Asian Journal of Advanced Research and Reports

Assessment of Ambient PM₂.₅ and PM₁₀ Concentrations in Early Childhood Development Education (ECDE) Centres in High-Traffic and Industrial Areas of Nairobi City County, Kenya

Maurice Kavai — 2026-06-20

Air pollution in urban learning environments remains an important public health concern for young children, particularly where schools are located close to major roads and industrial activities. Early Childhood Development Education centres located near high-traffic roads, transport corridors, and industrial zones are especially exposed to elevated concentrations of particulate matter, which poses significant risks to respiratory and cardiovascular health. This study assessed ambient particulate matter with aerodynamic diameters of less than 2.5 micrometres (PM₂.₅) and less than 10 micrometres (PM₁₀) in Early Childhood Development Education (ECDE) centres located in high-traffic and industrial areas of Nairobi City County, Kenya. A descriptive cross-sectional research design was used. The study involved 120 ECDE children selected from six centres, with teachers, school administrators, environmental officers and public health personnel providing supplementary contextual information. Data were collected using structured questionnaires, observation checklists, key informant interviews and portable particulate matter monitors. Quantitative data were analysed using descriptive statistics, independent-samples t-tests, Pearson correlation analysis and multiple regression analysis in SPSS version 27. The findings showed that measured PM₂.₅ and PM₁₀ concentrations exceeded the World Health Organization guideline limits in the monitored ECDE environments. Traffic-dominated locations generally recorded higher PM₂.₅ concentrations, whereas industrial locations contributed substantially to PM₁₀ exposure. Reported health symptoms among learners included coughing, wheezing, shortness of breath, frequent colds and eye irritation. Particulate matter exposure showed positive and statistically significant associations with respiratory symptoms, with combined PM₂.₅ and PM₁₀ exposure showing the strongest relationship. Regression analysis further indicated that PM₂.₅ exposure, PM₁₀ exposure and proximity to pollution sources were significant predictors of reported respiratory illness among ECDE children. The study concludes that ECDE learners in high-exposure urban settings may face increased health risks from sustained particulate matter exposure and recommends routine air quality monitoring, enforcement of environmental regulations, buffer zones, urban greening and public awareness interventions.

Enhancing Student Engagement and Conceptual Understanding in Class IV Science Using the 5E Inquiry-Based Model

Namkha Wangdi — 2026-06-22

As 21st-century learners require more active and student-centred learning experiences, Inquiry-Based Learning (IBL), particularly the 5E model, has emerged as an effective approach for enhancing student engagement, critical thinking, problem-solving skills and conceptual understanding in primary science education. This study employed a quantitative method to examine the effectiveness of the 5E IBL model in enhancing engagement and conceptual understanding in science lessons. A 5E model intervention, consisting of Engage, Explore, Explain, Elaborate and Evaluate phases, was implemented over three weeks with 23 Class IV students based on low achievement in science class tests. The study also analysed pre- and post-test scores, together with a post-intervention Likert-scale survey.

The survey revealed a positive shift in student attitudes. All student participants expressed positive views towards hands-on activities, with 65.2% strongly agreeing and 34.8% agreeing that practical activities make science exciting. Students preferred self-discovery learning (95.7%) over lecturing, and 100% affirmed that group work improved lesson comprehension.

In addition, the post-test results revealed improvement in academic performance. The overall class pass rate increased from 78.3% to 91.3% (≥40), and the class mean score rose to 68.2. Moreover, the failure rate dropped from 21.7% to 8.7% in the post-test. Thus, this study concludes that Inquiry-Based Learning kept students interested and helped them think critically.

Neonatal Survival and Risk Factors for Retinopathy of Prematurity among Infants Admitted in Tertiary Hospitals, Northern Tanzania

Emma Mwende — 2026-06-23

Background: Retinopathy of prematurity is a preventable cause of childhood visual impairment, particularly among premature infants who survive after neonatal intensive care. Improved neonatal care in low- and middle-income settings may increase the number of infants at risk, making local data on survival, incidence, and associated factors important for planning screening services.

Aim: This study assessed neonatal survival, the incidence of retinopathy of prematurity, and associated neonatal and maternal factors among premature infants admitted to tertiary hospitals in Northern Tanzania.

Methods: A hospital-based prospective cohort study was conducted among premature infants with gestational age below 37 weeks and/or birth weight below 2500 g admitted to Kilimanjaro Christian Medical Centre and Arusha Lutheran Medical Centre. Eligible infants underwent retinal examination, and findings were classified according to the International Classification of Retinopathy of Prematurity. Data were analysed using descriptive statistics and Fisher’s exact test to assess associations between selected risk factors and retinopathy of prematurity.

Results: Seventy premature infants were enrolled. Eleven infants died before completing 28 days of life, and the reported neonatal survival proportion was 84.2%. Retinopathy of prematurity was reported in 11 infants, representing 20.0% of the analytic sample. All affected infants had bilateral disease; nine had stage 1 disease and two had stage 2 disease. No infant developed stage 3, 4, or 5 disease, and all cases regressed completely during follow-up. Lower birth weight, neonatal infection, more than one blood transfusion, and maternal pre-eclampsia were significantly associated with retinopathy of prematurity.

Conclusion: In this cohort, neonatal survival was high and one-fifth of assessed infants developed mild to moderate retinopathy of prematurity. The findings support continued retinal screening among premature infants and careful monitoring of infants with low birth weight, neonatal infection, repeated blood transfusion, or exposure to maternal pre-eclampsia.

A Design and Mathematical Modeling of the Novel L(LCL)₃ Hybrid Low-Pass Filter for Power Grid-Connected Solar PV Systems

Unogwu, Daniel Ogbu — 2026-06-25

In the face of depleting natural resources, the efficient use of available energy sources is becoming increasingly important in reducing operational costs while satisfying ever-tighter pollution regulations. This paper presents the complete mathematical design framework and component-calculation methodology for the L(LCL)₃ filter, a novel high-order hybrid low-pass filter topology developed for the integration of utility-scale solar photovoltaic (PV) systems into high-voltage grid networks. The L(LCL)₃ filter extends the established LCL and LLCL filter architectures by incorporating three resonant trap circuits tuned to the inverter switching frequency (f_sw=10 kHz), its second harmonic (20 kHz), and a third attenuation band between four series inductors (L₁,L₂,L₃,L₄) distributed in a 0.40:0.25:0.20:0.15 ratio. The design employs a rigorous per-unit system analysis using HVDC-class constraints: total inductance ≤ 8% of base inductance, total capacitance ≤ 3% of base capacitance (limiting reactive power to ≤ 3 MVAr), and current ripple ≤ 20% of base current. For a 100 MVA, 33 kV reference system with f_grid= 50 Hz and f_sw=10 kHz, complete component calculations yield: L₁= 1.108 mH,L₂= 0.693 mH,L₃= 0.554 mH,L₄= 0.416 mH; C₁= 1.3 µF,C₂= 0.36 µF,C₃= 0.11 µF and damping network parameters R_d1= 6.0 Ω,R_d2= 4.0 Ω, R_d3= 3.0 Ω, R_d4= 2.0 Ω. The filter achieves a damping ratio ζ = 0.196 and quality factor Q = 2.55, ensuring well-damped operation with a primary resonance at 8,011 Hz. Resonance analysis confirms trap frequencies of 10,078 Hz (Trap 1) and 20,396 Hz (Trap 2) with less than 2% design error. MATLAB/Simulink simulation confirmed the analytical claims of grid-side THD 1.3% and primary resonance frequency within 3% of the analytically derived values, with filter efficiency exceeding 99.0% under rated operating conditions. The mathematical framework is presented in sufficient detail for direct replication and adaptation to other power ratings.

Assessment of PM₂.₅ and PM₁₀ Pollution Sources and Exposure in ECDE Centers in High-Traffic and Industrial Areas of Nairobi City County, Kenya

Maurice Kavai — 2026-06-26

Air pollution, particularly particulate matter (PM₂.₅ and PM₁₀), has emerged as a major environmental and public health challenge in rapidly urbanising cities, including Nairobi City County. Early Childhood Development Education (ECDE) centres located near high-traffic roads and industrial zones are especially vulnerable because of continuous exposure to emissions from vehicles, industrial activities, construction dust and other urban pollution sources. Young children are at higher risk because of their developing respiratory systems, higher breathing rates and prolonged exposure within school environments. This study aimed to assess and analyse the primary sources of PM₂.₅ and PM₁₀ pollution and determine their concentrations in selected ECDE centres in high-traffic and industrial areas. A descriptive cross-sectional research design was adopted, involving 120 ECDE children drawn from six ECDE centres. Data were collected using structured questionnaires, observation checklists, portable air-quality monitoring devices and key informant interviews with teachers and caregivers. Secondary data were obtained from the National Environment Management Authority (NEMA), Kenya Meteorological Department, World Health Organization, United Nations Environment Programme and peer-reviewed literature. Data were analysed using descriptive statistics, independent-samples t-tests, Pearson correlation and multiple regression analysis. The findings revealed that ECDE centres located near major highways recorded higher PM₂.₅ concentrations ranging from 38 to 82 µg/m³, while centres located in industrial zones recorded higher PM₁₀ concentrations ranging from 72 to 156 µg/m³. In both cases, the recorded levels exceeded the WHO recommended air-quality guidelines. The results further showed a strong positive correlation (r = 0.71, p < 0.01) between particulate matter exposure and the prevalence of respiratory symptoms among children aged 3–6 years, including coughing, wheezing and frequent colds. The study concludes that vehicular emissions and industrial activities are the primary contributors to elevated PM₂.₅ and PM₁₀ levels in ECDE environments and may pose respiratory health risks to children. It recommends stricter enforcement of air-quality regulations, strategic zoning of schools away from pollution hotspots and enhanced air-quality monitoring in urban educational settings to safeguard child health.