THE CORRELATION BETWEEN IN-SITU, REAL-TIME AEROSOL PHOTOEMISSION INTENSITY AND PARTICULATE POLYCYCLIC AROMATIC HYDROCARBON CONCENTRATION INCOMBUSTION AEROSOLS

Aerosol photoemission (APE) has been found to be an excellent surrogat e measure of particulate PAH concentration in combustion aerosols unde r a variety of laboratory and field conditions. Samples of oil stove, automobile exhaust, and urban air particulate matter were concurrently analyzed for aerosol photoemission intensity and particulate PAH conc entration. In-situ, real-time analysis of the particulate matter was p erformed by UV-induced electron photoemission. Two photon energies, 4. 9 and 6.7 eV, were chosen for irradiation. The latter energy was more sensitive and less selective. Particulate PAH concentrations were dete rmined by collecting the particulate matter on a filter, solvent extra cting the filter, and analyses of the extracts by gas chromatography/m ass spectroscopy. Linear correlations (0.84 less-than-or-equal-to r2 l ess-than-or-equal-to 1.00) were observed between aerosol photoemission intensities and the sum of particulate PAH concentrations for laborat ory and field studies under a wide variety of conditions. The studies performed to date cover a dynamic range of three orders of magnitude ( 1 to 1000 ng/m3). The time resolution is in the order of a few seconds .