This is the metadata for: MUMBA_PTRMS_2012-12-21_2013-02-15 (doi:10.1594/PANGAEA.871998) Measurement: VOCs - formaldehyde (mz/31), methanol (m/z33), acetonitrile (m/z42), acetaldehyde (m/z45), acetone (m/z59), isoprene (m/z 69), sum of methacrolein and methyl vinyl ketone (m/z71), benzene (m/z79), toluene (m/z 93), sum of C8H10 compounds (m/z 107), sum of C9H12 compounds (m/z 121), sum of monoterpenes (m/z 137) Instrument: Ionicon Proton-Transfer-Reaction Mass spectrometer Owner: CSIRO Campaign: MUMBA Location: Main measurement site - Nissan Hut Kids Campus / Campus East, Wollongong (-34.3972, 150.8996) Dates of operation: 21-Dec-2012 to 15-Feb-2013 Original measurement time resolution: ~3 minutes Averaging time: 1 hour Units: ppb Inlet/Installation: Ambient air sampled with 1/4" PTFE bypass flow at ~1.4L/min. Inlet was installed at a height of ~10m and protected by an inverted teflon cup Data collection detail: The PTR-MS was operated using H3O+ ions only and was programmed to scan through its range of mass-to-charge ratios (m/z) with a dwell time of one second, for a total cycle time of about three minutes. Voltage: 437, drift tube pressure: 2.1 mbar. The instrument performed zero measurements twice daily for 40 minutes each time (at 00:50 and at 15:00 local time) by sampling ambient air that had been stripped of volatile organic compounds (VOCs) by passing through a platinum-coated glass wool catalyst heated to 350°C. Data analysis detail (inc. references if needed): raw counts were normalised to 10^6 reagent ion counts. The ambient data were zero corrected using interpolated zero values (for every measurement, the interpolated zero value is the average of the zero periods immediately preceding and following it) whereas the calibration data was zero corrected using the zero period immediately preceding the calibration period. The response of the instrument to certain species in the calibration standards varied depending on the amount of water present in ambient air at the time of the calibration. For these species, water-dependent calibration factors were derived Calibration: Multi-species, single-point calibration performed daily (from 01:30 until 03:00 local time) by introducing a known flow of calibration standard into the zero air stream. Calibration mole fractions were ~10 to 20 ppb for each VOC present in the standard. m/z71 was calibrated using methacrolein, m/z107 using m-xylene, m/z121 using 1,3,5-trimethylbenzne and m/z137 using alpha-pinene Accuracy of standard: +-5% Issues: There are data gaps due to ion source issues (up to 29-Dec-2013), then due to excessive heat in the building housing the instrument (6/7-Jan-2013 and 18/19-Jan-2013). Between 29-Dec-2012 and 18-Jan-2013, the dwell time for m/z 55-190 was mistakenly set to 100 millisecond instead of 1 second Corrections: formaldehyde counts = (m/z 31 - 0.9* m/z49) (Inomata et al 2008), benzene counts = (m/z79 - 0.05*m/z61) (Baasandorj et al 2015) Uncertainty: +-15% Detection Limits : Detection limits varied over the campaign, mostly due to varying instrument conditions (e.g. ion source voltage and dwell time). These are summarised in table below. Dates formaldehyde (ppb) methanol (ppb) acetonitrile (ppb) acetaldehyde (ppb) acetone (ppb) isoprene (ppb) sum of methacrolein and methyl vinyl ketone (ppb) benzene (ppb) toluene (ppb) sum of C8H10 (ppb) sum of C9H12 (ppb) sum of monoterpenes (ppb) 21-Dec-2012 - 29-Dec-2012 0.205 0.050 0.002 0.018 0.010 0.003 0.004 0.010 0.005 0.003 0.003 0.007 29-Dec-2012 - 18-Jan-2013 0.105 0.033 0.001 0.007 0.013 0.005 0.005 0.012 0.008 0.016 0.013 0.016 19-Jan-2013 - 15-Feb-2013 0.186 0.062 0.002 0.012 0.007 0.003 0.002 0.007 0.002 0.009 0.006 0.007 Number of hourly measurements 1027 1027 1027 1027 1027 1029 1027 1029 1029 1029 1029 1029 Number of measurements