InLoc: Indoor Visual Localization with Dense Matching and View Synthesis

We seek to predict the 6 degree-of-freedom (6DoF) pose of a query photograph with respect to a large indoor 3D map. The contributions of this work are three-fold. First, we develop a new large-scale visual localization method targeted for indoor environments. The method proceeds along three steps: (i) efficient retrieval of candidate poses that ensures scalability to large-scale environments, (ii) pose estimation using dense matching rather than local features to deal with textureless indoor scenes, and (iii) pose verification by virtual view synthesis to cope with significant changes in viewpoint, scene layout, and occluders. Second, we collect a new dataset with reference 6DoF poses for large-scale indoor localization. Query photographs are captured by mobile phones at a different time than the reference 3D map, thus presenting a realistic indoor localization scenario. Third, we demonstrate that our method significantly outperforms current state-of-the-art indoor localization approaches on this new challenging data

Porous silica spheres as indoor air pollutant scavengers

Porous silica spheres were investigated for their effectiveness in removing typical indoor air pollutants, such as aromatic and carbonyl-containing volatile organic compounds (VOCs), and compared to the commercially available polymer styrene-divinylbenzene (XAD-4). The silica spheres and the XAD-4 resin were coated on denuder sampling devices and their adsorption efficiencies for volatile organic compounds evaluated using an indoor air simulation chamber. Real indoor sampling was also undertaken to evaluate the affinity of the silica adsorbents for a variety of indoor VOCs. The silica sphere adsorbents were found to have a high affinity for polar carbonyls and found to be more efficient than the XAD-4 resin at adsorbing carbonyls in an indoor environment

Health effects of home energy efficiency interventions in England: a modelling study

Objective: To assess potential public health impacts of changes to indoor air quality and temperature due to energy efficiency retrofits in English dwellings to meet 2030 carbon reduction targets. Design: Health impact modelling study. Setting: England. Participants: English household population. Intervention: Three retrofit scenarios were modelled: (1) fabric and ventilation retrofits installed assuming building regulations are met. (2) As with scenario (1) but with additional ventilation for homes at risk of poor ventilation. (3) As with scenario (1) but with no additional ventilation to illustrate the potential risk of weak regulations and non-compliance. Main Outcome: Primary outcomes were changes in quality adjusted life years (QALYs) over 50 years from cardiorespiratory diseases, lung cancer, asthma and common mental disorders due to changes in indoor air pollutants, including: second-hand tobacco smoke, PM2.5 from indoor and outdoor sources, radon, mould, and indoor winter temperatures. Results: The modelling study estimates showed that scenario (1) resulted in positive effects on net mortality and morbidity of 2,241 (95% credible intervals (CI) 2,085 to 2,397) QALYs per 10,000 persons over 50 years due to improved temperatures and reduced exposure to indoor pollutants, despite an increase in exposure to outdoor–generated PM2.5. Scenario (2) resulted in a negative impact of -728 (95% CI -864 to -592) QALYs per 10,000 persons over 50 years due to an overall increase in indoor pollutant exposures. Scenario (3) resulted in -539 (95% CI -678 to -399) QALYs per 10,000 persons over 50 years due to an increase in indoor exposures despite targeting. Conclusions: If properly implemented alongside ventilation, energy efficiency retrofits in housing can improve health by reducing exposure to cold and air pollutants. Maximising the health benefits requires careful understanding of the balance of changes in pollutant exposures, highlighting the importance of ventilation to mitigate the risk of poor indoor air quality

National mapping survey of indoor radon levels in the Maltese Islands (2010-2011)

Aim: To conduct a national geographically based survey to determine the distribution of the mean annual indoor radon gas concentration levels in dwellings in the Maltese Islands and map these levels; to identify any areas with annual mean indoor radon gas concentrations higher than the current proposed WHO reference level of 100 Bq/m3; to determine an advisory national reference level for radon concentration in buildings. Method: Radon measurements were carried out in 85 buildings distributed over the Maltese Islands between November 2010 and November 2011 using alpha-track radon detectors. Retrieved detectors were analysed by a Health Protection Agency-accredited laboratory in the UK. The overall annual arithmetic and geometric mean indoor radon gas concentrations for the Maltese Islands were calculated. Results: The mean annual indoor radon concentration for the Maltese Islands was 32 Bq/m3, with a geometric mean of 25 Bq/m3 (standard deviation (SD) 25). The maximum level measured was 92 Bq/m3 and the minimum 11 Bq/m3. A radon map of the Maltese Islands was produced using the geographic mean annual indoor radon gas concentration level for each building. Conclusion: The mean annual indoor radon concentration in Malta was found to be well below the lowest proposed WHO reference levels with no dwellings having a mean annual indoor radon gas concentration above 100 Bq/m3. This national mapping survey for mean annual indoor radon gas concentration in the Maltese Islands indicates that the current proposed reference level of 100 Bq/m3 by the WHO may be adopted as the national reference level for the Maltese Islands.peer-reviewe

Development of limiting dilution viability pcr method to assess the effectiveness of selected biocides to treat indoor fungi growth

Indoor fungal contamination should be treated with cost-effective and green methods. Biocides have direct biological effect on living organisms but the evidence on their control of indoor fungal contamination is scarce. Using conventional cultivation to evaluate their effectiveness is time consuming while polymerase chain reaction (PCR) provides a fast and reliable alternative. The incorporation of serial dilution technique and viability information in PCR has made it suitable to evaluate the effectiveness of biocides. Thus, this study aimed to assess the antifungal ability of biocides, zinc salicylate (ZS), calcium benzoate (CB) and potassium sorbate (KS) to treat indoor fungal contamination through developing limiting dilution viability PCR (vPCR). These biocides were selected as they successfully controlled the growth of indoor waterborne fungi previously. Indoor air sampling revealed that higher educational building of computer studies (Building A) and of civil engineering studies (Building B) were contaminated by 509 CFU/m3 and 805.7 CFU/m3 of indoor airborne fungi, respectively. Two indoor fungi, Talaromyces spp. and Aspergillus niger were identified. They were subjected to biocides-treatment and subsequent conventional cultivation and limiting dilution vPCR due to their potential risks against humans’ health. The limiting dilution vPCR was developed by incorporating the pre-treatment of propidium monoazide (PMA) before deoxyribonucleic acid (DNA) extraction and the serial dilution of the DNA template in PCR. This approach was proven to effectively enumerate the effectiveness of biocides to treat indoor fungi. KS was shown to have the best effectiveness (100%) to prevent the growth of Talaromyces spp, followed by ZS (80.8%) and CB (no effect). KS also showed the best effectiveness against A. niger (100%) at the early stage of the study but its effect reduced with time. ZS showed durable effect (66.67%) against A. niger Day 9 cultures. Inconstant results were indicated by cultivation method. This study has provided a cheaper, more accurate and suitable approach to determine the effectiveness of treatment of indoor fungi than cultivation methods

Improving air filter efficiency as a strategy to reduce children’s exposure to traffic related air pollutants in energy-efficient classrooms

This study was organised to quantify the effect of upgrading the filter efficiency in balance ventilation systems on indoor exposure to traffic-related air pollution, in 4 primary school classrooms. The standard air filters (EU F7) were compared with more efficient EU F9, and with F7+active carbon filters. Particulate matter (PM), ultrafine particles (UFP), black carbon (BC), PM2.5, organic/elemental carbon in PM2.5 (EC/OC), and NO2 were quantified, air tightness and air supply rates were assessed and pupils’ indoor comfort was surveyed. Analysis of indoor air as function of outdoor air and filter type indicated a significant but small reduction of indoor levels when upgrading the filter, except for PM10, TSP and UFP. The indoor comfort survey indicated a small but significant and positive effect as well