Answer:
Actually, this is true, most of the people don't realize that indoors we encounter several risks that attempt against our health and life.
A big example of this is Carbon monoxide (CO) poisoning, which is from burned fuel from the kitchen, automobiles and house heating. According to the Centers for Disease Control and Prevention (CDC), CO poisoning is highly dangerous because its characteristics, odorless and colorless. So, basically, people don't realize that they are being poisoned.
The high risk of this, it's because indoors, all domestic activities we perform are based on fuel, like stove, lanterns, gas range, and others. The symptoms of CO poisoning are headache, dizziness, weakness, nausea and vomiting.