A long-term analysis of oxidant (OX = O3 + NO2) and its local and regional levels in Tehran, Iran, a high NOx-saturated condition
Abstract Oxidant (OX), the sum of ozone (O3) and nitrogen dioxide (NO2), is used to determine nitrogen oxides (NOx)-independent regional contribution and NOx-dependent local contribution. This study investigates OX trends and its local and regional levels in Tehran, Iran using the data from 21 monit...
Saved in:
| Main Authors: | , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Nature Portfolio
2025-01-01
|
| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-024-82709-9 |
| Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
| _version_ | 1832585752468258816 |
|---|---|
| author | Ahmad Taheri Babak Khorsandi Mohammad Reza Alavi Moghaddam |
| author_facet | Ahmad Taheri Babak Khorsandi Mohammad Reza Alavi Moghaddam |
| author_sort | Ahmad Taheri |
| collection | DOAJ |
| description | Abstract Oxidant (OX), the sum of ozone (O3) and nitrogen dioxide (NO2), is used to determine nitrogen oxides (NOx)-independent regional contribution and NOx-dependent local contribution. This study investigates OX trends and its local and regional levels in Tehran, Iran using the data from 21 monitoring stations from 2012 to 2022 and satellite remote sensing data (TROPOMI) for 2022. The spatiotemporal trends of O3, NO2, and OX are first examined using ground-based and remote sensing data, and then the polar plots are employed to identify the dominant directions of OX transport and its sources. Subsequently, the local and regional contributions of OX were determined using OX-NOx relationship. The findings indicated that the OX trend is primarily affected by O3 fluctuations during the warmer months, whereas NO2 variations have a stronger correlation with OX during the remaining months. The emissions from the central zone of the city were mostly caused by the transportation fleet. The emissions from industries in the south also have a significant effect on the city’s OX concentration. Moreover, the local contribution of OX, reaching a maximum value of 0.15 ppb/ppb NOx (for both monthly and yearly analysis), contributes to the elevation of OX levels during nighttime. In contrast, the OX local contribution at daylight hours is mostly negative, with minimum values of − 0.15 ppb/ppb NOx for July and − 0.07 ppb/ppb NOx for 2012, indicating a decrease in the OX concentration with an increase in the local NOx emission. Furthermore, the OX levels, especially for daylight hours, is mostly related to its regional contribution with maximum of 100 ppb in July and 95 ppb in 2017, suggesting the necessity of considering regional emissions in developing mitigation scenarios. Lastly, our results indicate that the transportation fleet plays an undeniable role in contributing to the local emissions in Tehran. |
| format | Article |
| id | doaj-art-018741b960ab468f8db87fbb9d8ebb6d |
| institution | Kabale University |
| issn | 2045-2322 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj-art-018741b960ab468f8db87fbb9d8ebb6d2025-01-26T12:30:30ZengNature PortfolioScientific Reports2045-23222025-01-0115111510.1038/s41598-024-82709-9A long-term analysis of oxidant (OX = O3 + NO2) and its local and regional levels in Tehran, Iran, a high NOx-saturated conditionAhmad Taheri0Babak Khorsandi1Mohammad Reza Alavi Moghaddam2Department of Civil and Environmental Engineering, Amirkabir University of Technology (Tehran Polytechnic)Department of Civil and Environmental Engineering, Amirkabir University of Technology (Tehran Polytechnic)Department of Civil and Environmental Engineering, Amirkabir University of Technology (Tehran Polytechnic)Abstract Oxidant (OX), the sum of ozone (O3) and nitrogen dioxide (NO2), is used to determine nitrogen oxides (NOx)-independent regional contribution and NOx-dependent local contribution. This study investigates OX trends and its local and regional levels in Tehran, Iran using the data from 21 monitoring stations from 2012 to 2022 and satellite remote sensing data (TROPOMI) for 2022. The spatiotemporal trends of O3, NO2, and OX are first examined using ground-based and remote sensing data, and then the polar plots are employed to identify the dominant directions of OX transport and its sources. Subsequently, the local and regional contributions of OX were determined using OX-NOx relationship. The findings indicated that the OX trend is primarily affected by O3 fluctuations during the warmer months, whereas NO2 variations have a stronger correlation with OX during the remaining months. The emissions from the central zone of the city were mostly caused by the transportation fleet. The emissions from industries in the south also have a significant effect on the city’s OX concentration. Moreover, the local contribution of OX, reaching a maximum value of 0.15 ppb/ppb NOx (for both monthly and yearly analysis), contributes to the elevation of OX levels during nighttime. In contrast, the OX local contribution at daylight hours is mostly negative, with minimum values of − 0.15 ppb/ppb NOx for July and − 0.07 ppb/ppb NOx for 2012, indicating a decrease in the OX concentration with an increase in the local NOx emission. Furthermore, the OX levels, especially for daylight hours, is mostly related to its regional contribution with maximum of 100 ppb in July and 95 ppb in 2017, suggesting the necessity of considering regional emissions in developing mitigation scenarios. Lastly, our results indicate that the transportation fleet plays an undeniable role in contributing to the local emissions in Tehran.https://doi.org/10.1038/s41598-024-82709-9 |
| spellingShingle | Ahmad Taheri Babak Khorsandi Mohammad Reza Alavi Moghaddam A long-term analysis of oxidant (OX = O3 + NO2) and its local and regional levels in Tehran, Iran, a high NOx-saturated condition Scientific Reports |
| title | A long-term analysis of oxidant (OX = O3 + NO2) and its local and regional levels in Tehran, Iran, a high NOx-saturated condition |
| title_full | A long-term analysis of oxidant (OX = O3 + NO2) and its local and regional levels in Tehran, Iran, a high NOx-saturated condition |
| title_fullStr | A long-term analysis of oxidant (OX = O3 + NO2) and its local and regional levels in Tehran, Iran, a high NOx-saturated condition |
| title_full_unstemmed | A long-term analysis of oxidant (OX = O3 + NO2) and its local and regional levels in Tehran, Iran, a high NOx-saturated condition |
| title_short | A long-term analysis of oxidant (OX = O3 + NO2) and its local and regional levels in Tehran, Iran, a high NOx-saturated condition |
| title_sort | long term analysis of oxidant ox o3 no2 and its local and regional levels in tehran iran a high nox saturated condition |
| url | https://doi.org/10.1038/s41598-024-82709-9 |
| work_keys_str_mv | AT ahmadtaheri alongtermanalysisofoxidantoxo3no2anditslocalandregionallevelsintehraniranahighnoxsaturatedcondition AT babakkhorsandi alongtermanalysisofoxidantoxo3no2anditslocalandregionallevelsintehraniranahighnoxsaturatedcondition AT mohammadrezaalavimoghaddam alongtermanalysisofoxidantoxo3no2anditslocalandregionallevelsintehraniranahighnoxsaturatedcondition AT ahmadtaheri longtermanalysisofoxidantoxo3no2anditslocalandregionallevelsintehraniranahighnoxsaturatedcondition AT babakkhorsandi longtermanalysisofoxidantoxo3no2anditslocalandregionallevelsintehraniranahighnoxsaturatedcondition AT mohammadrezaalavimoghaddam longtermanalysisofoxidantoxo3no2anditslocalandregionallevelsintehraniranahighnoxsaturatedcondition |