TY - JOUR
T1 - Peroxyacetyl nitrate (PAN) and peroxyacetic acid (PAA) measurements by iodide chemical ionisation mass spectrometry
T2 - First analysis of results in the boreal forest and implications for the measurement of PAN fluxes
AU - Phillips, G. J.
AU - Pouvesle, N.
AU - Thieser, J.
AU - Schuster, G.
AU - Axinte, R.
AU - Fischer, H.
AU - Williams, J.
AU - Lelieveld, J.
AU - Crowley, J. N.
PY - 2013
Y1 - 2013
N2 - We describe measurements of peroxyacetyl nitrate (CH3C(O)O 2NO2, PAN) and peroxyacetic acid (CH3C(O)OOH, PAA) in the Boreal forest using iodide chemical ionization mass spectrometry (ICIMS). The measurements were made during the Hyytiälä United Measurement of Photochemistry and Particles - Comprehensive Organic Particle and Environmental Chemistry (HUMPPA-COPEC-2010) measurement intensive. Mixing ratios of PAN and PAA were determined by measuring the acetate ion signal (CH3C(O)O-, m/z = 59) resulting from reaction of CH 3C(O)O2 (from the thermal dissociation of PAN) or CH 3C(O)OOH with iodide ions using alternatively heated and ambient temperature inlet lines. During some periods of high temperature (∼ 30 C) and low NOx (< 1 ppbv), PAA mixing ratios were similar to, or exceeded those of PAN and thus contributed a significant fraction of the total acetate signal. PAA is thus a potential interference for ICIMS measurements of PAN, and especially eddy covariance flux measurements in environments where the PAA flux is likely to be a significant proportion of the (short timescale) acetate ion variability. Within the range of mixing ratios of NOx measured during HUMPPA-COPEC, the modelled ratio of PAA-to-PAN was found to be sensitive to temperature (through the thermal decomposition rate of PAN) and the HO 2 mixing ratio, thus providing some constraint to estimates of photochemical activity and oxidation rates in the Boreal environment.
AB - We describe measurements of peroxyacetyl nitrate (CH3C(O)O 2NO2, PAN) and peroxyacetic acid (CH3C(O)OOH, PAA) in the Boreal forest using iodide chemical ionization mass spectrometry (ICIMS). The measurements were made during the Hyytiälä United Measurement of Photochemistry and Particles - Comprehensive Organic Particle and Environmental Chemistry (HUMPPA-COPEC-2010) measurement intensive. Mixing ratios of PAN and PAA were determined by measuring the acetate ion signal (CH3C(O)O-, m/z = 59) resulting from reaction of CH 3C(O)O2 (from the thermal dissociation of PAN) or CH 3C(O)OOH with iodide ions using alternatively heated and ambient temperature inlet lines. During some periods of high temperature (∼ 30 C) and low NOx (< 1 ppbv), PAA mixing ratios were similar to, or exceeded those of PAN and thus contributed a significant fraction of the total acetate signal. PAA is thus a potential interference for ICIMS measurements of PAN, and especially eddy covariance flux measurements in environments where the PAA flux is likely to be a significant proportion of the (short timescale) acetate ion variability. Within the range of mixing ratios of NOx measured during HUMPPA-COPEC, the modelled ratio of PAA-to-PAN was found to be sensitive to temperature (through the thermal decomposition rate of PAN) and the HO 2 mixing ratio, thus providing some constraint to estimates of photochemical activity and oxidation rates in the Boreal environment.
UR - http://www.scopus.com/inward/record.url?scp=84873545708&partnerID=8YFLogxK
U2 - 10.5194/acp-13-1129-2013
DO - 10.5194/acp-13-1129-2013
M3 - Article
AN - SCOPUS:84873545708
SN - 1680-7316
VL - 13
SP - 1129
EP - 1139
JO - Atmospheric Chemistry and Physics
JF - Atmospheric Chemistry and Physics
IS - 3
ER -