Application of WRF-chem for predicting air quality resulting from the formation of photochemical compounds in a subtropical urban environment
Silva, L. F. M. d., Deroubaix, A., Brasseur, G., Gioda, A.. (2026). Application of WRF-chem for predicting air quality resulting from the formation of photochemical compounds in a subtropical urban environment. Urban Climate, doi:https://doi.org/10.1016/j.uclim.2025.102733
| Title | Application of WRF-chem for predicting air quality resulting from the formation of photochemical compounds in a subtropical urban environment |
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| Genre | Article |
| Author(s) | L. F. M. d. Silva, A. Deroubaix, Guy Brasseur, A. Gioda |
| Abstract | Modeling ozone (O3) concentrations in urban areas is challenging due to interactions between emissions inventory, meteorology, and atmospheric chemistry. This study evaluates the performance of WRF-Chem in simulating O3, NOx, SO2, and Ox (= NO2 + O3) in the Metropolitan Region of Rio de Janeiro (MRRJ), representing the first assessment of WRF-Chem against observations from the INEA automatic monitoring network. In three contrasting periods, the modeled hourly concentrations show moderate agreement with observations (R ≈ 0.6 for NOx, 0.5 for SO2, and 0.7 for O₃). O3 is overestimated during the day (≈ 20 ppb) and underestimated at night (≈ 10 ppb). NO2 is overestimated at night (≈ 20 ppb) and SO2 (≈ 25 ppb). Biases are persistent: there is daytime overestimation of O3 and Ox and nighttime underestimation. These discrepancies result mainly from the model's treatment of emissions inventory, particularly volatile organic compounds (VOCs) and NOx, which are important for the formation of O3 through photochemical reactions. The results indicate the need to improve the representation of total emission magnitudes, spatial allocation, and diurnal variability of anthropogenic sources, particularly VOCs and NOx, which strongly influence ozone production in the region. Spatial patterns suggest that uncertainties in VOC emissions, combined with urban meteorology (e.g., sea/land-breeze cycles, boundary-layer evolution), may contribute to O3 overestimation in industrial corridors such as Santa Cruz/RJ and Volta Redonda/RJ; however, this interpretation should be considered a hypothesis consistent with model limitations. For air quality management, the findings suggest priority actions: refining the magnitude, spatial allocation, and diurnal variability of anthropogenic emissions (especially VOC and NOx). These measures can guide contingency plans and O3 reduction strategies in the state of Rio de Janeiro. This research provides essential guidance for policymakers to implement emission controls and devise effective contingency plans for pollution episodes in tropical metropolitan areas. |
| Publication Title | Urban Climate |
| Publication Date | Feb 1, 2026 |
| Publisher's Version of Record | https://doi.org/10.1016/j.uclim.2025.102733 |
| OpenSky Citable URL | https://n2t.net/ark:/85065/d7n87gbq |
| OpenSky Listing | View on OpenSky |
| ACOM Affiliations | MODELING |