"ACE 1, Leg 1, PMEL 7-stage impactor data collected onboard the Discoverer." This is the text descriptor file for data contained in the file PMEL7_L1.csv. This data is PRELIMINARY. It should not be used without first contacting Trish Quinn (quinn@pmel.noaa.gov). Columns in the spreadsheet are: "1, sample number" "2,start time, GMT" "3, stop time, GMT" "4, start latitude" "5, stop latitude" "6,start longitude" "7, stop longitude" "8, average RH of the sampled air stream" "9, standard deviation of the RH of the sampled air stream" "10,volume of sample, m3 of air" "11,ion concentration in ng/m3 for Dp,1" "12, ion concentration in ng/m3 for Dp,2" "13, ion concentration in ng/m3 for Dp,3" "14, ion concentration in ng/m3 for Dp,4" "15, ion concentration in ng/m3 for Dp,5" "16, ion concentration in ng/m3 for Dp,6" "17, ion concentration in ng/m3 for Dp,7" Aerodynamic mean diameter (um) and dlogDp for each stage: These diameters are reported at the relative humidity of the sampled air stream. (These diameters are given for a flow rate of 23 lpm and are subject to change after calibration of the collection efficiency of each jet plate. This calibration is planned for the Fall of 1996). stage "mean D,aero" dlogDp 1 0.151 0.553 2 0.34 0.15 3 0.53 0.236 4 0.944 0.264 5 1.76 0.277 6 3.16 0.233 7 6.43 0.383 Codes used in the file: "M_Na_BB, Na concentration is below the blank value (< 210 ng / sample volume (m3))." "M_NH4_BB, NH4 concentration is below the blank value (< 20 ng / sample volume (m3))." "M_K_BB, K concentration is below the blank value (< 43 ng / sample volume (m3))." "M_Mg_BB, Mg concentration is below the blank value (< 41 ng / sample volume (m3))." "M_Ca_BB, Ca concentration is below the blank value (< 970 ng / sample volume (m3))." "M_Cl_BB, Cl concentration is below the blank value (< 450 ng / sample volume (m3))." "M_Br_BB, Br concentration is below the detection limit (< 8 ng / sample volume (m3))." "M_NO3_BB, NO3 concentration is below the blank value (< 11 ng / sample volume (m3))." "M_SO4_BB, SO4 concentration is below the blank value (< 140 ng / sample volume (m3))." "M_MSA_BDL, MSA concentration is below the detection limit (< 0.6 ng / sample volume (m3))." "T_Na_BB, Na concentration is below the blank value (< 350 ng / sample volume (m3))." "T_NH4_BB, NH4 concentration is below the blank value (< 19 ng / sample volume (m3))." "T_K_BB, K concentration is below the blank value (< 105 ng / sample volume (m3))." "T_Mg_BB, Mg concentration is below the blank value (< 88 ng / sample volume (m3))." "T_Ca_BB, Ca concentration is below the blank value (< 2700 ng / sample volume (m3))." "T_Cl_BB, Cl concentration is below the blank value (< 580 ng / sample volume (m3))." "T_Br_BB, Br concentration is below the detection limit (< 30 ng / sample volume (m3))." "T_NO3_BB, NO3 concentration is below the blank value (< 88 ng / sample volume (m3))." "T_SO4_BB, SO4 concentration is below the blank value (< 190 ng / sample volume (m3))." "M_MSA_BDL, MSA concentration is below the detection limit (< 0.6 ng / sample volume (m3))." "T_MSA_BDL, MSA concentration is below the detection limit (< 0.6 ng / sample volume (m3))."