Columbia subject headings:
Air--Pollution--Congresses.
Atmospheric diffusion--Congresses.
Transboundary pollution--Congresses.
Harvard subject headings:
Air--Pollution--Congresses
Atmospheric diffusion--Congresses.
Transboundary pollution--Congresses.
Princeton subject headings:
Air--Pollution--Congresses.
Atmospheric diffusion--Congresses.
Transboundary pollution--Congresses.