This document illustrates a family of approaches to quantify CO2 and NO2 emissions from point sources using CO2 and NO2 images retrieved from the upcoming Copernicus Carbon Dioxide Monitoring (CO2M) satellite constellation, in an automatic and lightweight fashion (i.e., without requiring atmospheric transport simulations, and being computationally cheap to apply globally). The Background section covers the scope and materials used for this report in more detail. The Plume detection and quantification methods section describes promising methods from the literature in more detail, which either work on images from a single satellite overpass, or on the temporal average of multiple overpasses of a single source. The section Potential issues and suggested solutions discusses a number of identified issues that can hinder the detection or quantification steps of these algorithms, as well as steps to mitigate these problems (if possible). Significant issues that are addressed at this stage are overcoming low signal-to-noise ratios and obtaining more accurate estimates of the wind speed and direction. Issues that are harder to overcome are the low annual number of expected plume detections for a given source, and providing good estimates of the background fields necessary to determine the plume enhancements. The approaches described here have been tested on a limited set of synthetic data but will be applied to a larger library of plumes developed within task 4.1, which in turn will be described in Deliverable 4.2. We would like to point out that this document only describes the various methods, while an evaluation of the performance of the different methods will be provided in Deliverable 4.4.