Review of low-cost sensors for indoor air quality: Features and applications

Humans spend the majority of their time indoors, where they are potentially exposed to hazardous pollutants. Within this context, over the past few years, there has been an upsurge of low-cost sensors (LCS) for the measurement of indoor air pollutants, motivated both by recent technological advances and by increased awareness of indoor air quality (IAQ) and its potential negative health impacts. Although not meeting the performance requirements for reference regulatory-equivalent monitoring indoors, LCS can provide informative measurements, offering an opportunity for high-resolution monitoring, emission source identification, exposure mitigation and managing IAQ and energy efficiency, among others. This article discusses the strengths and limitations that LCS offer for applications in the field of IAQ monitoring; it provides an overview of existing sensor technologies and gives recommendations for different indoor applications, considering their performance in the complex indoor environment and discussing future trends

Fast X-Ray Fluorescence Microtomography of Hydrated Biological Samples

Metals and metalloids play a key role in plant and other biological systems as some of them are essential to living organisms and all can be toxic at high concentrations. It is therefore important to understand how they are accumulated, complexed and transported within plants. In situ imaging of metal distribution at physiological relevant concentrations in highly hydrated biological systems is technically challenging. In the case of roots, this is mainly due to the possibility of artifacts arising during sample preparation such as cross sectioning. Synchrotron x-ray fluorescence microtomography has been used to obtain virtual cross sections of elemental distributions. However, traditionally this technique requires long data acquisition times. This has prohibited its application to highly hydrated biological samples which suffer both radiation damage and dehydration during extended analysis. However, recent advances in fast detectors coupled with powerful data acquisition approaches and suitable sample preparation methods can circumvent this problem. We demonstrate the heightened potential of this technique by imaging the distribution of nickel and zinc in hydrated plant roots. Although 3D tomography was still impeded by radiation damage, we successfully collected 2D tomograms of hydrated plant roots exposed to environmentally relevant metal concentrations for short periods of time. To our knowledge, this is the first published example of the possibilities offered by a new generation of fast fluorescence detectors to investigate metal and metalloid distribution in radiation-sensitive, biological samples

Bacterial shifts during in-situ mineralization bio-treatment to non-ferrous metal(loid) tailings

This is the author accepted manuscript. The final version is available from Elsevier via the DOI in this recordNonferrous mine tailings have caused serious problems of co-contamination with metal(loid)s. It is still a global challenge to cost-effectively manage and mitigate the effect of the mining wastes. We conducted an in-situ bio-treatment of non-ferrous metal(loid) tailings using a microbial consortium of sulfate reducing bacteria (SRB). During the bio-treatment, the transformation of metal(loid)s (such as Cu, Fe, Mn, Pb, Sb, and Zn) into oxidizable and residual fractions in the subsurface tended to be higher than that observed in the surface. As well the mineral compositions changed becoming more complex, indicating that the sulfur reducing process of bio-treatment shaped the bio-transformation of metal(loid)s. The added SRB genera, especially Desulfotomaculum genus, colonized the tailings suggesting the coalescence of SRB consortia with indigenous communities of tailings. Such observation provides new insights for understanding the functional microbial community coalescence applied to bio-treatment. PICRUSt analysis revealed presence of genes involved in sulfate reduction, both assimilatory and dissimilatory. The potential for the utilization of both inorganic and organic sulfur compounds as S source, as well as the presence of sulfite oxidation genes indicated that SRB play an important role in the transformation of metal(loid)s. We advocate that the management of microorganisms involved in S-cycle is of paramount importance for the in situ bio-treatment of tailings, which provide new insights for the implementation of bio-treatments for mitigating the effect of tailings.National Science Foundation of ChinaMinistry of Science and Technology of ChinaCentre National de la Recherche ScientifiqueRoyal Society Newton Mobility GrantNational Natural Science Foundation International Joint collaboration China-Swede

Office characteristics and dry eye complaints in European workers: The OFFICAIR study

Objectives Ocular discomfort is a prevalent health complaint in offices. It is hypothesized that, in addition to individual and occupational factors, the buildings' indoor environment may affect eye complaints. However, insight in potential building-related causal factors, needed to allow development of effective prevention strategies in building design, operation and maintenance is limited. This study aimed to investigate the relations between modern office building characteristics and dry eye complaints. Methods Comprehensive characteristics of 167 office buildings in eight European countries, were linked to questionnaire data from 7441 office workers. Multilevel modeling was applied to explore relations between building characteristics and self-reported dry eye complaints, in a cross-sectional study. Results Among office workers investigated, 34% declared dry eye complaints during the past four weeks. Majority of workers (91.2%) experiencing these symptoms, reported improvement on days away from the office. After full adjustment, the regression model revealed a significant increased risk for: proximity (<100 m) to potential sources of outdoor air pollution (OR: 1.41, 95% CI: 1.06–1.88), absence of operable windows (OR: 1.70, 95% CI: 1.34–2.16), portable humidifiers in the offices (OR: 1.58, 95% CI: 1.18–2.11), exposed concrete and/or plaster (OR: 1.29, 95% CI 1.02–1.62) and dispersion and/or emulsion paint as wall covering in offices (OR: 1.20, 95% CI: 1.01–1.41). A negative association was found for cleaning surfaces at least once per week (OR: 0.75, 95% CI: 0.61–0.91). Conclusions Building characteristics were associated with dry eye complaints of office workers. Focused studies are recommended to investigate underlying causes to prevent these symptoms.Architectural Engineering +TechnologyBuilding Physic

Perceived indoor environment and occupants’ comfort in European “modern” office buildings: The OFFICAIR study

Indoor environmental conditions (thermal, noise, light, and indoor air quality) may affectworkers’ comfort, and consequently their health and well-being, as well as their productivity.This study aimed to assess the relations between perceived indoor environment and occupants’comfort, and to examine the modifying effects of both personal and building characteristics.Within the framework of the European project OFFICAIR, a questionnaire survey was administered to7441 workers in 167 “modern” office buildings in eight European countries (Finland, France, Greece,Hungary, Italy, The Netherlands, Portugal, and Spain). Occupants assessed indoor environmentalquality (IEQ) using both crude IEQ items (satisfaction with thermal comfort, noise, light, and indoorair quality), and detailed items related to indoor environmental parameters (e.g., too hot/coldtemperature, humid/dry air, noise inside/outside, natural/artificial light, odor) of their officeenvironment. Ordinal logistic regression analyses were performed to assess the relations betweenperceived IEQ and occupants’ comfort. The highest association with occupants’ overall comfort wasfound for “noise”, followed by “air quality”, “light” and “thermal” satisfaction. Analysis of detailedparameters revealed that “noise inside the buildings” was highly associated with occupants’ overallcomfort. “Layout of the offices” was the next parameter highly associated with overall comfort.The relations between IEQ and comfort differed by personal characteristics (gender, age, and theEffort Reward Imbalance index), and building characteristics (office type and building’s location).Workplace design should take into account both occupant and the building characteristics in order toprovide healthier and more comfortable conditions to their occupants.Indoor Environmen