Spatiotemporal trends of ambient air CO in Urmia city

Zeynalabedin  Youzbashi; Saeed  Hosseinpour; Mostafa  Norouzi; Reza  Khorablu; Amir  Mohammadi

doi:10.18502/japh.v11i1.21273

Zeynalabedin Youzbashi Student Research Committee, Urmia University of Medical Sciences, Urmia, Iran
Saeed Hosseinpour Department of Environmental Health Engineering, School of Public Health, Urmia University of Medical Sciences, Urmia, Iran
Mostafa Norouzi Student Research Committee, Urmia University of Medical Sciences, Urmia, Iran
Reza Khorablu Student Research Committee, Urmia University of Medical Sciences, Urmia, Iran
Amir Mohammadi Social Determinants of Health Research Center, Clinical Research Institute, Urmia University of Medical Sciences, Urmia, Iran

DOI: https://doi.org/10.18502/japh.v11i1.21273

Keywords: Carbon monoxide; Urmia; Ambient air; Temporal variation

Abstract

Introduction: This descriptive-ecological study investigated the seasonal, diurnal, and spatial variations of Carbon monoxide (CO) concentration in Urmia's (Northwest of Iran) ambient air over a six-month period, spanning Winter and Spring.

Materials and methods: Sampling was conducted at 20 stations selected from various urban locations. At each station, a portable environmental gas analyzer was used to measure CO concentration during both morning and evening peak traffic hours. Results: The results revealed a significant seasonal and diurnal pattern. The highest CO means were observed in the cold months (January and February), peaking at an average of 6.19 ppm in January evenings. This increase is strongly linked to temperature inversion and heightened heating system usage. Statistical analysis confirmed a highly significant difference (P<0.001) in CO means across months and between morning and evening hours, with concentrations being significantly higher in the evening. Although monthly averages are generally below the 8-h national standard (9 ppm), their proximity to the limit and the registration of high peaks (up to 15.10 ppm) indicate a potential health risk during winter. Spatially, zoning maps showed the central, high-traffic area acts as the main pollution hotspot.

Conclusion: The study highlights that even short-term peak CO exposure can be significant, potentially causing headache and behavioral effects. Additionally, the river and surrounding open spaces help reduce pollution, emphasizing the need for integrated air quality management strategies that account for both seasonal and diurnal variations. These findings underscore the critical need for integrated management strategies sensitive to both the time of day and the season.