US COVID-19 Shutdown Demonstrates Importance of Background NO in Inferring NO Emissions From Satellite NO Observations.

Satellite nitrogen dioxide (NO) measurements are used extensively to infer nitrogen oxide emissions and their trends, but interpretation can be complicated by background contributions to the NO column sensed from space. We use the step decrease of US anthropogenic emissions from the COVID-19 shutdown to compare the responses of NO concentrations observed at surface network sites and from satellites (Ozone Monitoring Instrument [OMI], Tropospheric Ozone Monitoring Instrument [TROPOMI]). After correcting for differences in meteorology, surface NO measurements for 2020 show decreases of 20% in March-April and 10% in May-August compared to 2019.

Air Quality and Health Impact of Future Fossil Fuel Use for Electricity Generation and Transport in Africa.

Africa has ambitious plans to address energy deficits and sustain economic growth with fossil fueled power plants. The continent is also experiencing faster population growth than anywhere else in the world that will lead to proliferation of vehicles. Here, we estimate air pollutant emissions in Africa from future (2030) electricity generation and transport.