Increasing numbers of cohort studies have reported that long-term exposure to ambient particulate matter is associated with mortality. However, there has been little evidence from Asian countries. We aimed to explore the association between long-term exposure to particulate matter with a diameter ≤10 µm (PM₁₀) and mortality in South Korea, using a nationwide population-based cohort and an improved exposure assessment (EA) incorporating time-varying concentrations and residential addresses (EA1). We also compared the association across different EA approaches. We used information from 275,337 people who underwent health screening from 2002 to 2006 and who had follow-up data for 12 years in the National Health Insurance Service-National Sample Cohort. Individual exposures were computed as 5-year averages using predicted residential district-specific annual-average PM₁₀ concentrations for 2002–2006. We estimated hazard ratios (HRs) of non-accidental and five cause-specific mortalities per 10 µg/m³ increase in PM₁₀ using the Cox proportional hazards model. Then, we compared the association of EA1 with three other approaches based on time-varying concentrations and/or addresses: predictions in each year and addresses at baseline (EA2); predictions at baseline and addresses in each year (EA3); and predictions and addresses at baseline (EA4). We found a marginal association between long-term PM₁₀ and non-accidental mortality. The HRs of five cause-specific mortalities were mostly higher than that of non-accidental mortality, but statistically insignificant. In the comparison between EA approaches, the HRs of EA1 were similar to those of EA2 but higher than EA3 and EA4. Our findings confirmed the association between long-term exposure to PM₁₀ and mortality based on a population-representative cohort in South Korea, and suggested the importance of assessing individual exposure incorporating air pollution changes over time.

In South Korea, a Human Biomonitoring (HBM) program, known as the Korean National Environmental Health Survey (KoNEHS), was launched in 2009. This study aims to provide an overview of environmental chemical exposures in South Korea based on data from the KoNEHS cycle 4 (2018–2020). To ensure population representativeness, Koreans aged 3 years and older were recruited from 426 sites across the country. A total of 6381 participants joined in the collection of biospecimens, which were subsequently analyzed for 33 environmental chemicals or their metabolites, including nine that were not included in the previous cycle. The five most common PFASs were detected in more than 99.7% of the participants. The GM of serum PFOS was the highest in adults at 15.1 µg/L (13.9, 16.4) and in adolescents at 7.97 µg/L (7.42, 8.56). In adults, there was a gradual decrease in the detection rate and concentration of some heavy metals and phthalate metabolites. In children and adolescents, the detection rate of BPA in urine decreased, while the rate of its substitutes BPF and BPS increased, and the rate of propyl paraben in urine decreased significantly. The results of the KoNEHS cycle 4 indicate that exposure levels to certain environmental chemicals are still high, highlighting further monitoring and on-going surveys to determine their trends, especially for newly investigated substances, such as PFASs.

Particulate matter (PM) air pollution has challenged the global community and the International Agency for Research on Cancer (IARC) classified airborne particulate matter as carcinogenic to humans. However, while most studies of cancer examined a single cancer type using different cohorts, few studies compared the associations of PM between different cancer types. We aimed to compare the association of long-term exposure to PM (PM₁₀ and PM_2.5) and cancer mortality across 17 different types of cancer using a population-based cohort in the Seoul Metropolitan Area (SMA), South Korea; Our study population includes 87,608 subjects (mean age: 46.58 years) residing in the SMA from the National Health Insurance Services–National Sample cohort (NHIS–NSC) and followed up for 2007–2015. We used the time-dependent Cox proportional hazards model to estimate hazard ratios (HRs) and 95% confidence intervals (95% CIs) of each cancer mortality per 10 μg/m³ increase in PM concentrations, after adjusting for individual and areal characteristics. During eight years of follow-up, 1487 people died with any of 17 cancer types. Lung cancer death was the highest, followed by liver and stomach cancer. Although we did not find the association for all cancer types, possibly because of limited cancer cases, HRs of PM_2.5 were relatively high for lung, stomach, pancreas, non-Hodgkin’s lymphoma, prostate, esophagus, oral and pharynx, and brain cancer mortality (HRs = 1.44–7.14). High HRs for pancreas, non–Hodgkin’s lymphoma, esophagus, and oral and pharynx cancer were also seen for PM₁₀; our findings suggest PM air pollution as a potential risk factor of cancer mortality for upper digestive tracts, mouth, pancreas, and non–Hodgkin’s lymphoma in a highly urbanized population with high exposure to PM for a long time.

While short‐term studies of the adverse effects of air pollution have found regional differences, there has been insufficient evidence from long‐term studies. This study investigated the spatial variation of the association between long‐term exposure to particulate matter (PM) air pollution and cardiovascular disease (CVD) incidence and their relevant regional characteristics. We selected 155,017 adults who have lived over 13 years in each of the 16 regions of South Korea from the National Health Insurance Service‐National Sample Cohort. We assessed the individual long‐term exposure as a 5‐year average concentration at district‐level residential addresses estimated by previously validated exposure prediction models. We applied time‐dependent Cox‐proportional hazard models to explore the spatial variation of long‐term PM exposure's association with CVD incidence. After adjusting for individual‐level characteristics, we estimated the region‐specific hazard ratios (HRs) of incident CVD per 10 μg/m³ increase in PM₁₀ and PM_2.5. Then, we calculated the correlation coefficients between region‐specific HRs and 80 regional attributes in 13 categories across 16 regions to identify the related regional characteristics. Region‐specific HRs of CVD incidence for PM showed considerable variation in magnitude and direction across 16 regions. HRs of PM₁₀ and PM_2.5 were higher in major urban areas and lower in rural areas. Urbanicity and emission sources exhibited significant correlations with HRs of overall CVD. Our findings offer an opportunity to explore regional characteristics that derive the difference in air pollution‐associated health effects and help us provide guidance to target specific characteristics to avoid the adverse health effects of air pollution.

Heavy metals can adversely affect neurodevelopment, immune function, and overall health during early childhood. However, few studies have evaluated heavy metal exposure in children. Therefore, we assessed urinary metal concentrations in Korean children and their association with allergic rhinitis. The study included 648 preschool children aged 3-5 years who participated in the Korean National Environmental Health Survey (KoNEHS, 2021-2023) Cycle 5. Urinary Hg was measured using a mercury analyzer, whereas V, Mn, Ni, Mo, Cd, Sb, Pb, and Cr were analyzed using inductively coupled plasma mass spectrometry. The geometric mean concentrations of Ni (3.33 μg/L), Mo (113 μg/L), and Sb (0.088 μg/L) were more than 1.5-fold higher than those reported in international biomonitoring surveys. Ni was positively correlated with Mo (r = 0.531) and Cd (r = 0.573). Urinary Ni concentrations differed significantly based on allergic rhinitis status (p = 0.006), whereas Mo showed a marginally significant association(p = 0.054). Logistic regression analysis showed that a 1-unit increase in log-transformed urinary Ni concentration was associated with a 37% increase in the odds of allergic rhinitis (OR = 1.37, 95% CI = 1.09-1.73). In the multivariable model including Ni, Cd, and Mo, the odds of allergic rhinitis increased by 34% (OR = 1.34, 95% CI: 1.02-1.76). After adjusting for sex, age, and ponderal index, the association remained statistically significant, with 35% increased odds ratio (OR = 1.35, 95% CI: 1.02-1.77). The association between urinary Ni concentration and allergic rhinitis was consistent across models. These findings support continued monitoring of heavy metal exposure and associated health effects in Korean children.

Citizen behavior change can serve as an important contributor to improving air quality, when the change is related to traffic emission considered as a major source of air pollution. This study aimed to examine the shift of traffic counts attributed by the Emergency Fine Dust Reduction Measures (EFDRM) in Seoul, South Korea, where one of the major components is text alert service to promote public engagement. Specifically, we investigated the changes in traffic counts before and during EFDRM as well as between different hours and days of the week which could affect people's travel mode choices. We obtained hourly traffic counts, fine particle concentrations, and meteorological conditions in Seoul for 2016-2019. Using the difference-in-difference design and generalized additive model, we estimated the differences in traffic counts between the days with and without the EFDRM and between pre- and post-implementation periods after adjusting for fine particle air pollution, meteorology, and temporal trends. In addition, we compared these differences by rush and non-rush hours and by weekdays and weekends/holidays in order to examine the changes in travel behavior. The traffic counts on EFDRM days were significantly lower than on non-EFDRM days after the implementation, whereas no systematic reduction was observed before the implementation. This decrease was found on weekends/holidays and during weekday non-rush hours, but not during weekday rush hours, indicating the impact of the feasibility on behavioral changes in addition to perception. Our findings suggest that short-term air quality interventions can achieve the goal when accompanied with public communication targeting the alternative travel option.Implications: This study provides new evidence that short-term emergency actions can effectively reduce traffic counts through citizen behavioral changes. The findings highlight that the involvement of public communication and feasible alternative travel options to short-term actions can play an important role in the success of interventions. The reduction in traffic counts, particularly during non-rush hours and weekends, suggests that voluntary behavioral responses can contribute to improving air quality without imposing large regulatory costs. These results offer practical guidance for policymakers to design public engagement - based air quality measures and indicate that similar alert systems could be applied to other pollutants or urban contexts worldwide.