Indonesian peatland fires predominantly occur on Sumatra and Kalimantan Islands during the dry season, and emitted aerosols cause dense haze and serious environmental impacts in Southeast Asia. Information on chemical properties of the aerosols is indispensable to understand and evaluate their dynamic state in environment and environmental impact. We review studies on chemical characteristics of aerosols emitted from Indonesian peatland fires from the viewpoints of source, receptor, and transformation. First, chemical characteristics of aerosols (carbonaceous species, water-soluble inorganic ions, and trace elements) at the fire sources are presented. In particular, carbonaceous species are highlighted, because organic carbon accounted for 64–77% of aerosol mass at Indonesian peatland fire sources. Second, chemical characteristics of aerosols (ditto) affected by the fires at receptors in Indonesia, Malaysia, and Singapore are presented. Furthermore, chemical transformations of aerosols are discussed during transportation from the fire sources to receptors. Third, source contributions of Indonesian peatland fires to ambient aerosols at receptors are presented. Finally, future research directions are discussed.

We simultaneously measured the chemical composition of aerosol at three different sites in the Kyushu and Okinawa area in Japan during spring in 2016. Chinese emissions had decreased significantly since 2013. At all sites, the main species observed were sulfate and organics, with fractions of 60–80%. Nitrate was barely observed at Cape Hedo in Okinawa, while it accounted for over 10% on Fukue Island in Nagasaki and in Fukuoka City. The mass spectra of organic species observed were analyzed using the positive matrix factorization (PMF) method. Low-volatile oxygenated organic aerosol (LV-OOA) was the main component at all sites, with fractions of over 50%. Although Chinese emissions were significantly decreased since 2013, all three sites remained affected by the long-range transport of air pollutants from the Chinese continent.