Closed factories, empty roads, deserted streets, vacant shop fronts - these scenarios are becoming more and more pronounced across the world as the coronavirus pandemic advances at a seemingly unstoppable rate.
Perhaps the only potential non-toxic impact to be found as a result of the current health crisis is the apparent positive implications for the natural environment.
The abrupt decline in movement on the streets of Spain and many other countries under lockdown measures appears to have led to a significant drop in air pollution in many urban areas.
As Spain enters its third week of lockdown, satellite images have been released showing nitrogen dioxide (NO2) concentrations over Spain and other European countries that reveal the air has become notably cleaner - particularly across city spaces.
The satellite maps were produced by the Royal Netherlands Meteorological Institute (KNMI), using data from the Copernicus Sentinel-5P satellite to monitor both weather and pollution over Europe.
The comparisons being made are for concentrations in the air from 14 to 25 March with the monthly average of concentrations for March 2019.
The new images clearly illustrate a strong reduction of nitrogen dioxide concentrations over major cities across Europe – specifically Milan, Paris and Madrid.
Nitrogen dioxide is a harmful gas emitted when fossil fuels are burnt at high temperatures, most commonly at power plants and in motor vehicles.
Daily weather changes and events can influence atmospheric pollution, so the satellite pictures took a 10 day average and excluded readings where cloud cover reduced the quality of the data.
This new data helps to further reinforce previous observations from Madrid City Council's Air Quality Monitoring System who stated that air pollution had significantly reduced since quarantine measures were put into action.
After just a few days of lockdown, Madrid City Council's Air Quality Monitoring System declared the city's five districts as "very good" in the air quality index. In Barcelona, data from the Generalitat indicated that nitrogen dioxide (NO2) concentrations were halved after only three days of lockdown.
A similar impact was also apparent in Italy explained Josef Aschbacher from the European Space Agency (ESA) in a statement: "While there may be slight variations in the data due to cloudiness and climate change, we are very confident that the reduction in emissions we can see coincides with the closure in Italy that causes less traffic and industrial activity."
The KNMI team, in collaboration with scientists worldwide, have started to work on a more detailed analysis using ground data, weather data and inverse modelling to interpret the concentrations observed, in order to estimate the influence of the lockdown measures.
Henk Eskes, from KNMI explained: “For quantitative estimates of the changes in the emissions due to transportation and industry, we need to combine the Tropomi data from the Copernicus Sentinel-5P satellite with models of atmospheric chemistry. These studies have started, but will take some time to complete.”
Other countries including the Netherlands and the UK are also understood as being closely monitored - but in these cases scientists have noticed more variability as a result of weather changes.
Air quality improvement could save lives
According to the World Health Organisation, about 91% of the world's population lives in places where air quality levels exceed acceptable limits. These conditions are understood to account for approximately 4.2 million premature deaths annually, according to 2016 statistics.
"What surprises me most is that the measures we are ready to take to deal with this coronavirus are much more severe than the measures we would be ready to take to deal with climate change or air pollution," said François Gemenne, director of the Hugo Observatory, an environmental research centre.
The recent air condition changes are so dramatic that some believe these short-term reductions could potentially lead to significant long-term benefits for the planet.
Stanford University environmental resource economist Marshall Burke made a series of predictive calculations about the recent drop in air pollution in parts of China and the potential lives saved. "Given the significant amount of evidence that demonstrates breathing dirty air contributes directly to premature mortality, a natural, if perhaps strange, question is whether the lives saved from this reduction in pollution caused by the economic disruption of Covid-19 exceeds the number of deaths from the virus itself," Burke writes.
"Even under very conservative assumptions, I believe the answer is a clear yes”, he concluded.
While the economic disruption caused by Covid-19 might have reduced air pollution, Burke said it is vital not to think of this as a “silver lining” or a “benefit” of the pandemic. The pandemic is harmful to health directly and the broader disruption it is causing - lost incomes, inability to receive care for non-Covid-19 illnesses and injuries - could have far-reaching implications.