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%.