Do you know what kinds of bad smells at your home? I guess you may know several, such as pet, kitchen and so on. Now there are some tips for your reference:
Pet odors: Many people like pets and adopt them. But they have many bad smells and bacterias, such as pet dander, pet dander is composed of skin flakes and the most common source of that pet smell, which can be hard to get rid of with traditional methods.
Car odors: Many long and short haul will transport produce, livestock and many other items that leave behind a wide range of smells might require frequent odor removal in their vehicles. 
Cigarette smoke: If there are people smoke in your family, it will leave bda smells. These smoke is difficult to remove from the air and is dangerous to inhale, so this is one of the odors you should take immediate steps to mitigate.
Human smells and body odors: Houses that live or are occupied by people will leave an unpleasant smell that is difficult to remove by simple methods.