On board NASA's flying lab over South Korea

Seoul (CNN)NASA prepares its half-a-century old jetliner for take-off in an airbase in South Korea.

Thirty-four scientists teamed up in this Douglas DC-8 for a mission to measure the main pollutants in the air over South Korea, for clues as to what and who is causing it.
    Equipped with 25 state-of-the-art instruments, the highly-modified plane allows scientists to collect samples and data.
    The flying science laboratory flew through the length and breadth of South Korea for eight hours in May, taking samples and readings.
    South Korea's air quality is ranked 173 out of 180 countries, according to a recent study by Yale University. More than half the country's population is exposed to unsafe levels of fine particulate matters, the study found.