Methods for long term NOxy measurements at CARE (Egbert) station. Jan W Bottenheim Environment Canada

Transcription

1 Methods for long term NOxy measurements at CARE (Egbert) station Jan W Bottenheim Environment Canada

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3 Reactive Nitrogen Measurements 3 sites acquiring continuous measurements of NO, NO 2, NO y TEI 42 CTL-Y trace level chemiluminescence analysers (Molybdenum and photolytic converters) Egbert, Ontario 2 sites measuring Peroxyacetic nitric anhydride (PAN) PAN measurements by direct sample loop injection into a home built Gas Chromatograph equipped with a pulse discharge detector (GC/PDD) Page 3

4 Reactive Nitrogen Measurements Molybdenum Converter Cal. valve Ambient air Filter Filter NO/NO y Analyzer By-pass flow NO 2 Converter NO/NO c Analyzer Egbert, Ontario Calibrator NO Cal. gas NO NIST Ref. pump Zero air Generator PAN synthesis scrubber By-pass flow pump Compressor Datalogger/ Controller Computer scrubber Ambient air Filter PAN GC Data Acquisition System gases He and Xe/He Gas purifiers Page 4 pump

5 Automated Calibration Sequence Concentration, ppb :00 8:30 9:00 9:30 10:00 Time NO#1 NOc#1 NO#2 NOy#2 Ambient High Low Mid Titration Zero Ambient

6 Reactive Nitrogen Measurements Calibration NO/NO 2 /NO y - Automated calibration every 25 hours - Egbert, Ontario High, Low and Mid Spans, O 3 titration and zero Automated PAN Calibration performed several times daily using photochemically generated PAN standards. NIST reference of gas cylinders every 3 months Page 6

7 Reactive Nitrogen Measurements Data Analysis Determination of calibration factors and converter Egbert, Ontario efficiencies for each calibration QA/QC of preliminary calibration results Calibration data bracketed and applied to raw measurements Nighttime ambient zero can be used in calculations as NO free air very hard to synthesize and this is important in remote locations Page 7

8 100% Egbert NO y Distribution % of Total Individually Measured NOy Species 80% 60% 40% 20% 0% Jan- 04 Jul- 04 Jan- 05 Jul- 05 Jan- 06 Jul- 06 Jan- 07 Jul- 07 p-no3- HNO3 PAN NO2 NO Date Page 8

9 Measurements at the Centre for Atmospheric Research Experiments (CARE), Ontario, Canada preliminary results 8 7 Average Concentration, ppb NO NO 2 NO z NO y Year Measurements at Kejimkujik National Park, Nova Scotia, Canada preliminary results Average Concentration, ppb NO NO 2 NO z NO y Year

10 100% 80% 60% 40% 20% 0% Kejimkujik National Park, NS Egbert, Ontario Page 10 p-no3- HNO3 PAN NO2 NO Jan-03 Feb-03 Mar-03 Apr-03 May-03 Jun-03 Jul-03 Aug-03 Sep-03 Oct-03 Nov-03 Dec-03

11 Kejimkujik National Park, NS 10 Egbert, Ontario Concentration, ppb NO#1 NO#2 NOy NO2 PAN 0.01 Jul-02 Jan-03 Jul-03 Jan-04 Jul-04 Page 11

12 Reactive Nitrogen Measurements Egbert, Ontario Page 12 Egbert Keji Jan-03 Feb-03 Mar-03 Apr-03 May-03 Jun-03 Jul-03 Aug-03 Sep-03 Oct-03 Nov-03 NOy "Deficit" (%) Dec-03 The NOy Deficit

13 NOy HNO 3 HNO 3 + N 2 O 5 + wallco 2-3 wallno - 3 Sodium carbonate denuder (Co 3 2- ) Mo converter at 325 ºC NOy HNO 3 NO V2 Bypass ~ ~ V3 NOy NOy, N 2 /O 2 Mo converter at 325 ºC NOy NO NO analyzer Building

14 Correlation for HNO3 measurements on Saturna Isoland, Slope=1.05, Intercept =0.19 R2= HNO3Teco (ppb) HNO3 Denuder (ppb)

15 HNO3 at Egbert, June 17-July 14, HNO3 CAPMoN NOy-NO2-NO-PAN [HNO3], [NOy]-[NO]-[NO2]-[PAN] (ppbv)

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17 Ammonia Measurements Sample Head F.P. NO y Conv. 325 C Electrica l wiring F.P. NH 3 Conv. 750 C All electrical lin es to sampl e h ead Egbert, Ontario Electrical Housing Power Supply Temperature Controllers Calibration Valve Control F.P. Cal. Valve By-pass flow system Datalogger Ambient in Weather Shield Calibration source (NO) from existing Nitrogen system Aux.NO y Conv. 325 C 42CTL Raw Data Signals Computer Calibration source NH 3 permeation or NH 3 gas system Network cable for Remote control via PC Anywhere RS232 connected to existing Nitrogen network Page 17

18 Ammonia Measurements Converter Efficiency vs. Temp. 20 conc. ppb (std. 15 ppb) Egbert, Ontario Temp (C) -NH 3 converter efficiency close to 100% at 750 C Page 18

19 Ammonia Measurements Comparison to the Univ. of Toronto QC-TILDAS Egbert, Ontario /05/10 12: /05/11 0: /05/11 12: /05/12 0: /05/12 12: /05/13 0:00 Page 19

20 Ammonia Measurements Seasonal Variations in Ambient Ammonia Measured using a Developed Continuous NH 3 Analyzer at CARE (Preliminary Results) [NH 3 ], ppb 3 2 kjh kh kjh Average Am 1 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Page 20

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