Molecular singlet oxygen (¹O₂*) is the first excited state of O₂ and is produced when sunlight excites light-absorbing molecules in aerosols in the atmosphere. ¹O₂* can drive oxidation reactions and impact aerosol properties. This study is an inter-comparison of photoreactors, light sources and data analysis across 3 atmospheric chemistry laboratories, yielding a critical assessment of practices and recommendations for intercomparing ¹O₂* measurements and extrapolating to ambient particles.

Uncrewed aerial vehicles (UAVs) equipped with greenhouse gas (GHG) analyzers are crucial for monitoring hard-to-reach areas where traditional techniques are impractical. Here, we deployed UAVs with different types of GHG analyzers and applied three different emission rate quantification methods over a known geological methane seep. Our results demonstrate that UAV-based approaches can reliably quantify emissions from remote methane point sources that would otherwise be difficult to measure.

We developed methods to reduce noise in satellite images that track air pollution. By using clearer measurements of a related gas, our techniques improve image quality by up to 80 percent, allowing more accurate identification of pollution sources. Tested with simulated and real satellite data, this approach could enhance monitoring of emissions and support better environmental decisions.