TEDLAR is generally inert, but n my opinion ozone(highly reactive gas) should be determined on site - directly, whitout any "storage" of the gas.

regards

G

Dear Grzegorz,

Yes my idea is same. But, if we can show it with experimentAl data, It is good.

Piyal

Dear Piyal,

I don't think that Tedlar bags are more inert than glass, but even in the cleanest glass environments you will have a measurable ozone decay. One factor might be ozone photolysis due to visible light if the bag is kept at daylight.

Under optimum conditions (see doi:10.1063/1.3557512, for example), we get decay rates of 2e-3 per hour using Pyrex and teflon components only. One way to preserve ozone in bags could be to keep them in LN2. At these temperatures ozone condenses and can be stored for very long time scales.

In any case I agree with Grzegorz that ozone should be measured in situ.

Christof

Dear Christof Janssen,

thank you for explanation. if you could provide more research data, It is highly appreciateed.

PIyal Aravinna

Dear Piyal Aravinna

No problem:

1. If you use a bag that is transparent, you have (at least the visible) solar spectrum that penetrates. Ndengué et al. (2014), doi:10.1002/2013JD020033 (but you can find this also in many textbooks on atmospheric chemsitry) give graphical representations on Figs. 3 to 5, showing that most of ozone photodissociation on the Earth's ground is due to solar photons in the visible range (Chappuis band) and that the ozone molecule survives on the time scales of about 5h. Note that the loss of ozone is actually twice as fast as that number, because O liberated in the photodissociation then reacts with ozone to convert it into O2. So one single photon destroys two ozone molecules.

2. If you are interested in ozone life times in passivated reactors, I can give you two of our papers. In Janssen et al (2010), doi:10.1063/1.3557512 we have observed a decomposition rate of 0.4%/h in a dark all glass-teflon cell (life time of ~ 250 h) and in a multi-pass absorption cell made from a glass tube and gold coated metal parts a life time of 33 h (in the dark) has been achieved (Janssen & Tuzson (2005), doi:10.1007/s00340-005-2044-6).

Hope this helps.

Christof Janssen

Dear Christof Janssen,

Thank you for your dedicated Answer. I will go through them.

Piyal

DEAR COLLEAGUE,

TEDLAR BAGS ARE WIDELY USED FOR GAS SAMPLING BECAUSE THEY ARE STRONG AND DURABLE AND ABOVE ALL, THEY ARE CHEMICALLY INERT OR UNREACTIVE TO A WIDE RANGE OF SUBSTANCES. I AGREE WITH YOU THAT IF EXPOSED TO LIGHT, IT MAY UNDERGO PHOTOLYSIS.

Dear Ini Udosen Ubong,

Do you recommend It for O3 ?

Thank you

Piyal Aravinna