Experimental Measurements of VOC and Radon in Two Romanian Classrooms

First Steps towards a National Approach for Radon Survey in Romanian Schools

Schools are a category of public buildings with a high radon exposure risk, due to their high occupancy factor. In Romania, the elaboration of a methodology for radon measurements in schools is a necessity imposed both by the European legislation and by the relatively high percentage (about 10%) of the mapped territory with a potential increased risk of exposure to the action of ionizing radiation emitted by radon. In order to optimize the design of a national survey aimed to evaluate radon exposure of children in Romanian schools, we conducted a pilot study in two schools in Cluj-Napoca, following the screening measurements carried out in 109 schools and kindergartens from five counties. The specific steps that must be followed were described, taking into account the international protocols and particularities of Romanian territory. The proposed approach could act as a guide for other large buildings and is implicit for the implementation of National Radon Action Plan, approved by HG no. 526/12 July 2018 in accordance with Council Directive 2013/59/EURATOM. The obtained results indicate that a high probability of annual radon concentration above the national reference level is to be expected in schools.

Research on Best Solution for Improving Indoor Air Quality and Reducing Energy Consumption in a High-Risk Radon Dwelling from Romania

The purpose of this article is the assessment of energy efficiency and indoor air quality for a single-family house located in Cluj-Napoca County, Romania. The studied house is meant to be an energy-efficient building with thermal insulation, low U-value windows, and a high efficiency boiler. Increasing the energy efficiency of the house leads to lower indoor air quality, due to lack of natural ventilation. As the experimental campaign regarding indoor air quality revealed, there is a need to find a balance between energy consumption and the quality of the indoor air. To achieve superior indoor air quality, the proposed mitigation systems (decentralized mechanical ventilation with heat recovery combined with a minimally invasive active sub-slab depressurization) have been installed to reduce the high radon level in the dwelling, achieving an energy reduction loss of up to 86%, compared to the traditional natural ventilation of the house. The sub-slab depressurization system was installed in the room with the highest radon level, while the local ventilation system with heat recovery has been installed in the exterior walls of the house. The results have shown significant improvement in the level of radon decreasing the average concentration from 425 to 70 Bq/m³, respectively the carbon dioxide average of the measurements being around 760 ppm. The thermal comfort improves significantly also, by stabilizing the indoor temperature at 21 °C, without any important fluctuations. The installation of this system has led to higher indoor air quality, with low energy costs and significant energy savings compared to conventional ventilation (by opening windows).

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.

Indoor Radon Exposure in Italian Schools

Background: The aim of the study was to assess radon concentration in schoolrooms in a city located in the midwest of Italy. Methods: A two-phase environmental study was carried out in 19 school buildings of 16 primary, secondary, and tertiary schools. Results: Median (interquartile range—IQR) indoor radon concentration in schoolrooms was 91.6 (45.0–140.3) Bq/m³. The highest (median 952.8 Bq/m³) radon concentration was found in one (3.6%) classroom, located in a building of a primary school whose median concentration was 185 Bq/m³. Radon concentration was significantly correlated with the number of students and teachers, foundation wall construction material, and with the absence of underground floors. A geopedological survey was performed close to the building with highest radon level, showing the presence of granite and tonalithic granodiorite in the soil. Conclusions: Radon levels should be routinely assessed where individuals live or work. Schools are susceptible targets, because of childhood stay and the long daily stay of occupants. Low-cost interventions, such as implementation of natural air ventilation and school maintenance, can reduce radon levels, limiting individual exposure.

Monitoring key organic indoor pollutants and their elimination in a biotrickling biofilter

A biotrickling filter was evaluated to treat the air of the interior of a bioprocess research laboratory. Initially, various solid-phase microextraction (SPME) fibers were used to identify and quantify the volatile organic pollutants and hexane, methyl isobutyl ketone, benzene, toluene, and xylene were further selected as indicators due to their prevalence and relative abundance. The system treated organic loading rates between 0.16 mg_carbon m^-3 h^-1 and close to 30 mg_carbon m^-3 h^-1 achieving removal efficiencies (RE) over 85% during 136 operational days. Respirometry experiments demonstrated that moderate acidification (below 5.0), due to microbial activity, adversely affected biofilter performance and consequently pH control was necessary to maintain performance.

The effect of natural ventilation strategy on indoor air quality in schools

In order to reduce children's exposure to pollutants in classrooms a proper ventilation strategy need to be adopted. Such strategy is even more important in naturally ventilated schools where the air exchange rate is only based on the manual airing of classrooms. The present work aimed to evaluate the effect of the manual airing strategy on indoor air quality in Italian classrooms. For this aim, schools located in the Central Italy were investigated. Indoor air quality was studied in terms of CO₂, particle number and PM concentrations and compared to corresponding outdoor levels. In particular two experimental analyses were performed: i) a comparison between heating and non heating season in different schools; ii) an evaluation of the effect of scheduled airing periods on the dilution of indoor-generated pollutants and the penetration of outdoor-generated ones. In particular, different airing procedures, i.e. different window opening periods (5 to 20min per hour) were imposed and controlled through contacts installed on classroom windows and doors. Results revealed that the airing strategy differently affect the several pollutants detected in indoors depending on their size, origin and dynamics. Longer airing periods may result in reduced indoor CO₂ concentrations and, similarly, other gaseous indoor-generated pollutants. Simultaneously, higher ultrafine particle (and other vehicular-related pollutants) levels in indoors were measured due to infiltration from outdoors. Finally, a negligible effect of the manual airing on PM levels in classroom was detected. Therefore, a simultaneous reduction in concentration levels for all the pollutant metrics in classrooms cannot be obtained just relying upon air permeability of the building envelope and manual airing of the classrooms.