Bleach takes around 1 to 2 hours to dissipate depending on the size of the room and how much bleach you've used.
The less bleach you used and the larger the room the less time it will take for the bleach to dissipate and the more bleach you used and the smaller the room or even in a large room the bleach can take longer to dissipate.
Most bleach fumes though dissipate within 2 hours.
To ventilate a room after cleaning with bleach open all windows and doors and allow the bleach fumes to escape.
Using a fan or a couple of fans to help pull fresh air into the room and push the bleach fumes out of the room can also help to get rid of the bleach smell in the room.
You do need to ventilate when cleaning with bleach as the bleach fumes are toxic and can cause irritation to the throat, nose, eyes and even cause breathing issues so it's best to ventilate the room during and after cleaning with bleach.
The best way to get rid of bleach fumes is to open up windows and doors and create cross ventilation and even using a fan pointed towards a door or set in a window to draw the bleach fumes out can help get rid of bleach fumes.
After using bleach a room should be allowed to air out for at least 2 hours although sometimes 1 hour is enough.
If you can it's a good idea to open windows during the use of bleach when cleaning to allow the bleach fumes to escape during the cleaning process.
The smell of bleach can linger for several days in a room that is closed off with no airflow.
The simplest thing you can do to get rid of the smell of bleach is to open a window to allow in fresh air and let odorous fumes of the bleach escape.
Even better, create cross ventilation when using bleach or airing out a room after bleach by opening multiple windows.
If the strong odor of bleach remains after a few hours of ventilation, use a fan to push air out.
Bleach fumes can make you sick and so I always make sure to open a window at least when cleaning with bleach if I'm using more than just a little bleach.
If you do start to feel sick from the bleach fumes you should get outside and breathe in some fresh air and doing so can help you recover from the bleach fumes.
When chlorine in the bleach comes into contact with moist tissues such as the nose, eyes, throat, and lungs, it forms an acid (hydrochloric acid) and can damage the tissues.
Long-term (chronic) effects and long-term exposure to low levels of chlorine gas could cause permanent lung disease such as bronchitis and shortness of breath.
Bleach burns may take up to two weeks to fully heal.
During this period, your burn may blister.
Don't pop blisters if they form; these blisters protect delicate tissue and popping them may lead to infections.
Instead, leave the blister alone.
Bleach left behind on surfaces after cleaning, even when dried, can still be toxic.