# Development of an Automatic Low-Cost Air Quality Control System: A Radon Application  
[PERSON]  
1 RNASA-IMEDIR, Computer Science Faculty, University of A Coruna, 15071 A Coruna, Spain; jan.albunalbaud.ces (J.R.R. ); [EMAIL_ADDRESS] (A.P.) [PERSON]  
2 School of Architecture, University of A Coruna, 15071 A Coruna, Spain; [EMAIL_ADDRESS] (A.P.) [PERSON]  
1 RNASA-IMEDIR, Computer Science Faculty, University of A Coruna, 15071 A Coruna, Spain; jan.albunalbaud.ces (J.R.R. ); [EMAIL_ADDRESS] (A.P.) [PERSON]  
4 Department of Construction Technology, University College of Technical Architecture, University of A Coruna, 15071 A Coruna, Spain; [EMAIL_ADDRESS] (A.P.) [PERSON]  
1 RNASA-IMEDIR, Computer Science Faculty, University of A Coruna, 15071 A Coruna, Spain; jan.  
and illnesses from hazardous chemicals and air, water, and soil pollution and contamination, and to reduce the adverse per capita environmental impact of cities, including by paying particular attention to air quality and municipal and other waste management. Concretely, air pollution is a relevant issue in relation to human health and well-being: it is the fourth greatest overall risk factor for human health worldwide, after high blood pressure, dietary risks, and smoking. It includes both ambient air pollution (outdoors) and household air pollution (indoors), which combined cause about 6.5 million premature deaths to air pollution [7], as a result of increased mortality from stroke, heart disease, chronic obstructive pulmonary disease, lung cancer, and acute respiratory infections. It also implies relevant environmental and economic risks. Indoors or household air pollution includes both pollutants from cooking, heating, and lighting sources; as well as pollutants emitted from non-combustion sources. Within the second group, radon represents one of the biggest concerns, as recent studies on indoor radon in Europe, North America, and Asia indicate that lung cancers attributable to radon may range from 3% to 20% [8], making it the leading cause of lung cancer among non-smokers. Moreover, applying the United States Environmental Protection Agency (EPA) action level [9], radon has a role in 25% of all lung cancers [10]. Statistical data establishes that the causes of death in Spain due to radon gas exposure are between 600 and 2900 deaths per year. Radon is a naturally occurring radioactive gas that belongs to the 238U decay chain. It emanates from certain rock and soil formations and concentrates in buildings in the absence of adequate ventilation or evacuation systems. Outdoors, it quickly dilutes to very low concentrations and is generally not a matter of concern. However, it may be found in indoor environments, especially in below ground building areas, as they often lack proper ventilation systems. The exposure to radon in indoor environments such as homes, workplaces, and schools, may end up in a very high time of exposure to high radon levels [11; 12]. The increase in risk is assumed to be linear in relation to radon concentration (i.e., the risk is ten times higher at 1000 Bq/m\({}^{3}\) compared to 100 Bq/m\({}^{3}\)), and to increase linearly with exposure time as well [13]. Therefore, both radon levels and exposure time to high radon levels have to be taken into account when aiming to reduce health risks from indoor radon exposure. Strategies aiming at improved air quality concerning radon interact directly with other climate change mitigation targets, and with several aspects of socioeconomic nature: energy efficiency savings which could materialize in both resources and economic savings, a decrease in certain health issues which could also imply a reduction in healthcare costs, access to a healthy, comfortable living space of workspace, which could result in better performance and productivity [14]. One of the main solutions to decrease radon levels indoors in existing buildings is continuous ventilation, or the installation of a continuous ventilation system.