The need to provide food for growing populations puts pressure on agriculture operations to increase efficiency and scale, but the trend of growing operations can lead to increased emissions with larger environmental impacts. Agricultural production generates both primary and secondary aerosol, and characterization of these particles is necessary to understand their atmospheric fate and impacts. Recent focus on primary aerosol includes bioaerosols, dust, and combustion emissions and their impact on animals, workers, and the environment. Agricultural emissions of nitrogen compounds such as ammonia and amines and biogenic volatile organic compounds and their contribution to secondary aerosol are also of interest. This symposium solicits contributions providing insight into aerosols formed from agricultural production including measurement techniques, sources, atmospheric fate, environmental and health impacts, and remediation efforts.
Water, the main condensed-phase component of the atmosphere, plays a central role in aerosol chemistry. Aerosol water and cloud droplets provide bulk media and unique conditions (e.g., low pH) for uptake and chemical processing of soluble, reactive gases (e.g. SO2, N2O5, SOA precursors). Adsorbed layers of water may impact aerosol surface reactions, and absorbed water can influence the formation of highly viscous phases, which in turn have an impact on aerosol chemical processing. This symposium will highlight studies of aerosol chemistry involving water, from field, modeling, and laboratory perspectives, from the molecular to the regional and global levels.
Inhalation of microorganism containing aerosol particles is a recognized route of exposure for many infectious diseases. For some diseases, such as influenza, inhalation represents a natural route of exposure. Even when inhalation exposure has not been implicated in the natural spread of the disease, the inhalation route of exposure may still be relevant in cases where aerosols are intentionally generated for nefarious reasons or mechanically generated from contaminated materials, such as in the 2001 anthrax attacks or the flushing of contaminated toilets, respectively.In the period of time between aerosol generation and inhalation into the respiratory tract, aerosols containing infectious microorganisms are transported through the ambient environment and exposed to a variety of stresses and physical processes that impact exposure risk. Atmospheric constituents such as ultraviolet radiation, water vapor, and vaporous pollutants may be detrimental to the aerosolized microorganisms, ultimately resulting in loss of infectivity. Physical processes such as particle settling and re-aerosolization of deposited particles also influence the risk of exposure to an infectious aerosol. This symposium will highlight research on the fate of infectious aerosols in the environment, focusing on diseases which naturally spread via aerosols, factors which may influence survival and transport, and methodologies for investigating agent fate.
There is an urgent need to better understand sources and formation mechanisms of haze in China now, which is more severe in Northern China and more frequent in winter compared to other seasons. Fine particulate matter (PM) has been shown to be closely linked to haze. Reducing the high fine PM concentration is a clear objective in both fundamental and applied research areas in recent years in China. Sources and formation mechanisms of haze in China are different to some extent from other regions of the world. Coal is still major fuel in China especially during cold season in Northern China and the number of vehicles is rapidlyincreasingin megacities. This symposium will present studies of haze in China including source apportionment, formation mechanisms, aerosol chemistry, and optical properties of haze from measurement, modeling and laboratory studies, as well as reveal unresolved scientific questions and challenges China is facing now.