I have been dealing with a lingering smoke odor in my room and it is driving me crazy.
The smell came from someone smoking near my window and it seems like it soaked into the air and maybe even into the furniture.
I have been keeping the window open but the smell still comes back when the room is closed for a while.
Someone told me that an air purifier can help but I am not sure if it removes odors or only dust.
I see that some purifiers use HEPA and others use activated carbon and I do not know which one is better for smoke.
I really want something that can make the room feel fresh again because the smell is annoying.
I am also worried about whether the purifier will need a lot of maintenance.
Some reviews say filters clog fast if there is smoke.
My room is not big so I want to choose the right size for the space.
I would also like something that does not make too much noise because I want to run it at night.
If anyone has used an air purifier for smoke odor please share your results.
Does it actually remove the smell or does it only help with the particles from the smoke 
I used an air purifier with activated carbon after a small kitchen fire and it helped a lot with the smoke odor. The HEPA part only handled the particles but the carbon filter absorbed the smell. At first I did not notice much difference but after running it for a full day the air felt cleaner and the strong smell faded. If you pick a purifier that has a thick carbon filter you should see better results. Just keep in mind that the carbon will fill up fast when it deals with smoke so you might have to replace it more often than usual.
From my experience air purifiers do help with smoke odor but they do not remove it completely if the smell has already settled into fabrics. I had smoke come in from a neighbor and the purifier reduced the smell in the air but the curtains still held some of it. Once I washed the curtains the purifier kept the room fresh. So it works but it works best when combined with cleaning the items that absorbed the odor.
I will wash the fabrics too
I used a basic HEPA unit once and it did nothing for the smoke odor because it had no carbon filter. So make sure you do not get a HEPA only purifier. Smoke odor molecules are too small for HEPA to catch. You need carbon because carbon absorbs those odors. Once I switched to a purifier with a proper carbon layer the smell was far less noticeable. It took a few hours to see the difference but it definitely worked better.
When wildfires happened in my area last year the air purifier was a lifesaver. It removed a lot of the haze and reduced the strong smell that got inside. I still had to wipe some surfaces because smoke settles on everything. The purifier removed the floating odor but not the settled smell. Still it made the air easier to breathe and the room felt lighter. Carbon filters are the key for anything odor related.
I have used one mainly for cigarette smell from guests. It did not remove everything right away but it reduced the harshness of the odor by a lot. After a few hours it made the room much more comfortable. You should also ventilate when you can because purification and airflow work better together. The purifier alone helps but ventilation speeds up the process.
I think air purifiers work well for fresh smoke but old smoke odor that has been in a room for a long time is harder to remove. I tried using one in an old apartment that smelled like smoke from previous tenants. It helped the air feel cleaner but the furniture still smelled. I had to deep clean the place for the best result. So air purifiers help with the air but not with soaked in smells.
That explains why my furniture still smells
I used one that had both carbon and a special smoke mode. It pulled in the smoke smell quickly and reduced it within an hour. The filter turned dark fast which showed how much it caught. It works pretty well if you get a strong model. The cheaper ones do not have enough carbon to handle heavy odors. So look for something with a thick carbon layer if smoke is your main concern.
If you want it to work at night make sure to check the noise level. Some purifiers get loud when running at high speed and smoke mode usually uses high airflow. Mine has a night setting and during that mode the odor removal slows down but the noise becomes soft. I run it on high for an hour then switch to night mode and that works well for me 
I had a similar issue with smoke drifting into my room. The purifier helped reduce the smell but I still had to seal the window gaps to stop new smoke from coming in. If the source keeps entering the room the purifier will be fighting nonstop. Once I fixed the window and ran the purifier for a few hours the smell almost disappeared. So the purifier works best when you block the source.
I will check the window gaps
I used a purifier after someone smoked in my car and the results were decent. It removed the floating smell but the seats still held the odor. I think smoke is tricky because it sticks to surfaces so the purifier helps the air but not the surface smell. Still it made the car breathable again. If you combine it with cleaning the room you will see better results.
In my living room the purifier removed the heavy smell from cigar smoke within a few hours. The room felt fresher and the air was lighter. It did not fix everything but it made a strong difference. I think you will notice improvement if you pick a purifier built specifically for smoke. They usually mention carbon filters and odor control clearly on the box. That is the type you need.