| Clue | Source | Date |
|---|---|---|
| A breath away from making it fizzy (6,7) | ||
| C02 (6,7) | ||
| Chemical compound that is dry ice in condensed form (6,7) | ||
| Something in the air Commanding Officer also reported? | The Telegraph Toughie | 26 Nov 2019 |
| Greenhouse gas (2 words) | Family Time | 25 Nov 2018 |
| Respiratory gas represented in 36-Across | New York Times | 18 Sep 2018 |
| Respiratory gas represented in 36-Across | ||
| Gas in the atmosphere | The Times Concise | 13 Nov 2017 |
| Gas for dry ice | The Times Concise | 05 May 2017 |
| Paper expiration? |