Affect Indoor Air Quality Research Articles

Characteristics of urban air pollution in different regions of China between 2015 and 2019

The severity of urban air pollution problems in China increases with the city's size and population density. Outdoor air pollution not only affects indoor air quality but also increases building energy consumption. We analyzed the characteristics of urban air pollution in China based on long-period monitoring data with high temporal resolution (hourly) recorded between September 1, 2014 and August 31, 2019. We compared five key regions in detail: “2 + 26 cities,” the Yangtze River delta (YRD), the Pearl River delta (PRD), the Northeast China Plain (NECP), and the Sichuan Basin (SCB). The results show decreases in the annual mean concentrations of particulate matter, PM2.5 and PM10, SO2, and CO but an increase in the O3 concentration. The increasing O3 rate in the 2 + 26 cities region was nearly 14 times that of the global rate. In terms of diurnal variation, NO2 and CO reached maxima between 8:00 and 9:00 a.m. due to morning rush hour traffic, which was approximately 1 h before the PMs and SO2 reached their maxima. In the monthly variation profiles, the SO2 concentration magnitudes in the NECP were similar to those of the 2 + 26 cities during winter heating periods and the YRD region during the non-heating periods. Minima associated with “plum rain” and the rainy season were also observed in the O3 monthly variation profiles of the YRD and SCB regions, respectively. In the 2 + 26 cities region, each pollutant showed significantly large temporal variation relative to the spatial variation, which is indicative of the regional air pollution trend.

A Novel Indoor Air Quality Standards and Design Methods in Environmental Assessment

In recent years, indoor air pollution has become one of the research hotspots. In the environmental assessment project, the indoor air quality standards have been explicitly included in the control items of China’s green building environmental evaluation standards, and controlling the indoor environment has become important to achieve green buildings. Analysis of the main factors affecting indoor air quality and discussion of design methods based on typical pollutants for indoor air quality are important links for achieving green environmental assessment.

Simultaneous measurements of radon, thoron and their progeny for inhalation dose assessment in indoors of Srinagar, J&K, India

A variety of toxins are known to affect indoor air quality, thereby affecting the health of the inhabitants of that region. One such natural contaminant is radon, which is a dense, colourless, odourless and inert gas. As per BEIR-VI report (Chauhan and Chauhan in J Environ Radioact, 2015. https://doi.org/10.1016/j.jenvrad.2015.03.009), Radon alone contributes to more than 50% of the total natural background radiation and is the second leading element causing lung cancer after smoking. Therefore, its quantification is vital to assess any risk to human health. In order to assess health risks, a recently developed LR-115 detector based technique was employed for time-integrated passive measurements of radon, thoron and their progeny concentrations. The annual average radon concentration was found to be 35.6 Bq m−3 and thus lies well below the global average of 40 Bq m−3. However, thoron concentration exceeded the global average value of 10 Bq m−3.

Fuzzy based Dynamic Security Parameters Determination Method to Improve Energy Efficiency

Fine dust is a harmful substance that floats in the atmosphere. It is not filtered well in the bronchus and causes health problems when it accumulates in the body. Fine dust that is present in the air outside can flow into buildings through windows and other openings, adversely affecting indoor air quality. It has negative health effects on people who live indoors. As attention to problems associated with fine dust gradually rises, the importance of continuously managing the quality of indoor air through air purification rises. Therefore, recently, research and development into systems to periodically purify indoor air are being carried out. This paper introduces an air purification system, a Wireless Sensor Networks (WSNs)-based Internet of Things (IoT) air purification system. In the WSNs-based IoT air purification system, the IoT air purifier is controlled based on event information that the WSNs senses, so it is important to maintain the security of the event information. To this end, a WSNs security protocol, Interleaved Hop by hop Authentication (IHA), is used in this system. IHA is a security protocol in which sensor nodes and a Base Station (BS) detect and drop false reports if the number of compromised sensor nodes does not exceed a security threshold. That is, because the false report injection attack that the number of compromised sensor nodes exceeds security threshold can’t defend by IHA, it is detected and defended through Data Calibration. However, considerable energy of the sensor nodes is unnecessarily consumed in the process of forwarding false reports. Thus, this paper proposes a method of decreasing and increasing security thresholds dynamically according to the network situation using fuzzy logic. This proposed scheme has the advantages of improvements in both the overall energy efficiency and network lifetime in WSNs.

The effect of ventilation on volatile organic compounds produced by new furnishings in residential buildings

Abstract It can be difficult to tease apart the sources of the many chemical substances that can adversely affect indoor air quality (IAQ). These can be generated from primary sources, e.g. cleaning products, fragrances and wall decorations, and created in-situ (secondary emissions). Inputs due to human activities (heating, smoking, etc.) add to the catalogue of chemical possibilities. This study examines the effect of airtightness and ventilation on volatile organic compounds (VOC) concentration in newly-furnished unoccupied residential houses. Further objectives included investigating the effects of airtightness and mechanical ventilation on internal VOC concentrations in two rooms with controlled simulated occupancy. Chemicals that appear to have been generated directly from or supplemented by furnishings were acetone, 2-butanone, ethyl acetate and tert-butyl alcohol. In the absence of mechanical ventilation, total VOC (TVOC) concentrations were over three times greater in the more airtight room. The appearance of concentration maxima after furnishing and/or decoration was delayed in the airtight room and the subsequent decay rate was slower. With the exception of benzene, none of the individual compounds exceeded national guidelines for outdoor air (in the absence of IAQ guidelines). Mechanical ventilation reduced TVOC concentrations by 300 μg m−3 (more airtight room) and > 340 μg m−3 (less airtight room) to below European threshold recommendations; although the reduction took approximately five days. The time lag indicates that simply providing adequate ventilation during chemical use indoors may not be sufficient to protect inhabitants from prolonged exposure following use.

Simplified speciation and atmospheric volatile organic compound emission rates from non-aerosol personal care products.

Volatile organic compounds (VOCs) emitted from personal care products (PCPs) can affect indoor air quality and outdoor air quality when ventilated. In this paper, we determine a set of simplified VOC species profiles and emission rates for a range of non‐aerosol PCPs. These have been constructed from individual vapor analysis from 36 products available in the UK, using equilibrium headspace analysis with selected‐ion flow‐tube mass spectrometry (SIFT‐MS). A simplified speciation profile is created based on the observations, comprising four alcohols, two cyclic volatile siloxanes, and monoterpenes (grouped as limonene). Estimates are made for individual unit‐of‐activity VOC emissions for dose‐usage of shampoos, shower gel, conditioner, liquid foundation, and moisturizer. We use these values as inputs to the INdoor air Detailed Chemical Model (INDCM) and compare results against real‐world case‐study experimental data. Activity‐based emissions are then scaled based on plausible usage patterns to estimate the potential scale of annual per‐person emissions for each product type (eg, 2 g limonene person−1 yr−1 from shower gels). Annual emissions from non‐aerosol PCPs for the UK are then calculated (decamethylcyclopentasiloxane 0.25 ktonne yr−1 and limonene 0.15 ktonne yr−1) and these compared with the UK National Atmospheric Emissions Inventory estimates for non‐aerosol cosmetics and toiletries.

Fugitive Emissions of CO and PM2.5 from Indoor Biomass Burning in Chimney Stoves Based on a Newly Developed Carbon Balance Approach

Fugitive emissions of smoke from stoves directly affect indoor air quality. However, this important process has been very scarcely evaluated so far. In this study, a novel approach has been develop...

Are classroom thermal conditions, lighting, and acoustics related to teacher health symptoms?

Over half of schools surveyed in the United States reported one environmental problem affecting Indoor Air Quality. This study investigated environmental concerns in schools, teacher-reported symptoms, and performance in relation to thermal environment, lighting, and noise conditions in New York State classrooms. This cross-sectional study consisted of telephone surveys among teachers from 428 NYS public schools. Survey contents included teacher demographics, employment characteristics, and environmental factors. Unconditional logistic regression analyses were used to estimate odds ratios (OR) of health symptoms for classroom conditions including thermal environment, lighting, and acoustics. Although too dry, too hot, or cold were major thermal concerns, 78% of the teachers reported that they cannot control temperature through thermostat. Over 50% of NYS teachers reported almost all health symptoms worsening during workdays. We found the top five most common health symptoms reported by NYS teachers are all allergy-related symptoms. Additionally, all extreme thermal factors were significantly associated with work-related symptoms in teachers. "Too dry" had the highest risk for allergic symptoms (OR: 2.49, 95% CI: 2.01-3.10), and then followed by any noise (OR: 2.46, 95% CI: 1.80-3.36) associated with voice-related health, and "lighting too dim" (OR: 2.38, 95% CI: 1.77-3.19). Future studies are needed to confirm these findings.

Comparison on Reduction of VOCs Emissions from Radiata Pine (Pinus Radiata D. Don) between Sodium Bicarbonate and Ozone Treatments.

Volatile organic compounds (VOCs) in wood furniture are an important factor that affects indoor air quality. In this study, radiata pine (Pinus radiata D. Don) was treated with sodium bicarbonate and ozone aqueous solution to reduce the VOC contents without sacrificing mechanical properties. The VOCs of radiata pine were identified by gas chromatography-mass spectrometry (GC-MS), and the functional group changes of wood samples were characterized by Fourier-transform infrared spectroscopy (FTIR). The results showed that the main VOCs of radiata pine include alkenes, aldehydes, and esters. The sodium bicarbonate and ozone treatments almost eliminated the VOC contents of radiata pine. The two treatments mentioned above had little effect on compressive strength and surface color of radiata pine.

Determination of indoor air quality in collective living spaces utilizing Fuzzy logic analysis

Individuals have to work in collective living spaces which might be indoor or outdoor areas. In indoor works, people spend approximately 90% of their time in a closed space. There are many parameters affecting indoor air quality. Among these, for indoor and outdoor, important parameters can be listed as carbon monoxide (CO), carbon dioxide (CO2), sulfur dioxide (SO₂), particles, nitrogen oxides (NOx), various microorganisms, harmful allergens, and powders. Some health problems might emerge in people who stay in indoor environments for a long time. For instance, newborns and infants are more likely to stay indoors. It is the primary reason for occurring many acute and chronic diseases at an early age, as babies and children are more sensitive to environmental pollutants. Recently published studies, which report that appendicitis failures might be fatal and air pollution can increase the rate of these failures, are remarkable. On the other hand, there are many negative effects of polluted indoor air on human health such as attention deficit and excessive daytime sleepiness. Moreover, the negative effects of this kind of indoor air quality on human learning and perception can not be neglected. The researchers focusing on indoor air quality are conducting studies showing that air pollution has an effect on physical activity and neurological interaction in humans. Even though air pollutants in outdoor air content were evaluated with fuzzy logic method in many studies, there are quite few studies using the fuzzy approach for indoor air quality. In this study, through the standard formula developed by the United States Environmental Protection Agency (EPA), calculations were made using fuzzy logic in MATLAB utilizing air quality index. In the study, indoor air quality measurement parameters were evaluated with the “Mamdani” method used in fuzzy logic. In the study, the model suitable for the logic structure created with the fuzzy tool in MATLAB was analyzed with the help of Mamdani method, and the suitability of evaluating the indoor air quality with artificial intelligence was investigated. A set of suggestions has been made evaluating and criticizing the results

Covid-19 risk assessment in public transport using ambient sensor data and wireless communications

Covid-19 causes one of the most alarming global health and economic crises in modern times. Countries around the world establish different preventing measures to stop or control Covid-19 spread. The goal of this paper is to present methods for the evaluation of indoor air quality in public transport to assess the risk of contracting Covid19. The first part of the paper involves investigating the relationship between Covid-19 and various factors affecting indoor air quality. The focus of this paper relies on exploring existing methods to estimate the number of occupants in public transport. It is known that increased occupancy rate increases the possibility of contamination as well as indoor carbon dioxide concentration. Wireless data collection schemes will be defined that can collect data from public transportation. Collected data are envisioned to be stored in the cloud for data analytics. We will present novel methods to analyze the collected data by considering the historical data and estimate the virus contagion risk level for each public transportation vehicle in service. The methodology is expected to be applicable for other airborne diseases as well. Real-time risk levels of public transportation vehicles will be available through a mobile application so that people can choose their mode of transportation accordingly.

A Study on the Design Method of Indoor Fine Particulate Matter (PM2.5) Pollution Control in China.

Airborne fine particulate matter (PM2.5) is an important factor affecting indoor air quality and is significantly related to human health. A lot of research has been done on PM2.5 pollution control in buildings, but there is lack of systematic indoor PM2.5 pollution control for engineering applications. In this study, first, we propose an outdoor calculated concentration of PM2.5 in 74 cities, in China, using the “not guaranteed for five days” method, which is based on outdoor PM2.5 concentration monitoring data from 2016 to 2018. Then, different levels of indoor calculated concentrations of PM2.5 (25 μg/m3, 35 μg/m3, and 75 μg/m3) are put forward. Secondly, methods for selecting air purification equipment in centralized, semi-centralized, and decentralized air conditioning systems are proposed. Finally, PM2.5 pollution control measures and system energy-saving operation strategies in buildings are put forward. This study stipulates the calculation of PM2.5 concentration, unifies design methods, proposes control measures, and standardizes operations management. The aim of this study is to provide technical guidance for engineering design, construction and operation, and therefore to reduce the risk of indoor diseases caused by exposure to PM2.5.

Monitoring and Evaluation of Nearly-Zero Energy House (NZEH) with Hybrid HVAC for Cold Climate – Canada

A Nearly Zero Energy Home (NZEH) in Strathroy, Ontario, Canada was monitored and studied to evaluate its performance for both heating and cooling seasons. The house is a new built and is equipped with an electric-natural gas hybrid spacing heating system. A high efficiency natural gas furnace and an electric air source heat pump (ASHP) were coupled to meet the space heating demand of the house. The house also benefits from on-site renewable energy generation (solar PV). The original system was controlled by a simple switch over thermostat that drives furnace or ASHP based on the outdoor temperature as a single decision-making factor. The system then was upgraded with a cloud based Smart Dual Fuel Switching System (SDFSS) controller that considers time-of-use (TOU) pricing, fuel cost, weather forecast, and equipment efficiencies and capacities. This multi-variable decision-making process defines an optimal schedule for the hybrid system to run more efficiently and more economically. A detailed monitoring system, including sensors, meters, and data acquisition system, was installed to collect all required information at a 2-minute interval. The furnace and ASHP were studied separately to verify their capacities and efficiencies. Then the overall hybrid system and its controller were monitored to identify its effectiveness. A complete model of the house and the hybrid system were developed and validated with experimental data. Thereafter, the system was run by the SDFSS controller. All of these scenarios were compared against each other and benchmarked. In addition, the factors affect indoor air quality (IAQ) were studied in detail. The preliminary result has shown that SDFSS controller provides a cost effective, feasible, cleaner and healthier IAQ options to run the hybrid system in a NZEH.

The Factors of Affect Indoor Air Quality Inpatient at Private Hospital, Pekanbaru, Indonesia.

BACKGROUND:Air quality in inpatient rooms influenced by several factors. Room not qualified health can cause disease and can spread through equipment, the material used, food and drink, health workers, patients and visitors.AIM:The purpose of this study is to know the factors that affect air quality in the inpatient room at a private hospital, Pekanbaru.METHODS:The research is quantitative analytic by design cut latitude study. Samples from 120 nurses were selected overall sampling. The data do with the measurement directly, interviews and observation using a questionnaire. Data analysed by using the chi-square with significance p-value less than 0.05.RESULTS:The quality of the air in inpatient rooms has met the standard. Variables are affecting air quality in inpatient rooms in the hospital significantly with p-value more than 0.05 is temperature, dust, the germ, density occupancy, sanitation room. While the moisture, standard operating procedures and behaviour is not significant.CONCLUSION:The factors that significantly affect indoor air quality inpatient hospitalisation are temperature, dust, germ numbers, occupancy density, room sanitation.

The influence of relative humidity and ground material on indoor walking-induced particle resuspension

The resuspension of indoor particulate matters caused by people indoor walking could affect indoor air quality and human health. Therefore, it is particularly important to study the resuspension rules of the particulate matters in different indoor environments. The influence of the ground material and the relative humidity on resuspension of the particulate matters were investigated under three kinds of ground materials and three different relative humidity. Results showed that different relative humidity and different ground materials had different effects on the mass concentration of the particulate matters. In addition, different particle sizes had diverse influence on the mass concentration. Compared with low-level loop pile carpet and shaggy carpet, hardwood floor was more conductive to human health which was less likely to cause the resuspension of the particulate matters. At the same time, relative humidity had a great influence on the resuspension of the particulate matters. With the increase of relative humidity, the resuspension rate of fine particulate matters decreased.

A comprehensive evaluation method for indoor air quality of buildings based on rough sets and a wavelet neural network

Understanding the level of indoor air quality is very important to improve the quality of air that people breathe indoors. In this paper, a comprehensive evaluation method combining rough sets and a wavelet neural network is proposed to evaluate the indoor air quality of buildings. Through on-site inspections of the indoor air in six large shopping malls in Beijing, Wuhan and Guangzhou, raw data of the environmental parameters affecting the indoor air quality of large shopping malls are obtained. First, rough sets are used to reduce the dimension of features that affect indoor air quality by removing unimportant features, and important environmental parameters that affect indoor air quality are obtained. These important environmental parameters are used as input parameters of the wavelet neural network. Then, the structure of the wavelet neural network is determined, and an evaluation model of the indoor air quality of buildings based on rough sets and the wavelet neural network is established. Finally, the model is applied to the evaluation of indoor air quality in large shopping malls, and the back propagation neural network, fuzzy neural network and Elman neural network are introduced for comparison of the testing accuracy of the wavelet neural network in the sample testing stage. The results show that the structure of the wavelet neural network is optimized by using a rough set to reduce the redundant attributes of the data, and that the comprehensive evaluation method based on rough sets and a wavelet neural network can accurately evaluate the indoor air quality level of buildings. The results of this study have significance for and can guide the evaluation of the indoor air quality of buildings.

An Overview of iQOS® as a New Heat-Not-Burn Tobacco Product and Its Potential Effects on Human Health and the Environment.

Tobacco smoke from regular cigarettes contains a number of harmful chemicals such as nicotine, arsenic, benzene, carbon monoxide, heavy metals, and tobacco-derived nitrosamines. About 1% of over 7000 chemical substances formed by burning tobacco are identified as the leading causes or possible risk factors of smoking-related diseases such as lung cancer, cardiovascular diseases, and emphysema. The concept of heating tobacco without combustion and smoke has been designed for more than two decades. The products developed with this idea, known as "Heat-Not-Burn" tobacco cigarettes, were first introduced in the late 1980s but did not achieve commercial success. However, the tobacco giants have been trying to remarket tobacco heating systems with new technological and modified features for over 10 years. I-Quit-Ordinary-Smoking (iQOS®) is one of the latest heat-not-burn tobacco products, first launched in Japan and Italy. The company then made a submission to the Food and Drug Administration as a modified-risk tobacco product application to sell its own tobacco-heating device iQOS® under its Marlboro® brand in the USA with reduced-risk claims in 2016, but it was rejected. This device is, however, now sold in more than four dozen countries. There are some striking claims that iQOS®, which is described as a novel hybrid product between traditional cigarettes and electronic cigarettes, offers an alternative way to substantially reduce the amount of harmful components compared with traditional cigarettes by its new technology in which tobacco is heated up to 350°C instead of being burnt. It is claimed to produce vapour containing nearly 90% less toxic substances than cigarette smoke and not be a source of second-hand smoking negatively affecting indoor air quality. The purpose of this article is to objectively review the potential effects of iQOS® on human health and the environment by searching and integrating the published research findings.

Home energy efficiency and radon: An observational study.

Exposure to radon gas is the second leading cause of lung cancer worldwide behind smoking. Changing the energy characteristics of a dwelling can influence both its thermal and ventilative properties, which can affect indoor air quality. This study uses radon measurements made in 470 689 UK homes between 1980 and 2015, linked to dwelling information contained within the Home Energy Efficiency Database (HEED). The linked dataset, the largest of its kind, was used to analyze the association of housing and energy performance characteristics with indoor radon concentrations in the UK. The findings show that energy efficiency measures that increase the airtightness of properties are observed to have an adverse association with indoor radon levels. Homes with double glazing installed had radon measurements with a significantly higher geometric mean, 67% (95% CI: 44, 89) greater than those without a recorded fabric retrofit. Those with loft insulation (47%, 95% CI: 26, 69) and wall insulation (32%, 95% CI: 11, 53) were also found to have higher radon readings. Improving the energy performance of the UK's housing stock is vital in meeting carbon emission reduction targets. However, compromising indoor air quality must be avoided through careful assessment and implementation practices.

Positive pressure effect on moisture performance in a school building

Moisture excess in buildings constitutes a complex problem affecting indoor air quality, energy consumption and the lifetime of the building envelope. We investigate the effect on moisture transfer in structures as a positive pressure is applied inside the enclosure. It is found that, contrary to established belief, the positive pressure does not induce any negative effects on the structures’ moisture content in normally ventilated classrooms, even with high occupancy. Our case study consists of a school building in Finland, subject to temperature and relative humidity measurements after a small (5–7 Pa) positive pressure was realized through ventilation control. We first address analytically the moisture excess generated inside the classrooms for 14 days, using dynamical balance equations that account for both ventilation effects and occupants’ moisture release in the environment. It is found that the average moisture excess is very small, largely below 1 g/m3, even for ventilation rates that are half the design value. We also examine the moisture performance of the envelope, by addressing the moisture migration at upper and lower joints of the external walls for both measured and design values of the indoor absolute humidity (AH). A coupled numerical model of diffusion and convection shows that moisture accumulation in the envelope and the according stresses are negligible for any realistic AH values. This result is in agreement with field measurements at the school. In conclusion, it seems that applying a small overpressure in a well-ventilated school building during a standard service period resulted in no accumulation inside the external walls, even at high occupancy and with low ventilation. Remarkably, it slightly dried out the moisture content in structures under actual occupancy conditions. The positive pressure has accordingly no negative effects on moisture performance, and is capable to guarantee a good indoor air quality as well.

Particulate matter in residential buildings in New Zealand: Part II. The impact of building airtightness, mechanical ventilation using simulated occupancy

Abstract Many occupant activities can adversely affect indoor air quality which has been shown to be detrimental to human health. This research eliminated some of the variability of previous measured levels of indoor particulate matter (PM) by removing all human activity and providing baseline data on the contribution occurring from home furnishings. Further objectives included investigating the effects of airtightness and mechanical ventilation on internal PM concentrations with controlled simulated occupancy. With natural ventilation, PM concentrations were 15% greater in bedroom of the less airtight (Control) house than that of the (Test house), post-furnishing which indicates that there is a considerable amount of natural variation which may not be solely due to occupant activities. Simulated occupancy dramatically increased the concentration of PM found in both houses by just under 5-fold. With simulated occupancy, the majority of the PM was present as fine particles (≤PM1) for both houses (93–94%), whereas without simulated occupancy, the proportion of fine particles was lower (88–89%). After furnishing and without the use of mechanical ventilation, PM10 concentrations exceeded the WHO Guidelines for PM10 of 50 μg m−3 for 56% of the testing duration for the Control bedroom and 35% for the Test bedroom. The use of mechanical ventilation reduced the mean internal PM concentrations by approximately 90% for all PM sizes in both study bedrooms which highlights the importance of use and maintenance of effective ventilation systems especially after furnishing activities.