| # | Concept | Culture | Statement | Freq. |
|---|---|---|---|---|
| 1 | carbon dioxide | US | Carbon dioxide is a greenhouse gas that contributes to climate change and is a major environmental concern in industrialized nations. | 1 |
| 2 | carbon monoxide | United States | Carbon monoxide poisoning is a significant concern due to faulty home heating systems and vehicle emissions. | 1 |
| 3 | carbon monoxide | United States | Carbon monoxide poisoning is a concern due to the use of gas heating systems in homes. | 1 |