Measurements of reactive nitrogen compounds in GAW status and further needs

Transcription

1 Measurements of reactive nitrogen compounds in GAW status and further needs Stefan Gilge, Christian Plass Duelmer, Wolfgang Fricke 1

2 Outline: Introduction / Definitions Motivation / Examples for use of nitrogen oxide data Data Availability Measurement Techniques Present status Future Needs 2

3 Short Definition: NO x NO y NO z 3

4 Motives for Nitrogen Oxides Measurement Motivation for Nitrogen Oxides Measurement scientific political tropospheric ozone production impact on oxidation capacity of troposphere control of NOx emission reduction (prescriptive ( limit values limits) ) ozone mitigation strategies model validation gas to particle conversion NOx as tracer (key component) for anthropogenic emission acidification eutrophication human health acid rain formation quantification of potential background concentrations for evaluation of prescriptive limit values limits 4

5 Examples for use of NOx data (I) 300 NO 2 : relative deviations from the mean annual variation Ähtäri Burgas Fundata Hohe Warte MOHp Jarczew Jungf raujoch NO2 rel. deviation [%] Kamenicki Vis Kosetice K puszta Leba Oulanka Plovdiv Pleven Rucava Sniezka Sof ia Schauinsland Uto Virolahti Varna Zabljak 0 0 Zoseni mean all stat. median all stat. 5

6 Examples for use of NOx data (II) Model Validation: To improve model calculations, a full data set... of related trace gases must be compared. NOx data are essential to improve ozone...prediction models. Source: GEMS, Flentje, privat comm. 6

7 Examples for use of NOx data (III) Influence on the tropospheric oxidation capacity OH/j(O1D), 1/cm³/s 6.E+11 5.E+11 4.E+11 3.E+11 2.E+11 1.E+11 0.E NOx, ppb OH optimum at 1 2 ppb NOx Annual variation of NO 2 at MOHp Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan chemical regime at MOHp optimum for self cleaning NO2 [ppb] 7

8 Data availability : (at WDCGG) NO: NO 2 : NO y : 8

9 Nitrogen Oxides Measurement Techniques passive active remote sensing integrating integrating in situ column density profile impregnated filter, ion chromat. Saltzman Sodium..Iodide O 3 CLD (PLC/BLC) O 3 CLD (Mo) Luminol CLD DOAS TDLAS cavity ring down Satellite applications...(e.g. GOME) Brewer MAxDOAS weekly daily hourly 9

10 20 16 passive NO2 Passive sampling Sampling (µg/m³) NO 2 : Comparison CLD and Passive Sampling at MOHp, Jan. '00 Dec. '03 y = x R 2 = sodium NO2 (NaI) iodide [µg/m³] NO 2 Intercomparison: NaI versus PLC/CLD at MOHp y = x R 2 = NO 2 Chemiluminescence (µg/m³) chemiluminescence NO2 (PLC/CLD) [µg/m³] chemiluminescence The intercomparisons have shown good agreement between different monitors (using different standard gases) and even between different measuring techniques: NO 2 measurements are principally reliable (issues with Mo) it is possible to use existing data from different techniques (after careful QA/QC) for world wide monitoring of NO 2 free choice of monitoring method according to objectives and resources 10

11 Current Situation: some data from mostly European sites originating from different.:measuring methods, which in principle match some informal intercomparisons training courses on nitrogen oxides in GAWTEC WDCGG responsibility: SAG for Reactive Gases But no direct (Sub )SAG for nitrogen oxides no QA / SAC no DQO : no precision and accuracy or data completeness goals no SOP s no CCL / no primary standard no WCC 11

12 Citations GAW Report 172 and 143: Their (Nitrogen Oxides) measurement in the global atmosphere is..very important since NO has a large influence on both ozone and on..the hydroxyl radical. the satellite community who require extensive NO 2 measurements..for validation purposes. Nitrogen oxides play a crucial role. contribute to acid precipitation the need for knowledge of the abundance of these compounds is..unquestioned 12

13 Future needs: Appointment of a Sub SAG for Nitrogen Oxides Setup of DQO s and SOP s for nitrogen oxides (NO, NO 2, NO y ) Implementation of NO, NO 2 and NO y measurements at more GAW sites Intercomparison experiments to ensure comparability of different measurement methods (CLD, NaI, ) Implementation of CCL and WCC Implementation of PAN, HNO 3, NO 3, HNO 2 and other important NO y species at several GAW stations Details should be discussed at an upcoming workshop on NO x at Hohenpeissenberg Observatory in autumn 2009 (Interested persons please contact me!) 13

14 Thank You for Your Attention! Photo: Claudia Hinz 14