Pollution along lower Yangtze River (DI01897) Photo by William Bradford

Traffic in Denver, Colorado (DI01884)

Traffic in Mexico City (DI01874)

Air pollution, Mexico City (DI01873)

Air pollution, Mexico City (DI01872)

Air pollution, Mexico City (DI01871)

MIRAGE researcher (DI01868)

MIRAGE researcher (DI01867)

MIRAGE researcher (DI01866)

MIRAGE researchers (DI01865)

Tethered balloon (DI01864)

Heavy traffic (DI01702)