Sopittaporn Sillapapiromsuk

Industrialization in Thailand’s Eastern Economic Corridor raises concern about children’s indoor exposure to trace elements. As, Cr, Ni, Pb, Cu, Zn, Fe, Mn, and K were determined by ICP-OES in −6 to 3.3 × 10⁻⁵. For Pb, which has no reference dose, children’s margins of exposure were below 1 at 15 out of 25 preschools under upper-bound assumptions, so neurodevelopmental effects cannot be excluded. Wet cleaning and hand hygiene are recommended as precautions.

This study investigated trace element contamination, source characteristics, and associated health risks of indoor dust collected from 22 preschools across six districts of haze-affected Lampang Province, Thailand. Dust samples from urban, coal power plant, sub-urban, and rural areas were analyzed for As, Cr, Ni, Pb, Cu, Fe, Mn, Zn, and K using ICP-OES following acid digestion. Contamination levels were evaluated using the enrichment factor (EF), geo-accumulation index (Igeo), and potential ecological risk index (RI), while human health risks were assessed using non-carcinogenic (HQ, HI) and carcinogenic (CR, TCR) models. Fe, K, Zn, and Mn were the dominant elements, with Zn showing moderate contamination and strong anthropogenic influence, particularly from traffic emissions and biomass burning. Source apportionment indicated mixed contributions from soil dust, industrial activities, and combustion processes. Ecological risk remained low across all sites (RI < 150). Non-carcinogenic risks were negligible (HI < 1), although children were more susceptible than adults. Carcinogenic risks for As, Cr, and Ni through both ingestion and inhalation pathways were within acceptable limits (10-6 to 10-4), with ingestion representing the dominant exposure pathway. Overall, indoor dust posed low ecological and health risks; however, continued monitoring is recommended due to potential long-term exposure effects on children.

Humans spend a substantial proportion of their time indoors, where exposure to environmental pollutants such as radon gas and particulate contaminants in household dust is common. While radon is a well-established risk factor for lung cancer, household dust may serve as a reservoir for a complex mixture of indoor and outdoor pollutants. However, the biological effects of such exposures, particularly under sequential conditions, remain incompletely understood. This study aimed to investigate the cytotoxic and genotoxic effects of sequential exposure to household dust extract followed by indoor radon using human lung adenocarcinoma (A549) cells as an in vitro model. Household dust samples from upper northern Thailand were extracted and applied to cells, followed by controlled radon exposure. Cellular responses were evaluated using cell viability assays, cytokinesis-block micronucleus (MN) formation assays, and Western blot analysis of oxidative stress-related (Nrf2/HO-1), DNA damage-related (γ-H2AX), autophagy-related (LC3), and inflammatory-related (IL-6) protein expression. Exposure to household dust extract was associated with reduced cell viability and increased MN formation, while radon exposure alone produced relatively modest effects under the present conditions. Sequential exposure to household dust extract followed by indoor radon was associated with increased oxidative stress-related responses and elevated DNA damage than either treatment alone under the present experimental conditions. A trend toward autophagy-related responses was also observed, and the overall findings may indicate possible combined biological responses under sequential exposure conditions. These findings suggest that sequential exposure may be associated with changes in oxidative stress-related pathways, DNA damage responses, and autophagy-related processes in this in vitro model. However, the results should be interpreted with caution as they are derived from a single cancer cell line and there are limitations to the in vitro exposure model. Further studies using additional cell models and in vivo systems are warranted to further clarify the potential biological and human health relevance of these findings.

This study aimed to examine trace element concentrations in indoor dust and evaluate health risks in child development centers in haze and industrial areas of Thailand from November 2023 to April 2024. The samples were extracted using a microwave oven and analyzed via ICP-OES. The finding indicated that the levels of As, Cr, Pb, V, Fe, Mn, and Zn in the dust from child development centers in the industrial area were significantly higher than those in the haze area (p < 0.05). The presence of trace element contaminants in indoor dust is indicative of anthropogenic sources. Cd and Zn in both areas have shown significantly elevated risks, according to the probable ecological risk factor. Source apportionment identified traffic, road dust, and biomass combustion as the principal sources of pollution in the haze area, while traffic and combustion activities were significant in the industrial area. Non-carcinogenic risk assessments for children exposed to As, Pb, Cu, and Cr revealed potential health risks (HI > 1). Furthermore, the total cancer risk (TCR) linked to As, Cr, and Ni is considered acceptable within the criteria of 10⁻⁶ to 10⁻⁴. However, long-term exposure may increase the risk of cancer in children.

Nitrogen dioxide (NO2) is a major indoor air pollutant and a significant ambient air contaminant associated with health effects, especially for students and teachers who attend schools in the areas of traffic, roads and industry. This study aims to assess the impacts of NO2 exposure on the health of students in haze and industrial areas from November 2023 to March 2024. Researchers utilized tube-type passive samplers to collect indoor and outdoor NO2 samples, which were subsequently analyzed via spectrophotometry. The results revealed that the weekly mean indoor and outdoor NO2 concentrations in the haze areas (HA1–HA5) ranged between 4.4–29.0 and 4.0–37.9 µg m-3, respectively. The ranges of indoor and outdoor NO2 in industrial areas (ID1–ID5) were 4.9–34.7 and 5.0–37.9 µg m-3, respectively. The indoor levels of NO2 were lower than the World Health Organization (WHO) standard of 40 µg m-3, whereas the outdoor levels were above the WHO recommended limit of 10 µg m-3, approximately 84–89%. The highest levels of NO2 in haze and industrial areas were influenced by the haze episode in Thailand. NO2 and PM2.5 levels in haze (r = 0.441–0.475) and industrial areas (r = 0.667–0.734) were significantly correlated. The noncarcinogenic risk for chronic exposure to NO2, both indoors and outdoors (HQ>1.0), indicates that exposure significantly affects children and that long-term exposure could result in the accumulation of effects in adults, especially in industrial areas.