As the number of people working in offices has reduced, there has been a corresponding fall in road congestion and private car use, helping to improve air quality.
Wrth i nifer y bobl sy’n gweithi mewn swyddfeydd leihau, bu gostyngiad hefyd mewn tagfeydd traffig a’r defnydd o geir preifat, gan helpu i wella ansawdd yr aer.