Capturing the skies with the NO2 Camera

From space to the surface of the Earth

Valuable applications on Earth sometimes find their origin in space missions. The NO₂ camera is a prime example of such a transition. Based on the optical setup used in the ALTIUS satellite mission, this innovative instrument is designed to measure nitrogen dioxide (NO₂) emissions at ground level – a critical factor for air quality and human health.

As its name suggests, the NO₂ camera makes images of a scene from the ground. To obtain information about the NO₂ concentration in that scene, separate images are taken for different wavelengths. Since NO₂, a brownish-colored gas, absorbs specific wavelengths of light, its concentration in the air can be determined based on the amount of light absorbed at certain wavelengths.

Since its last feature in the annual report, several key components have been upgraded. These improvements include:

• an enhanced imaging chip,
• a pan-tilt system for automatic movement, and
• a newly designed enclosure to improve its resistance to weather conditions.

Results from recent campaigns

With these upgrades in place, the NO₂ camera has undergone extensive testing in two field campaigns.

• The first test campaign took place in Rome, where the camera was deployed to map the variations in NO₂ levels across the city. The camera successfully captured both spatial and temporal fluctuations in NO₂ concentrations, providing insight into daily pollution patterns.
   
• The NO₂ camera also participated in the CINDI-3 intercomparison campaign for air quality monitoring instruments in the Netherlands. It was one of three imaging instruments involved in this campaign. Currently, the results of this measurement campaign are still being processed.

Expanding applications

Encouraged by the camera’s successful performance, ESA and BELSPO, the Belgian Federal Science Policy Office, have committed further funding for its development. Over the next year, a pilot project will use the NO₂ camera to monitor NO₂ plumes from a cement factory and a power plant along the Belgian-German border.

Drones and satellite observations will complement these measurements for validation.

Additionally, the camera will return to Rome for long-term monitoring, capturing NO₂ field data continuously over 1.5 years. This extended deployment aims to provide deeper insights into pollution trends.

With continued advancements and growing interest, the NO₂ camera remains at the forefront of ground-based air quality monitoring, bridging the gap between satellite observations and local environmental assessments.