Ambient levels of the peroxyacyl nitrates PAN, PPN and MPAN in Atlanta, Georgia

Abstract

Ambient levels of the peroxyacyl nitrates [RC(O)OONO2] PAN (R = CH3), PPN (R = C2H5-) and MPAN [R = CH2 = C(CH3)-] have been measured in July - August 1992 in downtown Atlanta, Georgia. Ambient levels of PAN reached 2.9 ppb and averaged 0.71 ± 0.53 ppb (n = 817). PPN reached 0.37 ppb and averaged 0.14 ± 0.14 ppb (n = 119). Diurnal variations of PAN and PPN were similar and included nighttime minima and late afternoon/early evening maxima. MPAN was observed on only 12 occasions at levels averaging 0.32 ± 0.07 ppb. A brief descriptive analysis of the data is presented together with a documentation of our measurement and calibration protocols and the results of an interlaboratory comparison involving co-located measurements of ambient PAN.