its actually glycerine with only a tad bit of water and food grade flavoring(s) such as you can buy at a grocery or specialty store.
They use all of one of these or a combination (usually combo) propylene glycol or vegetable glycerin - PG is used in fog machines and hospital air cleaning systems, while VG is used in countless foods you eat everyday and you can simple drink it if you were so inclined with no hard.
i would ask your Dr. unless someone here can chime in and tell you they have not had any issues.
I fear inhaling a burnt/vaporized food flavoring more than i do the nic. or PG/VG. funny given the nic. is by far the worst, from what we know medically today.
also what you exhale is far from a vapor like you would see come from a cold or hot water humidifier or other vapor producing device.
it will linger in your house for 10's of minutes. though it is not as visible as cigarette smoke. with the sun shining in the windows you can clearly see smoke hovering in the air.
(that statement above is not FACT it is only my experience)
i have yet to have a Dr. tell me e-cigs were bad, they say that the only bad thing they are aware of is the nic.
but to be honest inhaling anything into our lungs aside from what mother nature provided us isnt good. but this is sure a heck of alot better than cig's.
here is a snippet, albeit i have not confirmed it's validity, from an article about ecig's
i think the pneumonia incident is limited, or the woman may have been prone to such things or allergic to the PG and/or VG.
which is the other spect, some people are alergic to PG, but i have not read about reactions such as pneumonia.
But now doctors have raised concerns about e-cigarette vapor separate from those about nicotine. A 42-year-old woman who had used e-cigarettes for seven months experienced shortness of breath, cough, and fever over the same period. The diagnosis was lipoid pneumonia—a chronic inflammation caused by fatty substances (lipids) in the lungs—due to e-cigarette use. The specific cause was repeated exposure to glycerin-based oils found in e-cigarette nicotine vapor. The patient’s symptoms improved after she stopped using e-cigarettes.1
A recent study also found that using an e-cigarette for five minutes began to restrict lung function. It was not clear which e-cigarette ingredient or combination of substances caused these reactions. However, other studies have shown that propylene glycol, the source of the e-cigarettes’ visible vapor, can bring on respiratory irritation and increase the chance of developing asthma.2
to be very frank with you, if you have COPD then i would suggest simply finding another addiction that doesnt involve your lungs.
your life is in your hands.... not a Dr's so you have the choice.
you can try it and find out, or simply decide not to risk it.