Air CO2 Concentration Research Articles

Time variability of cumulative carbon dioxide concentration for adequacy assessment of greenspace: A case study in Surabaya, Indonesia

Introduction: The upward movement of Carbon dioxide (CO2) mass into the air and downwards towards the earth's surface, especially vegetative areas, affected the variability of CO2 concentration in the ambient air. In this pattern, this study aimed to determine the net cumulative value of CO2 concentration (Net_CO2-Con) in an urban area to assess the adequacy of greenspace.
 Materials and methods: This research method uses CO2 concentration observations within 24 h in 137 observation locations covering an area of 350 km2 in Surabaya city. The sampling location was set at a height of 2 m above the local ground. The CO2 concentration observations were carried out in the dry season and the rainy season for a total of 640 air samples.
 Results: The results of this study obtained Net_CO2-Con values for ambient CO2 concentrations in a daily pattern. Starting at night there was a flow CO2 flux into the air, which reached its peak in the morning, in about 90% of the city area. This event was evidence of a lack of CO2 absorption due to the lack of extensive vegetative areas. On a bright day the CO2 flux flows towards the land, which indicated the presence of vegetation absorption in addition to soil absorption. The seasonal time variability of CO2 flux density had the same pattern for the daily time variability.
 Conclusion: Mapping for CO2 flux could be an approach to determine the adequacy of greenspace. Areas of upward movement of CO2 flux density were priority areas for greenspace intensification.
 

How Safe is Singing Under Pandemic Conditions? - CO[formula omitted]-Measurements as Simple Method for Risk Estimation During Choir Rehearsals

The SARS-CoV-2 pandemic has forced choirs to pause or at least to restrict rehearsals and concerts. Nevertheless, an uncertainty about the risks of infection while singing remains, especially with regard to distances, duration of singing, number of singers and their positions in the room, size of the room as well as ventilation strategies. Based on the assumption that CO2 is a suitable indicator for the exhaled aerosols in a room, it is the aim of this study to deduce recommendations for a choir rehearsal with a minimum risk of infection. During two choir rehearsals in a typical, nonventilated classroom, we installed 30 CO2 sensors, which allow spatial and temporal evaluation of the CO2 dispersion during singing. Various singing and ventilation phases were applied and the rates of CO2 increase during singing as well as its decrease during ventilation phases were evaluated and compared for different scenarios. The measurements reveal a linear relation between the duration of singing, size of the room and number of persons. For our size of the room of 200 m3 the average CO2 increase is 1.83 ppm/min per person. Masks or pure breathing without singing do - in contrast to aerosol dispersion - not influence the rate of CO2 increase. CO2 disperses fast and homogeneously on horizontal planes. However, a vertical layering with a maximum CO2 concentration is observed near the ceiling. Shock ventilation shows the largest CO2 decrease within the first 5 min, after 10 min of ventilation the outside base concentration of 400 ppm is reached again. The evaluated relations allow to calculate safe singing times for a defined number of singers and size of the room until a critical threshold of 800 ppm is reached. Furthermore, in order to monitor the actual CO2 concentration during choir rehearsal, just one CO2 sensor is representative for the air quality and CO2 concentration of the whole room and thus considered sufficient. For an early warning, it should be installed near the ceiling. Direct singing into a sensor should be avoided. A ventilation time of just 5 min is recommended which represents a compromise between strong CO2 reduction and still sufficient room temperature during winter time.

Climate Change Effects on Grapevine Physiology and Biochemistry: Benefits and Challenges of High Altitude as an Adaptation Strategy.

Grapevine berry quality for winemaking depends on complex and dynamic relationships between the plant and the environment. Winemakers around the world are demanding a better understanding of the factors that influence berry growth and development. In the last decades, an increment in air temperature, CO2 concentration and dryness occurred in wine-producing regions, affecting the physiology and the biochemistry of grapevines, and by consequence the berry quality. The scientific community mostly agrees in a further raise as a result of climate change during the rest of the century. As a consequence, areas most suitable for viticulture are likely to shift into higher altitudes where mean temperatures are suitable for grape cultivation. High altitude can be defined as the minimum altitude at which the grapevine growth and development are differentially affected. At these high altitudes, the environments are characterized by high thermal amplitudes and great solar radiations, especially ultraviolet-B (UV-B). This review summarizes the environmental contribution of global high altitude-related climatic variables to the grapevine physiology and wine composition, for a better evaluation of the possible establishment of vineyards at high altitude in climate change scenarios.

Light-Induced Synthesis of Oxygen-Vacancy-Functionalized Ni(OH)2 Nanosheets for Highly Selective CO2 Reduction.

Solar-driven CO2 reduction into fuels and chemicals has gained increasing attention in recent years. In this study, oxygen-vacancies-functionalized Ni(OH)2 (OVs-Ni(OH)2 ) nanosheets are synthesized by a photochemical method to serve as a catalyst for CO2 reduction. Characterization reveals that COOH* is the key intermediate for CO2 -to-CO photoreduction. Experimental results and theoretical calculations confirm that OVs modification can greatly modulate the interaction strength between the OVs-Ni(OH)2 and CO2 , while lowering the energy barrier for COOH* formation, thereby preferentially facilitating CO2 reduction. As a result, the OVs-Ni(OH)2 catalyst exhibits outstanding activity and selectivity for CO2 -to-CO photoreduction with visible light. A CO evolution rate of 31.58 μmol h-1 (0.35 mg catalyst, 90228 μmol h-1 g-1 ) with a selectivity of 98 % over OVs-Ni(OH)2 was achieved, outperforming most analogous reported catalysts. Moreover, even under a low CO2 concentration of 0.04 % (representative of the CO2 concentration in air) and low reaction temperature (273 K, 0 °C), this catalyst can still trigger CO2 reduction. This work provides a new method to synthesize OVs-Ni(OH)2 catalysts for efficient CO2 reduction and establishes a relationship between the OVs and the catalytic activity, which may guide the design of highly selective CO2 reduction catalysts.

Metrology for low-cost CO<sub>2</sub> sensors applications: the case of a steady-state through-flow (SS-TF) chamber for CO<sub>2</sub> fluxes observations

Abstract. Soil CO2 emissions are one of the largest contributions to the global carbon cycle, and a full understanding of processes generating them and how climate change may modify them is needed and still uncertain. Thus, a dense spatial and temporal network of CO2 flux measurements from soil could help reduce uncertainty in the global carbon budgets. In the present study, the design, assembly, and calibration of low-cost air enquirer kits, including CO2 and environmental parameters sensors, is presented. Different types of calibrations for the CO2 sensors and their associated errors are calculated. In addition, for the first time, this type of sensor has been applied to design, develop, and test a new steady-state through-flow (SS-TF) chamber for simultaneous measurements of CO2 fluxes in soil and CO2 concentrations in air. The sensors' responses were corrected for temperature, relative humidity, and pressure conditions in order to reduce the uncertainty in the measured CO2 values and of the following calculated CO2 fluxes based on SS-TF. CO2 soil fluxes measured by the proposed SS-TF and by a standard closed non-steady-state non-through-flow (NSS-NTF) chamber were briefly compared to ensure the reliability of the results. The use of a multiparametric fitting reduced the total uncertainty of the CO2 concentration measurements by 62 %, compared with the uncertainty that occurred when a simple CO2 calibration was applied, and by 90 %, when compared to the uncertainty declared by the manufacturer. The new SS-TF system allows the continuous measurement of CO2 fluxes and CO2 ambient air with low cost (EUR ∼1200), low energy demand (<5 W), and low maintenance (twice per year due to sensor calibration requirements).

Development of CO2 Concentration Prediction Tool for Improving Office Indoor Air Quality Considering Economic Cost

Ventilation is becoming increasingly important to improve indoor air quality and prevent the spread of COVID-19. This study analyzed the indoor air quality of office spaces, where occupants remain for extended periods, among multi-use facilities with an increasing need for ventilation system application. A “tool for office space CO2 prediction and indoor air quality improvement recommendation” was developed. The research method was divided into four steps. Step 1: Analysis of indoor air quality characteristics in office spaces was carried out with a questionnaire survey and indoor air quality experiment. Based on the CO2 concentration, which was found to be a problem in the indoor air quality experiment in the office space, Step 2: CO2 concentration prediction tool for office spaces, which requires inputs of regional and spatial factors and architectural and equipment elements, was developed. In Step 3: Development and verification of prediction tool considering economic feasibility, the cost of energy recovery ventilation systems based on the invoices of the energy recovery ventilation manufacturers was analyzed. In Step 4: Energy recovery ventilation proposal and indoor CO2 forecast, Office Space B, which can accommodate up to 15 people, was derived as an example of the proposed tool. As a result of the prediction, the optimal air volume of the energy recovery ventilation was determined according to the “office CO2 prediction and indoor air quality improvement recommendations”. This study introduced simple tools, which can be used by non-experts, that are capable of showing changes in indoor air quality, CO2 concentration and cost according to activities.

Effect of the odour compound from Periploca sepium Bunge on the physiological and biochemical indices, photosynthesis and ultrastructure of the leaves of Humulus scandens (Lour.) Merr.

Natural odour compounds could be a potential alternative to synthetic herbicides. The odour compound of Periploca sepium Bunge, named 2-hydroxy-4-methoxy-benzaldehyde (HMB), is a herbicidal compound. However, its herbicidal mechanism is unclear. In this experiment, the physiological and biochemical indices, ultrastructure, and photosynthetic function of the leaves of Humulus scandens (Lour.) Merr. treated by HMB were assessed to elucidate the herbicidal mechanism. The results of physiological and biochemical indices are as follows: First, after 4 h of treatment with 2.5 and 5.0 mg/mL, the damage rates in the membrane permeation assay were 74.7% and 89.1%, respectively. Second, compared to the negative control group, multiple physiological and biochemical indices of the two treated groups were changed, including catalase content (−18.5 and −26.5 ng/mL), superoxide dismutase content (−27.4 and −56.6 ng/mL), peroxidase content (382.0 and 880.0 ng/mL), reactive oxygen species content (16.7 and 27.2 ng/mL), malondialdehyde content (8.9 and 25.2 nmol/g), and water potential values (0.2 and 0.3 MPa), except for the photosynthetic pigment contents (chlorophyll a, b, and carotene). Furthermore, the results of transmission electron microscopy showed that the organelles in the mesophyll tissue cells disappeared and severe plasmolysis led to cell atrophy after 4 h of treatment. There were fewer starch granules after 24 h of treatment, but there was no obvious abnormality in the upper and lower epidermal cells. The results of photosynthetic function showed that in the light response, the net photosynthetic rate (Pn), transpiration rate (Tr), stomatal conductance (Gs), and stomatal limitation value of the tested leaves were lower than those of the negative control group by 26.6 μmol·m−2·s−1, 7.7 mmol·m−2·s−1, 0.9 mol·m−2·s−1, and 0.2, respectively. However, the intercellular CO2 concentration (Ci) increased and was higher than the air CO2 concentration. In the CO2 response, the Pn, Tr and Gs of the tested leaves first increased and then decreased, but the Ci value continuously increased and finally reached 1727.5 μmol·mol−1. It is obvious that HMB may have inhibited the effect on the photosynthetic system of the tested leaves. Overall, HMB killed the weeds by destroying the structure and multiple physiological functions of the tested leaves.

Cultivation of Scenedesmus dimorphus with air contaminants from a pig confinement building

The continual consolidation and concentration of animal feeding operations (AFOs) raises various environmental challenges, including air pollutant emission. Cost-effective mitigation technologies are pursued to protect the health and wellbeing of animals and farmers as well as the environment. Previous lab studies utilized ammonia (NH3) and carbon dioxide (CO2), two major air pollutants in AFOs, for microalgal cultivation. However, the field performance of this algae-based mitigation approach has yet to be investigated. In this study, two photobioreactors (PBRs) were tested in a nursery pig barn to mitigate NH3 and CO2 while growing Scenedesmus dimorphus (S. dimorphus). Pit air was fed into the PBRs where the two pollutants were adsorbed by S. dimorphus as nutrients to produce algal biomass and oxygen gas (O2). The cleaned air then recirculated back to the room space. S. dimorphus reached its maximum cell count on the 17th day of the experiment when NH3 and CO2 concentrations in the pit air were 25.6 ppm and 3150 ppm, respectively. The maximum biomass concentration occurred on the 11th day when the NH3 and CO2 concentrations were 14.6 and 2250 ppm, respectively. The average mitigation efficiency was 31–50% for NH3 and 1–1.7% for CO2. The costs for removing 1 g NH3 and CO2 were estimated to be $3.77 and $0.20, respectively. This study shows that an integrated PBR system is technically feasible for reducing pig barn air pollutant emission while producing microalgae as a valuable product.

Carbon dioxide enrichment of PDMS/PSf composite membranes for solving the greenhouse effect and food crisis

Carbon dioxide-enriched air can be used to promote the photosynthesis of plants, accelerate plant growth and fix more carbon dioxide which means that it can solve the food crisis and the greenhouse effect at the same time. The carbon dioxide-enriched air permeance and CO2 concentration in the permeate of the membrane must reach 2000 GPU and 800 ppm to meet the practical needs of accelerating the growth of plants. A polydimethylsiloxane (PDMS)/polysulfone (PSf) composite membrane with appropriate modification that can meet the set goals was successfully prepared. The structure of the membrane selective layer can be precisely adjusted by comprehensively surveying the thickness of the selective layer, the amount of crosslinking agent added, the UV/O3 treatment time and the heat treatment. The carbon dioxide-enriched air permeance and CO2 concentration in the permeate of the modified PDMS/PSf composite membrane reached 2336 GPU and 814 ppm, respectively. In this work, the prepared membrane was also applied to cultivate plants. Comparing Glebionis coronaria grown in an atmospheric environment with Glebionis coronaria grown in CO2-enriched air, the plant mass and plant height increased by 240% and 40%, respectively, after 4 weeks of growth. Experimental results show that the development of carbon dioxide-enriched PDMS/PSf-modified membranes has strong potential to capture CO2 and accelerate the food production.

Molecular and Genomic Characterization of the Pseudomonas syringae Phylogroup 4: An Emerging Pathogen of Arabidopsis thaliana and Nicotiana benthamiana

Environmental fluctuations such as increased temperature, water availability, and air CO2 concentration triggered by climate change influence plant disease dynamics by affecting hosts, pathogens, and their interactions. Here, we describe a newly discovered Pseudomonas syringae strain found in a natural population of Arabidopsis thaliana collected from the southwest of France. This strain, called Psy RAYR-BL, is highly virulent on natural Arabidopsis accessions, Arabidopsis model accession Columbia 0, and tobacco plants. Despite the severe disease phenotype caused by the Psy RAYR-BL strain, we identified a reduced repertoire of putative Type III virulence effectors by genomic sequencing compared to P. syringae pv tomato (Pst) DC3000. Furthermore, hopBJ1Psy is found exclusively on the Psy RAYR-BL genome but not in the Pst DC3000 genome. The plant expression of HopBJ1Psy induces ROS accumulation and cell death. In addition, HopBJ1Psy participates as a virulence factor in this plant-pathogen interaction, likely explaining the severity of the disease symptoms. This research describes the characterization of a newly discovered plant pathogen strain and possible virulence mechanisms underlying the infection process shaped by natural and changing environmental conditions.

Health impact of natural gas emission at Cava dei Selci residential zone (metropolitan city of Rome, Italy)

Natural gas hazard was assessed at Cava dei Selci, a residential neighbourhood of Marino (Rome) by a joint study of gas emissions and related health problems. Here a densely urbanized zone with 4000 residents surrounds a dangerous natural gas discharge where, along the years, dozens of animals were killed by the gas. Gas originates from Colli Albani volcano and consists mostly of CO2 with ~ 1 vol% of H2S. In recent years, several gas-related accidents occurred in the urbanized zone (gas blowouts and road collapses). Some houses were evacuated because of hazardous indoor air gas concentration. Gas hazard was assessed by soil CO2 flux and concentration surveys and indoor and outdoor air CO2 and H2S concentration measurements. Open fields and house gardens release a high quantity of CO2 (32.23 tonnes * day−1). Inside most houses, CO2 air concentration exceeds 0.1 vol%, the acceptable long-term exposure range. In several houses both CO2 and H2S exceed the IDLH level (Immediately Dangerous to Life and Health). An epidemiological cohort study was carried out on the residents of two Cava dei Selci zones with high (zone A) and medium (zone B) gas hazard exposure, using the rest of Marino as reference zone. We found excess mortality and emergency room visits (ERV) related to high exposure to CO2 and H2S; in particular, an increased risk of mortality and ERV for diseases of central nervous system (HR 1.57, 95% CI 0.76–3.25 and HR 5.82, 95% CI 1.27–26.56, respectively) was found among men living in zone A.

Experimental study on CO2 concentration and indoor thermal comfort pf different classrooms during new normal in the University of Kitakyushu

Indoor thermal comfort and indoor air quality in educational buildings are essential for students’ health and learning performance. In this pandemic situation, regulation of door and ventilation opening in the classroom for offline class become important for infection spread prevention. Based on Japan Ministry of Health, Labour and Welfare standard, CO2 concentration level shall not exceed 1,000 ppm to prevent infection spreading. Yet significant amount of door and ventilation opening may reduce the level of thermal comfort because the Air-conditioning leakage. This study aims to evaluate CO2 concentration and indoor thermal comfort in two classrooms with door and ventilation opening regulation. In this study, the experimental measurements conducted in spring and summer season in The University of Kitakyushu. The method used in this study is by measuring air temperature, relative humidity, and CO2 concentration. The research results are expected to be a reference for the optimal application of regulations for thermal comfort and infection spread prevention.

Innovative method for CO2 fixation and storage

The concentration of CO2 in Earth’s atmosphere has been gradually increasing since the Industrial Revolution, primarily as a result of the use of fossil fuels as energy sources. Although coal and oil have been vital to the development of modern civilization, it is now recognized that atmospheric CO2 levels must be reduced to avoid the serious effects of climate change, including natural disasters. Consequently, there is currently significant interest in developing suitable methods for the fixation of CO2 in the air and in exhaust gases. The present work demonstrates a simple yet innovative approach to the chemical fixation of extremely low and very high CO2 concentrations in air, such as might result from industrial sources. This process is based on the use of aqueous solutions of the water-soluble compounds NaOH and CaCl2, which react with CO2 to produce the harmless solids CaCO3 (limestone) and NaCl (salt) via intermediates such as NaHCO3 and Na2CO3. The NaCl generated in this process can be converted back to NaOH via electrolysis, during which H2 (which can be used as a clean energy source) and Cl2 are produced simultaneously. Additionally, sea water contains both NaCl and CaCl2 and so could provide a ready supply of these two compounds. This system provides a safe, inexpensive approach to simultaneous CO2 fixation and storage.

Field Measurements of Bedroom Environment in Winter and Summer on Qinghai-Tibet Plateau

Field measurements of the bedroom environment on Qinghai-Tibet Plateau was conducted by continuously measuring the air temperature, relative humidity, and CO2 concentration in the bedrooms of 197 residents (100 in winter and 97 in summer) for 7 days. And the daily environmental controls of residents were recorded. The results showed that the night-time thermal environment in bedrooms on the Qinghai-Tibet Plateau was more warmer and wetter in summer than in winter, but the CO2 concentration was lower in winter. On both winter and summer nights, drops in air temperature, relative humidity and CO2 concentration in the bedrooms were found when doors or windows were opened, increases in relative humidity and CO2 concentration in bedrooms were found when there were more occupants in the bedrooms. This study also found there was a greater reduction of CO2 concentrations when doors or windows were opened in the bedrooms of multiple occupants compared to the bedrooms of a single occupant. And on winter nights, the humidity increase in the bedrooms caused by the action of the humidifier was not affected by the status of doors and windows.

A Real-Time Output–Loss Method for Monitoring Heat Rate for Coal-Fired Power Plants

Abstract This paper describes a real-time performance monitoring method based on PTC 4-2013 for determining instantaneous heat rates for coal-fired power plants. The calculation protocol uses a modified output–loss approach applied to a control volume that closely conforms to the boiler. The largest energy balance term is the heat transfer rate to the steam, which is known accurately in real-time when the plant employs properly calibrated instrumentation. The first-law energy balance also requires a balanced combustion equation which depends on coal composition, which is not known in real-time. A periodic or alert-driven calibration utilizes an ultimate analysis of a carefully collected coal sample and historic plant data obtained during the collection time of the coal sample. This is used to calculate correction factors for the coal mass flowrate, air preheater leakage, and CO2 and SO2 concentrations at the economizer exit derived from continuous emissions monitoring systems (CEMS) measurements performed at that location. The iterative calculations required to determine the coal composition in real-time are presented. The real-time performance algorithm exhibited significant sensitivity associated with measurements of the steam heat transfer rate, which was the dominant term in the overall boiler energy balance. Other input parameters generally yielded a much lower influence on calculated heat rate. It was concluded that for optimal accuracy of the output–loss method the steam and coal mass flowrates must be measured as accurately as possible.

Assessment of productivity in different thermal working environments

In the paper the assessment of subjective productivity is presented as a function of indoor environment parameters on the example of students situated in the intelligent building. The volunteers in several different rooms (of various air temperature, humidity and CO2 concentration) filled in the questionnaires and assessed their current productivity. It might be related to both the educational performance and office work of low intensity. The physical parameters were measured with the microclimate high accuracy meter. The data obtained during the measurements of the indoor air parameters were compared with the subjective assessments of the volunteers and conclusions were drawn as to the impact of the working environment on the productivity of room users. The gathered experimental material might be useful for the building managers, so that proper indoor conditions within buildings might be applied that maximize productivity and working performance.

BioCro II: a software package for modular crop growth simulations

Abstract The central motivation for mechanistic crop growth simulation has remained the same for decades: to reliably predict changes in crop yields and water usage in response to previously unexperienced increases in air temperature and CO2 concentration across different environments, species and genotypes. Over the years, individual process-based model components have become more complex and specialized, increasing their fidelity but posing a challenge for integrating them into powerful multiscale models. Combining models is further complicated by the common strategy of hard-coding intertwined parameter values, equations, solution algorithms and user interfaces, rather than treating these each as separate components. It is clear that a more flexible approach is now required. Here we describe a modular crop growth simulator, BioCro II. At its core, BioCro II is a cross-platform representation of models as sets of equations. This facilitates modularity in model building and allows it to harness modern techniques for numerical integration and data visualization. Several crop models have been implemented using the BioCro II framework, but it is a general purpose tool and can be used to model a wide variety of processes.

Field Study of thermal comfort of indoor fitness places in cold region

A healthy body is the foundation of everything. The indoor environment comfort of fitness places has been paid more and more attention. However, there is a lack of relevant standards for the thermal environment of indoor sports and fitness venues in China, especially the research on the indoor thermal environment in different seasons. Therefore, in our study, physical environment parameters such as indoor temperature and humidity, black ball temperature, air flow rate and CO2 concentration in 9 indoor fitness places in Xi ‘an in different seasons were measured on site. At the same time, a subjective questionnaire survey was conducted on thermal sensation and acceptability of the people who were exercising in the fitness places. Through subjective questionnaire analysis, respondents generally have a high degree of satisfaction and acceptance of temperature, and the average thermal comfort vote is the highest when the indoor temperature is 17.9-23.9°C. In addition, the thermal comfort of different sports in the same space also has certain differences. The fitness people indoor have lower satisfaction with air flow and air quality. Based on the study of the factors affecting indoor thermal comfort, this paper puts forward the improvement strategies for improving indoor thermal comfort, and provides scientific basis for the design and operation of fitness venues.

Inhaled CO2 Concentration While Wearing Face Masks: A Pilot Study Using Capnography.

Background:Face masks are recommended based on the assumption that they protect against SARS-CoV-2 transmission, however studies on their potential side effects are still lacking. We aimed to evaluate the inhaled air carbon dioxide (CO2) concentration, when wearing masks.Methods:We measured end-tidal CO2 using professional side-stream capnography, with water-removing tubing, (1) without masks, (2) wearing a surgical mask, and (3) wearing a FFP2 respirator (for 5 minutes each while seated after 10 minutes of rest), in 146 healthy volunteers aged 10 to 90 years, from the general population of Ferrara, Italy. The inhaled air CO2 concentration was computed as: ([mask volume × end-tidal CO2] + [tidal volume − mask volume] × ambient air CO2)/tidal volume.Results:With surgical masks, the mean CO2 concentration was 7091 ± 2491 ppm in children, 4835 ± 869 in adults, and 4379 ± 978 in the elderly. With FFP2 respirators, this concentration was 13 665 ± 3655 in children, 8502 ± 1859 in adults, and 9027 ± 1882 in the elderly. The proportion showing a CO2 concentration higher than the 5000 ppm (8-hour average) acceptable threshold for workers was 41.1% with surgical masks, and 99.3% with FFP2 respirators. Adjusting for age, gender, BMI, and smoking, the inhaled air CO2 concentration significantly increased with increasing respiratory rate (mean 10 837 ±3712 ppm among participants ⩾18 breaths/minute, with FFP2 respirators), and among the minors.Conclusion:If these results are confirmed, the current guidelines on mask-wearing should be reevaluated.

3-D Geological Mapping of Rocks Potentially Suitable for Capturing Carbon Dioxide from the Atmosphere

Rapid increase of the Anthropocene ambient air CO2 concentration value is the main cause of the 1.2 o C global temperature rise creating the recent adverse climate and weather changes. Promising new methods to capture CO2 from the air are being developed but remain too expensive for worldwide applications. Mantle-derived rocks, primarily basalts, peridotites and serpentinites are likely to play an important role in future CO2 reduction because of relatively rapid disintegration of minerals (including olivine and serpentine) in these rocks potentially resulting in widespread CO2 capture. Examples to be discussed include artificially enhanced carbonization of water emitted from ophiolites, and acid dissolution of serpentinites resulting in indirect mineral carbonation by optimizing temperature and pressure conditions. Reconstruction of a large cone-shaped body of serpentinite situated within the Mount Albert peridotite intrusion in Québec is presented as an example of the rôle 3-D geologic mapping can play in future CO2 reduction efforts.