Effects of topographic variables on traffic-related pollutant concentrations: comparison of AERMOD and CAL3QHCR models

IntroductionThis study examines the spatial dispersion of traffic-related pollutants (CO, NOx, and PM10) along a major highway corridor that connects the Eastern Black Sea Region with northern Türkiye. The primary objective is to compare the performance of two atmospheric dispersion models—AERMOD an...

Full description

Saved in:
Bibliographic Details
Main Author: Kazım O. Demirarslan
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-07-01
Series:Frontiers in Environmental Science
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fenvs.2025.1577330/full
Tags: Add Tag
No Tags, Be the first to tag this record!
_version_ 1849253821053665280
author Kazım O. Demirarslan
author_facet Kazım O. Demirarslan
author_sort Kazım O. Demirarslan
collection DOAJ
description IntroductionThis study examines the spatial dispersion of traffic-related pollutants (CO, NOx, and PM10) along a major highway corridor that connects the Eastern Black Sea Region with northern Türkiye. The primary objective is to compare the performance of two atmospheric dispersion models—AERMOD and CAL3QHCR—and to evaluate how topographic variables influence their outputs.MethodsDispersion simulations were performed using AERMOD and CAL3QHCR under identical meteorological and traffic input scenarios. Model predictions were compared using Spearman’s rank correlation coefficient and validated against observational data from ten air quality monitoring stations. Fractional Bias (FB) and Normalized Mean Square Error (NMSE) were employed as statistical performance metrics.ResultsBoth models estimated higher pollutant concentrations near highways, but AERMOD consistently predicted higher maximum values (CO: 0.78 ppm; NOx: 1.48 ppm; PM10: 26.59 μg/m3). CAL3QHCR produced lower estimates (CO: 0.20 ppm; NOx: 0.09 ppm; PM10: 2.70 μg/m3), yet it showed better agreement with observed CO and NOx concentrations. Correlation analysis indicated strong negative correlations between pollutant levels and elevation (e.g., CO: r = −0.87). Both models captured the spatial decline in concentrations with increasing distance from the road, particularly within the first kilometer.DiscussionAERMOD was found to overpredict pollutant concentrations, while CAL3QHCR yielded closer estimates for CO and NOx. However, both models exhibited poor performance in simulating PM10, as indicated by high NMSE values and consistent underestimation. These findings highlight the significance of topography in dispersion modeling and the necessity of model calibration for PM-based assessments.
format Article
id doaj-art-8ca51780cd0a44fbae473085a71da95c
institution Kabale University
issn 2296-665X
language English
publishDate 2025-07-01
publisher Frontiers Media S.A.
record_format Article
series Frontiers in Environmental Science
spelling doaj-art-8ca51780cd0a44fbae473085a71da95c2025-08-20T03:56:12ZengFrontiers Media S.A.Frontiers in Environmental Science2296-665X2025-07-011310.3389/fenvs.2025.15773301577330Effects of topographic variables on traffic-related pollutant concentrations: comparison of AERMOD and CAL3QHCR modelsKazım O. DemirarslanIntroductionThis study examines the spatial dispersion of traffic-related pollutants (CO, NOx, and PM10) along a major highway corridor that connects the Eastern Black Sea Region with northern Türkiye. The primary objective is to compare the performance of two atmospheric dispersion models—AERMOD and CAL3QHCR—and to evaluate how topographic variables influence their outputs.MethodsDispersion simulations were performed using AERMOD and CAL3QHCR under identical meteorological and traffic input scenarios. Model predictions were compared using Spearman’s rank correlation coefficient and validated against observational data from ten air quality monitoring stations. Fractional Bias (FB) and Normalized Mean Square Error (NMSE) were employed as statistical performance metrics.ResultsBoth models estimated higher pollutant concentrations near highways, but AERMOD consistently predicted higher maximum values (CO: 0.78 ppm; NOx: 1.48 ppm; PM10: 26.59 μg/m3). CAL3QHCR produced lower estimates (CO: 0.20 ppm; NOx: 0.09 ppm; PM10: 2.70 μg/m3), yet it showed better agreement with observed CO and NOx concentrations. Correlation analysis indicated strong negative correlations between pollutant levels and elevation (e.g., CO: r = −0.87). Both models captured the spatial decline in concentrations with increasing distance from the road, particularly within the first kilometer.DiscussionAERMOD was found to overpredict pollutant concentrations, while CAL3QHCR yielded closer estimates for CO and NOx. However, both models exhibited poor performance in simulating PM10, as indicated by high NMSE values and consistent underestimation. These findings highlight the significance of topography in dispersion modeling and the necessity of model calibration for PM-based assessments.https://www.frontiersin.org/articles/10.3389/fenvs.2025.1577330/fullAERMODCAL3QHCRtraffic concentrationsair qualitytopography effect
spellingShingle Kazım O. Demirarslan
Effects of topographic variables on traffic-related pollutant concentrations: comparison of AERMOD and CAL3QHCR models
Frontiers in Environmental Science
AERMOD
CAL3QHCR
traffic concentrations
air quality
topography effect
title Effects of topographic variables on traffic-related pollutant concentrations: comparison of AERMOD and CAL3QHCR models
title_full Effects of topographic variables on traffic-related pollutant concentrations: comparison of AERMOD and CAL3QHCR models
title_fullStr Effects of topographic variables on traffic-related pollutant concentrations: comparison of AERMOD and CAL3QHCR models
title_full_unstemmed Effects of topographic variables on traffic-related pollutant concentrations: comparison of AERMOD and CAL3QHCR models
title_short Effects of topographic variables on traffic-related pollutant concentrations: comparison of AERMOD and CAL3QHCR models
title_sort effects of topographic variables on traffic related pollutant concentrations comparison of aermod and cal3qhcr models
topic AERMOD
CAL3QHCR
traffic concentrations
air quality
topography effect
url https://www.frontiersin.org/articles/10.3389/fenvs.2025.1577330/full
work_keys_str_mv AT kazımodemirarslan effectsoftopographicvariablesontrafficrelatedpollutantconcentrationscomparisonofaermodandcal3qhcrmodels