Maintenance Of Air Quality Research Articles

Poly3‐Hexylthiophene Titanium Dioxide (P3HT‐TiO2) Composite Sensor for High Response Detection of Ammonia at Room Temperature

AbstractGas sensors for ammonia (NH3) play a crucial role in the maintenance of air quality, preservation of the atmosphere, and evaluation of human health. However, the endeavor to attain a high level of sensitivity in detecting NH3 under ambient conditions remains a challenging task. In this work, poly(3‐hexylthiophene)s and titanium dioxide (P3HT‐TiO2) heterostructure NH3 gas‐sensitive material was prepared, and by drop‐casting the material onto a substrate with Au interdigital electrodes, a sensor for high‐response detection of NH3 at room temperature was constructed. The designed gas sensor exhibited a high response signal of 114.61 % toward 15 ppm NH3 at room temperature (25 °C) with good reproducibility, strong long‐term stability, and excellent selectivity. Moreover, by analyzing the response law of the sensor under different humidity conditions, it has been noted that both excessively high and excessively low levels of humidity adversely affect the sensor's response. The remarkable increase in NH3 sensing properties is attributed to the synergistic enhancement effect of P−N heterojunction formed between P3HT and TiO2. This NH3 gas sensor exhibits tremendous potential for use due to its straightforward structure and outstanding ammonia sensing performance.

Oxidative stress caused by lead in the lichen Xanthoria parietina

The assessment of the air quality is a major concern to the current time. The monitoring and maintenance of air quality necessarily pass by detecting and estimating the overall air pollution. The use of lichens must be an assessmenttool to be studied. In our work we were interested about the toxicity of lead on the various parameters of stress in the lichen Xanthoria parietina. For this purpose, lichen thalli have been incubated at lead concentrations of 0, 0.5, 1.0, 5.0 and 10.0 mM, for time scale of 0, 24, 48 and 96 hours. The obtained results showed that lead has an action on the various studied parameters, and the intensity of oxidative stress observed in lichens thalli depends on the concentration, and time of exposure. Lead induced a decrease in chlorophyll and protein contents, and an increase in the contents of catalase, hydrogen peroxide and reduced glutathione. Furthermore, the results also showed that high concentrations of lead caused total destruction of reduced glutathione.

Integrating perceptions of ecosystem services in adaptive management of country parks: A case study in peri-urban Shanghai, China

As a type of peri-urban green space with natural environments and countryside features, country parks provide numerous ecosystem services (ES) for human beings. In China, the multifunctional characteristics and diverse social groups related to the country park construction in the context of urbanization indicate that these ES need to be managed in the social dimension through adaptive decision-making. However, little work has focused on the perceptions of ES for country park management. In this study, we developed a three-step research framework aiming to integrate ES perceptions in adaptive country park management. We carried out face-to-face photo-elicitation questionnaire surveys (n = 229) in a country park pilot in Shanghai to analyze the perceptions of ES by park users. Multiple analytical methods, including statistical analyses, importance-performance analysis, and ES indexes, were applied to reveal the linkages among perceived ES, users’ characteristics, and specific landscape features. Our results showed that water and air quality maintenance, aesthetic, habitat, and physical and mental health, were perceived as the most important, highest performance, and highest priority ES. Users’ education level and their self-reported knowledge about the country park were the two most important variables that explained perceived ES. Perceptions of user groups differed along the distance of the place of residence from the study area, with locals assigning high priorities to provisioning ES and cognitive cultural ES and more distant visitors assigning high priority to education. Semi-natural landscape features, such as lakes and rivers, marsh, swamp forest, and lotus ponds, were perceived as providing the most ES. We further communicated and discussed the results with managers and experts, and provided insights for the next stage of management. We argue that adaptive management should be woven toward environmental justice by understanding the diverse perspectives and views of users on ES.

Fabrication and characterization of a TiO2 nanoparticles polypropylene membrane: application in indoor air quality maintenance

The production of innovative materials with improved features applicable in many domains is a key application of nanotechnology with far-reaching implications for modern society. Nanoparticle-based polymer composites are quickly becoming one of the most promising new materials, with potential uses spanning the chemical, physical, and biological sciences as well as engineering. Application of nanoparticle-based polymer composites for indoor air quality maintenance was discussed, as were their production, hybrid functionalization, and feasible synthesis procedures (filter membrane). The batch foaming procedure has been used to create foam from the thermoplastic polymer polypropylene (PP). Foaming is a blown process, where carbon dioxide is utilised as the blowing agent. Nanoparticles of titanium oxide (nano TiO2) are also used for reinforcement. Scanning electron microscopy (SEM) was utilised to investigate the NTPMs' surface morphology, while other physio-chemical characteristics were investigated by means of various analytical methods, including Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermo-gravimetric analysis (TGA). The adsorption isotherm and kinetics of water vapours were analysed to get insight into the water vapour adsorption characteristics of the NTPMs. The kinetics of adsorption pointed to a combination of intraparticle diffusion and liquid field driving processes for the transport of water vapours. Because of their high dehumidification effectiveness, synthetic NTPMs have the potential to replace many of the currently used traditional solid desiccant materials

Indoor Air Quality Diagnosis Program for School Multi-Purpose Activity and Office Spaces

This study presents a simple indoor air quality diagnosis program for school office spaces, which are occupied for long durations by teachers, and indoor sports facilities, whose utilization has been on the rise in response to high concentrations of pollutants in outdoor air. The proposed program was made with Visual Basic for Applications (VBA) and Microsoft Excel. This program requires inputs which can be easily determined or measured even by nonexperts and can check the current status of indoor air quality such as CO2 and PM2.5 concentrations and predict the effect if changes are made. In addition, it is possible to diagnose indoor air quality before and after class and compare it with the initial plan so that if it exceeds the indoor air quality maintenance standard range, it can be improved by using a ventilation system and an air purifier. The development of the program was divided into four stages. First, prior research on the influencing factors was investigated. Second, influencing factors affecting the changes in PM2.5 and CO2 concentrations were selected by category to accommodate the various factors, and those selected as input were presented. Third, mass and concentration conservation equations were utilized to derive PM2.5 and CO2 concentration prediction equations according to activity and passage of time, and a VBA code was used for constructing the program. For verification of the developed program, the calculation results were compared with the measured data. The mean absolute percentage error (MAPE) was 19.47% for PM2.5 concentration. In order to improve accuracy, Simulation 2, in which the wind speed and indoor/outdoor air pressure difference are corrected, is presented. The MAPE of PM2.5 concentration by the corrected Simulation 2 was lowered 5.15%.

Characteristics of the thermal environment, air quality, and passenger comfort in the underground transfer space of metro stations in Beijing

With the increase in Beijing's metro mileage and passenger numbers, it is becoming especially necessary to investigate the indoor environment and passenger comfort of metro stations. In this study, the transfer spaces in the top seven transfer stations with the largest passenger flow within the Beijing metro system were selected for conducting indoor environment (thermal environment and air quality) measurements and a subjective comfort survey of over 600 passengers. The results showed that the thermal environment and air quality experienced by passengers changed dynamically with the passenger transfer process. Indoor temperature and relative humidity (RH) were affected by not only aboveground weather changes but also station depth, and the indoor temperature in winter was more comfortable than that in summer. The trend in subjective feelings of passengers' thermal comfort was similar to that of the relative warmth index (RWI) evaluation of seven transfer stations during the measurement periods, and passengers' thermal comfort during the summer morning rush hours was not ideal but was slightly hot overall. Although the concentrations of carbon dioxide (CO2) and particulate matter (PM: including PM2.5 and PM10) met the indoor air quality maintenance standards, the percentage of passengers uncomfortable with the air quality exceeded 80% during both seasons, and the centralized tendency in winter was very uncomfortable. Passengers are very concerned about air quality, and their subjective feelings are relatively susceptible to psychological factors. Regarding the overall comfort trend, passengers' subjective feelings of comfort during the morning rush hours in summer and winter were both “slightly uncomfortable”. This paper provides a valuable reference for further research on environmental, health, and energy saving issues in metro stations and presents reliable primary research data for the design and operation management of ventilation and air conditioning systems in metro stations.

PM2.5 Exposure and Health Risk Assessment Using Remote Sensing Data and GIS.

Assessing personal exposure risk from PM2.5 air pollution poses challenges due to the limited availability of high spatial resolution data for PM2.5 and population density. This study introduced a seasonal spatial-temporal method of modeling PM2.5 distribution characteristics at a 1-km grid level based on remote sensing data and Geographic Information Systems (GIS). The high-accuracy population density data and the relative exposure risk model were used to assess the relationship between exposure to PM2.5 air pollution and public health. The results indicated that the spatial-temporal PM2.5 concentration could be simulated by MODIS images and GIS method and could provide high spatial resolution data sources for exposure risk assessment. PM2.5 air pollution risks were most serious in spring and winter, and high risks of environmental health hazards were mostly concentrated in densely populated areas in Shanghai-Hangzhou Bay, China. Policies to control the total population and pollution discharge need follow the principle of adaptation to local conditions in high-risk areas. Air quality maintenance and ecological maintenance should be carried out in low-risk areas to reduce exposure risk and improve environmental health.

The Internet of things and indoor air quality on ship

Air quality monitoring is an actively developing area in maintaining a proper environment for people’s activity and health. In maritime transport, crews of ships are at constant risk of exposure to hazardous air pollutants, which makes the task of air quality maintenance especially important. The solution proposed in the project - a device for monitoring the air quality in the areas of a ship is developed on the principles of the Internet of Things and uses the latest gas sensors based on microelectromechanical systems. The data collected by the network made of the proposed devices is used for effective control of the ship’s heating, ventilation, and air conditioning system.

Exploring Pattern of Green Spaces (GSs) and Their Impact on Climatic Change Mitigation and Adaptation Strategies: Evidence from a Saudi Arabian City

Green spaces (GSs) are significant, nature-based solutions to climate change and have immense potential to reduce vulnerability to heat waves while enhancing the resilience of urban areas in the light of climate change. However, in the Saudi context, the availability of GSs across cities and their perceived role in climate change mitigations and adaptation strategies remain unexplored. This study aimed to examine the per capita availability of GSs in the Jeddah megacity in Saudi Arabia, and their role in climate change mitigation and adaptation strategies. This study assessed the per capita availability of GS in Jeddah city using GIS techniques, and a questionnaire survey (online and an onsite) was conducted to assess the GSs users’ perception of the role of GSs on climate change mitigation and adaptation strategies. Non-parametric tests were also used to find differences in roles based on socio-demographic attributes. The findings of the study revealed that: (i) the per capita availability of GS in Jeddah is relatively low in comparison to international organization recommendations (such as World Health Organization and European Union). As per the survey result, it was reported that GSs play crucial role for climate change mitigation such as temperature regulation, reduction in heat stress, enhancement outdoor thermal comfort, and the maintenance of air quality. More than 85% of the total respondents agreed with the very high importance of GSs for climate change mitigation. More than 80% of respondents in the city highly agreed with climate change adaptation strategies such as the enhancement of accessibility to GSs, ecosystem-based protection of GSs, and the improvement of per capita availability of GSs. The findings of the study will be very helpful to planners and policymakers in implementing nature-based solutions to reduce vulnerability to climate change in Jeddah city, and particularly other cities in a desert environment.

Environmental Law that Affects the Green Behaviour of Undergraduates at Northeastern University

The objectives of this study were.to study environmental damage, natural resource damage, ecological damage, civil liability, criminal liability, administrative liability, and green behaviour levels and to study the independent variables comprising environmental damage, natural resource damage, ecological damage, civil liability, criminal liability, and administrative liability affecting the dependent variable of the green behaviour of undergraduates. The research instrument was the questionnaire, and it was used for data collection from 400 undergraduates. The inferential statistics that were used was the multiple regression analysis. Research results was revealed that the mean scores of environmental damages, natural resource damage, ecological damage, civil liability, criminal liability, administrative liability, and green behaviour levels were at high levels for all aspects. Moreover, it was found that the criminal liability had the most effect towards people’s air quality maintenance behaviour at a rate of 23.6 percent and was statistically significant at the level of 0.01. It was followed by administrative liability with 17.00 percent, which was statistically significant at the level of 0.01. This might indicate that the undergraduates realized to the important of criminal liability to enforces the people’s air quality maintenance. Therefore, in order to control air quality effectively, the criminal liability is needed to use to accomplish the air quality control.

Road Tunnel Axial Fan Performance In Situ Test: Taking Qinling Zhongnan Mountain Highway Tunnel as an Example

Axial fans play a pivotal role in the road tunnel ventilation system. Qualified performance of the axial fan is important for both safety and air quality maintenance reasons. Axial fans performance in situ test of Qinling Zhongnan Mountain highway tunnel, the second longest road tunnel in the world, is presented in this research. Performance test items and the qualification criterion, as well as a general framework for the road tunnel axial fan assessment, are recommended. Log-Tchebycheff method is suggested to confirm the location for the measuring lines and points. The precision of the log-Tchebycheff method in air flow rate measuring is verified by comparing with the biharmonic spline interpolation fitting result. The research shows that the log-Tchebycheff method has high precision and good efficiency in the air flow rate measurement of the road tunnel air duct. What is more, the biharmonic spline interpolation fitting method can be applied to obtain a more accurate result. The number of interpolation points of the biharmonic spline interpolation fitting method should be bigger than 2000 to provide quality results.

Development and application of a comprehensive ecological risk assessment indicator system in Xiamen, China

ABSTRACTUrban ecological risk is one of the important factors that may restrict the social and economic development. Therefore, it is of great significance to carry out a comprehensive assessment of ecological risks so that an ecological risk prevention and control plan can be scientifically formulated. In this paper, a comprehensive ecological risk assessment indicator system of Xiamen was established based on local ecological properties and socioeconomic status. This indicator system covers seven indicators including air pollution, soil pollution, water pollution, fresh water consumption, change in land use, occupation of key zones with ecological functions, and road network expansion. Based on this indicator system and in conjunction with the single factor assessment of ecological risks, this study constructed a model of comprehensive ecological risk assessment and forecasted the comprehensive ecological risk of Xiamen in 2020. The results showed that the comprehensive ecological risk level of Xiamen in 2020 is medium and the main stressors are the discharge of air and water pollutants. From the perspective of risk receptors, i.e. the ecosystem services, the risk posed to the ecosystem services associated to the maintenance of air quality and water purification is the highest. Therefore, this study proposed the recommendations on ecological risk prevention and regulation in Xiamen based on the comprehensive assessment of ecological risks, in the hope to provide scientific support for local ecological protection and sustainable development.

Indoor environment and passengers’ comfort in subway stations in Seoul

The purpose of this study is to investigate the indoor environment of subway stations and passengers’ comfort in three seasons. Six subway stations in Seoul were selected for physical environment measurements and a survey of 5282 passengers; these two components were conducted together. The questionnaire addressed thermal, air, light, acoustic and overall comfort. Seoul subway stations had large differences in air temperature in some seasons, and the air temperature in winter was very low. The concentration of particulate matter (PM) and carbon dioxide satisfied the indoor air quality maintenance criteria. Most survey respondents felt ‘neutral’ about or ‘comfortable’ with the environment in the subway stations, even in very low temperatures. From the results of the correlation analysis between the SET* and the percentage of uncomfortable passengers, the comfort range was 16.1–31.2 SET*°C for the concourses and 15.9–31.5 SET*°C for the platforms, which was a wider range than previous studies from other countries.

Fluid-dynamic characterisation of the Mont Blanc tunnel by multi-point airflow measurements

Long road and railway tunnels necessitate of a fine-tuned control of the ventilation system to be activated, for both safety and air quality maintenance reasons. This, in turn, requires that the main fluid-dynamic parameters of the tunnel are known with sufficient accuracy, so that the system behaviour can be predicted with reasonable confidence under standard and emergency operative conditions. As a first step in the modelling of the complex system embodying the 11,611m long Mont Blanc road tunnel, and its ventilation facilities, a movable 5-point survey rake was designed and built-up, for detecting the distribution of the axial velocity on the tunnel cross-section. Two extensive experimental campaigns were carried out, where the airflow-rates were either measured at different stations along the tunnel length (C1), or at a fixed location, under purely axial main-flow conditions and varying the number of the activated axial fan pairs (C2). A simplified dynamic model of the tunnel was developed, and the airflow data from the experiments were used for the model fine-tuning, additional CFD analyses having provided extra information on concentrated pressure losses connected with air inlet and discharge through the tunnel ends. The Mont Blanc tunnel was finally characterised in terms of friction factors and jet-fans installation efficiency.

A project to improve psychiatric nursing station air quality

Ambient air at the psychiatric nursing station in our hospital had been notably poor for an extensive period of time. CO2 levels at the station averaged 1211 ppm during August, 2009 and a specialist team estimated a CO2 abnormality ratio of 32%. Analysis identified key issues in three problem areas, including (1) ENVIRONMENT: air at the station was not refreshed and electronic equipment was in constant operation; (2) Staff: the station had a high staff-to-space ratio and staffs lacked practical knowledge on indoor air quality maintenance; and (3) Policy: the hospital had no guidelines addressing indoor air quality maintenance. The purpose of this project was to reduce ambient CO2 levels at the hospital's acute psychiatric ward in order to create a high-quality working environment for all staff. The short-term goal was to reduce the CO2 abnormality ratio from 32% to 10%. Long-term goals were to maintain an ambient CO2 level in the ward below 1000ppm and further reduce the abnormality ratio to 0%. To address environment-related issues, we increased the number of indoor plants and turned certain computers off at night. To address staff-related issues, we rearranged staff activity space and educated staff on how to maintain indoor air quality. To address the policy-related issue, we drafted proposed hospital guidelines on indoor air quality maintenance. Post-intervention measurements made in October, 2011 found significantly improved ambient air quality, with CO2 levels at 997ppm and a CO2 abnormality ratio of 0%. Results demonstrate that improvement measures implemented can effectively improve the quality of ambient air at psychiatric nursing stations. A post-intervention survey further found that staffs were both more satisfied with ward air quality and perceived a friendlier ward work environment.

Multivalent Landscape: The Salvation Army Kroc Community Center Case Study

This case study research uses quantitative methods to assess the contributions of landscape components to the delivery of multiple ecosystem services at the Salvation Army Kroc Community Center (SAKCC), a 12.4-acre former brownfield site located in Philadelphia, Pennsylvania. The term valence is used to describe the quantitative measure of a design component’s capacity to contribute to the production of ecosystem services, such as water regulation, air quality maintenance, and pollination. The selection and use of multivalent materials in design may have direct and measurable benefits on the production of ecosystem services in multifunctional landscapes. To this end, construction waste mitigation, stormwater mitigation, carbon sequestration, and plant stewardship were calculated using site-specific calculations or online calculators.

울산지역 학교의 실내공기질 평가

The purpose of this study was to investigate the concentration of indoor air pollutants at 63 elementary schools, 41 middle schools and 51 high schools in Ulsan from the beginning of May to the end of December, 2008. To assess the indoor air quality of the various classrooms, the 8 indoor air pollutants such as <TEX>$CO_2$</TEX>, CO, <TEX>$NO_2$</TEX>, <TEX>$O_3$</TEX>, <TEX>$PM_{10}$</TEX>, TVOCs, HCHO and TBC were measured and analyzed. The mean concentrations of <TEX>$PM_{10}$</TEX> and TBC in the elementary schools were significantly higher than those of middle and high schools (p < 0.01). For the HCHO, the multi-use practice rooms showed an average 1.5 times higher than general classrooms. In schools located in urban areas, the concentrations of CO, <TEX>$O_3$</TEX>, <TEX>$PM_{10}$</TEX>, HCHO and TBC were lower than in the vicinity of industrial complexes. The exceeding rate of the school air quality maintenance limits in the 6 air pollutants by law were 6.7%, 3.5%, 1.7%, 18.2%, 13.0% and 18.4% for <TEX>$CO_2$</TEX>, <TEX>$NO_2$</TEX>, <TEX>$O_3$</TEX>, <TEX>$PM_{10}$</TEX>, HCHO and TBC, respectively. Based on these results <TEX>$PM_{10}$</TEX> and TBC have to be in the order of priority of need to improve the classroom air quality in elementary school of Ulsan.

Large-Eddy Simulation on turbulent flow and plume dispersion over a 2-dimensional hill

Abstract. The dispersion analysis of airborne contaminants including radioactive substances from industrial or nuclear facilities is an important issue for air quality maintenance and safety assessment. In Japan, many nuclear power plants are located at complex coastal terrains. In these cases, terrain effects on the turbulent flow and plume dispersion should be investigated. In this study, we perform Large-Eddy Simulation (LES) of turbulent flow and plume dispersion over a 2-dimensional hill flow and investigate the characteristics of mean and fluctuating concentrations.

The value of biodiversity

In addition to its intrinsic value (nature working as it is; species are the product of a long history of continuing evolution by means of ecological processes, and so they have the right to continued existence), biodiversity also plays a fundamental role as ecosystem services in the maintenance of natural ecological processes. The economic or utilitarian values of biodiversity rely upon the dependence of man on biodiversity; products that nature can provide: wood, food, fibers to make paper, resins, chemical organic products, genes as well as knowledge for biotechnology, including medicine and cosmetic sub-products. It also encompasses ecosystem services, such as climate regulation, reproductive and feeding habitats for commercial fish, some organisms that can create soil fertility through complex cycles and interactions, such as earthworms, termites and bacteria, in addition to fungi responsible for cycling nutrients like nitrogen, phosphorus and sulfur and making them available to plant absorption. These services are the benefits that people indirectly receive from natural ecosystem functions (air quality maintenance, regional climate, water quality, nutrient cycling, reproductive habitats of commercial fish, etc.) with their related economic values.

Trends in cabin air quality of commercial aircraft: industry and passenger perspectives.

The small air space available per person in a fully occupied aircraft passenger cabin accentuates the human bioeffluent factor in the maintenance of air quality. The accumulation of carbon dioxide and other contributions to poor air quality that can occur with inadequate ventilation, even under normal circumstances, is related to the volume of available air space per person and various ventilation rates. This information is compared with established air quality guidelines to make specific recommendations with reference to aircraft passenger cabins under both normal and abnormal operating conditions. The effects of respiration on the air quality of any enclosed space from the respiration of a resting adult are estimated using standard equations. Results are given for different volumes of space per person, for zero air exchange, and for various air change rates. The required ventilation rates estimated in this way compared closely with results calculated using a standard empirical formula. The results confirm that the outside air ventilation required to achieve a target carbon dioxide concentration in the air of an occupied enclosed space remains the same regardless of the volume of that space. The outside air ventilation capability of older and more recent aircraft is then reviewed and compared with the actual measurements of cabin air quality for these periods. The correlation between calculated and measured aircraft cabin carbon dioxide concentrations from other studies was very good. Respiratory benefits and costs of returning to the 30% higher outside air ventilation rates and 8% higher cabin pressures of the 1960s and 1970s are outlined. Consideration is given to the occasional occurrence of certain types of aircraft malfunction that can introduce more serious contaminants to the aircraft cabin. Recommendations and suggestions for aircraft builders and operators are made that will help improve aircraft cabin air quality and the partial pressure of oxygen that is available to passengers at minimal cost. Also suggested are some measures that passengers can take to help improve their comfort and decrease their risk of illness, particularly on long-haul flights.