Lidia Morawska

Bio: Lidia Morawska is an academic researcher from Queensland University of Technology. The author has contributed to research in topics: Particle number & Ultrafine particle. The author has an hindex of 100, co-authored 746 publications receiving 95412 citations. Previous affiliations of Lidia Morawska include University of Surrey & Jinan University.

Effect of local factors on concentrations and flora of viable fungi in school buildings

Abstract: A wide range of health effects among occupants are associated with the exposure to bioaerosols from fungal sources. Although the accurate role of these aerosols in causing the symptoms and diseases is poorly understood, the important effect of bioaerosol exposure on human health is well recognized. Thus, there is a need to determine all of the contributing factors related to the concentration of fungi in indoor air. In this study, we reviewed and summarized the different factors affecting the concentrations of viable fungi in school buildings. The literature research was conducted using Pubmed and Google Scholar. In addition, we searched the lists of references of selected articles. According to the literature, the main factors influencing the concentration of viable fungi in the school buildings are moisture damage in building structures, the season (temperature and humidity conditions), the type and rate of ventilation, the number and activities of occupants and diurnal variations. This study offers valuable information that can be used in the interpretation of the fungal analysis and to decrease microbial exposure by reducing known sources and/or contributing factors. However, more studies of different local factors contributing to the human microbial exposure in school buildings—as well as other type of buildings and different indoor environments—are needed. Keywords—Fungi, concentration, indoor, school, contributing factor.

Room ventilation and the risk of airborne infection transmission in a tertiary hospital

Abstract: Outdoor air ventilation is a key mechanism controlling the airborne spread of several diseases. However, ventilation guidelines for hospitals are not typically based on preventing infection transmission. Aim: We sought to assess the effectiveness of current ventilation rates on infection risks for influenza, tuberculosis (TB) and rhinovirus within three distinct rooms in a major tertiary hospital in Australia. Methods: The rooms targeted were a Lung Function Laboratory, negative pressure isolation room in the Emergency Department and an Outpatient Consultation Room. Air exchange measurements were performed in each by using CO2 decay, and the proportion of outdoor air supplied was determined by CO2 mass-balance at the air handling unit. Gammaitoni and Nucci's infection risk model, based on the traditional Wells-Riley model, was then employed to model scenarios typical of those experienced by patients. Results: Current outdoor air exchange rates in the Lung Function Laboratory and Isolation Room were appropriate, and infection risks for all modelled scenarios were <3.6%. Influenza risk for patients entering the OPD Room after an infectious patient departed ranged from 3.6 to 20.7% depending on the occupancy time of the susceptible and infectious patient. Conclusions: In the absence of definitive guidelines, air exchange measurements combined with modelling afford a useful means of assessing, on a case-by-case basis, the suitability of room ventilation at preventing airborne transmission.

What are the driving factors influencing the size distribution of airborne synthetic clay particles emitted from a jet milling process

Abstract: In the field of workplace air quality, measuring and analyzing the size distribution of airborne particles to identify their sources and apportion their contribution has become widely accepted, however, the driving factors that influence this parameter, particularly for nanoparticles (< 100 nm), have not been thoroughly determined. Identification of driving factors, and in turn, general trends in size distribution of emitted particles would facilitate the prediction of nanoparticles’ emission behavior and significantly contribute to their exposure assessment. In this study, a comprehensive analysis of the particle number size distribution data, with a particular focus on the ultrafine size range of synthetic clay particles emitted from a jet milling machine was conducted using the multi-lognormal fitting method. The results showed relatively high contribution of nanoparticles to the emissions in many of the tested cases, and also, that both surface treatment and feed rate of the machine are significant factors influencing the size distribution of the emitted particles of this size. In particular, applying surface treatments and increasing the machine feed rate have the similar effect of reducing the size of the particles, however, no general trend was found in variations of size distribution across different surface treatments and feed rates. The findings of our study demonstrate that for this process and other activities, where no general trend is found in the size distribution of the emitted airborne particles due to dissimilar effects of the driving factors, each case must be treated separately in terms of workplace exposure assessment and regulations.