Context :

Aims : To increase the observational samples of star formation around expanding H ii  regions , we analyzed the interstellar medium and star formation around N22 .

Methods : We used data extracted from the seven large-scale surveys from infrared to radio wavelengths .
In addition we used the JCMT James Clerk Maxwell Telescope   http : //www.jach.hawaii.edu/JCMT/ observations of the J = 3-2 line of ^ { 12 } CO emission data released on CADC The Canadian Astronomy Data Centre   http : //www3.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/ and the ^ { 12 } CO J = 2-1 and J = 3-2 lines observed by the KOSMA KOSMA   http : //www.astro.uni-koeln.de/kosma/ 3 m telescope .
We performed a multiwavelength study of bubble N22 .

Results : A molecular shell composed of several clumps agrees very well with the border of N22 , suggesting that its expansion is collecting the surrounding material .
The high integrated ^ { 12 } CO line intensity ratio R _ { I _ { { CO ( 3 - 2 ) } } / I _ { { CO ( 2 - 1 ) } } } ( ranging from 0.7 to 1.14 ) implies that shocks have driven into the molecular clouds .
We identify eleven possible O-type stars inside the H ii  region , five of which are located in projection inside the cavity of the 20 cm radio continuum emission and are probably the exciting-star candidates of N22 .
Twenty-nine YSOs ( young stellar objects ) are distributed close to the dense cores of N22 .
We conclude that star formation is indeed active around N22 ; the formation of most of YSOs may have been triggered by the expanding of the H ii  region .
After comparing the dynamical age of N22 and the fragmentation time of the molecular shell , we suggest that radiation-driven compression of pre-existing dense clumps may be ongoing .

Conclusions :