11.   Team member Richard Zare, a chemist at Stanford, used lasers and an extremely sensitive detector called a mass spectrometer to spot molecules called polycyclic aromatic hydrocarbons.

12.   The chemicals are called polycyclic aromatic hydrocarbons, or PAHs.

13.   The chemicals are technically known as polycyclic aromatic hydrocarbons.

14.   The debris, which also includes potentially carcinogenic polycyclic aromatic hydrocarbons, or PAHs, spews out the windows into the river.

15.   The smog is also heavily laced with polycyclic aromatic hydrocarbons, which are produced when organic materials, such as trees and undergrowth, are burned.

16.   Words like particulates, benzene and polycyclic aromatic hydrocarbons pop up in her speech.

17.   During a normal work day, barehanded workers handle toxic heavy metals, potentially cancer-causing polycyclic aromatic hydrocarbons and asbestos.

18.   He and most astronomers favor a family of complex carbon-based molecules, known as polycyclic aromatic hydrocarbons, as the cause of the DIBs.

19.   The researchers said the Allan Hills meteorite contained organic molecules called polycyclic aromatic hydrocarbons, or PAHs, that can be associated with life processes.

20.   Then they looked at PAHs, or polycyclic aromatic hydrocarbons, produced by the burning of fossil fuels.