Long-term cumulative respirable wood-dust exposure may contribute to obstructive and restrictive lung function impairments, yet evidence on cumulative exposure (CE) and its multiplicative interactions with smoking and older age remains limited among tropical rubberwood workers. This retrospective study included 372 rubberwood furniture workers in Southern Thailand. Secondary data on respirable wood-dust concentrations and annual spirometry from 2012 to 2023 were analyzed. Crude and adjusted odds ratios (ORs) with 95% confidence intervals (CIs) were estimated using logistic regression adjusted for age, gender, body mass index, smoking status, work experience, and asthma history. Multiplicative interactions between CE and smoking or age were evaluated using interaction terms. Despite a wood-dust concentration of 0.40 ± 0.20 mg/m³ (eight-fold below the Thai standard of 5 mg/m³), obstructive and restrictive impairments were observed in 17.5% and 16.4% of workers, respectively. Lung-function status differed across CE quartiles, with the highest quartile Q4 (>4.44 mg·year/m³) showing 29.2% obstructive and 18.5% restrictive impairment. CE was associated with obstructive impairment in Q3 (AOR = 2.66; 95%CI: 1.32–5.55) and with restrictive impairment in Q3 (2.52; 1.26–5.30) and Q4 (2.88; 1.15–7.30). Age ≥40 and work experience ≥10 years were associated with obstructive impairment. A significant multiplicative interaction was observed between CE Q4 and smoking for restrictive impairment (12.06; 1.63–89.06; p = 0.015). CE was associated with both impairment patterns despite exposure remaining below the Thai standard. High CE combined with smoking substantially increased the odds of restrictive impairment, supporting enhanced dust control, smoking cessation, and targeted spirometric surveillance.
The International Maritime Organization (IMO) introduced a global sulfur cap in 2020, reducing the maximum sulfur content of marine fuel oil from 3.5% to 0.5%. This study evaluated changes in ship-related PM₂.₅ across coastal and inland areas of Kyushu, western Japan, using eight years (2016–2023) of PM₂.₅ chemical composition data from eight monitoring sites. Positive matrix factorization (PMF) resolved seven source factors, including a heavy oil combustion factor characterized by high fractions of V and Ni and interpreted as predominantly ship-related. Bivariate polar plots provided complementary directional information supporting the source interpretation. The heavy oil combustion contribution decreased markedly between the pre-regulation (2016–2019) and post-regulation (2020–2023) periods at all eight sites, with reductions ranging from 68.6% to 90.9%. The decrease was observed at both coastal and inland sites, indicating that the regulatory response extended beyond immediate coastal areas. The mean heavy oil combustion contribution decreased from 0.755 to 0.119 µg/m³, a decrease of 0.636 µg/m³, which represented approximately 19% of the observed decrease in total PM₂.₅ between the two periods. These results demonstrate a clear source-specific reduction in predominantly ship-related heavy oil combustion contributions following IMO 2020, while indicating that this source accounted for only part of the overall regional decrease in PM₂.₅.
Air pollution exposure during pregnancy has been associated with various neurobehavioral outcomes in children, including autism spectrum disorder (ASD). However, less is known about whether perinatal exposure to fine particulate matter (PM2.5) is associated with quantitatively measured autism-related traits across children with and without an ASD diagnosis, or whether specific developmental windows and sex-specific associations exist. This study examined associations between PM2.5 exposure before, during, and after pregnancy and autism-related traits measured using the Social Responsiveness Scale (SRS). Participants were selected from the Nurses’ Health Study II. Cases were children diagnosed with ASD, while controls had not been diagnosed with ASD and were frequency matched to cases by year of birth. Main analyses included 165 ASD cases and 1,011 controls whose mothers did not change residential address before or after pregnancy. Monthly PM2.5 concentrations at maternal residential addresses were estimated using a nationwide spatiotemporal model and averaged across pregnancy-wide, trimester-specific, and month-specific exposure windows. Adjusted linear regression models accounting for case status and other covariates were used to estimate associations between PM2.5 and SRS scores. Positive associations were observed primarily among males. Associations were elevated during the second trimester and peaked around the seventh month of pregnancy. Our findings extend previous research by examining autism-related traits as a continuous outcome across children with and without an ASD diagnosis and by evaluating exposure at fine temporal resolutions. These results suggest that PM2.5 exposure during specific periods of pregnancy may be associated with increased autism-related traits, particularly among male offspring. Identifying potentially sensitive developmental windows may help inform strategies to reduce harmful air pollution exposure during pregnancy.
The International Maritime Organization (IMO) introduced a global sulfur cap in 2020, reducing the maximum sulfur content of marine fuel oil from 3.5% to 0.5%. This study evaluated changes in ship-related PM₂.₅ across coastal and inland areas of Kyushu, western Japan, using eight years (2016–2023) of PM₂.₅ chemical composition data from eight monitoring sites. Positive matrix factorization (PMF) resolved seven source factors, including a heavy oil combustion factor characterized by high fractions of V and Ni and interpreted as predominantly ship-related. Bivariate polar plots provided complementary directional information supporting the source interpretation. The heavy oil combustion contribution decreased markedly between the pre-regulation (2016–2019) and post-regulation (2020–2023) periods at all eight sites, with reductions ranging from 68.6% to 90.9%. The decrease was observed at both coastal and inland sites, indicating that the regulatory response extended beyond immediate coastal areas. The mean heavy oil combustion contribution decreased from 0.755 to 0.119 µg/m³, a decrease of 0.636 µg/m³, which represented approximately 19% of the observed decrease in total PM₂.₅ between the two periods. These results demonstrate a clear source-specific reduction in predominantly ship-related heavy oil combustion contributions following IMO 2020, while indicating that this source accounted for only part of the overall regional decrease in PM₂.₅.
