Development of an online analysis method for measuring refractory sulfate and organic aerosols

2022 Fiscal Year Final Research Report

• Project/Area Number: 20H04310
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 63010:Environmental dynamic analysis-related
• Research Institution: Tokyo Metropolitan University
• Principal Investigator: Takegawa Nobuyuki 東京都立大学, 理学研究科, 教授 (00324369)
• Co-Investigator(Kenkyū-buntansha): 三澤 健太郎 東京都立大学, 理学研究科, 助教 (10431991)
• Project Period (FY): 2020-04-01 – 2023-03-31
• Keywords: 環境分析 / 難揮発性エアロゾル / 質量分析計 / 熱脱離 / オンライン分析

Outline of Final Research Achievements

Sulfate and organic compounds contribute to the major fraction of fine particle mass in the atmosphere. We have developed a novel particle mass spectrometer to measure non-refractory and refractory sulfate and organic compounds (rTDMS). Aerosol particles introduced into a vacuum chamber are collected on a cup-shaped graphite particle collector. A focused carbon dioxide laser coupled with the graphite collector enables a high desorption temperature (~1200 K). The temporal profiles of ion signals associated with increases in the temperature of the graphite collector were analyzed to separately quantify non-refractory and refractory sulfate compounds. We have also proposed a new method to quantify sodium and potassium salts (nitrate, chloride, and sulfate) using the rTDMS. The laboratory experiments demonstrated the proof of concept under well-controlled conditions. Further modifications are needed to deploy the rTDMS for ambient measurement of sea salt particles.

Free Research Field

大気化学

Academic Significance and Societal Importance of the Research Achievements

硫酸塩と有機物は微小エアロゾルの主成分であり、グローバルな対流圏に普遍的に存在する。エアロゾルの直接・間接効果は、気候変動予測の主要な不確実要因となっている。本研究で開発した装置において、グラファイト製粒子捕集体と炭酸ガスレーザーの効果的な組み合わせにより、従来法では困難であった難揮発性硫酸塩エアロゾルのオンライン定量が初めて可能となった。本装置を広域大気観測に応用することで、難揮発性成分を含む硫酸塩・硝酸塩・有機エアロゾルの全体像の解明に貢献することが期待される。