| 61. |
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| 62. |
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| 63. |
- Malmborg, Vilhelm, et al.
(författare)
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Aerosol formation and emissions from realistic compartment fires
- 2022
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Ingår i: ; , s. 10-10
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Konferensbidrag (refereegranskat)abstract
- Firefighters are occupationally exposed to a large number of toxic compounds (IARC 2010). The occupational exposure of firefighters has been classified as potentially carcinogenic (class 2B, IARC; (Straif K. et al. 2007)). Poorly quantified emission factors and low understanding of when various aerosol emissions are likely to form during a fire event (initiation, combustion, extinguishing) inhibit efforts to reduce exposure by interventions to the firefighting strategy. The study was designed to evaluate firefighters’ exposure to air pollutants and to allow identification of how aerosol emissions respond to burning conditions and interventions of the firefighting. The study was conducted at the MSB firefighter training facility in Revinge outside Lund, Sweden. Eight small (5x3x2 m) sheds were built to imitate small compartment environments: apartment, bedroom, workshop, etc. These sheds were ignited under realistic fire scenarios (e.g., accident, arson) and later used for training new fire investigators (forensic police). Firefighter students and teachers monitored and extinguished the fires in similar procedures to real fire events. A supervisor monitored the combustion conditions, allowing or restricting fresh-air flow into the fire by opening or closing of the main door.Fire emissions were extracted from the fire through a 10 m (Ø 6 mm) stainless steel pipe, diluted ~1:50 with HEPA and active charcoal filtered air. The diluted emissions were monitored with a battery of aerosol monitoring instruments. Instrumentation included an aerosol mass spectrometer (Aerodyne SP-AMS, Billerica USA), an aethalometer (AE33, Magee Sci. USA), a differential mobility spectrometer (DMS500, Cambustion, UK), CO2 monitor (LI-COR, USA), and a NO/NO2 monitor (2BTech, USA). Complementary background measurements were positioned downwind or sidewind of the fires. With this equipment we collected data with the aim to resolve relationships between combustion conditions and pollution formation during different phases of a fire response. The results showed that total particle mass (PM1) emissions correlated with CO2 emissions and thus fire intensity. The emissions were speciated according to equivalent black carbon (eBC), organic aerosol (OA) and polycyclic aromatic hydrocarbon (PAH) derived from AMS data. When speciated, different particle emissions were found to depend on activities of the firefighting and the supervisor responsible for allowing or restricting fresh air into the combustion environment. Most evidently, we found that restricting the access to O2 by closing the door resulted in a sharp increase of OA and even more pronounced, PAH. PAH increased by several orders of magnitude, suggesting that PAH exposure-risks may increase drastically when fires become under-ventilated. Extinguishing the fire with water quickly decreased all particle emissions. The results described are illustrated in Figure 1.Further analysis involves additional off-line analyses, derivation of emission factors, time-resolved speciated emission analysis and evaluation of relationships between emissions, burning conditions and firefighting strategies.
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| 64. |
- Marc-Derrien, Youna, et al.
(författare)
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Acute Cardiovascular Effects of Hydrotreated Vegetable Oil Exhaust
- 2022
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Ingår i: Frontiers in Physiology. - : Frontiers Media SA. - 1664-042X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Ambient air pollution is recognized as a key risk factor for cardiovascular morbidity and mortality contributing to the global disease burden. The use of renewable diesel fuels, such as hydrotreated vegetable oil (HVO), have increased in recent years and its impact on human health are not completely known. The present study investigated changes in cardiovascular tone in response to exposure to diluted HVO exhaust. The study participants, 19 healthy volunteers, were exposed in a chamber on four separate occasions for 3 h and in a randomized order to: (1) HVO exhaust from a wheel loader without exhaust aftertreatment, (2) HVO exhaust from a wheel loader with an aftertreatment system, (3) clean air enriched with dry NaCl salt particles, and (4) clean air. Synchronized electrocardiogram (ECG) and photoplethysmogram (PPG) signals were recorded throughout the exposure sessions. Pulse decomposition analysis (PDA) was applied to characterize PPG pulse morphology, and heart rate variability (HRV) indexes as well as pulse transit time (PTT) indexes were computed. Relative changes of PDA features, HRV features and PTT features at 1, 2, and 3 h after onset of the exposure was obtained for each participant and exposure session. The PDA index A13, reflecting vascular compliance, increased significantly in both HVO exposure sessions but not in the clean air or NaCl exposure sessions. However, the individual variation was large and the differences between exposure sessions were not statistically significant.
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| 65. |
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| 66. |
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| 67. |
- Markowicz, Pawel, et al.
(författare)
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A study on particles and some microbial markers in waterpipe tobacco smoke.
- 2014
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Ingår i: Science of the Total Environment. - : Elsevier BV. - 1879-1026 .- 0048-9697. ; 499, s. 107-113
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Tidskriftsartikel (refereegranskat)abstract
- Waterpipe smoking is becoming increasingly popular worldwide. Research has shown that cigarette smoke, in addition to hundreds of carcinogenic and otherwise toxic compounds, may also contain compounds of microbiological origin. In the present study we analyzed waterpipe smoke for some microbial compounds. Both of the two markers studied, viz 3-hydroxy fatty acids of bacterial lipopolysaccharide (LPS) and ergosterol of fungal biomass, were found in waterpipe tobacco, in amounts similar as previously found in cigarette tobacco, and in smoke. Waterpipe mainstream smoke contained on average 1800 pmol LPS and 84.4ng ergosterol produced per session. An average concentration of 2.8 pmol/m(3) of LPS was found in second hand smoke during a 1-2-h waterpipe smoking session while ergosterol was not detected; corresponding concentrations from smoking five cigarettes were 22.2 pmol/m(3) of LPS and 87.5ng/m(3) of ergosterol. This is the first time that waterpipe smoking has been shown to create a bioaerosol. In the present study we also found that waterpipe smoking generated several polycyclic aromatic hydrocarbons, carbon monoxide, and high fraction of small (<200nm) particles that may have adverse effects on human health upon inhalation.
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| 68. |
- Morawska, Lidia, et al.
(författare)
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A paradigm shift to combat indoor respiratory infection
- 2021
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Ingår i: Science (New York, N.Y.). - : American Association for the Advancement of Science (AAAS). - 1095-9203 .- 0036-8075. ; 372:6543, s. 689-691
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Tidskriftsartikel (refereegranskat)abstract
- Building ventilation systems must get much better
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| 69. |
- Morawska, Lidia, et al.
(författare)
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COVID-19 and airborne transmission : science rejected, lives lost : can society do better?
- 2023
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Ingår i: Clinical infectious diseases : an official publication of the Infectious Diseases Society of America. - : Oxford University Press (OUP). - 1537-6591. ; 76:10, s. 1854-1859
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Tidskriftsartikel (refereegranskat)abstract
- This is an account that should be heard of an important struggle: the struggle of a large group of experts who came together at the beginning of the Covid-19 pandemic to warn the world about the risk of airborne transmission and the consequences of ignoring it. We alerted the World Health Organization (WHO) about the potential significance of the airborne transmission of SARS-CoV-2 and the urgent need to control it, but our concerns were dismissed. Here we describe how this happened and the consequences. We hope that by reporting this story, we can raise awareness of the importance of interdisciplinary collaboration and the need to be open to new evidence, and to prevent it from happening again. Acknowledgement of an issue and the emergence of new evidence related to it, is the first necessary step towards finding effective mitigation solutions.
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| 70. |
- Morawska, Lidia, et al.
(författare)
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How can airborne transmission of COVID-19 indoors be minimised?
- 2020
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Ingår i: Environment International. - : Elsevier BV. - 1873-6750 .- 0160-4120. ; 142
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Tidskriftsartikel (refereegranskat)abstract
- During the rapid rise in COVID-19 illnesses and deaths globally, and notwithstanding recommended precautions, questions are voiced about routes of transmission for this pandemic disease. Inhaling small airborne droplets is probable as a third route of infection, in addition to more widely recognized transmission via larger respiratory droplets and direct contact with infected people or contaminated surfaces. While uncertainties remain regarding the relative contributions of the different transmission pathways, we argue that existing evidence is sufficiently strong to warrant engineering controls targeting airborne transmission as part of an overall strategy to limit infection risk indoors. Appropriate building engineering controls include sufficient and effective ventilation, possibly enhanced by particle filtration and air disinfection, avoiding air recirculation and avoiding overcrowding. Often, such measures can be easily implemented and without much cost, but if only they are recognised as significant in contributing to infection control goals. We believe that the use of engineering controls in public buildings, including hospitals, shops, offices, schools, kindergartens, libraries, restaurants, cruise ships, elevators, conference rooms or public transport, in parallel with effective application of other controls (including isolation and quarantine, social distancing and hand hygiene), would be an additional important measure globally to reduce the likelihood of transmission and thereby protect healthcare workers, patients and the general public.
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