From September 14 to 16, 2022, at Osaka Metropolitan University, at the 63rd Annual Meeting of the Atmospheric Environment Society, our graduate student Rui Kato (Specializing in Management Engineering, Department of Integrated Systems Engineering) received the "Outstanding Student and Early-Career Oral Presentation Award."

The Atmospheric Environment Society was founded in 1959 and has over 700 members. It is one of the longest-established academic societies in Japan’s environmental field and is highly regarded both domestically and internationally. The society has made significant contributions to improving air pollution in Japan. This year’s Outstanding Student and Early-Career Award was given without distinction between students and early-career researchers. Among 32 oral presentations and 101 poster presentations, eight awards in total were granted, including four oral presentation awards and four poster presentation awards.

★Comment from Awardee Rui Kato:
The title of my presentation was "Changes in the Sources of Ammonium Ions in PM2.5 in Dhaka, Bangladesh during the COVID-19 Pandemic" (Rui Kato, Hiroto Kawashima, JOY Khaled Shaifullah, FARAH Jeba, Abdus Salam). Our research focuses on estimating the sources of ammonium ions in PM2.5 in Dhaka, Bangladesh — one of the cities with the highest PM2.5 concentrations worldwide — by using nitrogen stable isotope ratios of ammonium ions. In particular, we are investigating how air quality has changed due to factors such as COVID-19 lockdowns in recent years. Our results showed that, compared to 2019 before the pandemic, there was little long-term effect of COVID-19 on PM2.5 levels overall. However, the source of ammonium ions shifted slightly, with a decrease in non-agricultural sources such as vehicular emissions, which are anthropogenic. This suggests that although human activities decreased due to the pandemic, PM2.5 itself was not significantly affected.

Source analysis of ammonium ions in PM2.5 using nitrogen stable isotope ratios has been mainly conducted in China and the United States, and rarely in other countries. Since our study covers a long-term period during the COVID-19 pandemic, it provides unique data rarely reported in other papers. I presented this research at the Atmospheric Environment Society conference and was relieved that it attracted interest. Currently, I am preparing a manuscript to submit to an international academic journal, and the questions and comments received at this opportunity have deepened our analysis.

This is the fourth time our laboratory has received this Outstanding Student and Early-Career Award. I was truly surprised when I received the notification email, as I did not expect to be honored in this way. Professor Kawashima was also surprised, and we shared our joy. This award made me feel the support of those who have quietly encouraged us. I am also honored to continue the legacy of our predecessors who received this award. During my oral presentation, I focused on what I wanted to convey most and considered what the audience expected. Many researchers in atmospheric environment listened attentively and provided questions and comments. I will seriously address the questions and suggestions we received and reflect them in the manuscript I am currently writing to improve its quality.

During the conference, I had meals with Professor Kawashima’s seniors. I had the opportunity to hear their passion for research and received advice on my own work. Initially, I was nervous about discussing research topics, but I was very happy that senior researchers showed interest in my work, making it a very meaningful time. This conference presentation has greatly motivated me to continue my research. On the way back, I also visited Tekijuku (the school founded by Koan Ogata) in Osaka city. This was a very valuable conference experience. I want to embody the spirit and soul of Tekijuku and further dedicate myself to research.

Finally, I would like to express my sincere gratitude to Professor Hiroto Kawashima for his guidance, to all members of our laboratory who work and discuss research with me daily, to Mr. Gaku Fujishima who supports our research, and to everyone at Dhaka University who assisted with sampling for this project.