Investigation on the effect of environmental factors on the pattern of Covid-19 cases in Selangor, Malaysia / Norezuan Abdul Gani

This study examines the significant role of environmental factors in shaping the pattern of COVID-19 cases during the global pandemic. Specifically, it investigates the effects of temperature, relative humidity, wind speed, rainfall amount, and population density on the transmission and distribution of COVID-19 cases. The analysis focuses on the Selangor region, comparing confirmed cases from October 1, 2020, to October 30, 2021. Using the Global-Moran Index and Geographic Information System (GIS), the study identifies hotspot and cold spot areas at the district level, revealing spatial clusters of COVID-19 cases. Hotspots are predominantly found in high-density areas, while cold spots are concentrated in low-density areas. The study further examines the duration of the spread and decay stages using the Spearman rank correlation coefficient and the bell-shaped model method. The analysis indicates variability within hotspot areas, with adjusted R2 values of 0.32 and 0.18 for the spread and decay stages, respectively, highlighting the influence of population density. Employing the general additive model (GAM), the study explores the relationship between environmental factors and COVID-19 transmission. The findings demonstrate the statistical significance (p < 0.05) of all factors in relation to COVID-19 cases. Average temperature and humidity exhibit an S-shaped exposure response relationship, with COVID-19 cases peaking within the range of 25°C to 30°C. Conversely, wind speed, rainfall, and the index of wind effect (K) display a linear decreasing relationship with COVID-19 cases, suggesting a negative association. The study also identifies a significant linear increasing relationship between the Temperature Humidity Index (THI) and COVID-19 cases. Overall, this investigation highlights the critical role of environmental factors in shaping the pattern of COVID-19 cases in Selangor. Understanding these factors can inform effective strategies and interventions to mitigate the impact of the virus.