Effects of national affiliations and international collaboration on scientific findings: The case of transboundary air pollution in Northeast Asia

•Air pollution research in Northeast Asia reflects possible political influences.•Japanese research and Korean research both focus on China as source of pollution.•China’s researchers do not highlight China’s air pollution contributions nor minimize them.•Chinese-Japanese collaborations attribute transboundary air pollution to China.•Chinese-Korean collaborations do not attribute transboundary air pollution to China.