the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
An investigation into atmospheric nitrous acid (HONO) processes in South Korea
Abstract. Nitrous acid (HONO) is a main precursor of hydroxyl radicals (OH), which contribute to the formation of numerous secondary air pollutants in the troposphere. Despite its importance in atmospheric chemistry, HONO chemistry has not been fully incorporated into many chemical transport models (CTMs). Due to the lack of atmospheric HONO processes, CTM simulations often tend to underestimate atmospheric mixing ratios of HONO. This study was undertaken because simulations with current Community Multiscale Air Quality (CMAQ) model have a strong tendency to underestimate the HONO mixing ratio. In search of missing sources of atmospheric HONO, we attempted to sequentially incorporate the following potential HONO sources and processes into the CMAQ modeling framework: (i) gas-phase HONO reactions; (ii) traffic HONO emissions; (iii) soil HONO emissions; (iv) heterogeneous HONO production on the surfaces of aerosols; (v) heterogeneous HONO formation on tree leaf and building surfaces; (vi) photolysis reactions of particulates and deposited HNO3/nitrates called ‘renoxification’. The simulation performances of the modified CMAQ models were then evaluated by comparing the modeled HONO mixing ratios with the HONO mixing ratios observed at the Olympic Park station in Seoul, South Korea. When HONO processes were fully added to the CMAQ model, average daily HONO mixing ratios increased from 0.06 ppb to 1.18 ppb. The daytime HONO mixing ratios produced from the CMAQ model run with a full account of atmospheric HONO processes were found to be in better agreement with observations than those from the original CMAQ model (CMAQv5.2.1) runs with improved statistical metrics (e.g., IOA increased from 0.59 to 0.68, while MB decreased dramatically from -0.57 ppb to -0.34 ppb). In addition, we investigated the contributions of individual atmospheric HONO processes to HONO mixing ratios, as well as the impacts of HONO atmospheric processes on the concentrations of other atmospheric species in South Korea. All these issues are also discussed in this manuscript.
- Preprint
(2382 KB) - Metadata XML
-
Supplement
(1135 KB) - BibTeX
- EndNote
Status: closed
-
RC1: 'Comment on egusphere-2024-886', Anonymous Referee #1, 06 May 2024
In this study, the author attempted to sequentially incorporate several potential HONO sources and processes into the CMAQ modeling framework. And the simulation performances of the modified CMAQ models were then evaluated by comparing the modeled HONO mixing ratios with the HONO mixing ratios observed at the Olympic Park station in Seoul, South Korea. The simulation results have been improved than the original CMAQ model. However, there are several issues in the article.
- In Lines 179-180, the average values of simulation results in Table S2 are not sufficient to confirm the good prediction of the model, and the comparisons of time series of observation and modeled outputs are needed.
- In table 1, the emission factor of gasoline and diesel vehicles are 0.8% and 2.3% in all studies areas. However, there are significant differences in traffic volumes and vehicle types in different areas.
- In lines 205-207, is the equation for the relationship between JNPHEand JNO2 also in this reference (Stockwell et al., 1990)? And how JHONO is calculated?
- In table 3, how HONO emission rates of traffic calculated?
- In lines 276-277, why are the uptake coefficients of NO2at nighttime and daytime are 8.0×10-6 and 1.3×10-4, respectively? Also how is the 900 for this factor taken into account? The same issue in Lines 292-293.
- In Line 412, is there much improvement in model results if NO2daytime sources are enhanced?
- In Line 447, “Its contribution increases to 4.2% during the daytime”,which source is this contribution?
Citation: https://doi.org/10.5194/egusphere-2024-886-RC1 - AC2: 'Reply on RC1', Kiyeon Kim, 23 Jul 2024
-
RC2: 'Comment on egusphere-2024-886', Anonymous Referee #2, 14 Jun 2024
- AC1: 'Reply on RC2', Kiyeon Kim, 23 Jul 2024
Status: closed
-
RC1: 'Comment on egusphere-2024-886', Anonymous Referee #1, 06 May 2024
In this study, the author attempted to sequentially incorporate several potential HONO sources and processes into the CMAQ modeling framework. And the simulation performances of the modified CMAQ models were then evaluated by comparing the modeled HONO mixing ratios with the HONO mixing ratios observed at the Olympic Park station in Seoul, South Korea. The simulation results have been improved than the original CMAQ model. However, there are several issues in the article.
- In Lines 179-180, the average values of simulation results in Table S2 are not sufficient to confirm the good prediction of the model, and the comparisons of time series of observation and modeled outputs are needed.
- In table 1, the emission factor of gasoline and diesel vehicles are 0.8% and 2.3% in all studies areas. However, there are significant differences in traffic volumes and vehicle types in different areas.
- In lines 205-207, is the equation for the relationship between JNPHEand JNO2 also in this reference (Stockwell et al., 1990)? And how JHONO is calculated?
- In table 3, how HONO emission rates of traffic calculated?
- In lines 276-277, why are the uptake coefficients of NO2at nighttime and daytime are 8.0×10-6 and 1.3×10-4, respectively? Also how is the 900 for this factor taken into account? The same issue in Lines 292-293.
- In Line 412, is there much improvement in model results if NO2daytime sources are enhanced?
- In Line 447, “Its contribution increases to 4.2% during the daytime”,which source is this contribution?
Citation: https://doi.org/10.5194/egusphere-2024-886-RC1 - AC2: 'Reply on RC1', Kiyeon Kim, 23 Jul 2024
-
RC2: 'Comment on egusphere-2024-886', Anonymous Referee #2, 14 Jun 2024
- AC1: 'Reply on RC2', Kiyeon Kim, 23 Jul 2024
Viewed
HTML | XML | Total | Supplement | BibTeX | EndNote | |
---|---|---|---|---|---|---|
403 | 104 | 26 | 533 | 53 | 16 | 16 |
- HTML: 403
- PDF: 104
- XML: 26
- Total: 533
- Supplement: 53
- BibTeX: 16
- EndNote: 16
Viewed (geographical distribution)
Country | # | Views | % |
---|
Total: | 0 |
HTML: | 0 |
PDF: | 0 |
XML: | 0 |
- 1