Which of the following are sources of Carbon monoxide (CO) in the home?

The correct answer encompasses all the listed sources, highlighting that these are common contributors to carbon monoxide (CO) presence in the home environment.

Unvented gas space heaters can produce CO as a byproduct of combustion when gas is burned for heating. These devices often lack proper ventilation, leading to the accumulation of CO indoors, especially in poorly ventilated spaces.

A gas stove also generates carbon monoxide during combustion. When natural gas or propane is used for cooking, incomplete combustion can occur, producing CO, particularly if the stove is not functioning properly or if the burners are not adjusted correctly.

Cigarette smoke is another less commonly recognized source of CO in residential settings. The combustion of tobacco releases not only harmful chemicals but also carbon monoxide, which can contribute to indoor air pollution and impact health.

Since all these sources can contribute to the levels of CO inside a home, selecting the option that acknowledges all of them is crucial for a comprehensive understanding of indoor CO risks. Thus, the answer that includes all of the above accurately reflects the various origins of carbon monoxide in the home environment.