the Creative Commons Attribution 4.0 License.
the Creative Commons Attribution 4.0 License.
Surface and tropospheric ozone over East Asia and Southeast Asia from observations: distributions, trends, and variability
Abstract. High level of ozone throughout the troposphere is an emerging concern over East Asia and Southeast Asia. Here we analyzed available surface ozone measurements in the past two decades (2005–2021) over eight countries, and ten ozonesonde and aircraft measurements within this region. At surface, seasonal mean ozone over 2017–2021 varies from 30 ppb in Southeast Asia to 75 ppb in summer in North China. The metric of seasonal 95th percentile ozone can identify the multiple hotspots of ozone pollution of over 85 ppb in Southeast Asia. The new WHO peak season ozone standard indicates that both East Asia and Southeast Asia face a widespread risk of long-term exposure. The surface ozone increase in South Korea and Southeast Asia from 2005 was leveling off or even decreased in the past decade, while ozone increase in 2000s over China has amplified after 2013. Surface ozone trends in Japan and Mongolia were flat in the past decade. In the troposphere, the available measurements show an overall increasing tendency at different altitudes from a three-decade perspective and its trend in the past decade remains unclear due to data availability. The difference in tropospheric ozone level between East Asia and Southeast Asia is likely due to the high background ozone from stratospheric intrusion over Northeast Asia. In terms of ozone controls, our results suggest that anthropogenic emissions determine the occurrence of high ozone levels but the underappreciated strong ozone climate penalty, particularly over Southeast Asia, will make ozone controls harder under a warmer climate.
Competing interests: Some authors are members of the editorial board of Atmospheric Chemistry and Physics.
Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this preprint. The responsibility to include appropriate place names lies with the authors.- Preprint
(10290 KB) - Metadata XML
-
Supplement
(3667 KB) - BibTeX
- EndNote
Status: open (until 04 Mar 2025)
-
RC1: 'Comment on egusphere-2024-3756', I. Pérez, 28 Jan 2025
reply
This is an excellent paper about the ozone concentrations in East and Southeast Asia. Key features are the quantity of surface stations in eight countries with different air quality standards, together with ozonesonde data from 10 sites. Another noticeable feature is the period investigated, which extended above 10 years in some sites. The authors presented the annual cycle of mean values, the 95th percentile, the number of threshold exceedances and trends. Tropospheric ozone profiles are presented and their trends. Finally, a relationship with nitrogen oxides and temperature is considered. Since the paper is quite complete, only some minor comments should be required before its final acceptance.
Since the number of surface stations included in this study is noticeable, the authors could comment if noticeable outliers have been recorded, i.e. if there are stations that provide anomalous values.
The paper focus is on the high values. However, low values could be highlighted. The authors should indicate if such values belong to remote sites or if are linked to high concentrations of other substances.
The authors could indicate if it is possible to classify the stations following the ozone origin by transport or by precursors or if site classifications have been discarded.
Since the number of stations depends on the country. Some means presented in Figure 8 may be more robust against others. The authors could consider this fact.
Finally, the temperature is considered. However, meteorological features are varied in different latitudes. The synoptic pattern evolution may be quite different in the analysed region. The authors could comment the possible influence of such features on ozone concentrations.
Minor remarks.
L. 403. Dot instead of semicolon.
L. 580. Introduce one space in “forthe”.
L. 583. Introduce subscript in NO2.
Citation: https://doi.org/10.5194/egusphere-2024-3756-RC1 -
CC1: 'Comment on egusphere-2024-3756', Owen Cooper, 10 Feb 2025
reply
This comment can be found in the attached pdf.
-
RC2: 'Comment on egusphere-2024-3756', Anonymous Referee #2, 11 Feb 2025
reply
Please see attached document for full review
Viewed
HTML | XML | Total | Supplement | BibTeX | EndNote | |
---|---|---|---|---|---|---|
264 | 49 | 18 | 331 | 29 | 4 | 2 |
- HTML: 264
- PDF: 49
- XML: 18
- Total: 331
- Supplement: 29
- BibTeX: 4
- EndNote: 2
Viewed (geographical distribution)
Country | # | Views | % |
---|
Total: | 0 |
HTML: | 0 |
PDF: | 0 |
XML: | 0 |
- 1