and 7.8 ng/g, respectively), with the overall contribution of 50 % to the ∑PFAS concentration. Only L-PFOA was found in wristbands at a median concentration of 0.02 ng/g. Significant correlations were found between the concentrations of several PFAS in dust and serum, and in dust and wristbands, suggesting that the indoor environment could be a significant contributor to the personal and internal PFAS exposures in seniors. Our findings demonstrate that residents of assisted living facilities are widely exposed to PFAS, with several PFAS found in blood of each study participant and in the assisted living environment.

Public health assessment of Kenyan ASGM communities using multi-element biomonitoring, dietary and environmental evaluation.

The Kakamega gold belt's natural geological enrichment and artisanal and small-scale gold mining (ASGM) have resulted in food and environmental pollution, human exposure, and subsequent risks to health. This study aimed to characterise exposure pathways and risks among ASGM communities. Human hair, nails, urine, water, and staple food crops were collected and analysed from 144 ASGM miners and 25 people from the ASGM associated communities. Exposure to PHEs was predominantly via drinking water from mine shafts, springs and shallow-wells (for As>Pb>Cr>Al), with up to 366 µg L-1 arsenic measured in shaft waters consumed by miners. Additional exposure was via consumption of locally grown crops (for As>Ni>Pb>Cr>Cd>Hg>Al) besides inhalation of Hg vapour and dust, and direct dermal contact with Hg. Urinary elemental concentrations for both ASGM workers and wider ASGM communities were in nearly all cases above bioequivalents and reference upper thresholds for As, Cr, Hg, Ni, Pb and Sb, with median concentrations of 12.3, 0.4, 1.6, 5.1, 0.7 and 0.15 µg L-1, respectively. Urinary As concentrations showed a strong positive correlation (0.958) with As in drinking water. This study highlighted the importance of a multidisciplinary approach in integrating environmental, dietary, and public health investigations to better characterise the hazards and risks associated with ASGM and better understand the trade-offs associated with ASGM activities relating to public health and environmental sustainability. Further research is crucial, and study results have been shared with Public Health and Environmental authorities to inform mitigation efforts.

Fates and models for exposure pathways of pyrethroid pesticide residues: A review.

Pyrethroids (PYs) are widely applied pesticides whose residues pose potential health risks. This review describes current knowledge on PY chemical properties, usage patterns, environmental and food contamination, and human exposure models. It evaluates life cycle assessment (LCA), chemical alternatives assessment (CAA), and high-throughput screening (HTS) as tools for pesticide policy. Despite efforts to mitigate PY presence, their pervasive residues in the environment and food persist. And the highest concentrations ranged from 54,360 to 80,500 ng/L in water samples from agricultural fields. Food processing techniques variably reduce PY levels, yet no method guarantees complete elimination. This review provides insights into the fates and exposure pathways of PY residues in agriculture and food, and highlights the necessity for improved PY management and alternative practices to safeguard health and environment.

Exposure to ambient air pollution and cognitive function: an analysis of the English Longitudinal Study of Ageing cohort.

BACKGROUND: An increasing number of studies suggest adverse effects of exposure to ambient air pollution on cognitive function, but the evidence is still limited. We investigated the associations between long-term exposure to air pollutants and cognitive function in the English Longitudinal Study of Ageing (ELSA) cohort of older adults. METHODS: Our sample included 8,883 individuals from ELSA, based on a nationally representative study of people aged ≥ 50 years, followed-up from 2002 until 2017. Exposure to air pollutants was modelled by the CMAQ-urban dispersion model and assigned to the participants' residential postcodes. Cognitive test scores of memory and executive function were collected biennially. The associations between these cognitive measures and exposure to ambient concentrations of NO2, PM10, PM2.5 and ozone were investigated using mixed-effects models adjusted for time-varying age, physical activity and smoking status, as well as baseline gender and level of education. RESULTS: Increasing long-term exposure per interquartile range (IQR) of NO2 (IQR: 13.05 µg/m3), PM10 (IQR: 3.35 µg/m3) and PM2.5 (IQR: 2.7 µg/m3) were associated with decreases in test scores of composite memory by -0.10 (95% confidence interval [CI]: -0.14, -0.07), -0.02 [-0.04, -0.01] and -0.08 [-0.11, -0.05], respectively. The same increases in NO2, PM10 and PM2.5 were associated with decreases in executive function score of -0.31 [-0.38, -0.23], -0.05 [-0.08, -0.02] and -0.16 [-0.22, -0.10], respectively. The association with ozone was inverse across both tests. Similar results were reported for the London-dwelling sub-sample of participants. CONCLUSIONS: The present study was based on a long follow-up with several repeated measurements per cohort participant and long-term air pollution exposure assessment at a fine spatial scale. Increasing long-term exposure to NO2, PM10 and PM2.5 was associated with a decrease in cognitive function in older adults in England. This evidence can inform policies related to modifiable environmental exposures linked to cognitive decline.

Exposure and biomonitoring of PAHs in indoor air at the urban residential area of Iran: Exposure levels and affecting factors.

The concentration of polycyclic aromatic hydrocarbons (PAHs) in the air inside residential houses in Iran along with measuring the amount of 1-OHpyrene metabolite in the urine of the participants in the study was investigated by gas chromatography-mass spectrometry (GC-MS). Demographic characteristics (including age, gender, and body composition), equipment affecting air quality, and wealth index were also investigated. The mean ± standard error (SE) concentration of particulate matter 10 (PM10) and ∑PAHs in the indoor environment was 43.2 ± 1.98 and 1.26 ± 0.15 µg/m3, respectively. The highest concentration of PAHs in the indoor environment in the gaseous and particulate phase related to Naphthalene was 1.1 ± 0.16 µg/m3 and the lowest was 0.01 ± 0. 0.001 µg/m3 Pyrene, while the most frequent compounds in the gas and particle phase were related to low molecular weight hydrocarbons. 30% of the samples in the indoor environment have BaP levels higher than the standards provided by WHO guidelines. 68% of low molecular weight hydrocarbons were in the gas phase and 73 and 75% of medium and high molecular weight hydrocarbons were in the particle phase. There was a significant relationship between the concentration of some PAH compounds with windows, evaporative coolers, printers, and copiers (p < 0.05). The concentration of PAHs in houses with low economic status was higher than in houses with higher economic status. The average concentration of 1-hydroxypyrene metabolite in the urine of people was 7.10 ± 0.76 µg/L, the concentration of this metabolite was higher in men than in women, and there was a direct relationship between the amount of this metabolite in urine and the amount of some hydrocarbon compounds in the air, PM10, visceral fat and body fat. This relationship was significant for age (p = 0.01). The concentration of hydrocarbons in the indoor environment has been above the standard in a significant number of non-smoking indoor environments, and the risk assessment of these compounds can be significant. Also, various factors have influenced the amount of these compounds in the indoor air, and paying attention to them can be effective in reducing these hydrocarbons in the air.

Assessing pesticides in the atmosphere: A global study on pollution, human health effects, monitoring network and regulatory performance.

Pesticides are widely used in agriculture, but their impact on the environment and human health is a major concern. While much attention has been given to their presence in soil, water, and food, there have been few studies on airborne pesticide pollution on a global scale. This study aimed to assess the extent of atmospheric pesticide pollution in countries worldwide and identify regional differences using a scoring approach. In addition to analyzing the health risks associated with pesticide pollution, we also examined agricultural practices and current air quality standards for pesticides in these countries. The pollution scores varied significantly among the countries, particularly in Europe. Asian and Oceanic countries generally had higher scores compared to those in the Americas, suggesting a relatively higher level of air pollution caused by pesticides in these regions. It is worth noting that the current pollution levels, as assessed theoretically, pose minimal health risks to humans. However, studies in the literature have shown that excessive exposure to pesticides present in the atmosphere has been associated with various health problems, such as cancer, neuropsychiatric disorders, and other chronic diseases. Interestingly, European countries had the highest overall pesticide application intensities, but this did not necessarily correspond to higher atmospheric pesticide pollution scores. Only a few countries have established air quality standards specifically for pesticides. Furthermore, pollution scores across states in the USA were investigated and the global sampling sites were mapped. The findings revealed that the scores varied widely in the USA and the current sampling sites were limited or unevenly distributed in some countries, particularly the Nordic countries. These findings can help global relevant environmental agencies to set up comprehensive monitoring networks. Overall, the present research highlights the need to create a pesticide monitoring system and increase efforts to enhance pesticide regulation, ensure consistency in standards, and promote international cooperation.

Systematic investigation of organochlorine pesticides and polychlorinated biphenyls blood levels in Greek children from the Rhea birth cohort suggests historical exposure to DDT and through diet to DDE.

The blood levels of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) have been thoroughly investigated in Greek children from the Rhea birth cohort study. This investigation aimed to assess exposure levels, explore their possible relationship with children's age and sex, and indicate potential sources of exposure. Exposure patterns and common sources of PCBs and OCPs were analyzed using bivariate and multivariate statistics. A total of 947 blood samples from study participants were analyzed for OCP and PCB exposure, with 375 samples collected at 4 years old, 239 at 6.5 years old, and 333 at 11 years old. Elevated levels of DDE were observed in 6.5-year-old children compared to corresponding levels in other European countries. Higher levels of DDE were found in 4-year-old children, with the lowest concentrations in the 11-year-old group. The DDT/DDE ratio was consistently less than 1 among all the examined subjects. These results indicate exposure to DDT and DDE both in utero and through breastfeeding and dietary intake. For the entire cohort population, the highest concentration was determined for PCB 28, followed by PCBs 138, 153, and 180. The sum of the six indicator PCBs implied low exposure levels for the majority of the cohort population. Spearman correlations revealed strong associations between PCBs and OCPs, while principal component analysis identified two different groupings of exposure. DDE exhibited a correlation with a series of PCBs (153, 156, 163, 180), indicating a combined OCP-PCB source, and an anticorrelation with others (52, 28, 101), implying a separate and competing source.

Occurrence of organophosphorus flame retardants in Xiangjiang River: Spatiotemporal variations, potential affecting factors, and source apportionment.

The environmental occurrence of organophosphorus flame retardants (OPFRs) is receiving increasing attention. However, their distribution in the Xiangjiang River, an important tributary in the middle reaches of the Yangtze River, is still uncharacterized, and the potential factors influencing their distribution have not been adequately surveyed. In this study, the occurrence of OPFRs in the Xiangjiang River was comprehensively investigated from upstream to downstream seasonally. Fourteen OPFRs were detected in the sampling area, with a total concentration (∑OPFRs) ranging from 3.16 to 462 ng/L, among which tris(1-chloro-2-propyl) phosphate was identified as the primary pollutant (ND - 379 ng/L). Specifically, ∑OPFRs were significantly lower in the wet season than in the dry season, which may be due to the dilution effect of river flow and enhanced volatilization caused by higher water temperatures. Additionally, Changsha (during the dry season) and Zhuzhou (during the wet season) exhibited higher pollution levels than other cities. According to the Redundancy analysis, water quality parameters accounted for 35.7% of the variation in the occurrence of OPFRs, in which temperature, ammonia nitrogen content, dissolved oxygen, and chemical oxygen demand were identified as the potential influencing factors, accounting for 28.1%, 27.2%, 24.1%, and 11.5% of the total variation, respectively. The results of the Positive Matrix Factorization analysis revealed that transport and industrial emissions were the major sources of OPFRs in Xiangjiang River. In addition, there were no high-ecological risk cases for any individual OPFRs, although tris(2-ethylhexyl) phosphate and tributoxyethyl phosphate presented a low-to-medium risk level. And the results of mixture risk quotients indicated that medium-risk sites were concentrated in the Chang-Zhu-Tan region. This study enriches the global data of OPFRs pollution and contributes to the scientific management and control of pollution.

Association between Fine Particulate Matter Exposure and Cerebrospinal Fluid Biomarkers of Alzheimer's Disease among a Cognitively Healthy Population-Based Cohort.

BACKGROUND: Epidemiological evidence suggests air pollution adversely affects cognition and increases the risk of Alzheimer's disease (AD), but little is known about the biological effects of fine particulate matter (PM2.5, particulate matter with aerodynamic diameter ≤2.5µm) on early predictors of future disease risk. OBJECTIVES: We investigated the association between 1-, 3-, and 5-y exposure to ambient and traffic-related PM2.5 and cerebrospinal fluid (CSF) biomarkers of AD. METHODS: We conducted a cross-sectional analysis using data from 1,113 cognitively healthy adults (45-75 y of age) from the Emory Healthy Brain Study in Georgia in the United States. CSF biomarker concentrations of Aß42, tTau, and pTau, were collected at enrollment (2016-2020) and analyzed with the Roche Elecsys system. Annual ambient and traffic-related residential PM2.5 concentrations were estimated at a 1-km and 250-m resolution, respectively, and computed for each participant's geocoded address, using three exposure time periods based on specimen collection date. Associations between PM2.5 and CSF biomarker concentrations, considering continuous and dichotomous (dichotomized at clinical cutoffs) outcomes, were estimated with multiple linear/logistic regression, respectively, controlling for potential confounders (age, gender, race, ethnicity, body mass index, and neighborhood socioeconomic status). RESULTS: Interquartile range (IQR; IQR=0.845) increases in 1-y [ß:-0.101; 95% confidence interval (CI): -0.18, -0.02] and 3-y (ß:-0.078; 95% CI: -0.15, -0.00) ambient PM2.5 exposures were negatively associated with Aß42 CSF concentrations. Associations between ambient PM2.5 and Aß42 were similar for 5-y estimates (ß:-0.076; 95% CI: -0.160, 0.005). Dichotomized CSF variables revealed similar associations between ambient PM2.5 and Aß42. Associations with traffic-related PM2.5 were similar but not significant. Associations between PM2.5 exposures and tTau, pTau tTau/Aß42, or pTau/Aß42 levels were mainly null. CONCLUSION: In our study, consistent trends were found between 1-y PM2.5 exposure and decreased CSF Aß42, which suggests an accumulation of amyloid plaques in the brain and an increased risk of developing AD. https://doi.org/10.1289/EHP13503.