Different people suggesting different means against mold here, but in the end, you have to find the root of the problem and eliminate it. Otherwise, you are fighting symptoms.

1. Air filters might reduce the airborne spores, but if you have mold already growing behind some wardrobe you are wasting time.

2. Hydrogen peroxide, chloride, and isopropyl alcohol are all good tools to fight it when you find a place where it grows, but ultimately you have to solve the problem at a deeper level as mold has excellent survival skills (you might clean the wall but the spores in the air infect it again right afterward).

3. In order to eliminate mold, you have to change the environmental conditions. As most living organisms mold requires food and water. The water comes either from inside the wall (that is something only your landlord can fix) or from the air. So try to maintain a low humidity level within your apartment (<50% should be okay). The easiest way to achieve that is by using your heating and replacing all air within your apartment by opening all windows for 5 minutes (to let in cold air, no longer, as it will cool down the temperature of the wall otherwise), three times a day. Mold nourishes itself from organic material. Very often that means fabric, wood or wallpapers (yes removing your wallpaper might be a good idea). Since water condenses in cold spots first, those are the place you want to keep looking for (walls next to windows, corners of a room).

Three years ago I had a mold problem in my apartment. Following the above advice, the mold didn't come back (except for a few spots in the shower, but that is kinda difficult to keep dry).

I lived in a small studio in a damp part of SF and we discovered mold growing behind a beureu, I had cold like symptoms for months before which I think was related to a mold allergy. We moved all furniture away from wall, cleaned with mix of bleach and water then invested in a $200 Frigidaire 50 pint dehumidifier (like this one Frigidaire FAD504DWD Energy Star 50-pint Dehumidifier https://www.amazon.com/dp/B00AU7GYXA/ref=cm_sw_r_cp_apa_n8i7...) and it solved the problem for us. It would pull a gallon or more of water out of the air everyday. I tried some smaller/cheaper dehumidifiers but they really didn't compare.

Or a cleaning solution with chloride.

I've heard that vinegar is better for mould, as it leaves the surface rather more "acidy" than aseptic, as chloride does.

In my experience a one-two punch with chloride to kill the mold quickly, followed by a dousing with distilled white vinegar, results in a good short and long term solution for surface mold.

Safety advice: If you decide to try this at home, please keep in mind that mixing chloride based cleaning agents with an acid will release chlorine, which is toxic enough to have been used as a WW1 weapon.

Or similarly toxic chloramine gas, when combined with cleaning agents containing ammonia, such as Mr. Clean.

Chloramine is responsible for the classic "swimming pool smell", as the chlorination in the pool reacts with urine, sweat, and other nitrogen-containing organics. Chloramine is a less effective disinfectant than free chlorine, and more irritating to swimmers, and diffuses out of the water more slowly, so this is why you shouldn't pee in the pool, and why you should rinse off in a shower for a minute before entering. Mainly, just don't pee in the pool.

If you smell "swimming pool" where no pool exists, it might be prudent to leave the area immediately and take a 1000 mg vitamin C tablet, before making any attempts to discover the source of the smell. (Taking vitamin C after the damage is already done won't help.) If the odor is especially strong, or if it causes any irritation to your nose and eyes, evacuate, and do not return. Call your emergency services number and tell them you smelled a strong chlorine odor.

Don't combine bleach cleaners with ammonia cleaners, ever. Don't even store them in the same place. Also avoid mixing bleach with acids, such as vinegar.

My bathtub in my apartment would smell like that after using Tilex. I don't pee in the tub either, so I guess it can only be from sweat.

Chlorine can react with about anything that contains ammonia or amines to form chloramine, so shampoos, lotions, shaving foams, or conditioners could also be responsible. Amino acids are named thus for their amine groups, so anything containing proteins or protein fragments will react. Amine oxides and triethanolamine are used as surfactants in cosmetics. Sweat is unlikely to be the culprit. Check the ingredients in your cosmetics.

In what way does vitamin C help in this case?

I just googled chloramine and found this:

https://en.wikipedia.org/wiki/Chloramine#Safety

I guess I didn't realize someone would try this without letting the chlorine evaporate first. I should have worded it better: Chloride to kill the mold on contact, let dry, then vinegar to keep the mold away.