Rice is a staple crop best known for its crucial role in feeding humans. In Cambodia, the human population depends on rice as its staple food. Increased rice production results in an increase in straw residue. The extensive residue caused by straw burning significantly contributes to high concentrations of air pollution, which are associated with critical health issues. As such, our objective in this study was to assess the human health impact of rice straw production in Cambodia. In this assessment, we focused on primary and secondary fine particulate matter formation (PM_2.5, NH₃, NO_x, and SO₂) from fertilizer, combustion of fuel in rice production processing, and burning of straw. We assessed endpoint impact by the following methods: (1) We estimated the proportion of rice straw from the annual rice production of the Ministry of Agriculture, Forestry, and Fisheries (MAFF) of Cambodia subjected to open burning in all 25 Cambodian provinces. (2) We calculated air pollutants emissions in terms of kilograms of pollutants per ton of rice produced by following the air pollutant emission inventory (EI) in the EMEP/EEA Guidebook for 2019, using data for fertilizer and fuel combustion that was applied in the field, based on a face-to-face survey of farmers. (3) We analyzed health impact in terms of DALYs using the characterization factor (CF) adapted from the ReCiPe 2016 v1.1 method. The results showed that the total health impact of rice straw production was 13,093.50 DALYs. Our analysis showed that open burning alone contributed 98.55% of the total health impact considered in this study, while fertilizers and combustion contributed only 0.12% and 1.33%, respectively. As the major of the total health impact arose from open burning, a policy of zero open burnings should be an effective way to reduce health impacts. These findings provide information for policymakers on how to alleviate air quality issues caused by the practice of open straw burning by adopting alternative techniques of rice straw management.

A linear matrix inequality (LMI)-based robust stabilizing control is proposed in this paper for a three-phase grid-connected inverter (GCI) with L-filtered output. Previous research, such as MPC, required high computational power and precise modeling in order to obtain offset-free performance. Achieving optimal performance in the case of PI control poses a persistent chal-lenge in terms of gain tuning. This proposed control strategy effectively addresses the afore-mentioned issues by the utilization of systematic control design, incorporating integral action to mitigate the presence of offset error. The set of state feedback and integral gain is obtained by solving the LMI-based optimization problem to maximize the convergence rate to a steady state in the presence of uncertainty in the L-filter. The mentioned uncertainties are represent-ed by potential ranges of the inductor values. Output power delivery can be simply regulated by a computed reference state using a given power reference and measured grid current and voltage. The effectiveness of the proposed method is verified through simulations. The pro-posed robust control method demonstrates a significant decrease in ripple, with a reduction of 86.66% when compared to the conventional PI control approach.

Airborne microplastics (AMPs) are increasingly recognized as an emerging air pollutant. However, observational data remains scarce in Southeast Asia. This study provides the first observations of AMPs in Phnom Penh, Cambodia, using µFTIR-ATR imaging. Number concentration, morphology, polymer composition, aerodynamic size distribution, Feret diameter, and surface aging characteristics were investigated together with meteorological parameters, gaseous pollutants, water-soluble ionic tracers, and HYSPLIT backward trajectories for source attribution. AMPs were dominated by polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET), with 52% classified as fragments and 82% having Feret diameters smaller than 30 µm. AMP concentrations ranged from 0.55 to 1.27 MP m^-3 in TSP (mean: 0.97 ± 0.30 MP m^-3, n = 134) and from 0.23 to 0.49 MP m^-3 in PM2.5 (mean: 0.33 ± 0.10 MP m^-3, n = 46). Carbonyl and hydroxyl indexes indicate that PE and PP were relatively fresh and in low-to-moderate photo-oxidative aging states. Correlation analysis further indicates that PE and PP were mainly associated with local waste fragmentation, whereas PET was linked to precipitation scavenging and resuspension processes. In addition, HYSPLIT backward trajectories suggest regional transport of AMPs by the Southwest Monsoon from marine source regions, including the Indian Ocean, Arabian Sea, and Andaman Sea. These findings provide the first baseline dataset for AMP pollution in Phnom Penh, Cambodia and highlight the combined importance of local emissions and regional atmospheric transport in Southeast Asia.

Airborne microplastics (AMPs) are increasingly recognized as an emerging air pollutant. However, observational data remain scarce in Southeast Asia. This study provides the first observations of AMPs in Phnom Penh, Cambodia, using µFTIR-ATR imaging. Number concentration, morphology, polymer composition, aerodynamic size distribution, Feret diameter, and surface aging characteristics were investigated together with meteorological parameters, gaseous pollutants, water-soluble ionic tracers, and HYSPLIT backward trajectories to examine possible source attribution. AMPs were dominated by polyethylene (PE), polypropylene (PP), and polyethylene terephthalate (PET), with 52% classified as fragments and 82% having Feret diameter smaller than 30 µm. Across four independent 72-h sampling periods (n = 4), AMP concentrations ranged from 0.55 to 1.27 MP m⁻³ in TSP, with a mean ± standard deviation of 0.97 ± 0.30 MP m⁻³, and from 0.23 to 0.49 MP m⁻³ in the PM_2.5 fraction, with a mean ± standard deviation of 0.33 ± 0.10 MP m⁻³. In total, 134 particles were identified in TSP, of which 46 were detected in the PM_2.5 fraction. Carbonyl and hydroxyl indices indicated that PE and PP were relatively fresh and in low-to-moderate surface aging states. Pearson correlations suggested that the abundances of individual polymers were varied differently in relation to local environmental and precipitation-related variables; however, the limited number of sampling periods precludes source or process attribution. In addition, HYSPLIT backward trajectories showed that some air masses arriving in Phnom Penh had passed over marine regions under southwest monsoon flow. These findings provide the first baseline dataset for AMP pollution in Phnom Penh, Cambodia, and highlight the combined importance of local emissions and regional atmospheric transport in Southeast Asia.

This study examines the seasonal and diurnal variations in ultrafine particles (PM_0.1) and their carbonaceous components (OC and EC), collected at the Institute of Technology of Cambodia in Phnom Penh. Sampling was conducted over 14 consecutive days in September 2024 (during the wet season) and February 2025 (during the dry season). The average mass concentration of PM_0.1 in February (8.5 μg/m³; range: 3.9–11.3 μg/m³) was approximately three times greater than that in September, driven by a corresponding increase in OC concentration. Conversely, average EC concentrations remained almost stable across both seasons, indicating consistent local emission sources. Total carbonaceous compounds (OC + EC) constitute approximately 50% of the PM_0.1 mass in both seasons. Primary organic carbon (POC) concentration increases almost four times in February compared to September. Secondary organic carbon (SOC) concentrations were significantly elevated during February daytime (1.4 ± 1.0 μg/m³), indicating active photochemical formation. Backward trajectory analysis and satellite hotspot data revealed that September air masses originated from maritime sources without significant local burning influences, while February pollution events were likely influenced by short-range transboundary transport from biomass-burning areas across the Cambodia–Vietnam border.