Bioaerosol

About: Bioaerosol is a research topic. Over the lifetime, 1347 publications have been published within this topic receiving 34791 citations.

Investigation of ice nucleation properties onto soot, bioaerosol and mineral dust during different measurement campaigns

Abstract: Atmospheric aerosols have an impact on the climate through direct and indirect interactions with solar radiations. Ice nucleation in the atmosphere has an influence on cloud radiative properties and the hydrological cycle. The average temperature of mixed-phase clouds encountered in the atmosphere is above the homogeneous freezing threshold of cloud droplets, i.e. -38◦C. Therefore heterogeneous ice nucleation within mixed-phase clouds takes place via one of the four nucleation modes, which are deposition, immersion, contact and condensation ice nucleation. Ice nuclei properties have been studied for decades but still remain not fully understood especially for black carbon particles and bioaerosols. Atmospheric ice nuclei also lack of in-situ characterization in the free and upper troposphere where mixed-phase and cold clouds formation occurs. This thesis presents the characteristics and principle of the Portable Ice Nucleation Chamber (PINC) and results from different measurement campaigns performed with PINC on different types of aerosol particles. The ice nucleation ability of non aged and aged (organic coating) diesel and wood combustion particles has been investigated during the Paul Scherrer Institute IMBALANCE measurement campaign 2009. The experiments have been performed at three different temperatures, -30◦C, -35◦C and -40◦C. The results showed that no ice nucleation occurred at -30◦C for both diesel and wood combustion particles. At -35◦C, diesel combustion particles showed ice formation only after coating with α-pinene, whereas wood combustion particles triggered ice nucleation for both aged and non aged particles only at a relative humidities of 158% and 106% with respect to ice (RHi) and water (RHw), respectively. At -40◦C, aged and non aged diesel and wood combustion particles nucleated ice in the deposition mode at about 140% RHi and 92% RHw. The use of a thermodenuder removing volatile compounds increased the ice nucleation onset of diesel particles in one experiment. Furthermore, ice nucleation of three types of bacteria, Pseudomonas Syringae 13B-2 and CC242 and Pseudomonas Fluorescens ANT1 have been investigated at two temperatures -8◦C and -10◦C. All the studied bacteria triggered ice nucleation via condensation freezing and showed an ice active fraction below 1%. ANT1 showed the highest ice nucleation activity at -8◦C and therefore it was then tested with an anthropogenic and oceanic cultivation medium. The results showed that the cultivation medium did not significantly modify the ice nucleation activity of ANT1. Further results showed variability in the ice nucleation activity for the same cultivation medium. Finally, PINC was operating at the high alpine research station Jungfraujoch from February 24th to March 10th, 2009 and from June 1st to June 16th, 2009. IN measurements at constant thermodynamic conditions (temperature of -31◦C, 127% RHi and 91% RHw) were performed during these measurement periods and results in the deposition nucleation mode showed an average IN concentration of 8 particles per liter in March and 14 particles per liter in June. No correlation between the IN number concentration and the BC mass concentration was found. Two Saharan dust events were detected on June 15th and 16th. The IN number concentration increased up to several hundreds per liter on June 15th but only up to 50 IN per liter on June 16th, suggesting that the intensities of the two events were different. A correlation between the IN number concentration and the particle sizes below 1 μm aerodynamic diameter has been found. A higher correlation was found for larger particles, inferring that an increase in the number of larger particles induced a higher IN number concentration.

Airborne particles and microorganisms in a dental clinic: Variability of indoor concentrations, impact of dental procedures, and personal exposure during everyday practice.

Abstract: This study presents for the first time comprehensive measurements of the particle number size distribution (10 nm to 10 μm) together with next-generation sequencing analysis of airborne bacteria inside a dental clinic. A substantial enrichment of the indoor environment with new particles in all size classes was identified by both activities to background and indoor/outdoor (I/O) ratios. Grinding and drilling were the principal dental activities to produce new particles in the air, closely followed by polishing. Illumina MiSeq sequencing of 16S rRNA of bioaerosol collected indoors revealed the presence of 86 bacterial genera, 26 of them previously characterized as potential human pathogens. Bacterial species richness and concentration determined both by qPCR, and culture-dependent analysis were significantly higher in the treatment room. Bacterial load of the treatment room impacted in the nearby waiting room where no dental procedures took place. I/O ratio of bacterial concentration in the treatment room followed the fluctuation of I/O ratio of airborne particles in the biology-relevant size classes of 1-2.5, 2.5-5, and 5-10 μm. Exposure analysis revealed increased inhaled number of particles and microorganisms during dental procedures. These findings provide a detailed insight on airborne particles of both biotic and abiotic origin in a dental clinic.

Sampling for airborne influenza virus using RNA preservation buffer : a new approach

Abstract: Characterizing airborne influenza virus exposure is important for infection prevention and exposure control in health care and public settings. Detecting airborne influenza virus is important in assessing infection risk. The virus must also be protected from deterioration during aerosol sampling and long term storage. RNA preservation buffers (RNAPBs) may stabilize influenza virus after sampling and during storage. Bioaerosol samplers are used to collect airborne influenza virus, and many different types of samplers are available. The objectives of this experiment were to: 1) compare influenza virus concentrations across bioaerosol samplers; 2) compare the efficacy of RNAPB over Hanks Balanced Salt Solution (HBSS) as a sample collection media; and 3) determine whether RNAPB stabilizes viral particles stored over time. In this experiment we aerosolized active influenza virus (H1N1) in a bioaerosol chamber and compared sampling efficiencies using two different samplers: the SKC Biosampler and NIOSH Biosampler, and two different medias: Hanks Balanced Salt Solution (HBSS) and an RNAPB. Ten 15-minute experimental trials were completed. We also compared HBSS and RNAPB in terms of the maintenance of virus RNA integrity during storage at room temperatures. Samples were stored at room temperature for 1, 4, 7, and 14 days. Virus concentrations were measured and compared at each time point. Significant differences were found between sampler and media type – the SKC Biosampler collected a higher concentration of virus than the NIOSH Biosampler, and HBSS collected a higher concentration of virus than RNAPB. In storage at room temperature conditions, RNAPB maintained virus in concentrations significantly greater

Analysis of Microbial Air Quality in the Surrounding Hospital's Wastewater Treatment Plants in Jakarta, Indonesia

Abstract: As hospitals require the usage of various hazardous drugs and chemicals in its daily operation, the often contaminated wastewater of health facilities needs to be processed to comply with the quality standards specified in Regulation of the Governor of DKI Jakarta No. 65/2013. However, wastewater treatment plants (WWTP) can also pollute not only water but also the ambient air of facilities. The objective of this research is to identify airborne bacteria and the concentration of fungi due to the presence of WTP and to analyse the types of bacteria that exist through Gram Staining. Microbial air samples taken using EMS E6 showed that the average concentration of bioaerosol at hospital’s WWTP was about 810-1,915 CFU/m 3 for bacteria and 1,450-1,955 CFU/m 3 for fungi. Furthermore, the highest concentration of bacteria and fungi found in the surrounding equalization and aeration tanks was 1,915 CFU/m 3 and 1,955 CFU/m 3 , respectively, which far exceeded the background value of 80 CFU/m 3 for bacteria and 440 CFU/m 3 for fungi. Gram staining of the bacteria found in the air surrounding WWTP showed 94% Gram-negative with the bacteria being pathogenic. Therefore, it is pertinent that further action is taken to prevent bioaerosol from spreading around WWTP by building better ventilation surrounding the plants, indicating the technology of the treatment plant to be used, and enforcing personal safety measures on WWTP’s employees.