Abstract
INTRODUCTION: Carbon-monoxide (CO) is a major component of motor-vehicles related air pollution. Motor-vehicles emissions are a major source of air pollution in urban areas and give significant adverse effects on human life. AIM: This study aimed to assess the change of expiratory carbon-monoxide levels after using four-type of masks in people around Universitas Sumatera Utara. METHODS: This was an experimental study with a consecutive sampling technique involved 100 non-smoker subjects. They were divided into four groups based on masks given: fabric, surgical, carbon, and an N95 mask. Expiratory CO was measured by a smokerlyzer device. Data were analyzed using SPSS software with Wilcoxon and Kruskal Wallis Test. RESULTS: There was a significant change of carbon-monoxide mean level after using the mask for 8 hours in a surgical mask, N95 mask, and carbon mask (p-value: 0.002; 0.000; 0.000). After analyzed using Kruskal Wallis Test, there was a significant difference in the change of mean of pre and post wearing mask (ΔCO) among four-type of masks with p-value < 0.001. Post Hoc Analysis showed the significant difference was in the comparison between N95 mask vs Fabric Mask and Carbon Mask vs Fabric Mask (p-value: 0.002; 0.021). CONCLUSION: All three type of masks such as surgical mask, N95 mask, and carbon mask was effective to reduce CO levels from air pollution with the most significant was N95 and carbon mask. Fabric mask has the poorest protection from CO levels.