On first glance the answer to this question appears to be yes. The unprecedented falls in economic activity, particularly in transport, have cut emissions and projections by the International Energy Agency at the end of April suggest they will be 8% down on 2019. As fossil fuel consumption has declined so has air pollution, and perhaps people in major urban areas will want to keep their clean air and blue skies. However this is the sort of cut we need to sustain every year, and emissions are likely to go back up as economic activity resumes after lockdowns, as they did after the financial crash in 2008. Recessions may mean lower green house gas emissions in the short term but can be bad in the long term for the transition to zero carbon: they reduce investment so when economic activity picks up so does consumption of fossil fuels.
Of more lasting impact may be changes that this experience of living through a pandemic and the measures brought in to tackle it bring about to our mindsets and ways of thinking.