An investigation of PM2.5 concentration changes in Mid-Eastern China before and after COVID-19 outbreak

Association between long-term exposure to PM2.5 and thyroid nodules in school-aged children and adolescents: a cross-sectional study in Eastern China

BACKGROUND

Long-term exposure to particulate matter with aerodynamic diameter ≤ 2.5 μm (PM2.5) are linked to thyroid nodules in adults, but epidemiological evidence in children and adolescents and adjustments for key confounders are lacking. This study aimed to explore the association between long-term exposure to PM2.5 and the prevalence of thyroid nodules in school-aged children and adolescents.

METHODS

A cross-sectional study including 10,739 primary and junior high school students was conducted in Jiangsu Province, China, in 2021. Annual PM2.5 concentrations were estimated by a satellite based space-time model based on machine learning. Individual exposure concentrations were assigned according to the school addresses of the participants. High-resolution diagnostic ultrasound imaging was used to detect the thyroid nodules. After adjustment for covariates, the link between the two-year (2019-2020) average PM2.5 concentrations and thyroid nodules was estimated using a generalized linear mixed-effects model. The concentration-response (C-R) curves were smoothed using a restricted cubic spline function. Stratified analyses were performed to evaluate the modification effects of covariates on associations.

RESULTS

The average age of the 10,067 participants (51.9% boys) was 11 years, with a thyroid nodule prevalence of 30.5%. A non-linear positive correlation was found between the increase in prevalence of thyroid nodules and two-year average exposure concentration of PM2.5. The C-R relationship curve between thyroid nodules and PM2.5 had a J-shaped structure with a threshold value of 39.7 µg/m3. Following covariates adjustment, the odds ratio (OR) and 95% confidence interval (CI) linked to thyroid nodules were 1.515 (1.199, 1.915) for per standard deviation (SD) increase in two-year average PM2.5 concentrations (> 39.7 µg/m3). The sex-specific associations found among adults were not observed in our stratified analyses.

CONCLUSIONS

Our findings demonstrated that long-term exposure to PM2.5 was associated with a higher prevalence of thyroid nodules in children and adolescents. Strategies that consistently reduce PM2.5 pollution levels to ease the burden of non-communicable diseases have important public health implications.

Spatiotemporal analysis of the association between Kawasaki disease incidence and PM2.5 exposure: a nationwide database study in Japan

BACKGROUND

Kawasaki disease (KD) is an acute vasculitis primarily affecting children. While some studies suggest a link between KD and PM2.5 exposure, findings remain inconsistent. This study aimed to perform spatiotemporal analysis to investigate the impact of monthly and annual exposure to PM2.5 and other air pollutants on the incidence of KD before and after the advent of the COVID-19 pandemic.

METHODS

In this retrospective analysis, we used the Japanese administrative claims database to identify the incidence of KD in children under age 5 in 335 secondary medical care areas across Japan before (from July 2014 to December 2019) and during (from January 2020 to December 2021) the COVID-19 pandemic. For each of these periods, we developed hierarchical Bayesian models termed conditional autoregressive (CAR) models that can address the spatiotemporal clustering of KD to investigate the association between the monthly incidence of KD and exposure to PM2.5, NO, NO2 and SO2 over 1-month and 12-month durations. The pollution data were collected from publicly available data provided by the National Institute for Environmental Studies.

RESULTS

In the before-pandemic and during-pandemic periods, 55 289 and 14 023 new cases of KD were identified, respectively. The CAR models revealed that only 12-month exposure to PM2.5 was consistently correlated with KD incidence, and each 1 µg/m3 increase in annual PM2.5 exposure corresponded to a 3%-10% rise in KD incidence. Consistent outcomes were observed in the age-stratified sensitivity analysis.

CONCLUSIONS

Annual exposure to PM2.5 was robustly linked with the onset of KD. Further research is needed to elucidate the underlying mechanism by which the spatiotemporal distribution of PM2.5 is associated with KD.

Effects of Naphtho[2,1-a]pyrene Exposure on CYP1A1 Expression: An in Vivo and in Vitro Mechanistic Study Exploring the Role of m6A Posttranscriptional Modification

BACKGROUND

Currently, many emerging polycyclic aromatic hydrocarbons (PAHs) have been found to be widely present in the environment. However, little has been reported about their toxicity, particularly in relation to CYP1A1.

OBJECTIVES

This study aimed to explore the toxicity of naphtho[2,1-a]pyrene (N21aP) and elucidate the mechanism underlying N21aP-induced expression of CYP1A1.

METHODS

The concentration and sources of N21aP were detected and analyzed by gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) and diagnostic ratio analysis. Then the effects of CYP1A1 on the toxicity of N21aP were conducted in male wild-type (WT) and Cyp1a1 knockout mice exposed to N21aP (0.02, 0.2, and 2 mg / kg ) through intratracheal instillation. Further, the aryl hydrocarbon receptor (AhR) pathway was examined through luciferase and chromatin immunoprecipitation (ChIP) assays. N 6 -methyladenosine (m 6 A ) modification levels were measured on global RNA and specifically on CYP1A1 mRNA using dot blotting and methylated RNA immunoprecipitation-quantitative real-time polymerase chain reaction (MeRIP qRT-PCR), with validation by m 6 A inhibitors, DAA and SAH. m 6 A sites on CYP1A1 were identified by bioinformatics and luciferase assays, and CYP1A1 mRNA's interaction with IGF2BP3 was confirmed by RNA pull-down, luciferase, and RNA binding protein immunoprecipitation (RIP) assays.

RESULTS

N21aP was of the same environmental origin as benzo[a]pyrene (BaP) but was more stably present in the environment. N21aP could be metabolically activated by CYP1A1 to produce epoxides, causing DNA damage and further leading to lung inflammation. Importantly, in addition to the classical AhR pathway (i.e., BaP), N21aP also induced CYP1A1 expression with a posttranscriptional modification of m 6 A in CYP1A1 mRNA via the METTL14-IGF2BP3-CYP1A1 axis. Specifically, in the two recognition sites of METTL14 on the CYP1A1 mRNA transcript (position at 2700 and 5218), a methylation site (position at 5218) in the 3'-untranslated region (UTR) was recognized by IGF2BP3, enhanced the stability of CYP1A1 mRNA, and finally resulted in an increase in CYP1A1 expression.

DISCUSSION

This study systematically demonstrated that in addition to AhR-mediated transcriptional regulation, N21aP, had a new additional mechanism of m 6 A -mediated posttranscriptional modification, jointly contributing to CYP1A1 expression. Given that PAHs are the metabolic substrates of CYP1A1, this study not only helps to understand the significance of environment-genetic interactions for the toxicity of PAHs but also helps to better understand the health risks of the emerging PAHs at environmental exposure levels. https://doi.org/10.1289/EHP14055.

Adverse Associations of Long-Term Exposure to PM2.5 and Its Components with Platelet Traits among Subway Shift-Workers without Air Purifier Use

Air purifier use, shift work, and long-term exposure to fine particulate matter (PM2.5) are linked to platelet abnormality. However, the role of air purifier use and shift work in the individual or joint associations of PM2.5 and its components with platelet indices are largely unknown. A total of 8772 participants were recruited from a population of subway workers in China. PM2.5 and its component data were obtained from the Tracking Air Pollution in China dataset. The role of air purifier use and shift work in the association between PM2.5 and its components and platelet indices were analyzed. Among shift workers without air purifier use, positive associations of PM2.5 and each component in PM2.5 with the mean platelet volume (MPV) or platelet counts (PLT) were observed, whereas negative associations of PM2.5 and each component in PM2.5 with the platelet distribution width (PDW) were observed. Furthermore, estimated changes (95%CIs) in PLT, MPV, and PDW in response to each 10th percentile increment in the mixture of PM2.5 and its components were 0.8657 (0.2496, 1.4819), 0.0192 (0.0054, 0.0329), and -0.0648 (-0.0945, -0.0351), respectively, and sulfate in PM2.5 was the major contributor to those associations. Long-term exposure to PM2.5 and its components was related to increased platelet disorders among shift workers without air purifier use, and those associations were mainly attributed to sulfate in PM2.5.

Effects of COVID-19 on coastal and marine environments: Aggravated microplastic pollution, improved air quality, and future perspective

The COVID-19 pandemic during 2020-2023 has wrought adverse impacts on coastal and marine environments. This study conducts a comprehensive review of the collateral effects of COVID-19 on these ecosystems through literature review and bibliometric analysis. According to the output and citation analysis of these publications, researchers from the coastal countries in Asia, Europe, and America payed more attentions to this environmental issue than other continents. Specifically, India, China, and USA were the top three countries in the publications, with the proportion of 19.55%, 18.99%, and 12.01%, respectively. The COVID-19 pandemic significantly aggravated the plastic and microplastic pollution in coastal and marine environments by explosive production and unproper management of personal protective equipment (PPE). During the pandemic, the estimated mismanaged PPE waste ranged from 16.50 t/yr in Sweden to 250,371.39 t/yr in Indonesia. In addition, the PPE density ranged from 1.13 × 10-5 item/m2 to 2.79 item/m2 in the coastal regions worldwide, showing significant geographical variations. Besides, the emerging contaminants released from PPE into the coastal and marine environments cannot be neglected. The positive influence was that the COVID-19 lockdown worldwide reduced the release of air pollutants (e.g., fine particulate matter, NO2, CO, and SO2) and improved the air quality. The study also analyzed the relationships between sustainable development goals (SDGs) and the publications and revealed the dynamic changes of SDGs in different periods the COVID-19 pandemic. In conclusion, the air was cleaner due to the lockdown, but the coastal and marine contamination of plastic, microplastic, and emerging contaminants got worse during the COVID-19 pandemic. Last but not least, the study proposed four strategies to deal with the coastal and marine pollution caused by COVID-19, which were regular marine monitoring, performance of risk assessment, effective regulation of plastic wastes, and close international cooperation.

Development of surface observation-based two-step emissions adjustment and its application on CO, NOx, and SO2 emissions in China and South Korea

It is challenging to estimate local emission conditions of a downwind area solely based on concentrations in the downwind area. This is because air pollutants that have a long residence time in the atmosphere can be transported over long distances and influence air quality in downwind areas. In this study, a Two-step Emissions Adjustment (TEA) approach was developed to adjust downwind emissions of target air pollutants with surface observations, considering their long-range transported emission impacts from upwind areas calculated from air quality simulations. Using the TEA approach, CO, NOx, and SO2 emissions were adjusted in China and South Korea between 2016 and 2021 based on existing bottom-up emissions inventories. Simulations with the adjusted emissions showed that the 6-year average normalized mean biases of the monthly mean concentrations of CO, NOx, and SO2 improved to 0.3 %, -2 %, and 2 %, respectively, in China, and to 5 %, 7 %, and 4 %, respectively, in South Korea. When analyzing the emission trends, it was estimated that the annual emissions of CO, NOx, and SO2 in China decreased at a rate of 7.2 %, 4.5 %, and 10.6 % per year, respectively. The decrease rate of emissions for each of these pollutants was similar to that of ambient concentrations. When considering upwind emission impacts in the emissions adjustment, CO emissions increased by 1.3 %/year in South Korea, despite CO concentrations in the country decreasing during the study period. During the study period, NOx and SO2 emissions in South Korea decreased by 3.9 % and 0.5 %/year, respectively. Moreover, the TEA approach can account for drastic short-term emission changes (e.g., social distancing due to COVID-19). Therefore, the TEA approach can be used to adjust emissions and improve reproducibility of concentrations of air pollutants suitable for health studies for areas where upwind emission impacts are significant.

A simple air-liquid interface exposure system for exposing cultured human 3D epidermis and cornea to PM2.5 collected through cyclonic separation

Particulate matter (PM) is among the major air pollutants suspended in the atmosphere. PM2.5 has a particle size of 2.5 µm; it is known to cause inflammation, especially in the respiratory tract and skin. Since the skin acts a primary barrier against harmful environmental substances that may enter the body, it is highly exposed to PM2.5 present in the environment. However, the adverse health effects of PM2.5 exposure on human skin have not been accurately examined due to the lack of a system that exposes human epidermal tissue to the actual environmental concentration of PM2.5. In this study, we developed an air-liquid interface exposure system for exposing cultured human 3D epidermis and cornea to PM2.5 collected through cyclonic separation. PM2.5 suspension was nebulized in an acrylic chamber, and the resulting mist was pumped through a diffusion dryer into a glass exposure chamber. A particle counter was connected to the exposure chamber to continuously measure the spatial mass concentration of PM. Human 3D epidermis was cultured in the exposure chamber. Exposure of the human 3D epidermis to PM aerosol increased interleukin-8 release into the media around 50 µg/m3. Mass concentrations above 100 µg/m3 caused cell death. Furthermore, a human corneal model showed similar responses against PM2.5 exposure as 3D epidermis. The air-liquid interface exposure system developed in this study is considered useful for evaluating the health effects induced by environmental PM2.5 and can be used as an alternative to experiments involving actual human or animals.