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• Effect of Maturity Stages on the Quality of Cold Storage Iceberg Lettuce (Lactuca sativa var. capitate) for Export

  Techane Alemu Tolcha, Vu Thi Kim Oanh

  Received: Sep 29, 2023 / Published: Mar 29, 2024

   Abstract PDF

  Iceberg lettuce is one of the most important vegetables economically and nutritionally, but its perishable nature poses challenges for storage and long-distance transportation. This study investigated the effect of maturity stages on the quality of iceberg lettuce for export under cold storage conditions. A completely randomized design with three replications was used to evaluate four maturity stages based on days after planting (DAP): 52, 55, 58, and 61 DAP. The lettuce heads were stored at 3±2oC and a 95% relative humidity, and quality parameters were analyzed every three days until the end of storage. Sensory properties, weight loss, color change, total soluble solids, total phenolics, and decay rates were evaluated. The results showed that maturity stages significantly (P <0.05) affected the quality attributes of iceberg lettuce and that harvesting at the optimal stage is very important. Findings from this study confirmed that the quality parameters were preserved for the 58 DAP samples throughout the storage time. They indicated that at three weeks of storage time, the lowest weight loss (5.9%), color change (14.1), and decay rate (8.3%), and the highest sensory analysis (5 scores) and appearance were shown by the 58 DAP maturity stage lettuce. Therefore, harvesting iceberg lettuce at 58 DAP is recommended for long-distance exportation. 

• Quantifying the Contribution of Road Traffic to Total Suspended Particle Pollution in Dong Thap Province, Vietnam

  Tran Anh Quan, Nguyen Thi Hong Ngoc

  Received: Aug 23, 2024 / Accepted: May 08, 2025 / Published: Jun 28, 2025

   Abstract PDF

  Total suspended particles (TSP) from transportation sources pose a growing environmental and public health concern in rapidly developing regions like Vietnam's Mekong Delta. This study investigated TSP emissions and dispersion patterns in Dong Thap province, an area undergoing significant economic transformation. Using the AERMOD air quality model integrated with R-LINE, we simulated TSP dispersion from 43 major roads divided into 88 segments. The model incorporated high-resolution ERA5 meteorological data from 2021-2023, Vietnam-specific emission factors, and detailed traffic data for eight vehicle categories. The results revealed significant spatial and temporal variations in TSP concentrations. In extreme scenarios, TSP levels in urban centers like Cao Lanh city reached up to 1,100 μg m-³ for 1-hour averages and 350 μg m-³ for 24-hour averages, substantially exceeding national standards. Annual average TSP concentrations in urban areas approached or potentially exceeded the 100 μg m-³ national standard, even when considering only transportation sources. The region's flat terrain facilitated long-range TSP transport, with concentrations up to 100 μg m-³ detected beyond provincial borders under extreme scenarios. Atmospheric stability strongly influenced TSP dispersion, with very stable conditions contributing to elevated TSP levels. The study highlights the critical need for targeted air quality management in Dong Thap, particularly in urban areas and along major transportation routes.