Limonene 50ppb onBeta-Caryo SOA

25.06.2008

Lights on at 10:11

20 min of lights

AMS is measuring much more than the DMPS at this stage

37ugm-3

178ugm-3

Less than 2 hours of lightnumber and mass passed their peaks

• The PTRMS is showing that the beta-caryo has already been consumed.. This is much faster than what was suggested from the Nov campaign results.

• O3 formation is a good indicator for beta-caryo consumption.. It really works

An update (2.5h of lights)..

• Number and mass peaked

• PTRMS: no more beta-caryo left

• O3 is forming (6ppb now)

• NO is coming down (5ppb now) and NO2 is increasing (22ppb now)

• Waiting for the rest of the NO to be converted to NO2 before starting dilution and limonene injection

It appears like a second mode is coming in… no effect on the number though!

• After 3 hours of light, stopped the exp and flushed most of the bag onto a filter

• Injected Limonene and diluted the bag

• Injected more NO2 to get to 25ppb NOx but ended up with more than needed (47ppb) due to incomplete fill of the bag (mass came down to target)!

Limonene 50ppb onto B-caryo SOA

Mode and mass increased while cpc saw no nucleation…

Nucleation started at ~ 14:15

• AMS and DMPS are now in fairly good agreement while when measuring beta-caryo SOA alone the AMS was around a factor of 3 higher!! Could the DMPS be loosing too much beta-caryo mass because of volatility??

Dilution followed by fresh SOA formation

Particles are getting really big now

New fresh mode is growing

Nucleation stopped and mass still increasing

DMPS is seeing more mass than the AMS now!!! See next slide

And the AMS is seeing two modes

Mass has peaked (~2 hours of lights)

Almost 4 hours of lights (second phase)

Lights off 17:39