Litter conditions can also impact the health of farm workers via the effects of ammonia and dust. Litter is a source of dust in meat chicken sheds. Inhalation of dust by workers (Jerez et al., 2014) may contribute to conditions such as chronic obstructive pulmonary disease (COPD) and organic dust toxic syndrome (ODTS) (Viegas et al., 2013). DEEDI (2010) suggested that poultry farm workers should wear appropriate dust masks (e.g. P2 Australian Standard or N95 USA Standard), as the air within poultry sheds can contain large numbers of fine particles (<1μm).
The presence of pathogenic microorganisms (such as mould, fungi, bacteria etc.) also poses a risk to the health of workers. Impacts to human health are typically less of a concern than impacts to meat chickens due to the reduced contact time of workers and lower susceptibility to pathogens at concentrations present in sheds. For example, two bacterial pathogens that are present in chickens and litter and pose a problem to human health are Salmonella and Campylobacter jejuni, which both cause gastrointestinal illnesses. However, both require ingestion rather than inhalation to cause infection. A study of litter and aerosols by Chinivasagam et al., (2009) determined that although both Salmonella and Campylobacter jejuni are commonly found in litter, they present a low risk to human health. The levels of these organisms transferring into internal and external environments as aerosols are of little significance in terms of human infections.
Ammonia is generated in the litter in poultry sheds and is a severe respiratory tract irritant in humans, known to cause severe damage and death, although only in doses well above typical workplace conditions within sheds. It is listed as an airborne contaminant under Australian workplace health and safety standards.