Posted on: August 19, 2020 at 9:36 AM    

Over the last few months, the internet has been rife with articles discussing the impacts of COVID-19, including a few contemplating the upsides for society and the environment.

Decreases in transport and industrial activities due to COVID-19 restrictions have led to improvements in air quality. Fascinating maps of EuropeChina and other places have been shared by the European Space Agency (ESA). These show dramatic reductions in nitrogen dioxide (NO2) concentrations. NO2 is a short-lived pollutant that primarily gets in the air from burning fossil fuels. It is also harmful to human health and increases the likelihood of developing respiratory problems (see more).

The ESA NO2 data comes from their Sentinel-5P satellite, part of the Copernicus Programme. This satellite, launched in 2017, detects air pollutants around the world. A new map portal made available by the ESA presents this data but unfortunately, New Zealand has been left off the map again - this time due to our low NO2 emissions relative to other major urban centres.

In light of this, our Location Solutions team decided to create a map ourselves. To understand the impact of the alert level restrictions on NO2 concentrations we averaged the data over four periods: before lockdown (early 2019), during alert level 4, during alert levels 3 and 2 and also after we returned to level 1. Averaging over multiple weeks also allowed the elimination of some the variation seen from short term weather changes and cloud cover.

The maps show significant decreases in NO2 concentrations over the period of the alert level 4 lockdown. Emissions have increased again as the country returns to normal activities. These results were anticipated but we found it fascinating to see the NO2 concentration patterns visualised. Please get in touch if you can provide any other insights into these emission patterns.

The impact of COVID-19 on air pollution has given us a glimpse of the possible improvements from reduced fuel burning activities, even after only a short period of time. If the way we travel and generate electricity continues to change we may see these clean air patterns again in the future.

Blog written by Andy Bartle and Sam McIntosh, Spatial Advisors

Tropospheric map cropped