Ambient air pollution, including airborne particulate matter (PM) derived from combustion of fossil fuels (FF) or biomass (BM), has detrimental inflammatory effects on human health. Myeloid antigen presenting cells, including dendritic cells (DCs) regulate immune responses in the airway and sample inhaled PM. This study tests the hypothesis that PM interacts with multiple environmental sensing pathways in DCs with outcomes that depend on particle size and composition as determined by combustion source. The effects of different sized PM (< 10μm, PM10; < 2.5μm, PM2.5), derived from the combustion of FF or BM, on human monocyte-derived or ex vivo sputum DCs, were examined. DC activation status, cytokine production and aryl hydrocarbon receptor (AhR) signalling were assessed by flow-cytometry, multiplex ELISA and qRT-PCR, following exposure to PM. Pathway-specific antagonists were used to explore underlying mechanisms. Particle size and combustion source influenced the effects of PM on DCs. Irrespective of combustion source, PM10 but not PM2.5, induced MoDC maturation and stimulated production of inflammatory cytokines, including IL-1β and IL-18, indicative of inflammasome activation. These responses were dependent, at least in part, on TLR4 as was the induction of IDO by PM10. AhR signalling was induced by PM in both MoDC and ex vivo sputum DC. It was stimulated by both PM10 and PM2.5 and was induced more strongly by BM-derived PM. AhR activation was independent of DC maturation and TLR4 signalling. Additionally, BM- but not FF-derived PM increased NADH levels in DC suggestive of altered metabolism. Thus, PM induces a complex programme of DC activation, influenced by size and combustion source, which includes classical maturation, inflammasome dependent cytokine release and AhR signalling as well as potential metabolic changes. In the airway, exposure to different PM and the changes in DCs induced by them may lead to altered responses to inhaled antigen.

Urban health problems and visibility degradation problems are associated with particulate matter in the air, especially PM10 and PM25 (particles with aerodynamic diameter less than 10 j.tm and 2.5 jsm, respectively). The aim of this study was to investigate the characteristics and sources of PM25 and PM20 aerosols in Brisbane. This study collected aerosol samples over a period of two and a half years at five sites around Brisbane. Source samples of soil dusts, road-side dusts and sea salt were also collected and analysed to provide information on source emission composition. The aerosol samples were analysed by a wide range of techniques, including Ion Beam Analysis and Scanning Electron Microscopy, for their chemical composition and particle size distribution. Some methodologies have been specifically developed in this study. The results presented here show that the chemical composition of PM20 aerosols in Brisbane varies largely with particle size and locations. The chemical composition of the samples are generally related to the land use near the monitoring sites. On average, the major components in the PM10 aerosol samples at five sites in Brisbane were identified as: crustal matter (27% by mass), organic matter (16%), sea salt (12%), soot (11%), and ammonium sulphate (7%). Among the Australian studies, in general, the results show that the composition of the PM25 aerosol samples collected at the Griffith University site (Brisbane) is closest to those of the New South Wales samples. The samples from Melbourne and Perth are generally richer in industry-and vehicle-related species. The major components of the PM25 aerosols at the GU site were identified as: organic matter (27% by mass), elemental carbon (23%), ammonium sulphate (14%), sea salt (9%) and crustal matter (6%). The results show that contribution of emission sources also has large particle size, temporal and spatial variations. Based on the results of source apportionment from the chemical mass balance method, the major contributors of PM20 aerosol mass in samples collected at five sites in Brisbane were found to include: soiL/road-side dusts (25% by mass, results of analysis also indicate a higher contribution from road-side dusts than from soil dusts), motor vehicle exhausts (13%, more than 80% of which are from diesel trucks/buses), elemental carbon and secondary products (around 15%), sea salt (12%), Ca/Ti-rich compounds from cement plant and mineral processing industries (11%), and biomass burning and bioaerosols (7%). On average, the PM25 aerosol mass at the Griffith University (GU) site was found to have contributions mainly from sources related to combustion. These sources include elemental carbon (24% by mass), secondary organics (21%), biomass burning (15%) and secondary sulphate (14%). Although motor vehicle exhausts contribute directly to only 6% of the PM25 aerosol mass at the GU site, their actual contribution could be substantial because most of the elemental carbon and secondary products are related to motor vehcile exhausts. On average, the results show that the visibility degradation problems in Brisbane are worse in winter/autumn than in summer. Soot and sulphate particles are the main visibility degrading species. In terms of visibility degrading sources, the main contributors are (excluding the contribution of NO2 gas): motor vehicles (up to 50%, including the secondary products), secondary sulphates (17%) and biomass burning (10%). In general, emission sources which contribute more to the fine particle fraction, and to gaseous pollutants, are most responsible for the aerosol associated health problems and visibility degradation problems. In Brisbane, these sources include motor vehicle exhausts, soil dusts, biomass burning and industrial dust.

The demand for meat and other animal products over the past couple decades has led to a changeover from small family operated farms, into large commercial facilities. The increase in animal density and population has created new issues related to waste management and pollution. Aerial pollutants, such as carbon dioxide, methane, ammonia, nitrous oxide and particulate matter, are all byproducts of agricultural processes. This study examines the concentrations, emission rates, and emission factors of ammonia, methane, and particulate matter that are emitted from a commercial dairy barn. The commercial dairy facility was located near New Hamburg in Ontario, Canada. It has the capacity to house 501 animals total, split between lactating cows, dry cows, heifers, bulls and calves. Lactating cows are confined in tie stalls while the rest of the herd used free stall pens. The barn is mechanically ventilated and uses a set of 14 fans with diameters of 1.22 m to ventilate the barn. Concentration data were measured over two sampling periods; the first took place in January – March 2013 and the second from May – July 2013. The pollutant concentrations, ventilation rates, and animal weights were used to generate emission factors based on an animal unit (AU – equivalent to 500 kg live mass) basis. The emission factors for ammonia, methane, PM10 and PM2.5 averaged over the two campaigns were 1.12 g hr-1 AU-1, 25.08 g hr-1 AU-1, 9.33 mg hr-1 AU-1 and 4.96 mg hr-1 AU-1, respectively and agree well with reported values in the literature. The time of year had an impact on the emission levels as all of the pollutants, except methane, were higher in the second sampling campaign compared to the first. A large increase was seen in the ammonia and particulate matter, while a more moderate change was seen in the methane. Peaks in ammonia emissions correlated well with feed times, and are highly influenced by animal activity. Methane emissions were dominated by the digestive process in the rumen, and have a lag period after feeding before the emissions spike. Although particulate matter increased, it was not correlated to a specific event in the barn. / Agriculture and Agri-Food Canada, Ontario Ministry of Agriculture Food, Ontario Ministry of Rural Affairs, Dairy Farmers of Canada, Dairy Farmers of Ontario

The high incidence of upper respiratory diseases, contamination of waterways due to pathogens and nutrients from human and animal wastes, unsustainable deforestation, gender disparities in burden of disease due to unequal exposure to indoor air pollutants, and carbon black emissions from the burning of solid fuels are interrelated problems in many developing countries. Small scale anaerobic digestion provides a means of alleviating these problems by treating livestock waste onsite to produce biogas (methane and carbon dioxide) in rural areas in developing countries. Fuel can then be used for cooking, lighting, and heating. Methane fuel is an alternative to traditional three-stone fires, improved cook stoves, and liquid petroleum gas. However, there is a lack of information available on design methods for these systems. The goal of this research was to develop a design tool that could be used for anaerobic digester sizing based on livestock waste availability. An Excel spreadsheet model was developed for sizing the bioreactor and the gas container based upon recommended values from a literature review. Needed monitoring parameters for operation of an anaerobic digester in the field were identified and standard methods of analysis were recommended. Sample preservation techniques were detailed. Guidelines for pathogen reduction in thermophilic anaerobic digestion were identified. Further study of pathogen reduction in low temperature reactors currently in use in developing countries was recommended. Three digester designs included in the Excel spreadsheet model were: the polyethylene tubular digester, the floating drum digester, and the fixed dome digester. The design tool may be requested from Dr. Sarina Ergas, sergas(at)usf.edu. An organic loading rate of 1.0 kg VS/(m3*d) was chosen for use in the design tool based upon a review of the literature. A semi-empirical kinetic model was developed for defining the SRT based on the temperature inputted by the user. Three case studies, based upon livestock waste availability in a rural community in the Dominican Republic, were analyzed using the sizing design tool. The case studies were conducted on three scales: one household, six households, and a village of 48 households. The specific biogas production rates were, for Case Studies one through three, respectively, 0.0076, 0.0069, and 0.010 m3 biogas/kg Volatile Solids reduced. Additional future work included: characterization of human feces and guinea pig manure, laboratory and field testing of the Excel spreadsheet design tool, and promotion of anaerobic digesters by development workers, non-governmental organizations, and governments.