scholarly journals Can Public Spaces Effectively Be Used as Cleaner Indoor Air Shelters during Extreme Smoke Events?

2021 ◽  
Vol 18 (8) ◽  
pp. 4085
Author(s):  
Amanda J. Wheeler ◽  
Ryan W. Allen ◽  
Kerryn Lawrence ◽  
Christopher T. Roulston ◽  
Jennifer Powell ◽  
...  
Keyword(s):  
Air Quality ◽  
Indoor Air ◽  
Air Conditioning ◽  
High Efficiency ◽  
Public Library ◽  
Public Building ◽  
Central Air Conditioning ◽  
The Media ◽  
The Impact ◽  
Pm2.5 Concentration

During extreme air pollution events, such as bushfires, public health agencies often recommend that vulnerable individuals visit a nearby public building with central air conditioning to reduce their exposure to smoke. However, there is limited evidence that these “cleaner indoor air shelters” reduce exposure or health risks. We quantified the impact of a “cleaner indoor air shelter” in a public library in Port Macquarie, NSW, Australia when concentrations of fine particulate matter (PM2.5) were elevated during a local peat fire and nearby bushfires. Specifically, we evaluated the air quality improvements with central air conditioning only and with the use of portable high efficiency particulate air (HEPA) filter air cleaners. We measured PM2.5 from August 2019 until February 2020 by deploying pairs of low-cost PM2.5 sensors (i) inside the main library, (ii) in a smaller media room inside the library, (iii) outside the library, and (iv) co-located with regulatory monitors located in the town. We operated two HEPA cleaners in the media room from August until October 2019. We quantified the infiltration efficiency of outdoor PM2.5 concentrations, defined as the fraction of the outdoor PM2.5 concentration that penetrates indoors and remains suspended, as well as the additional effect of HEPA cleaners on PM2.5 concentrations. The infiltration efficiency of outdoor PM2.5 into the air-conditioned main library was 30%, meaning that compared to the PM2.5 concentration outdoors, the concentrations of outdoor-generated PM2.5 indoors were reduced by 70%. In the media room, when the HEPA cleaners were operating, PM2.5 concentrations were reduced further with a PM2.5 infiltration efficiency of 17%. A carefully selected air-conditioned public building could be used as a cleaner indoor air shelter during episodes of elevated smoke emissions. Further improvements in indoor air quality within the building can be achieved by operating appropriately sized HEPA cleaners.

scholarly journals Field measurement of PM2.5 concentration in office buildings

2019 ◽  
Vol 111 ◽  
pp. 06064
Author(s):  
Naoki Kagi ◽  
U Yanagi ◽  
Kenichi Azuma ◽  
Hoon Kim
Keyword(s):  
Indoor Air ◽  
Air Conditioning ◽  
Office Buildings ◽  
Central System ◽  
Outdoor Concentration ◽  
Central Air Conditioning ◽  
Building Characteristics ◽  
The Individual ◽  
Pm2.5 Concentration

The characterization of indoor PM2.5 has been concerned about health effects. PM2.5 in indoor air is affected by not only indoor emissions but also penetrations from outdoor air. Therefore, it is important for indoor PM2.5 to take into account of penetration factors of PM2.5 through air conditioning units in buildings. This study aimed at investigating PM2.5 concentrations and I/O ratios (indoor/outdoor concentration) in office buildings. As a result, the relationships between PM2.5 concentrations or I/O ratios and building characteristics could be classified as the types of buildings, such as specific or non-specific, and air conditioning units, such as the individual or central system. The I/O ratio for the specific buildings, over 3,000 m2 of total floor area and buildings that had the central air conditioning unit was relatively low because of medium performance filter in air conditioning units.

Bioactive Nano-Filters to Control Legionella on Indoor Air

2012 ◽  
Vol 506 ◽  
pp. 23-26
Author(s):  
P.A.F. Rodrigues ◽  
S.I.V. Sousa ◽  
Maria José Geraldes ◽  
M.C.M. Alvim-Ferraz ◽  
F.G. Martins
Keyword(s):  
Air Pollution ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Legionella Pneumophila ◽  
Air Conditioning ◽  
Indoor Air Pollution ◽  
High Efficiency ◽  
Respiratory Infections ◽  
Public Health Issue

Several factors affect the indoor air quality, among which ventilation, human occupancy, cleaning products, equipment and material; they might induce the presence of aerosols (or bioaerosols in the presence of biological components) nitrogen oxides, ozone, carbon monoxide and dioxide, volatile organic compounds, radon and microorganisms. Microbiological pollution involves hundreds of bacteria and fungi species that grow indoors under specific conditions of temperature and humidity. Exposure to microbial contaminants is clinically associated with allergies, asthma, immune responses and respiratory infections, such as Legionnaires Disease and Pontiac Feaver, which are due to contamination byLegionella pneumophila. Legionnaire's Disease has increased over the past decade, because of the use of central air conditioning. In places such as homes, kindergartens, nursing homes and hospitals, indoor air pollution affects population groups that are particularly vulnerable because of their health status or age, making indoor air pollution a public health issue of high importance. Therefore, the implementation of preventive measures, as the application of air filters, is fundamental. Currently, High Efficiency Particulate Air (HEPA) filters are the most used to capture microorganisms in ventilation, filtration and air conditioning systems; nevertheless, as they are not completely secure, new filters should be developed. This work aims to present how the efficiency of a textile nanostructure in a non-woven material based on synthetic textiles (high hydrophobic fibers) incorporating appropriate biocides to controlLegionella pneumophila, is going to be measured. These bioactive structures, to be used in ventilation systems, as well as in respiratory protective equipment, will reduce the growth of microorganisms in the air through bactericidal or bacteriostatic action. The filter nanostructure should have good air permeability, since it has to guarantee minimum flows of fresh air for air exchange as well as acceptable indoor air quality.

scholarly journals Characterization of Indoor Air Quality in Relation to Ventilation Practices in Hospitals of Lahore, Pakistan

2021 ◽  
Vol 50 (6) ◽  
pp. 1609-1620
Author(s):  
Afzal Nimra ◽  
Zulfiqar Ali ◽  
Zaheer Ahmad Nasir ◽  
Sean Tyrrel ◽  
Safdar Sidra
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Air Conditioning ◽  
Ventilation System ◽  
Temporal Variations ◽  
Emergency Rooms ◽  
Group I ◽  
Central Air Conditioning ◽  
Air Conditioning Systems

Temporal variations of particulate matter (PM) and carbon dioxide (CO2 ) in orthopedic wards and emergency rooms of different hospitals of Lahore, Pakistan were investigated. Hospitals were classified into two groups, I (centrally air-conditioned) and II (non-central air-conditioned) based on the ventilation system. Statistical analysis indicated significantly lower PM and CO2 levels in centrally air-conditioned hospitals in comparison to non-central air-conditioned. The low indoor-outdoor (I/O) ratio of PM2.5 in the ward and emergency rooms of group I (0.62, 0.45) as compared to group II (0.70, 0.83), respectively, suggested that indoor spaces equipped with central air-conditioning systems efficiently filter particulates as compared to non- central air conditioning systems. Apart from the ventilation type, increased visitor and doctors’ activities, and cleaning sessions were observed to contribute significantly to indoor air quality. This study adds up to the understanding of temporal variations in PM emissions and the role of ventilation systems in context of hospitals in the urban centers in Pakistan. The findings can inform the development of intervention strategies to maintain the appropriate air quality in health care built environment in developing countries.

scholarly journals Effects of Climatic Conditions, Season and Environmental Factors on CO2 Concentrations in Naturally Ventilated Primary Schools in Chile

2021 ◽  
Vol 13 (8) ◽  
pp. 4139
Author(s):  
Muriel Diaz ◽  
Mario Cools ◽  
Maureen Trebilcock ◽  
Beatriz Piderit-Moreno ◽  
Shady Attia
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Primary Schools ◽  
Co2 Concentration ◽  
Building Design ◽  
Climatic Conditions ◽  
Indoor Environmental Quality ◽  
Co2 Concentrations ◽  
The Impact

Between the ages of 6 and 18, children spend between 30 and 42 h a week at school, mostly indoors, where indoor environmental quality is usually deficient and does not favor learning. The difficulty of delivering indoor air quality (IAQ) in learning facilities is related to high occupancy rates and low interaction levels with windows. In non-industrialized countries, as in the cases presented, most classrooms have no mechanical ventilation, due to energy poverty and lack of normative requirements. This fact heavily impacts the indoor air quality and students’ learning outcomes. The aim of the paper is to identify the factors that determine acceptable CO2 concentrations. Therefore, it studies air quality in free-running and naturally ventilated primary schools in Chile, aiming to identify the impact of contextual, occupant, and building design factors, using CO2 concentration as a proxy for IAQ. The monitoring of CO2, temperature, and humidity revealed that indoor air CO2 concentration is above 1400 ppm most of the time, with peaks of 5000 ppm during the day, especially in winter. The statistical analysis indicates that CO2 is dependent on climate, seasonality, and indoor temperature, while it is independent of outside temperature in heated classrooms. The odds of having acceptable concentrations of CO2 are bigger when indoor temperatures are high, and there is a need to ventilate for cooling.

scholarly journals Window operation behaviour and indoor air quality during lockdown: A monitoring-based simulation-assisted study in London

2021 ◽  
pp. 014362442110177
Author(s):  
Farhang Tahmasebi ◽  
Yan Wang ◽  
Elizabeth Cooper ◽  
Daniel Godoy Shimizu ◽  
Samuel Stamp ◽  
...  
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Energy Demand ◽  
Natural Ventilation ◽  
Probabilistic Models ◽  
Performance Model ◽  
Outdoor Environment ◽  
Ventilation Strategies ◽  
The Impact

The Covid-19 outbreak has resulted in new patterns of home occupancy, the implications of which for indoor air quality (IAQ) and energy use are not well-known. In this context, the present study investigates 8 flats in London to uncover if during a lockdown, (a) IAQ in the monitored flats deteriorated, (b) the patterns of window operation by occupants changed, and (c) more effective ventilation patterns could enhance IAQ without significant increases in heating energy demand. To this end, one-year’s worth of monitored data on indoor and outdoor environment along with occupant use of windows has been used to analyse the impact of lockdown on IAQ and infer probabilistic models of window operation behaviour. Moreover, using on-site CO2 data, monitored occupancy and operation of windows, the team has calibrated a thermal performance model of one of the flats to investigate the implications of alternative ventilation strategies. The results suggest that despite the extended occupancy during lockdown, occupants relied less on natural ventilation, which led to an increase of median CO2 concentration by up to 300 ppm. However, simple natural ventilation patterns or use of mechanical ventilation with heat recovery proves to be very effective to maintain acceptable IAQ. Practical application: This study provides evidence on the deterioration of indoor air quality resulting from homeworking during imposed lockdowns. It also tests and recommends specific ventilation strategies to maintain acceptable indoor air quality at home despite the extended occupancy hours.

The impact of mechanical ventilation operation strategies on indoor CO2 concentration and air exchange rates in residential buildings

2020 ◽  
pp. 1420326X2096076
Author(s):  
Pedro F. Pereira ◽  
Nuno M. M. Ramos
Keyword(s):  
Mechanical Ventilation ◽  
Air Quality ◽  
Exchange Rates ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Residential Buildings ◽  
Ventilation Strategy ◽  
The Impact ◽  
Mechanical Extraction ◽  
Air Exchange

In Portugal, residential buildings commonly have their ventilation strategy changed after commissioning. This occurs due to the building managers' willingness to reduce shared costs with the electricity needed for fan operation. However, this option is not technically supported, and the effects of such a strategy on indoor air quality-related to human pollutants are yet to be quantified. CO2 was monitored in 15 bedrooms and air exchange rates were calculated for each room. The air exchange rate values ranged from 0.18 to 0.53 h−1 when mechanical extraction ventilation was off, and from 0.45 to 0.90 h−1 when mechanical extraction ventilation was on, which represents an average increase of 119%. With the current intermittent ventilation strategy, all rooms remain above 1500 ppm for a given percentage of time, and 12 rooms presenting CO2 concentrations above 2000 ppm. Simulations of theoretical CO2 concentrations, for a non-interrupted mechanical ventilation strategy show that no rooms would accumulate CO2 concentrations above 2000 ppm, and only 25% would present CO2 concentrations above 1500 ppm. Pearson correlations between the monitored CO2 and human and spatial factors identified two relevant parameters. Those parameters correspond to ratios between CO2 generation and floor area ([Formula: see text]), and airflow with CO2 generation ([Formula: see text]). The proposed ratios could be used as ways to optimise ventilation costs and indoor air quality.

scholarly journals Thermal history and comfort in a Brazilian subtropical climate: a 'cool' addiction hypothesis

2016 ◽  
Vol 16 (1) ◽  
pp. 7-20 ◽  
Author(s):  
Renata De Vecchi ◽  
Christhina Maria Cândido ◽  
Roberto Lamberts
Keyword(s):  
Air Temperature ◽  
Indoor Air ◽  
Thermal History ◽  
Air Conditioning ◽  
Prolonged Exposure ◽  
Temperature Fluctuations ◽  
Subtropical Climate ◽  
Indoor Thermal Comfort ◽  
Air Speed ◽  
The Impact

Abstract Currently, there is a rising trend for commercial buildings to use air conditioning to provide indoor thermal comfort. This paper focuses on the impact of prolonged exposure to indoor air-conditioned environments on occupants' thermal acceptability and preferences in a mixed-mode building in Brazil. Questionnaires were administered while indoor microclimatic measurements were carried out (i.e., air temperature, radiant air temperature, air speed and humidity). Results suggest significant differences in occupants' thermal acceptability and cooling preferences based on thermal history; differences were found between groups based on different physical characteristics (i.e., different gender and body condition). The findings also indicated a significant potential to implement temperature fluctuations indoors when occupants are exposed to air conditioning environments in warm and humid climates.

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