ICUC12-971, updated on 21 May 2025
https://doi.org/10.5194/icuc12-971
12th International Conference on Urban Climate
© Author(s) 2025. This work is distributed under
the Creative Commons Attribution 4.0 License.
Co-benefits of low-carbon strategy in Japan on surface ozone concentration in cities
Natsumi Kawano1, Tatsuya Nagashima2, Syuich Itahashi3, Toshimasa Ohara4, Jun-ichi Kurokawa4, Tatsuya Hanaoka2, and Itsushi Uno
Natsumi Kawano et al.
  • 1Center of Environmental Science in Saitama, Japan
  • 2National Institute for Environmental Sciense, Japan
  • 3Kyusyu University, Japan
  • 4Japan Environmental Sanitation Center Asia Center for Air Pollution Research, Japan

Achieving carbon neutrality by 2050 announced in Japan is expected to substantially affect air quality. Therefore, the effects of climate change and GHG reduction strategies on the emission of air pollutants are of great interest to environmentalists and policymakers. However, the co-benefits of carbon neutrality on air quality in Asian regions are still discussed.

Here, we projected the future surface ozone (O3) concentration in 2050 by conducting regional air quality simulations based on a low-carbon emission scenarios for the Asian region considering the newly developed technologies.

First of all, we verified Business as usual (BAU) scenario which considers the low-carbon measures currently envisaged and results in 40% and 45% reduction of O3 precursors emissions (VOCs and NOx, respectively) from the present (the year 2017) situation. Surface O3 in the BAU increased ~2.5ppbv compare to that in present in some metropolitan areas which were driven by the reductions of O3 precursors.

To quantify the impact of further reductions of VOCs and NOx on surface O3, three additional strict regulation strategies were examined: additional 40% reduction of VOCs emission from the BAU (80redVOCs), additional 45% reduction of NOx emission from the BAU (85redNOx), and the combination of 80redVOCs and 85redNOx (80redVOCs_85redNOx).

The 80redVOCs decreased O3 concentration by ~1.5 ppbv in metropolitan areas compared to that in the BAU. Otherwise, the 85redNOx and 80redVOCs_85redNOx showed a similar pattern of the change in O3 concentration compared to the BAU scenarios with larger impacts than that in the 80redVOCs. The largest difference in surface O3 between these strategies and BAU scenarios occurred in the central part of Japan, where O3 concentration decreased ~4.5 ppbv, but increased to 3 ppbv in Tokyo metropolitan area. We will present the co-benefit of the Japanese low-carbon strategy on surface O3 concentration particularly in metropolitan areas by using indexes.

How to cite: Kawano, N., Nagashima, T., Itahashi, S., Ohara, T., Kurokawa, J., Hanaoka, T., and Uno, I.: Co-benefits of low-carbon strategy in Japan on surface ozone concentration in cities, 12th International Conference on Urban Climate, Rotterdam, The Netherlands, 7–11 Jul 2025, ICUC12-971, https://doi.org/10.5194/icuc12-971, 2025.

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