1. The Steam Jet Aerosol Collector SJAC
Harry ten Brink, Rene Otjes, Sjaak Slanina
ECN Netherlands

2. BACKGROUND Climate-effects aerosols
WHY data with temporal details and size-resolution:
· Source apportionment:
good time-resolution
Ultrafines: size-resolution
Climate-effects aerosols

3. CLIMATE EFFECTS Size is key factor Only effective when sun shines
Not at night
Conditional sampling / information

4. Why not with manual collectors
Filters and cascade-impactors
· Handling leads to contamination and thus
loss of sensitivity

5. · Loss of semi-volatiles -ammonium nitrate
-OC
Cascade-Impactors:
· Number of samples is too costly for analysis in
monitoring

6. OUR APPROACH Automated "SJAC" Steam-Jet Aerosol Collector
Steam-Jet Aerosol Collector
with on-line wet-chemical analysis of Composition
·      Steam is condensed onto aerosols
·      Large droplets form

8. Droplets are easily collected and drained to analysis
systems (use of cyclone: does not clog)
Analysis in the drain water is similar to that of manual
samples, BUT without handling
-Anions measured with Ion Chromatograph (15 min)
-Ammonium with continuous method
Interfering gases are removed with wet-denuder
(and measured): HNO3, NH3, SO2

9. EXAMPLE
Atalanta super site 1999
From start on working well (4 week period)

10. Add-on Set of impactors for size-selection Via parallel sampling lines
Set of impactors for size-selection
Via parallel sampling lines
Full cycle (including gas analysis of denuder)
takes 2 hours

11. Cannibalised MO(UD)I impactor for stages
Cut-off diameters: Compromise after pilot studies mm
1.0
0.56
0.32
0.18
0.1 mm (ultrafines) not yet possible
because of too high pressure drop

12. EXAMPLE Fully automated operation on a meteo-tower
June-August
Shown on next page is nitrate for period of 4 days
Lines show the concentrations in particles smaller than the
given size
Also the blank at that time

14. Recent extension “Organic Carbon”
(Showing versatiliy of collection in water)
“Organic Carbon”
with TOC-analyser, used for water analysis
Tested in European field intercomparison

15. Latest target
Black Carbon
As colloidal suspension

16. Coming years National climate research programme Meteo-tower Cabauw
From start: Ionic species
Planned
In a year: BC
2 years: OC

17. Remark SJAC-type monitors ask for affinity with aqueous-
phase analytical chemistry