Radón residencial y cáncer de pulmón. Un estudio ecológico en Galicia

Design and Development of a New Methodology Based on Expert Systems Applied to the Prevention of Indoor Radon Gas Exposition Risks

Exposure to high concentration levels of radon gas constitutes a major health hazard, being nowadays the second-leading cause of lung cancer after smoking. Facing this situation, the last years have seen a clear trend towards the search for methodologies that allow an efficient prevention of the potential risks derived from the presence of harmful radon gas concentration levels in buildings. With that, it is intended to establish preventive and corrective actions that might help to reduce the impact of radon exposure on people, especially in places where workers and external users must stay for long periods of time, as it may be the case of healthcare buildings. In this paper, a new methodology is developed and applied to the prevention of the risks derived from the exposure to radon gas in indoor spaces. Such methodology is grounded in the concurrent use of expert systems and regression trees that allows producing a diagram with recommendations associated to the exposure risk. The presented methodology has been implemented by means of a software application that supports the definition of the expert systems and the regression algorithm. Finally, after proving its applicability with a case study and discussing its contributions, it may be claimed that the benefits of the new methodology might lead on to an innovation in this field of study.

Radon Gas in the City of Alicante. High Risk of Low Indoor Air Quality in Poorly Ventilated Buildings

In December 2019, Spain considered for the first time the presence of radon to the Technical Building Code (Basic Document HS 6: Radon Exposure Protection), although it only mentions minimum presences and the need for ventilation. This research shows that in buried structures or in places with little ventilation, even in soils with a low probability of granite, a high content of radon gas can be found. The city of Alicante has been used as a measurement location for different architectural sites; here, the level of 100 Bq/m³ is the first threshold where the gas must be monitored, and the level of 300 Bq/m³ is the maximum threshold above which corrective ventilation measures must be taken. The research conducted during the years 2015 and 2016 shows that it is necessary to account for also the areas considered to be “low presence of radon gas” to achieve healthy constructions. The renewal of air in the different places will be tested for the presence of radon, i.e., the greater the accumulation is, the less ventilation and the greater the risk of accumulation of radon gas. This study is located in the city of Alicante, where the seven civil constructions are located: two Civil War shelters, the Santa Barbara Castle, the Ereta Powder Keg, the Luceros-Marq and Serra Grossa railway tunnels and the Británica underground deposits. Radon gas is currently a concern for major health and medical agencies because it is considered to be a chemical element that is very harmful to people. The World Health Organization is one of the organisations that has the objective of studying and researching this element, to develop solutions. Radon gas is normally found in a gaseous state and is highly radioactive. It is present in many terrains and it is mostly found in those with granite; although the presence of this element is very low, there is always a minimum presence. In the past, in nongranite soils, the dose of radon was considered to be so low that it was insignificant. Therefore, in this research, the aim is to consider the high presence of radon gas in nongranite soils as long as the conditions for its accumulation are present.

Ventilation as an Indispensable Tool for Healthy Constructions: Comparison of Alicante’s Urban Railway Tunnels

The majority of scientific agencies in the field of medicine and health, including the World Health Organization, consider radon gas a very harmful element for humans. This element, in its gaseous state, is radioactive and is present in almost all land in which buildings are implanted, especially in granitic soils, which present higher levels of radon gas. Nongranitic soils have traditionally been considered to have low radon levels. In addition to the contributions made by this article, it is very relevant that there are many countries, including Spain, in which the technical codes for their construction regulations do not include the maximum radon dose that a building can hold so that it is not harmful to humans nor do they hold the measures necessary to remedy excessive accumulation. The main objective of this research is to demonstrate the need for ventilation in buried works. To do this, a comparison is made between two railway tunnels in the urban fabric of the city of Alicante: one of them is in operation (Benacantil Mount) and the other is in the excavation phase (Serra Grossa). When underground railway installations are planned, they are equipped with large air ventilation systems due to the pollutants generated by ground exposure. These mechanical systems consist of suction turbines that expel the air to the outside. Research shows that radon gas is an indicator of an area’s air quality. In addition, ventilation in railway tunnels (mechanical and natural) allows for air renewal and improves the air quality.

Radon Gas as an Indicator for Air Quality Control in Buried Industrial Architecture: Rehabilitation of the Old Británica Warehouses in Alicante for a Tourist Site

The infrastructure of the Británica warehouses in Alicante is a very important industrial architectural element in the history of Spain, although it is unknown to almost all of the inhabitants of the city. The former fuel refinery is located in the Serra Grossa Mountains and served much of the country until 1966. This research is based on the plans of the city of Alicante to convert a historical element, the Británica warehouses, into a unique tourist site. Currently, the network of storage domes in this facility, which has an approximate footprint of 20,000 m 2 and domes approximately 20 m high, is in a state of neglect, and there are neighborhood initiatives for its rehabilitation to become a cultural or tourist site. Therefore, it is necessary to take into account the quality of the indoor air. Radon gas is analyzed as a control element for future refurbishment of the facility. Alicante is a nongranite area and therefore is not very susceptible to generation of radon gas indoors, but the conditions of a buried and poorly ventilated space make the site appropriate for analysis. Most scientific agencies in the field of medicine and health, including the World Health Organization, consider radon gas to be very harmful to humans. This element in its gaseous state is radioactive and is present in almost all the land in which the buildings are implanted, with granitic type soils presenting higher levels of radon gas. Nongranitic soils have traditionally been considered to have low radon levels. The city of Alicante, where the installation is located, is a nongranitic area and therefore is not very susceptible to generating radon gas in buildings, but the conditions of buried and poorly ventilated places make the site appropriate for analysis to support air quality control and decision-making.

The Importance of Checking Indoor Air Quality in Underground Historic Buildings Intended for Tourist Use

This article demonstrates the importance of quantifying the air quality with radon gas level as indicator in any heritage building, especially those intended for the use of people. The tourist activity or historical guide represents a typology where people spend a certain time, that is to say, in no case do they spend the same amount of hours as in their homes or jobs. Different gases that may be present in the environment must be controlled. The Séneca Square shelter, in Alicante, is a very important place for the history of the city during the Spanish Civil War that has recently been rehabilitated for exposure to people. The source of most radon gas inside a building is the ground. Many countries, including Spain, in which the building regulations, regarding the accumulation of radon gas, do not specify in their technical codes, the maximum dose that a building can sustain so that it is not harmful to people, or, the measures required to correct excessive accumulation. The possible existence of radon is verified in any underground building, regardless of the characteristics of the soil (whether granitic or not), the importance of defining and unifying the regulations that specify the different levels of radon in any architectural constructions is evident. Most of the scientific agencies in the field of medicine and health, consider that radon gas is a very harmful element for people. This element in its gaseous state is radioactive and it is present in almost all soils in which buildings are implanted, with granitic types of soil presenting higher levels of radon gas. Non-granitic soils have traditionally been considered to have very low radon levels. However, this work, providing the results of the research carried out in the underground air raid shelter in Seneca Square in Alicante (Spain), demonstrates the relevant presence of radon in non-granitic soils. This research addresses the constructive typology of the underground building and the radon presence in its interior obtained using rigorous measurement techniques.

The Radon Gas in Underground Buildings in Clay Soils. The Plaza Balmis Shelter as a Paradigm

In healthy buildings, it is considered essential to quantify air quality. One of the most fashionable indicators is radon gas. To determine the presence of this element, which is harmful to health, in the environment, the composition of the soil is studied. The presence of radon gas within a building depends both on the terrain in which it is located and on the composition of the materials of which it is composed, and not as was previously believed, only by the composition of the soil (whether granitic or not). Many countries are currently studying this phenomenon, including Spain where the building regulations regarding the accumulation of radon gas, do not list in their technical codes, the maximum dose that can a building can hold so that it is not harmful to people and the measures to correct excessive accumulation. Therefore, once the possible existence of radon in any underground building has been verified, regardless of the characteristics of the soil, the importance of defining and unifying the regulations on different levels of radon in all architectural constructions is evident. Medical and health science agencies, including the World Health Organization, consider that radon gas is a very harmful element for people. This element, in its gaseous state, is radioactive and it is present in almost soils in which buildings are implanted. Granitic type soils present higher levels of radon gas. Non-granitic soils have traditionally been considered to have very low radon levels. However, this paper demonstrates the relevant presence of radon in non-granitic soils, specifically in clayey soils, by providing the results of research carried out in the underground air raid shelter at Balmis Square in Alicante (Spain). The results of the measurements of radon accumulation in the Plaza Balmis shelter are five times higher than those obtained in a similar ungrounded building. This research addresses the constructive typology of an under-ground building and the radon presence in its interior obtained using rigorous measurement techniques.

Residential radon and lung cancer: a cohort study in Galicia, Spain

Case-control studies show an association between residential radon and lung cancer. The aim of this paper is to investigate this association through a cohort study. We designed an ambispective cohort study using the Galician radon map, Spain, with controls drawn from a previous case-control study. Subjects were recruited between 2002 and 2009. The data were cross-checked to ascertain lung cancer incidence and then analysed using a Cox regression model. A total of 2,127 subjects participated; 24 lung cancer cases were identified; 76.6% of subjects were drawn from the radon map. The adjusted hazard ratio was 1.2 (95%CI: 0.5-2.8) for the category of subjects exposed to 50Bq/m3 or more. This risk rose when subjects from the case-control study were analyzed separately. In conclusion, we did not observe any statistically significant association between residential radon exposure and lung cancer; however, it appears that with a sample of greater median age (such as participants from the case-control study), the risk of lung cancer would have been higher.

Residential radon and COPD. An ecological study in Galicia, Spain

PURPOSE

Radon is a human lung carcinogen but it might be linked with other respiratory diseases. We aimed to assess the relationship between residential radon exposure and COPD (chronic obstructive pulmonary disease) prevalence and hospital admissions at a municipal level.

MATERIALS AND METHODS

We designed an ecological study where we included those municipalities with at least three radon measurements. Using mixed Poisson regression models, we calculated the relative risk (RR) for COPD for each 100 Bq/m³ of increase in radon concentration and also the relative risk for COPD using a cut-off point of 50 Bq/m³. We did not have individual data on cigarette smoking and therefore we used a proxy (bladder cancer standardized mortality rate) that has proved to account for tobacco consumption. We performed separate analyses for sex and also sensitivity analysis considering age and rurality.

RESULTS

A total of 3040 radon measurements and 49,393 COPD cases were included. The relative risk for COPD prevalence was 0.95 (95% CI: 0.92-0.97) while for hospital admissions the RR was 1.04 (95% CI: 1.00-1.10) for each 100 Bq/m³. Relative risks were higher for women compared to men. Using a categorical analysis with a cut-off point of 50 Bq/m³, the RR for COPD prevalence was 1.06 (95% CI: 1.02-1.10) and for hospital admissions it was 1.08 (95% CI: 1.00-1.17) for women living in municipalities with more than 50 Bq/m³. All risks were also higher for women. No relevant differences were observed for age, rurality or other categories for radon exposure.

CONCLUSION

While the influence of radon on COPD prevalence is unclear depending on the approach used, it seems that residential radon might increase the risk of hospital admissions in COPD patients. Women have a higher risk than men in all situations. Since this is an ecological study, results should be interpreted cautiously.