Summary and product recommendation
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To remove cigarette smoke, unpleasant odours or heavily contaminated air you should use an air purifier that is powerful enough to drag all of the air in the room through the filters around 8 times an hour (ACH) for it to be genuinely effective. To get around 8 air changes per hour in your room measuring between 5 and 10 m2 you need an air purifier with a clean air delivery rate (CADR) in the range of 99-199 m3/h. CADR rating indicates how fast an air purifier can clean the air within a particular size room. It provides a way to compare air purifiers taking into account both airflow and a filter's efficiency.
To effectively remove harmful gases, smoke, unpleasant household odours and volatile organic compounds (VOC's) an air purifier should have a good quality activated carbon filter.
Activated carbon is carbon that has been chemically treated to increase the amount of oxygen it contains. It acts as an adsorbent which traps smoke and unpleasant odours inside helping you breathe a little easier.
For a bedroom or baby room, you may want to use a quieter air purifier that comes with "night" mode. Air purifiers with "night" mode run quietly in the background allowing you to enjoy clean air while you sleep.
This tool is for guidance only and does not replace professional advice on product selection.