scholarly journals Concentration and size distribution of biological particles in school classrooms

2017 ◽  
pp. 5085-5091 ◽  
Author(s):  
Dr. Mona Mostafa
Keyword(s):  
Lung Diseases ◽  
Size Range ◽  
Aerosol Particles ◽  
Fungal Growth ◽  
Bacterial Concentration ◽  
Biological Particles ◽  
Guide Value ◽  
Bacterial Aerosol ◽  
Fungal Particles ◽  
Main Factor

Fungal and bacterial aerosol particles concentrations are measured in a school classrooms at two different floors using the 6-stage Andersen impactor as a bioaersol sampler. The average bacterial concentration is higher than the average fungal concentration. The concentrations were 957 and 955 cfu/m3 for bacterial particles at first and second floors, respectively while the fungal particles  concentrations were 146 and 235 cfu/m3 at first and second floors, respectively. Most of the biological particles were concentrated at the size range of respirable particles (< 5 µm ) that can penetrate into the alveoli and may cause lung diseases. The human activity is a main factor for the production of microbiological particles. Environmental factors play also a role on the fungal growth. Bacterial concentration is almost twice the guide value of WHO while the fungal concentration is underestimation.

scholarly journals Laser ablation aerosol particle time-of-flight mass spectrometer (LAAPTOF): performance, reference spectra and classification of atmospheric samples

2018 ◽  
Vol 11 (4) ◽  
pp. 2325-2343 ◽  
Author(s):  
Xiaoli Shen ◽  
Ramakrishna Ramisetty ◽  
Claudia Mohr ◽  
Wei Huang ◽  
Thomas Leisner ◽  
...  
Keyword(s):  
Laser Ablation ◽  
Aerosol Particle ◽  
Mass Spectrometer ◽  
Size Range ◽  
Aerosol Particles ◽  
Time Of Flight ◽  
Polystyrene Latex ◽  
Dust Particles ◽  
Data Set ◽  
Flight Mass Spectrometer

Abstract. The laser ablation aerosol particle time-of-flight mass spectrometer (LAAPTOF, AeroMegt GmbH) is able to identify the chemical composition and mixing state of individual aerosol particles, and thus is a tool for elucidating their impacts on human health, visibility, ecosystem, and climate. The overall detection efficiency (ODE) of the instrument we use was determined to range from  ∼  (0.01 ± 0.01) to  ∼  (4.23 ± 2.36) % for polystyrene latex (PSL) in the size range of 200 to 2000 nm,  ∼  (0.44 ± 0.19) to  ∼  (6.57 ± 2.38) % for ammonium nitrate (NH4NO3), and  ∼  (0.14 ± 0.02) to  ∼  (1.46 ± 0.08) % for sodium chloride (NaCl) particles in the size range of 300 to 1000 nm. Reference mass spectra of 32 different particle types relevant for atmospheric aerosol (e.g. pure compounds NH4NO3, K2SO4, NaCl, oxalic acid, pinic acid, and pinonic acid; internal mixtures of e.g. salts, secondary organic aerosol, and metallic core–organic shell particles; more complex particles such as soot and dust particles) were determined. Our results show that internally mixed aerosol particles can result in spectra with new clusters of ions, rather than simply a combination of the spectra from the single components. An exemplary 1-day ambient data set was analysed by both classical fuzzy clustering and a reference-spectra-based classification method. Resulting identified particle types were generally well correlated. We show how a combination of both methods can greatly improve the interpretation of single-particle data in field measurements.

scholarly journals Stable carbon and nitrogen isotope ratio in PM1 and size segregated aerosol particles over the Baltic Sea

2019 ◽  
Vol 59 (3) ◽  
Author(s):  
Inga Garbarienė ◽  
Vidmantas Remeikis ◽  
Agnë Mašalaitė ◽  
Andrius Garbaras ◽  
Tpmasz Petelski ◽  
...  
Keyword(s):  
Baltic Sea ◽  
Size Range ◽  
Road Traffic ◽  
Aerosol Particles ◽  
Nitrogen Isotope ◽  
Total Carbon ◽  
Formation Mechanisms ◽  
The Baltic Sea ◽  
Air Masses ◽  
The Baltic

We analysed δ13C of total carbon (TC) and δ15N of total nitrogen (TN) in submicron (PM1) and size segregated aerosol particles (PM0.056–2.5) collected during a cruise in the Baltic Sea from 9 to 17 November 2012. PM1 were characterized by the highest δ13C (–26.4‰) and lowest δ15N (–0.2 and 0.8‰) values when air masses arrived from the southwest direction (Poland). The obtained δ13C values indicated that combined emissions of coal and diesel/gasoline combustion were the most likely sources of TC. The depleted δ15N values indicated that TN originated mainly from liquid fuel combustion (road traffic, shipping) during this period. The lowest δ13C and highest δ15N values were determined in PM1 samples during the western airflow when the air masses had no recent contact with land. The highest δ15N values were probably associated with chemical aging of nitrogenous species during long-range transport, the lowest δ13C values could be related to emissions from diesel/gasoline combustion, potentially from ship traffic. The δ13C analysis of size-segregated aerosol particles PM0.056–2.5 revealed that the lowest δ13C values were observed in the size range from 0.056 to 0.18 µm and gradual 13C enrichment occurred in the size range from 0.18 to 2.5 µm due to different sources or formation mechanisms of the aerosols.

scholarly journals Ice nucleating particles at a coastal marine boundary layer site: correlations with aerosol type and meteorological conditions

2015 ◽  
Vol 15 (12) ◽  
pp. 16273-16323 ◽  
Author(s):  
R. H. Mason ◽  
M. Si ◽  
J. Li ◽  
C. Chou ◽  
R. Dickie ◽  
...  
Keyword(s):  
Size Distribution ◽  
Marine Boundary Layer ◽  
Aerosol Particles ◽  
Meteorological Conditions ◽  
Marine Aerosols ◽  
Coastal Site ◽  
Carbon Particles ◽  
Biological Particles ◽  
Ice Nuclei ◽  
Coastal Marine

Abstract. Information on what aerosol particle types are the major sources of ice nucleating particles (INPs) in the atmosphere is needed for climate predictions. To determine which aerosol particles are the major sources of immersion-mode INPs at a coastal site in Western Canada, we investigated correlations between INP number concentrations and both concentrations of different atmospheric particles and meteorological conditions. We show that INP number concentrations are strongly correlated with the number concentrations of fluorescent bioparticles between −15 and −25 °C, and that the size distribution of INPs is most consistent with the size distribution of fluorescent bioparticles. We conclude that biological particles were likely the major source of ice nuclei at freezing temperatures between −15 and −25 °C at this site for the time period studied. At −30 °C, INP number concentrations are also well correlated with number concentrations of the total aerosol particles ≥ 0.5 μm, suggesting that non-biological particles may have an important contribution to the population of INPs active at this temperature. As we found that black carbon particles were unlikely to be a major source of ice nuclei during this study, these non-biological INPs may include mineral dust. Furthermore, correlations involving tracers of marine aerosols and marine biological activity indicate that the majority of INPs measured at the coastal site likely originated from terrestrial rather than marine sources. Finally, six existing empirical parameterizations of ice nucleation were tested to determine if they accurately predict the measured INP number concentrations. We found that none of the parameterizations selected are capable of predicting INP number concentrations with high accuracy over the entire temperature range investigated.

scholarly journals Fungal Contaminants in Energy Efficient Dwellings: Impact of Ventilation Type and Level of Urbanization

2020 ◽  
Vol 17 (14) ◽  
pp. 4936 ◽  
Author(s):  
Hélène Niculita-Hirzel ◽  
Shen Yang ◽  
Corinne Hager Jörin ◽  
Vincent Perret ◽  
Dusan Licina ◽  
...  
Keyword(s):  
Energy Efficient ◽  
Natural Ventilation ◽  
Strong Association ◽  
Fungal Growth ◽  
Mechanically Ventilated ◽  
Respiratory Problems ◽  
Settled Dust ◽  
Building Characteristics ◽  
Fungal Contaminants ◽  
Fungal Particles

The presence of growing fungi in the indoor environment has been associated with the development of respiratory problems such as asthma or allergic rhinitis, as well as the worsening of respiratory pathologies. Their proliferation indoors could be a result of water leakage or inadequate ventilation. Although the factors promoting mould growth have been widely investigated in traditional dwellings, little work has been done in energy efficient dwellings. Here, the effectiveness of ventilation type, i.e., natural or mechanical, in influencing mould development was estimated in 44 recent and 105 retrofitted energy efficient dwellings. Fungi growing on surfaces were investigated in the dwellings situated in rural, peri-urban, and urban regions of Switzerland. The presence of these fungi was also investigated in bedroom settled dust. Information on building characteristics and owners’ lifestyle were collected. Significant associations were found with the level of urbanisation, the location of mouldy area in dwellings, and the diversity of fungal taxa. Dwellings in peri-urban zones showed the most frequent fungal contamination in the owners’ bedroom and the highest diversity of fungal genera among dwellings. While the urbanisation level or the ventilation type favoured no specific genus, we found marked disparities in the diversity of fungi growing on surfaces in naturally ventilated versus mechanically ventilated dwellings. Aspergillus, in particular, was a frequent surface contaminant in bedrooms with natural ventilation, but not in those mechanically ventilated. We observed a strong association between fungal growth on surfaces and the number of fungal particles counted in the settled dust of owners’ bedrooms. These results demonstrate the importance of ventilation systems in energy efficient dwellings in controlling fungal proliferation in living areas.

scholarly journals The mathematical principles and design of the NAIS – a spectrometer for the measurement of cluster ion and nanometer aerosol size distributions

2013 ◽  
Vol 6 (4) ◽  
pp. 1061-1071 ◽  
Author(s):  
S. Mirme ◽  
A. Mirme
Keyword(s):  
Size Range ◽  
Aerosol Particles ◽  
Charged Particles ◽  
Cluster Ions ◽  
Size Distributions ◽  
Neutral Cluster ◽  
Design Data ◽  
Cluster Ion ◽  
Principles Of Design ◽  
Spectrum Deconvolution

Abstract. The paper describes the Neutral cluster and Air Ion Spectrometer (NAIS) – a multichannel aerosol instrument capable of measuring the distribution of ions (charged particles and cluster ions) of both polarities in the electric mobility range from 3.2 to 0.0013 cm2 V−1 s−1 and the distribution of aerosol particles in the size range from 2.0 to 40 nm. We introduce the principles of design, data processing and spectrum deconvolution of the instrument.

scholarly journals Experimental evidence of the rear capture of aerosol particles by raindrops

2017 ◽  
Vol 17 (6) ◽  
pp. 4159-4176 ◽  
Author(s):  
Pascal Lemaitre ◽  
Arnaud Querel ◽  
Marie Monier ◽  
Thibault Menard ◽  
Emmanuel Porcheron ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Size Range ◽  
Collection Efficiency ◽  
Aerosol Particles ◽  
Experimental Studies ◽  
Laboratory Measurements ◽  
Experimental Proof ◽  
Theoretical Approaches ◽  
Capture Mechanism ◽  
Mode Size

Abstract. This article presents new measurements of the efficiency with which aerosol particles of accumulation mode size are collected by a 1.25 mm sized raindrop. These laboratory measurements provide the link to reconcile the scavenging coefficients obtained from theoretical approaches with those from experimental studies. We provide here experimental proof of the rear capture mechanism in the flow around drops, which has a fundamental effect on submicroscopic particles. These experiments thus confirm the efficiencies theoretically simulated by Beard (1974). Finally, we propose a semi-analytical expression to take into account this essential mechanism to calculate the collection efficiency for drops within the rain size range.

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