Particulate Matter Exposure Research Articles

Assessment of controlled assistance from e-bikes as a mitigation strategy for individual PM exposure

Abstract Background While promoting active mobility and outdoor activities can benefit health (HLT), it also increases Exposure (EXP) to air pollutants, such as particulate matter (PM), due to the increased ventilation rate (VR) under physical activity. Traditional assessments of individual (IND) PM EXP involve costly equipment inaccessible to the public, but real-time low-cost sensors (LCS) are now emerging. This study presents a proof of concept to demonstrate the use of LCS for examining the real-time IND respiratory dose deposited (RDD) to PM cycling across the Brescia province. Methods An e-bike was ridden 33 times between 2022 and 2023 wearing a LCS for PM concentration [PM] linked to a GPS. Respiratory dose deposited(RDD) was calculated for six different locations within each route based on experimental PM and various VR. Results The LCS allows for the study of the spatial and temporal variability of [PM], revealing a significant difference (p < 0.01) according to the heating system operation and no significant difference (p > 0.05) depending on the location. RDD increases with [PM] and VR. Real-time and integrated RDD is calculated for routes with high (> 50 µg/m3), medium (25 µg/m3), and low (<10 µg/m3) [PM2.5]. The e-bike assistance is activated when the WHO interim target 4 of [PM] is reached to reduce VR, which corresponds to a shift to a lower physical activity intensity. The RDD calculated using the e-bike assistance over the path reduces RDD by about 23% and 11% over the high and medium [PM], while it never activates for the low [PM]. Conclusions This study demonstrates that the use of LCS allows the estimation of IND RDD, and the implementation of mitigation strategies based on controlled assistance from e-bikes would enable the reduction of PM individual EXP. Key messages • The integration of HLT data from wearable and air quality LCS enables the promotion of active mobility and outdoor activities controlling the EXP to air pollutants. • Establishing generalized guidelines based on this mitigation strategies for individual exposure reduction may also inform policy recommendations for promoting active and green mobility.

The effect of outdoor air pollution on Alzheimer’s disease: a systematic review

Abstract Air pollution is one of the largest global environmental risks to public health. Over recent years, neuroimaging techniques have started to uncover the detrimental impact air pollution has had on brain health, including the development of Alzheimer’s Diseases (AD). We systematically reviewed the literature to evaluate the effects of long-term exposure (months to years) to outdoor air pollutants on the development of AD-like neurology. This review was registered on PROSPERO (CRD42023482979) and followed PRISMA guidelines. Four large databases (MEDLINE, Embase, Scopus, and CINAHL) were searched in November 2023 using terms associated with air pollution, neuroimaging, and AD. Only peer-reviewed primary research articles using neuroimaging data to examine AD-like pathology after long-term exposure to air pollutants (Particulate Matter (PM2.5, PM10), SO2, NO2, O3, and/or CO) were included. Titles, abstracts and full-texts were screened, and included articles were quality assessed using the Newcastle Ottawa Scale. A narrative synthesis was conducted to analyse the studies. Our search yielded 397 results, of which eight articles met our inclusion criteria. Articles focused on changes to white matter (n = 5), cortical thickness (n = 6), and grey matter (n = 2). Exposure to PM2.5 was commonly associated with white matter reductions, and PM10 and NO2 exposure was associated with reduced cortical thickness. The effect of exposure to different outdoor pollution on grey matter was inconclusive, with both increases and decreases in grey matter volume observed. This review highlighted how PM2.5, PM10 and NO2 exposure was associated with neurological changes commonly seen in AD. These findings can be used by policymakers and researchers to identify specific pollutants that need greater restrictions and regulations to improve population health. Key messages • PM2.5, PM10 and NO2 exposure are associated with neurological changes commonly seen in AD. • Greater restrictions and regulations are needed on specific pollutants to improve population health.

A wearable real-time particulate monitor demonstrates that soaking hay reduces dust exposure.

Affordable particulate matter (PM) monitors suitable for use on horses will facilitate the evaluation of PM mitigation methods and improve the management of equine asthma. Calibrate a real-time wearable PM monitor (Black Beauty [BB]) and compare the PM exposures of horses fed dry or soaked hay. Laboratory calibration; complete cross-over feed trial. Side-by-side sampling with BB monitors and tapered element oscillating microbalances (TEOMs) was performed under varying concentrations of PM from alfalfa hay. Linear regression was used to derive a calibration formula for each unit based on TEOM PM measurements. Precision was evaluated by calculating the coefficient of variation and pairwise correlation coefficients between three BB monitors. PM exposure was measured at the breathing zone of 10 horses for 8 h after they were fed dry or soaked hay. Repeated measures generalised linear models were constructed to determine the effect of hay treatment and measurement duration (initial 20-min vs. 8-h) upon exposure to PM with diameters smaller than or equal to 10 μm (PM10) and 2.5 μm (PM2.5). BB monitor PM2.5 and PM10 measurements were linearly correlated with TEOM data (coefficient of determination r2 > 0.85 and r2 > 0.90 respectively), but underestimated PM2.5 mass concentrations by a factor of 4 and PM10 concentrations by a factor of 44. Measures from the three BB monitors had a coefficient of variation <15% and pairwise r > 0.98. Feeding soaked hay significantly reduced average PM2.5 exposures (20-min: dry: 160 μg/m3, soaked: 53 μg/m3, p < 0.0001; 8-h: dry: 76 μg/m3, soaked: 31 μg/m3, p = 0.0008) and PM10 exposures (20-min: dry: 2829 μg/m3, soaked: 970 μg/m3, p < 0.0001; 8-h: dry: 1581 μg/m3, soaked: 488 μg/m3, p = 0.008). No health outcome measures were collected. With appropriate corrections, the BB monitor can be used to estimate horse PM exposure. While 20-min measurements yielded higher estimates of exposure than 8-h measurements, both intervals demonstrate that soaking hay reduces PM exposures by more than 50%.

Long-term effects of air pollution on daily outpatient visits for allergic conjunctivitis from 2013 to 2020: a time-series study in Urumqi, China

IntroductionThis study aimed to elucidate the effects of outdoor air pollution and allergic conjunctivitis and population-based lagged effects of air pollution.MethodsWe included data on six major air pollutants, PM10, PM2.5, carbon monoxide (CO), sulfur dioxide (SO2), nitrogen dioxide (NO2), and ozone (O3), and 3325 allergic conjunctivitis outpatient visits in Urumqi, northwest China, from 1 January 2013 to 31 December 2020. We developed quasi-Poisson generalized linear regression models with distributed lagged nonlinear models (DLNM), and single and multi-pollutant models were constructed to investigate single-day and cumulative lagged effects in detail.ResultsOur results confirmed that elevated PM10 and NO2 levels are significantly associated with increased allergic conjunctivitis outpatient visits with lags of 2 and 3 days respectively, and subgroup analyses further suggest that the effects of PM10 and NO2 on allergic conjunctivitis are more pronounced during the warm season. Women are more sensitive to PM10 exposure and the effect of air pollution on allergic conjunctivitis is influenced by age (e.g., infancy and older people).DiscussionOur work provides the first time-series study in Urumqi, the world's furthest inland city from the ocean. Further implementation of specific outdoor air pollution controls such as the burning of fossil fuels like coal, as well as special population protection policies remain necessary. Multicenter studies with larger sample sizes are needed.

Long-term exposure to fine particulate matter constituents, genetic susceptibility, and incident heart failure among 411 807 adults.

Long-term fine particulate matter (PM2.5) exposure has been linked to incident heart failure (HF), but the impacts of its constituents remain unknown. We aimed to investigate the associations of PM2.5 constituents with incident HF, and further evaluate the modification effects of genetic susceptibility. PM2.5 and its constituents, including elemental carbon (EC), organic matter (OM), ammonium (NH4 +), nitrate (NO3 -), and sulfate (SO4 2-), were estimated using the European Monitoring and Evaluation Programme model applied to the UK (EMEP4UK) driven by Weather and Research Forecast model meteorology. A polygenic risk score (PRS) was calculated to represent genetic susceptibility to HF. We employed Cox models to evaluate the associations of PM2.5 constituents with incident HF. Quantile-based g-computation model was used to identify the main contributor of PM2.5 constituents. Among 411 807 individuals in the UK Biobank, 7554 participants developed HF during a median follow-up of 12.05 years. The adjusted hazard ratios of HF for each interquartile range increase in PM2.5, EC, OM, NH4 +, NO3 -, and SO4 2- were 1.50 (1.46-1.54), 1.31 (1.27-1.34), 1.12 (1.09-1.15), 1.42 (1.41-1.44), 1.26 (1.23-1.29), and 1.25 (1.24-1.26), respectively. EC (43%) played the most important role, followed by NH4 + and SO4 2-. Moreover, synergistic additive interactions accounted for 9-16% of the HF events in individuals exposed to both PM2.5, NH4 +, NO3 -, and SO4 2- and PRS. Long-term exposure to PM2.5 constituents may elevate HF risk, and EC was the major contributor. Additive effects of PM2.5 constituents and PRS on HF risk were revealed.

PM2.5 Exposure as a Risk Factor for Optic Nerve Health in Type 2 Diabetes Mellitus

(1) Objective: This study investigated the relationship between long-term particulate matter (PM2.5) exposure and optic disc parameters—vertical cup-to-disc ratio (vCDR), vertical optic disc diameter (vDD), and vertical optic cup diameter (vCD)—in patients with type 2 diabetes mellitus (T2DM). (2) Methods: A cross-sectional analysis was conducted using data from 65,750 T2DM patients in the 2017–2018 Shanghai Cohort Study of Diabetic Eye Disease (SCODE). Optic disc parameters were extracted from fundus images, and PM2.5 exposure was estimated using a random forest model incorporating satellite and meteorological data. Multivariate linear regression models were applied, adjusting for confounders including age, gender, body mass index, blood pressure, glucose, time of T2DM duration, smoking, drinking, and physical exercise. (3) Results: A 10 μg/m3 increase in PM2.5 exposure was associated with significant reductions in vCDR (−0.008), vDD (−42.547 μm), and vCD (−30.517 μm) (all p-values &lt; 0.001). These associations persisted after sensitivity analyses and adjustments for other pollutants like O3 and NO2. (4) Conclusions: Long-term PM2.5 exposure is associated with detrimental changes in optic disc parameters in patients with T2DM, suggesting possible optic nerve atrophy. Considering the close relationship between the optic nerve and the central nervous system, these findings may also reflect broader neurodegenerative processes.

The impact of changing exposure to PM2.5 on mortality for US diplomats with multiple international relocations: a modelling study.

Current evidence linking long-term exposure to fine particulate matter (PM2.5) exposure and mortality is primarily based on persons that live in the same residence, city and/or country throughout the study, with few residential moves or relocations. We propose a novel method to quantify the health impacts of PM2.5 for United States (US) diplomats who regularly relocate to international cities with different PM2.5 levels. Life table methods were applied at an individual-level to US mortality statistics using the World Health Organization's database of city-specific PM2.5 annual mean concentrations. Global Burden of Disease concentration-response (C-R) functions were used to estimate cause-specific mortality and days of life lost (DLL) for a range of illustrative 20-year diplomatic assignments for three age groups. Time lags between exposure and exposure-related mortality risks were applied. Sensitivity analysis of baseline mortality, exposure level, C-R functions and lags was conducted. The effect of mitigation measures, including the addition of air purifiers, was examined. DLL due to PM2.5 exposure for a standard 20-year assignment ranged from 0.3 days for diplomats' children to 84.1 days for older diplomats. DLL decreased when assignments in high PM2.5 cities were followed by assignments in low PM2.5 cities: 162.5 DLL when spending 20 years in high PM2.5 cities compared to 62.6 DLL when spending one of every four years (5 years total) in a high PM2.5 city for older male diplomats. Use of air purifiers and improved home tightness in polluted cities may halve DLL due to PM2.5 exposure. The results were highly sensitive to lag assumptions: DLL increased by 68% without inception lags and decreased by 59% without cessation lags for older male diplomats. We developed a model to quantify health impacts of changing PM2.5 exposure for a population with frequent relocations. Our model suggests that alternating assignments in high and low PM2.5 cities may help reduce PM2.5-related mortality burdens. Adding exposure mitigation at home may help reduce PM2.5 related mortality. Further research on outcome-specific lag structures is needed to improve the model.

Impact of physical activity levels on the association between air pollution exposures and glycemic indicators in older individuals

BackgroundAir pollution may exacerbate diabetes-related indicators; however, the longitudinal associations between air pollutant concentrations and glycemic markers remain unclear. In this prospective cohort study, we examined the longitudinal associations between air pollution and glycemic indicators among older individuals with normoglycemia at baseline and determined whether these associations differed according to changes in physical activity levels.MethodsOverall, 1,856 participants (mean age, 70.9 years) underwent baseline and 4-year follow-up surveys. We used linear mixed-effect models to examine the associations between previous 1-year exposures to air pollutants and glycemic indicators. We further investigated associations between previous 5-year exposures to air pollutants and glycemic indicators after the inverse probability of treatment weighting (IPTW). We explored effect modifications by the level of physical activity maintenance and changes in metabolic equivalent of task (METs) for physical activity.ResultsLevels of particulate matter with aerodynamic diameters ≤ 10 μm (PM10) and ≤ 2.5 μm, and nitrogen dioxide (NO2) were significantly associated with increased fasting blood glucose, Hemoglobin A1c, insulin, and homeostatic model assessment for insulin resistance (HOMA-IR) values. After IPTW, the associations remained significant for PM10 and NO2. The positive associations of NO2 with insulin and HOMA-IR remained significant in the maintained inactive group, but not in the maintained moderate-to-vigorous active group. The positive associations of PM10 or NO2 with insulin and HOMA-IR remained significant in the group with increased METs, but not in those with decreased METs. In the post-hoc analysis of non-linear relationships between an increase in METs and glycemic indicators, insulin and HOMA-IR remarkably increased in the higher PM10 and NO2 exposure group from the point of 12,000 and 13,500 METs-min/week increase, respectively.ConclusionsWe demonstrated longitudinal associations between air pollution exposures and increased insulin resistance in older individuals. Maintaining moderate-to-vigorous physical activity may mitigate the adverse effects of air pollution on insulin resistance. In older individuals dwelling in highly polluted areas, an increase of less than 12,000 METs-min/week may be beneficial for insulin resistance.

Delineating Urbanicity and Rurality: Impact on Environmental Exposure Assessment.

Environmental exposures and their health impacts can vary substantially between urban and rural areas. However, different methods for classifying these areas could lead to inconsistencies in environmental exposure and health studies, which are often overlooked. We constructed different urban/rural classification systems based on multiple population-based (e.g., total population, population density, and commuting) and built-environment-based (e.g., nighttime light intensity, building density, road density, distance to urban centers, point of interest density, and urban area coverage) indicators and various classification schemes. These classification systems were applied to Virginia and West Virginia, United States. We compared differences in urban/rural spatial patterns, demographic compositions, and exposures of particulate matter (PM2.5), greenspace, and land surface temperature using these urban/rural classification systems to understand their impacts on environmental exposure and health research. Our findings reveal clear differences in spatial patterns and demographic compositions across various systems. We also observed that different systems can lead to changes in the magnitude and direction of urban/rural disparities in environmental exposure assessment. Addressing the complexities in delineating urbanicity and rurality may include careful consideration of classification systems to reflect those aspects of urbanicity and rurality that are relevant to the research question or the use of multiple, complementary systems.

The influence of frailty: How the associations between modifiable risk factors and dementia vary

BackgroundThe Lancet Commission has highlighted 12 modifiable risk factors for dementia. However, the effects of addressing these risk factors among the heterogeneous older adult population is not fully understood. We compared the association between risk factors and dementia by frailty, conceptualized as an explanation for the underlying health heterogeneity in old age. MethodsData were from the UK Biobank, a cohort study with over 500,000 participants aged 37–73 between 2006 and 2010. Frailty was measured by five criteria: slowness, weakness, exhaustion, inactivity, and shrinking. Participants meeting 0, 1–2, and 3–5 criteria were considered non-frail, prefrail, and frail, respectively. We included 13 modifiable risk factors. We used logistic regression to determine the associations of risk factors with 10-year dementia among non-frail, pre-frail, and frail individuals, respectively. Additionally, we adopted a g-computation method to estimate the individual and combined population intervention effects (PIE) of the risk factors for dementia. ResultsOf 381,419 participants, 58.4 %, 38.2 %, and 3.4 % were classified as non-frail, pre-frail, and frail, respectively. Except for smoking, depression, and excessive alcohol use, the other 10 risk factors had a stronger association with dementia among frailer individuals. We observed the highest PIEs among frail individuals when considering hypothetical interventions targeting low education, physical inactivity, central obesity, social isolation, hearing impairment, hypertension, diabetes, high nitrogen dioxide (NO2) exposure, high exposure of particulate matter with a diameter less than or equal to 2.5 micrometers (PM2.5), and traumatic brain injury individually. For the hypothetical interventions targeting all 13 risk factors together, we found a graded increase in the PIE across frailty status. ConclusionThe associations between modifiable risk factors and dementia were stronger among the frail. We advocate for incorporating frailty assessments to pinpoint those most likely to benefit from targeted risk factor interventions.

Childhood Air Pollution Exposure Associated with Self-reported Bronchitic Symptoms in Adulthood.

Rationale: Few studies have examined the effects of long-term childhood air pollution exposure on adult respiratory health, including whether childhood respiratory effects underlie this relation. Objectives: To evaluate associations between childhood air pollution exposure and self-reported adult bronchitic symptoms while considering child respiratory health in the Southern California Children's Health Study. Methods: Exposures to nitrogen dioxide (NO2), ozone, and particulate matter <2.5 μm and <10 μm in diameter (PM10) assessed using inverse-distance-squared spatial interpolation based on childhood (birth to age 17 yr) residential histories. Bronchitic symptoms (bronchitis, cough, or phlegm in the past 12 mo) were ascertained via a questionnaire in adulthood. Associations between mean air pollution exposure across childhood and self-reported adult bronchitic symptoms were estimated using logistic regression. We further adjusted for childhood bronchitic symptoms and asthma to understand whether associations operated beyond childhood respiratory health impacts. Effect modification was assessed for family history of asthma, childhood asthma, and adult allergies. Measurements and Main Results: A total of 1,308 participants were included (mostly non-Hispanic White [56%] or Hispanic [32%]). At adult assessment (mean age, 32.0 yr; standard deviation [SD], 4.7), 25% reported bronchitic symptoms. Adult bronchitic symptoms were associated with NO2 and PM10 childhood exposures. Odds ratios per 1-SD increase were 1.69 (95% confidence interval, 1.14-2.49) for NO2 (SD, 11.1 ppb) and 1.51 (95% confidence interval, 1.00-2.27) for PM10 (SD, 14.2 μg/m3). Adjusting for childhood bronchitic symptoms or asthma produced similar results. NO2 and PM10 associations were modified by childhood asthma, with greater associations among asthmatic individuals. Conclusions: Childhood NO2 and PM10 exposures were associated with adult bronchitic symptoms. Associations were not explained by childhood respiratory health impacts; however, participants with childhood asthma had stronger associations.

Implications of Traditional Cooking on Air Quality and Female Health: An In-Depth Analysis of Particulate Matter, Carbon Monoxide, and Carbon Dioxide Exposure in a Rural Community

Indoor air pollution, particularly in rural communities, is a significant health determinant, primarily due to the prevalence of traditional cooking practices. The WHO estimates 4.3 million annual deaths related to household air pollution. This study quantifies indoor pollutants and assesses health impacts and perceptions regarding traditional cooking. Using Extech air quality monitoring equipment, the study measured particulate matter (PM), carbon monoxide (CO), and carbon dioxide (CO2) in 48 rural homes. A survey of 39 women gathered insights on their use of wood for cooking and perceptions of air quality. This dual approach analyzed both environmental and social dimensions. Findings showed fine particulate matter (0.3, 0.5, 1.0, and 2.5 μm) exceeded safety limits by threefold, while coarser particulates (5.0 and 10 µm) were concerning but less immediate. CO levels were mostly acceptable, but high concentrations posed risks. CO2 levels indicated good ventilation. Survey responses highlighted reliance on wood and poor air quality perceptions demonstrating little awareness of health risks. Common symptoms included eye discomfort, respiratory issues, and headaches. The study emphasizes the need for interventions to reduce exposure to indoor pollutants and increase awareness of health risks to encourage cleaner cooking practices in rural communities.

The impact of exposure assessment on associations between air pollution and cardiovascular mortality risks in the city of Rio de Janeiro, Brazil

Despite a growing literature for complex air quality models, scientific evidence lacks of the influences of varying exposure assessments and air quality data sources on the estimated mortality risks. This case-crossover study estimated cardiovascular mortality risks from fine particulate matter (PM2.5) and ozone (O3) exposures, using varying exposure methods, to aid understanding of the impact of exposure methods in the health risk estimation. We used individual-level cardiovascular mortality data in the city of Rio de Janeiro, 2012–2016. PM2.5 and O3 exposure levels (from the date of death to seven prior days [lag0–7]) were estimated at the individual level or district level using either the WRF-Chem modeling data or monitoring data, resulting in a total of 10 exposure methods. The exposure-response relationships were estimated using multiple logistic regressions. The changes in cardiovascular mortality were represented as an odds ratio (OR) and 95% confidence intervals (CIs) for an interquartile range (IQR) increase in the exposures. Results showed that socioeconomically more advantaged populations had lower access to the stationary monitoring networks. Higher variance in the estimated exposure levels across the 10 exposure methods was found for PM2.5 than O3. PM2.5 exposure was not associated with mortality risk in any exposure methods. WRF-Chem-based O3 exposure estimated for each individual of the entire population found a significant mortality risk (OR = 1.06, 95% CI: 1.01, 1.11), but not the other exposure methods. Higher risks for females and older populations were suggested for O3 estimates estimated for each individual using the WRF-Chem data. Findings indicate that decisions on exposure methods and data sources can lead to substantially varying implications for air pollution risks and highlight the need for comprehensive exposure and health impact assessments to aid local decision-making for air pollution and public health.

Comparative analysis of particle exposure in commuters: Evaluating different modes of transportation in Tehran

Daily commuting significantly contributes to the overall exposure to particulate matter (PM) in urban areas, underscoring the need to understand the factors influencing PM exposure. This study assessed personal exposure levels and inhalation doses of PM2.5, and PM10 across various transportation modes in Tehran, Iran. The study included buses, open-window taxis, subways, walking, and cycling for over 125 trips. Data were collected during the morning and evening peak hours using low-cost sensors, with an average trip distance of 7.50 km. On average, buses exhibited the highest mean PM2.5 concentration (25.0 μgm3), followed by subways (17.0 μgm3), taxis (14.4 μgm3), cycling (13.5 μgm3), and walking (8.80 μgm3). Pearson correlation analysis showed a strong relationship between traffic volume and PM concentrations in taxi and bus modes (r = 0.78 and 0.56, respectively). Subway commuters experienced the lowest PM2.5 inhalation dose (2.50 μg), whereas bus commuters experienced the highest (6.20 μg). Pedestrians had the highest average inhalation dose of PM2.5 with 20.7 μg due to longer trip durations. The daily average PM2.5 levels in all transportation modes exceeded the WHO thresholds by 1.60 times. These findings offer crucial insights into personal exposure concentrations among commuters and serve as a basis for effective air quality management plans and broader global investigations of air pollution.

EV-miRNA associated with environmental air pollution exposures in the MADRES cohort

ABSTRACT Air pollution is a hazardous contaminant, exposure to which has substantial consequences for health during critical periods, such as pregnancy. MicroRNA (miRNA) are an epigenetic mechanism that modulates transcriptome responses to the environment and have been found to change in reaction to air pollution exposure. The data are limited regarding extracellular-vesicle (EV) miRNA variation associated with air pollution exposure during pregnancy and in susceptible populations who may be disproportionately exposed. This study aimed to identify EV-miRNA expression associated with ambient, residential exposure to PM2.5, PM10, NO2, O3 and with traffic-related NOx in 461 participants of the MADRES cohort, a low income, predominantly Hispanic pregnancy cohort based in Los Angeles, CA. This study used residence-based modeled air pollution data as well as Nanostring panels for EVmiRNA extracted with Qiagen exoRNeasy kits to evaluate 483 miRNA in plasma in early and late pregnancy. Average air pollution exposures were considered separately for 1-day, 1-week and 8-week windows before blood collection in both early and late pregnancy. This study identified 63 and 66 EV-miRNA significantly associated with PM2.5 and PM10, respectively, and 2 miRNA associated with traffic-related NOX (FDR-adjusted p-value&amp;lt;0.05). Of 103 unique EV-miRNA associated with PM, 92% were associated with lung conditions according to HMDD (Human miRNA Disease Database) evidence. In particular, EV-miRNA previously identified with air pollution exposure also associated with PM2.5 and PM10 in this study were: miR-126, miR-16-5p, miR-187-3p, miR200b-3p, miR486-3p, and miR-582-3p. There were no significant differences in average exposures in early vs late pregnancy. Significant EV-miRNA were only identified in late pregnancy with an eight-week exposure window, suggesting a vulnerable timeframe of exposure, rather than an acute response. These results describe a wide array of EV-miRNA for which expression is affected by PM exposure and may be in part mediating the biological response to ambient air pollution, with potential for health implications in pregnant women and their children.

Effects of dust loading on the long-term performance of portable HEPA air cleaner to woodsmoke – A laboratory investigation

Portable air cleaners (PACs) equipped with high-efficiency particulate air (HEPA) filters are recommended to reduce indoor particulate matter (PM) exposure from wildfire smoke, particularly in regions like the Pacific Northwest, where seasonal wildfires affect air quality. While many studies have evaluated the long-term effectiveness of HEPA PACs, few have focused on the effects of dust loading and their performance in filtering woodsmoke over extended periods. This study investigated the impact of filter dust loading on the performance of a HEPA PAC (Winix C535, Winix America) in reducing woodsmoke particles. Filters were pre-loaded with varying amounts of ASHRAE ISO 12103–1 A2 fine test dust, and an exposure chamber was used to assess clean air delivery rate (CADR), airflow rate, and power consumption. Results indicated a significant decline in PAC performance with increasing filter loading, highlighting the importance of regular filter replacements to maintain effective operation. Based on simulations considering dynamic indoor PM2.5 concentration, in a typical scenario with a 90-m² room, baseline PM2.5 emission rates, and continuous operation at fan speed Level 2 (5-year mean indoor PM2.5: 2.99 μg/m3), it would take over 5 years for the PAC filters to accumulate 46 g of dust – an amount associated with a significant drop in CADR observed in the study. These findings suggest that the commonly recommended 1-year replacement schedule by manufacturers may be overly conservative for such conditions. By utilizing indoor air quality sensors to monitor PM concentrations, users can tailor filter replacement schedules to maintain optimal PAC performance in real-world environments.

Early life air pollution exposures and thyroid function in children: A prospective cohort study

Studies on early life ambient air pollution exposures and childhood thyroid function are scarce. This study aimed to evaluate the relationships between early life fine particulate matter (≤2.5 μm; PM2.5) and nitrogen dioxide (NO2) exposures and thyroid function in children. We measured the levels of thyrotropin, triiodothyronine, and free thyroxine in children (n = 684) residing in a rural Korean area at age 2, 4, 6, or 8 years from 2012 to 2020 in the Environment and Development of Children cohort. The relationship between residential average exposure levels of PM2.5 and NO2 during pregnancy and 1-year average levels before visit and thyroid function during childhood were analyzed. Inverse association between increases of 10 μg/m3 in PM2.5 during the first trimester and thyrotropin levels at aged 4 (β, −0.12; 95% CI: −0.22, −0.02) and 6 years (β, −0.16; 95% CI: −0.26, −0.06) were observed. No association was found between PM2.5 exposure during the second and third trimester and childhood TSH levels. Childhood PM2.5 exposure was positively associated with thyrotropin rise at aged 4 (β, 0.2; 95% CI: 0.06, 0.35) and 6 years (β, 0.16; 95% CI: 0.02, 0.29) and inversely related with free thyroxine levels at aged 8 years (β, −0.04; 95% CI: −0.07, −0.01). No relationship between NO2 exposure and thyroid function was found. In conclusion, association between PM2.5 exposure and childhood thyrotropin levels varied depending on exposure timing. Early gestational exposure showed an inverse relationship, whereas childhood exposure were positively associated with childhood thyrotropin levels. The long-term effects of early life air pollution exposure and underlying mechanisms should be investigated in future studies.

A pilot study of thecardiopulmonary effects in healthy volunteers after exposure to high levels of PM2.5 in a New York City subway station.

Subway systems are becoming increasingly common worldwide transporting large populations in major cities. PM2.5 concentrations have been demonstrated to be exceptionally high when underground, however. Studies on the impact of subway PM exposure on cardiopulmonary health in the United States are limited. Healthy volunteers in New York City were exposed to a 2-h visit on the 9th Street Station platform on the Port Authority Trans-Hudson train system. Blood pressure, heart rate variability (HRV), spirometry, and forced impulse oscillometry were measured, and urine, blood spot, and nasal swab biosamples were collected for cytokine analysis at the end of the 2-h exposure period. These endpoints were compared against individual control measurements collected after 2-h in a "clean" control space. In addition to paired comparisons, mixed effects models with subject as a random effect were employed to investigate the effect of the PM2.5 concentrations and visit type (i.e., subway vs. control). Mean PM2.5 concentrations on the platform and during the control visit were 293.6 ± 65.7 (SD) and 4.6 ± 1.9µg/m3, respectively. There was no change in any of the health metrics, but there was a non-significant trend for SDNN to be lower after subway exposure compared to control exposure. Total symptomatic scores did increase post-subway exposure compared to reported values prior to exposure or after the control visit. No significant changes in cytokine concentrations in any specimen type were observed. Mixed-effects models mostly corroborated these paired comparisons. Acute exposures to PM on a subway platform do not cause measurable cardiopulmonary effects apart from reductions in HRV and increases in symptoms in healthy volunteers. These findings match other studies that found little to no changes in lung function and blood pressure after exposure in underground subway stations. Future work should still target potentially more vulnerable populations, such as individuals with asthma or those who spend increased time underground on the subway such as transit workers.

Air Pollution and Breast Cancer Incidence in the Multiethnic Cohort Study.

Recent studies suggested fine particulate matter (PM2.5) exposure increases the risk of breast cancer, but evidence among racially and ethnically diverse populations remains sparse. Among 58,358 California female participants of the Multiethnic Cohort (MEC) Study followed for an average of 19.3 years (1993-2018), we used Cox proportional hazards regression to examine associations of time-varying PM with invasive breast cancer risk (n = 3,524 cases; 70% African American and Latino females), adjusting for sociodemographics and lifestyle factors. Subgroup analyses were conducted for race and ethnicity, hormone receptor status, and breast cancer risk factors. Satellite-based PM2.5 was associated with a statistically significant increased incidence of breast cancer (hazard ratio [HR] per 10 μg/m3, 1.28 [95% CI, 1.08 to 1.51]). We found no evidence of heterogeneity in associations by race and ethnicity and hormone receptor status. Family history of breast cancer showed evidence of heterogeneity in PM2.5-associations (Pheterogeneity = .046). In a meta-analysis of the MEC and 10 other prospective cohorts, breast cancer incidence increased in association with exposure to PM2.5 (HR per 10 μg/m3 increase, 1.05 [95% CI, 1.00 to 1.10]; P = .064). Findings from this large multiethnic cohort with long-term air pollutant exposure and published prospective cohort studies support PM2.5 as a risk factor for breast cancer. As about half of breast cancer cannot be explained by established breast cancer risk factors and incidence is continuing to increase, particularly in low- and middle-income countries, our results highlight that breast cancer prevention should include not only individual-level behavior-centered approaches but also population-wide policies and regulations to curb PM2.5 exposure.

Anti-inflammatory diet mitigate cardiovascular risks due to particulate matter exposure in women during pregnancy: A perspective cohort study from China

BackgroundParticulate matter (PM) exposure during pregnancy may increase cardiovascular risk (CVR). However, the specific time windows of exposure contributing to this association and the potential biological mechanisms underlying it remain unclear. ObjectiveTo determine the sensitive time window for CVR related to PM exposure. We investigated whether levels of inflammatory biomarkers mediate the relationship between PM exposure and CVR, and examined the potential impact of an anti-inflammatory diet on this association. MethodsFrom 2015 to 2021, 9294 pregnant women from three Hefei hospitals were included. We used a 1 × 1 km satellite dataset to assess PM1, PM2.5, and PM10 exposure. High-sensitivity C-reactive protein (hs-CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) were measured as inflammatory biomarkers. The empirical dietary inflammatory pattern (EDIP) score, based on a validated food frequency questionnaire. The CVR score was calculated using five clinical metrics based on American Heart Association criteria. ResultsWe found a significant association between PM exposure and increased CVR score, especially during the 2nd to 8th weeks of the first trimester. For every increase of 10-μg/m3 of PM1, PM2.5, and PM10, there was an associated increase in CVR of 0.51 (95%CI: 0.21, 082), 0.25 (95% CI: 0.11 to 0.39), and 0.29 (95% CI: 0.09 to 0.37), respectively. Mediation analysis revealed that the proportion of the association between PM1, PM2.5, and PM10 exposure and CVR mediated by inflammatory biomarkers was 24.3%, 22.4%, and 20.1%, respectively. Stratified analyses showed no positive correlation between PM exposure and CVR in the anti-inflammatory diet (low EDIP) group. The β coefficients were 0.52 for PM1 (95% CI: -0.06 to 1.11), 0.31 for PM2.5 (95% CI: -0.04 to 0.79), and 0.25 for PM10 (95% CI: -0.03 to 0.54). ConclusionsPM exposure, particularly during weeks 2–8 of pregnancy, correlates with CVR, partly mediated by levels of inflammatory biomarkers. An anti-inflammatory diet mitigates CVR associated with PM exposure.