1. Research Questions How is the chemical composition* of the aerosol burden in Northern Europe modulated? –What are the chemical properties of the burden during high pollution events? –What is the vertical distribution of the aerosol chemical composition? What role does chemical composition play in the resultant impacts of the aerosol burden? Can we represent the observed spatial distribution using a sophisticated regional model treatment? –Focus upon ammonium nitrate *Chemical composition = stuff that is measurable with an AMS

2. A quick advert… Examine 41 flights based out of the UK –Thats £1,025,000 just for the flying! Represents air masses from NW Europe and NE Atlantic Period covers 05/04/05 to 27/09/2006 Focus upon profiles from the Q-AMS (Quadrupole Aerosol Mass Spectrometer) Compare with surface measurements at Harwell How does meteorology impact the aerosol burden and its composition? Vertical Distribution of Sub-micron Aerosol Chemical Composition from North-Western Europe and the North-East Atlantic. Morgan et al., 2009, ACPD submitted. *SLR: Straight & Level Run

3. Full dataset Crosses are individual data points (grey are those below the detection limit). Red lines are 25 th, 50 th and 75 th percentiles for 500m altitude bins. Right panel shows mean and error about the mean.

4. Atlantic vs Easterley Atlantic Easterley

5. Positive Matrix Factorisation (PMF) Typically Resolved Organic Components: HOA: Hydrocarbon-like Organic Aerosol OOA-1: Aged Oxygenated Organic Aerosol – characteristic of background/rural mass spectra OOA-2: Fresher Oxygenated Organic Aerosol HOA is analogous to Primary Organic Aerosol (POA). OOA is considered to be representative of Secondary Organic Aerosol (SOA).

6. HOA versus primary markers (a) Allan 2004 – Urban Manchester; (b) Kirchstetter et al., 1999 – Tunnel Study (Diesel Trucks); (c) Kirchstetter et al., 1999 – Tunnel Study (Light Duty Vechiles)

7. Regional scale dominated by OOA

8. Continental Europe Example B366 – 8 th May 2008 Pollution episode dominated by nitrate and OOA-2 (r=0.81)

9. Complex Vertical Structure Crosses are mean concentration and bars are standard deviation. Cabauw inlet situated at 60m. Radiosonde launched from Cabauw at 16:04.

10. Complex Vertical structure No PMF information from Cabauw yet Partitioning is biased towards the particle phase at lower temperature and increased relative humidity

11. Aging of organic aerosol Relationship between OOA-2 and nitrate is influenced by OOA-1 organic mass fraction

12. So what does it all do? Large increases in mass driven strongly by nitrate – major driver of scattering intensity

13. What about the indirect effect? CCN data is not yet finalised but could be interesting…

14. Comparison of CMAQ-MADRID Predictions & AMS Measurements Measurements along track of aircraft between 11:30 and 12:30

15. Paper Plans 1.Aging and partitioning of atmospheric aerosol: Aircraft measurements across Northern Europe –Evolution of OOA component from fresh to aged –Partitioning of nitrate and organic matter –Focus upon high pressure period during LONGREx –Compare with April and September ADIENT flying 2.Measurement and modelling of ammonium nitrate aerosol in Northern Europe and its resultant impacts –Spatial gradients during high pressure phase of LONGREx –Broad range of pollution levels during ADIENT –Particular focus upon the vertical distribution in light of partitioning –Also compare extinction and aerosol optical depth with in-situ and remote sensing data?