Pedestrian exposure to Nitrogen Dioxide (NO2) and Carbon Monoxide (CO): A case study of Surabaya, Indonesia

The increase in motor vehicles used every day also increases the rate of pollution. Motor vehicles are the main source of the nitrogen dioxide (NO₂) and carbon monoxide (CO) pollutants that can be dangerous for human health in excessive amounts. This study investigates the patterns of NO₂ and CO concentrations in the ambient air, specifically on the sidewalks of two big streets in Surabaya. Measurements were taken over a period of 15 hours using a portable monitoring device. The results indicated that the NO₂ concentration would decrease by 0.008 mg/m³ and 0.012 mg/m³, respectively, at peak times during the day and night. Meanwhile, the CO concentration would increase by 1.486 mg/m³ during the peak time at night. The factors that significantly influenced NO₂ were day variation (weekday or weekend), morning peak hour, noon peak hour, night peak hour, and temperature. Regression with these factors had an R² value of 30.7%. For CO, the significant factors were night peak time, temperature, wind direction, and the number of vehicles, with an R² value of 16.9%. (paper)