The NASA TEMPO (Tropospheric Emissions: Monitoring of Pollution) mission has enabled scientists to track morning nitrogen dioxide (NO₂) emissions that contribute to afternoon ozone (O₃) formation along the New York–Washington corridor. This detailed monitoring, conducted in May 2026, provides an unprecedented view of the daily dynamics of air pollution in one of the most densely populated regions of the United States.

Nitrogen dioxide is a key pollutant emitted by vehicles, power plants, and industrial processes. It acts as a precursor in the formation of tropospheric ozone, a secondary pollutant that forms when nitrogen oxides and volatile organic compounds react in the presence of sunlight. Ground-level ozone is harmful to human health and vegetation, and its concentration varies significantly throughout the day, peaking in the afternoon.

TEMPO's ability to monitor pollution with hourly temporal resolution from a geostationary orbit is crucial. Unlike previous satellites that only provided one or two daily snapshots, TEMPO can observe changes in NO₂ and other pollutant concentrations throughout the day. This information is vital for understanding the emission and chemical reaction cycles that lead to ozone pollution, enabling more accurate air quality models and more effective mitigation strategies.