What the blazes do you want? The selection of questions this morning seems to be the poorest in many days.

Yours is among the least inspiring, but, it is more than three words.

Since it's an exhaust stack with no additional air intake to dilute it , the gas composition and concentration will be the same throughout , regardless of where you sample it from .

As for using a portable meter , as long as it can detect all the different gases you wish to detect in the correct range, why not ?

Thank u Mr. Dvader. I got so many discussion at worksite regarding this question. Some people are just they argument blindly. Practically i observed and i proved also. even the people are not accepting. Thank u so much for ur advise.

DVader1000,

I would disagree:

As the exhaust gases cool in the stack, I believe that some constituent chemicals could very easily undergo chemical reactions (e.g., varying NOX species concentrations, interaction of S and C with CO, CO2 & O2, etc.), as well as undergoing physical change due to drop in temperature (i.e., condensation).

In fact, in order to perform regulatory compliant emissions monitoring, depending upon the actual stack sample point, one must collect the sample via temperature-controlled heated sampling "hose" to control for these effects...

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Just my $0.02...

There are several factors which can change concentrations of the various compounds at different points in the stack if there is a large temperature difference in the stack. If the gas is very hot when it enters the stack, but reaches near ambient temperatures at the top, condensation and other reactions can occur. In the case of high water content, water will be in the gas phase as it enters, but will condense as it rises. It may then "rain" down inside the stack, which can dissolve the water soluble compounds. Thus, the concentrations of these compounds would have a higher concentration at the bottom of he stack than at the top.

Compounds such as ammonia and SO2 may exist as separate compounds at high temperatures, but will combine to form compounds such as ammonium sulfate at lower temperatures. There are other reactions that can take place as well, depending on the residence time in the stack.

For reaction between SO2 and ammonia to become a Ammonium sulfate, the oxygen influence is very much. The reaction rate is related with % of oxygen and Temperature levels. I think Temp should be around 40-60 degc. I dont think that heaters stack gases contains more oxygen. At high oxygen levels the ammonium sulfate deposits will be formed.