Thus far, measuring/monitoring chemicals in, across, and between different media (e.g. water, soil, air or biological material) has been the main strategy to map the exposome chemical space. This strategy is reliant on three complementary approaches namely, targeted, suspect, and non-targeted analysis (NTA). Targeted analysis could be quantitative and focused on a limited number of pre-selected structures, for example less than a few hundred chemicals are actively and routinely monitored in different matrices. Suspect screening/analysis, on the other hand, has been employed to identify chemicals based on user curated lists of preselected compounds and/or presence in databases/libraries using full-scan high-resolution mass spectrometry (HRMS) data. Finally, NTA is considered the most agnostic approach for chemical measurement and identification in samples, where the collected signals are translated into candidate structures and confirmed via target analysis. Both suspect and non-target analysis are reliant on full scan data generated via HRMS coupled to a separation technique such as gas or liquid chromatography (GC/LC-HRMS). For 4 a structurally unknown chemical to be identified via suspect or non-target analysis, it must be measurable with our current analytical strategies (i.e. separation and detection). 12, What is measurable/analyzable with our current analytical technologies is unknown. We are only aware of the identified fraction of the measurable chemical space (see the description below). Therefore, there may be chemicals highly relevant to the exposome that are not measurable with routine methods and may require the development of specific methods for their analysis (e.g. PFOA or glyphosate). Currently less than 10% of the signals acquired for suspect and NTA assays are successfully identified/annotated. For example, even for a single surface water sample, the pre-processing reveals thousands of chemical signals to be identified. The existing identification workflows, at best, can confirm less than a few hundreds chemicals in complex samples.