Continuous Speciation Monitors for Particulate Matter and Gases

1. Continuous Speciation Monitors for Particulate Matter and Gases Purnendu K. (Sandy) Dasgupta Texas Tech University William A. McClenny, USEPA-NERL

2. Texas Tech Gas Particle Analysis System As Deployed In Tampa, FL 2003

3. Reduced substantially in size by 2004

4. 95 mm 76 mm

6. Tampa 2003

7. A Continuous Analyzer for Soluble Anionic Constituents and Ammonium in Atmospheric Particulate Matter R. Al-Horr, G. Samanta and P. K. Dasgupta Environmental Science and Technology 2003, 37,5711-5720

8. To get meaningful results for sticky gases like HNO3, must operate a separate denuder without cyclone or other inlet

9. Limits of Detection 15 min time resolution, 5 L/min Ammonia/Ammonium 5-8 ng/m3 Strong acid gases HCl, HNO3, SO2, etc 0.1-1 ng/m3 Particulate Cl- SO42- NO3- Ox2- 0.1-1 ng/m3

11. The correlation between the Pulsed Fluorescence and present instrument is excellent (r2 0.985) 9,416 data points over >1 month, no rejected datum. Sulfur Dioxide Comparison

13. Measured data from collocated ammonia monitoring instruments. Top Panel: Photoacoustic instrument – Line-switched CO2 laser (Nitrolux™-200 by Pranalytica, Inc.) 30 s average. Bottom Panel: Ion chromatograph (Texas Tech University) 15 min average.

15. Case Study: Why is HCl Concentration so much higher in Tampa compared to larger, denser, more heavily industrialized cities? Why is HNO3 concentration lower, especially when some power plants in Tampa has been fined for excess NOx emissions???

17. Clues: While sulfate is almost completely in the fine particle fraction (less than 1 µm) nitrate and chloride are both in the large particle fraction, peaking about 4 µm in diameter and closely following each other and sodium in size distribution Nitrate is formed at the expense of chloride and HCl is being released Salt has gone to Peter? NaCl + HNO3 NaNO3 + HCl ? Main Entry: salt·pe·terPronunciation: 'solt-'pE-t&rFunction: nounEtymology: Middle English salt petre, alteration of salpetre, from Middle French, from Medieval Latin sal petrae, literally, salt of the rockDate: 14th century1: POTASSIUM NITRATE2: SODIUM NITRATE

18. HCl(g) = (a+b HNO3(g))/(1+(exp(c/T –d)/(f – g (RH))) Henry’s Law temp dependence term Aerosol liquid water content term Constant Production term Nitric acid generated term

19. Blue is modeled Orange is measured Missing areas in blue indicate necessary data is missing

26. Pilot Dionex GPIC Instruments vs R&P 8400N – EPA-NERL, McClenny and Long

27. However, lab testing of the 8400N instrument also showed that the Nitrate-NO conversion efficiency decreases at high nitrate, high water conditions using synthetic standards

28. The Instruments tracked each other OK, but…. GPIC

29. But overall there was a large bias at high nitrate concns

30. Really New Directions????????

31. Hatsis and Lucy, Analyst, 2002

32. Kuban and Dasgupta: Open tubular IC

33. It is not only smaller, the flow path is membrane enclosed No leakage into air path, permits a syringe pump The present parallel plate denuder is attitude-sensitive (just like my teenager) None of the present wet denuders can fly because of attitude problems Hmmm, denuders have fear of flying too! Would like to get to a situation where syringe pumps can be used. No more pump tube changing.. Much smaller system footprint Takeuchi, Anal Chem 2004

34. In the Making, TTU

35. Wavelength Discriminated Size DiscriminatedAethalometer