Investigation of potential wood smoke impact on air quality in a Melbourne suburb.

An air monitoring program was conducted during 2005 to measure the impact of wood smoke from solid fuel heaters in a Melbourne residential suburb where there is extensive use of solid fuel heaters. A number of air pollutants including fine and course particles, organic air toxics benzene, polyaromatic hydrocarbons, formaldehyde, carbon monoxide and oxides of nitrogen were monitored to determine the impact on air quality. Air quality was assessed by comparing the monitoring results to national and State air quality policy objectives and advisory reporting standards. Measured levels were also compared to other EPA air monitoring sites in Melbourne. The study found the main impact to air quality was caused by particles measured during April and May by coarse particles from surrounding soil and mainly by fine particles from wood smoke. Elevated fine particle levels were measured on nine days during June, highest concentration of 43 µg/m³ being measured. Multielemental analysis by Ion Beam Analysis was also undertaken to characterise the fine particles. Measured levels were also compared to other EPA air monitoring sites in Melbourne. The findings of this study are summarised in this paper.International Union of Air Pollution Prevention and Environmental Protection Associations (IUAPPA); Clean Air Society of Australia and New Zealand (CASANZ); ECOTEC

Modeling the Afferent Dynamics of the Baroreflex Control System

In this study we develop a modeling framework for predicting baroreceptor firing rate as a function of blood pressure. We test models within this framework both quantitatively and qualitatively using data from rats. The models describe three components: arterial wall deformation, stimulation of mechanoreceptors located in the BR nerve-endings, and modulation of the action potential frequency. The three sub-systems are modeled individually following well-established biological principles. The first submodel, predicting arterial wall deformation, uses blood pressure as an input and outputs circumferential strain. The mechanoreceptor stimulation model, uses circumferential strain as an input, predicting receptor deformation as an output. Finally, the neural model takes receptor deformation as an input predicting the BR firing rate as an output. Our results show that nonlinear dependence of firing rate on pressure can be accounted for by taking into account the nonlinear elastic properties of the artery wall. This was observed when testing the models using multiple experiments with a single set of parameters. We find that to model the response to a square pressure stimulus, giving rise to post-excitatory depression, it is necessary to include an integrate-and-fire model, which allows the firing rate to cease when the stimulus falls below a given threshold. We show that our modeling framework in combination with sensitivity analysis and parameter estimation can be used to test and compare models. Finally, we demonstrate that our preferred model can exhibit all known dynamics and that it is advantageous to combine qualitative and quantitative analysis methods