Glossary

Term	Definition
Sensing Device / Low-cost sensor device	A Sensing Device refers to a compact electronic device that uses one or more than one sensor and other electronic components to detect, monitor, and/or report on specific environmental parameters or phenomena at a relatively affordable price. These sensing devices are often built using economical components and simplified designs, making them accessible to a wide range of users, including citizen scientists, educators, and community groups. Despite their lower cost, they are engineered to provide reasonably accurate measurements, allowing for meaningful data collection and analysis. Sensing devices play a vital role in democratising scientific research, enabling individuals and communities to monitor and understand their local environment, address environmental concerns, and contribute to scientific knowledge and public policy decisions. In this document we mostly refer to Sensing Devices to monitor air pollution. During the creation of this document, we decided to adopt the terminology Sensing Device, to avoid detrimental connotations that can be associated with the term “low-cost”, as for example, of worse quality. However, the term low-cost sensor is still widely recognised and used by the Citizen Science and the academic community.
Open science	UNESCO defines Open Science as a set of principles and practices that aim to make scientific research from all fields accessible to everyone for the benefits of scientists and society. Open science is about making sure not only that scientific knowledge is accessible but also that the production of that knowledge itself is inclusive, equitable and sustainable. Open science advocates for transparency, accessibility and reproducibility, principles that have a larger potential of benefiting society. The use of open source and open science can contribute to increase acceptance of data in science and policy, as it moves away from black boxes and unknown proprietary algorithms.
Free and open source (FOSS)	FOSS refers to groups of technology that are licensed to freely use, copy, study, and modify in any way, without charge. Here the word ‘free’ is used in the sense of ‘free speech’, not ‘free beer’ (Richard Stallman, GNU 2011).
Open Source	Open source refers to making the underlying source code or designs of a technology publicly available so that people are encouraged to re-use, re-purpose, or improve the design. This is in contrast to proprietary software, or hardware designs where the technology is under restrictive copyright or licensing and the source code or designs are hidden from the users.
Metadata	Metadata refers to descriptive information that provides context, structure, and meaning to data. It serves as a set of data about data, encompassing details such as the origin, format, content, and usage of a dataset or individual data elements. Metadata helps users understand and interpret data by providing essential attributes and properties, such as creation date, authorship, location, and data quality indicators. It facilitates data discovery, organisation, retrieval, and management, enabling efficient data integration, sharing, and analysis across different systems, platforms, and domains. Metadata plays a crucial role in data governance, data management, and data-driven decision-making processes, ensuring the reliability, accuracy, and usability of data assets throughout their lifecycle.
Provenance	Data provenance refers to the documentation of the origin, history, and transformations applied to a piece of data throughout its lifecycle. It provides a detailed record of the processes involved in data creation, manipulation, and sharing, enabling users to trace back to the original sources and understand how the data has been modified or used over time.
Citizen Observatories	Citizen Observatories (COs) are community-based environmental monitoring and information systems, typically at the community level or in a specific location, even if linked to a national or global environmental concern.
Accuracy	"Accuracy" generally refers to the degree of conformity of a measured or calculated quantity to its actual value. In data analysis or data processing, accuracy refers to the correctness or precision of the data. It indicates how well the data reflects the real-world phenomenon it represents. Factors such as data collection methods, instrumentation, and human error can affect data accuracy.
Reliability	"Reliability" generally refers to the consistency, stability, and dependability of a system, process, measurement, or result over time and under varying conditions. Measurement reliability refers to the consistency and stability of measurements or data obtained from a measurement instrument or procedure. It assesses the extent to which repeated measurements yield consistent results.
Accessibility	"Accessibility" generally refers to the degree to which products, services, environments, or digital content are usable by people with disabilities, including those with visual, auditory, motor, cognitive, or other impairments. Digital accessibility focuses on ensuring that websites, software applications, electronic documents, and digital content are usable by people with disabilities. This includes considerations such as screen reader compatibility, keyboard navigation, alternative text for images, and captions for audio and video content.
Usability	"Usability" refers to the extent to which a product, system, or service can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use.
Analysis Ready Data (ARD)	"Analysis ready data" (ARD) refers to geospatial or remote sensing data that has been pre-processed and optimized for analysis and interpretation by end-users. In CitiObs, we use the term ARD to sensor data that has been Quality Controlled and Corrected. Open algorithms for quality control and correction are being tested and developed within the project and made openly available.
Decision Ready Information (DRI)	"Decision-ready information" refers to data, reports, or analyses that have been processed, organized, and presented in a format that enables decision-makers to make informed decisions. In CitiObs, we use the term DRI to refer for example to air quality maps generated using a combination of sensor data and model or satellite data, as well as, data reports aggregating ARD sensor data, spatially or temporally.