The House Observations of Microbial and Environmental Chemistry (HOMEChem) study was a large-scale collaborative experimental investigation probing indoor air composition and chemistry.

In continuously stocked swards or pastures the frequency at which individual tillers and individual leaves are defoliated by ruminant livestock, relative to leaf lifespan of the grass species within the sward, determines the proportion of each leaf defoliated before senescence, and hence the efficiency of harvesting of herbage. In this paper, sets of data obtained in a range of climatic conditions and with a range of grass species are used in order to document this relationship. It is shown that the frequency of defoliation of individual tillers or individual leaves is closely linked to the average stocking density used within a period of time for maintaining a steady state sward or pasture height, herbage mass or leaf area index. Consequently, any decrease in herbage growth rate should lead to a decrease in the efficiency of harvesting of herbage and then to a more than proportional decrease in total herbage consumption by ruminant livestock. These effects will be more important for grass species having short leaf lifespan than for species with long lifespan. In rotational stocking, the link between herbage growth rate and frequency of defoliation of leaves can be broken by controlling the grazing interval, so any decrease in herbage growth would not be systematically associated with a decrease in efficiency of harvesting of herbage. Rotational stocking should be more efficient than continuous stocking in low herbage production conditions, while in high herbage production systems rotational and continuous stocking would have similar efficiency. The implications of these conclusions for the management of swards and pastures to meet different objectives are discussed briefly.

Deposition and surface-mediated reactions of adsorbed species can play a role in the level of exposure of occupants to indoor pollutants, which include gases and particles. Detailed molecular-level descriptions of these processes occurring on indoor surfaces are difficult to obtain because of the ever-increasing types of surfaces and their proximity to a variety of different indoor emission sources. The results of an investigation of interactions of glass surfaces in unique indoor environments are described here. Window glass, a ubiquitous indoor surface, was placed vertically in six different locations to assess differences in particle and coating depositions. Atomic force microscopy− photothermal infrared (AFM−PTIR) spectroscopic analysis of these glass surfaces reveals differences in morphology and chemical composition, which reflects the diversity of surface processes found in local environments indoors. Overall, this detailed microspectroscopic imaging method shows deposition of particles and the formation of organic thin films that increase the surface area and surface roughness of the glass surface. PTIR spectroscopy demonstrates that depositions can be linked to primary emitters intrinsic to each of the different local environments.

Microspectroscopic analyses of glass surfaces following a single day of cooking events reveal organic depositions that can be traced back to emission sources and airborne distributions.

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