noun
National Institute of Environmental Pollution Research
Proper noun; refers to a specific Japanese research institute. The abbreviation 'pn' in the English gloss likely stands for 'proper noun'.
国立公害研究所は環境汚染の研究を行っている。
The National Institute of Environmental Pollution Research conducts research on environmental pollution.
Compound of 国立 (national), 公害 (pollution), and 研究所 (research institute).