The Effect ofLegionella PneumophilaContamination in the Surface Dust of the Air Ducts of Central Air Conditioning Systemson Indoor Air Quality

2015 ◽  
Vol 14 (3) ◽  
pp. 231-240
Author(s):  
B Y Zhang ◽  
F Liu ◽  
X D Chen
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Air Conditioning ◽  
Surface Dust ◽  
Central Air Conditioning

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 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 Transient Effects of Different Ventilation Methods on Car Indoor Air Quality

2015 ◽  
Vol 2 (1) ◽  
pp. 70 ◽  
Author(s):  
Feng-Chyi Duh
Keyword(s):  
Carbon Dioxide ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Air Conditioning ◽  
Heat Index ◽  
Transient Effects ◽  
Air Conditioning System ◽  
Carbon Dioxide Concentrations ◽  
Volatile Organic

This study investigated transient effects on the air quality of parked cars and moving cars with and without operating air conditioning. Carbon dioxide, carbon monoxide, volatile organic compounds, and formaldehyde concentrations were measured for comparative analysis. The results showed that simply changing the air conditioning system from internal circulation to external circulation to introduce air from outside reduces carbon dioxide concentrations by more than 50%, volatile organic compound concentrations by more than 77%, and the heat index from 0.1℃/min to less than 0.05 ℃/min. In order to conserve energy and improve car indoor air quality, this study can serve as a reference on healthy car environments.

scholarly journals Indoor Air Quality Enhancement Performance of Liquid Desiccant and Evaporative Cooling-Assisted Air Conditioning Systems

2019 ◽  
Vol 11 (4) ◽  
pp. 1036 ◽  
Author(s):  
Beom-Jun Kim ◽  
Junseok Park ◽  
Jae-Weon Jeong
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Reference System ◽  
Air Conditioning ◽  
Evaporative Cooling ◽  
Quality Enhancement ◽  
Liquid Desiccant ◽  
Air Conditioning Systems ◽  
Indoor Pm2.5

The main objective of this study is to investigate the indoor air quality enhancement performance of two different liquid desiccant and evaporative cooling-assisted air conditioning systems, such as the variable air volume (VAV) system with the desiccant-enhanced evaporative (DEVap) cooler, and the liquid desiccant system with an indirect and direct evaporative cooling-assisted 100% outdoor air system (LD-IDECOAS), compared with the conventional VAV system. The transient simulations of concentration variations of carbon dioxide (CO2), coarse particles, and fine particles (PM10 and PM2.5) in a model office space served by each system were performed using validated system models that were found in the literature. Based on the hourly thermal loads of the model space predicted by the TRNSYS 18 program, each air conditioning system was operated virtually using a commercial equation solver program (EES). The results indicated that the LD-IDECOAS provided the lowest annual indoor CO2 concentration among all the systems considered in this research, while the VAV system with DEVap cooler exceeded the threshold concentration (i.e., 1000 ppm) during the cooling season (i.e., July, August, and September). For the indoor particulate contaminant concentrations, both liquid desiccant and evaporative cooling-assisted air conditioning systems indicated lower indoor PM2.5 and PM10 concentrations compared with the reference system. The LD-IDECOAS and the VAV with a DEVap cooler demonstrated 33.3% and 23.5% lower annual accumulated indoor PM10 concentrations than the reference system, respectively. Similarly, the annual accumulated indoor PM2.5 concentration was reduced by 16% using the LD-IDECOAS and 17.1% using the VAV with DEVap cooler.

Empirical analysis of indoor air quality enhancement potential in a liquid-desiccant assisted air conditioning system

2017 ◽  
Vol 121 ◽  
pp. 11-25 ◽  
Author(s):  
Joon-Young Park ◽  
Dong-Seob Yoon ◽  
Shiying Li ◽  
Junseok Park ◽  
Jong-Il Bang ◽  
...  
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Empirical Analysis ◽  
Indoor Air ◽  
Air Conditioning ◽  
Quality Enhancement ◽  
Liquid Desiccant ◽  
Air Conditioning System

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 Planning and Design of Low-Power-Consuming Full-Outer-Air-Intake Natural Air-Conditioning System

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Chien-Lun Weng ◽  
Lih-Jen Kau
Keyword(s):  
Air Quality ◽  
Low Power ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Air Conditioning ◽  
Ambient Air ◽  
Living Environment ◽  
Air Conditioning System ◽  
Solvent Vapor ◽  
Air Intake

A person stays indoors for about 85%∼90% time of his lifetime, and the need for a comfortable indoor environment is getting higher; thus, the air-conditioning dependency becomes intense too. Nowadays, residents focus on both the comfortable living environment and indoor air quality. A closed environment will become hazardous because of carbon dioxide released during respiration and toxic organic solvent vapor released from interior decoration. In order to improve the indoor air quality (IAQ), we must allow outer fresh air into the indoor space and release the dirty air out. But while taking in fresh air, the heat and factory/vehicle exhaust are also introduced. Indoor CO2, HCHO, and VOCs and outer dirty gas threaten human health badly. To solve this problem, we bring up an innovative low-power-consuming full-outer-air-intake natural air-conditioning system that completely separates intake and exhaust air, which is a solution for cross-contamination and makes mass/energy exchange by means of air and water. Design airflow exceeds 300∼500 CFM, steam evaporation mass rate reaches 3.13∼3.88 kg/hr, and heat exchange capacity becomes 1,855∼2,300 kcal/hr. The sensible heat effectiveness is 71%∼112%, and EER exceeds 14.05∼17.42 kcal/W·h. In addition, the system under design can be of positive or negative pressure status according to the user’s or work’s requirement. It creates a comfortable and healthy living environment by supplying clean and fresh outer ambient air with low power consumption.

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