Exposure to air pollutants among cyclists: A comparison of different cycling routes in Perth, Western Australia

Cycling is often promoted as a means of reducing vehicular congestion, greenhouse gases, noise and air pollutant emissions in urban areas. It is also endorsed as a healthy means of transportation in terms of reducing the risk of developing a range of physical and psychological conditions. However, people might not be aware of the negative health impacts of cycling near heavy traffic. This study aimed to compare personal exposure with particulate air pollution among cyclists commuting in Perth, Western Australia. The study involved 122 number of cyclists riding bicycles in four different routes: two routes within community areas (Route 1 and Route 2) and two routes near freeways (Route 3 and Route 4). The participants were males and females aged between 20 and 55 years with the selection criteria including non-smokers who cycle at least 150 km/week—ideally along one of the four study routes. Personal exposure of respirable particulate air pollution during cycling at the high and low level of exertions (self-perceived) were assessed. Ambient concentrations of selected air pollutants were also measured at each cycling route. We found that Route 3 appeared to be the most polluted route and concentrations of nitrogen dioxide and sulphur dioxide exceeded the Australian standards. This study concluded that personal exposure to respirable particles was influenced by the speed, time of cycling and seasonal variation

Environmental Conditions, Air Pollutants, and Airways

Air pollution is a major problem worldwide, which could be even more serious for athletes who train in urban environments. Exercise increases minute ventilation and exposure to pollutants, but the literature on the effects of air pollution in athletes is relatively scarce, with the exception of chlorine exposure in athletes of aquatic sports and air pollution secondary to ice resurfacing in athletes performing in ice arenas. Although air pollution may exert detrimental effects on athletic performance, little has been published on this topic. The largest body of information regards the impact of air pollution during urban active transport, i.e., walking and cycling in cities, due to the potential risk of air pollution in citizens and the need to rethink urban transportation strategies accordingly. In healthy subjects, the benefits of physical activity largely outweigh the disadvantages of exposure to air pollutants. In susceptible individuals, however, such as patients with cardiac or respiratory disease and children, detrimental effects have been demonstrated. Improvement in air quality, individual protective behaviors, and prompt communication to the population of dangerous air quality may help to limit the negative effects of air pollution on respiratory health

An intrusion-related origin for Cu–Au mineralization in iron oxide–copper–gold (IOCG) provinces

Major Cu–Au deposits of iron oxide–copper–gold (IOCG) style are temporally associated with oxidized, potassic granitoids similar to those linked to major porphyry Cu–Au deposits. Stable and radiogenic isotope evidence indicates fluids and ore components were likely sourced from the intrusions. IOCG deposits form over a range of crustal levels because CO2-rich fluids separate from the magmas at higher pressures than in CO2-poor systems, thereby, promoting partitioning of H2O, Cl and metals to the fluid phase. At deep levels, the magma–fluid system cannot generate sufficient mechanical energy to fracture the host rocks as in porphyry systems and the IOCG deposits therefore form in a variety of fault-related structural traps where the magmatic fluids may mix with other fluids to promote ore formation. At shallow levels, the IOCG deposits form breccia and fracture-hosted mineralization styles similar to the hydrothermal intrusive breccias and sulphide vein systems that characterize many porphyry Cu–Au deposits. The fluids associated with IOCG deposits are typically H2O–CO2–salt fluids that evolve by unmixing of the carbonic phase and by mixing with fluids from other sources. In contrast, fluids in porphyry systems typically evolve by boiling of moderate salinity fluid to produce high salinity brine and a vapor phase commonly with input of externally derived fluids. These different fluid compositions and mechanisms of evolution lead to different alteration types and parageneses in porphyry and IOCG deposits. Porphyry Cu–Au deposits typically evolve through potassic, sericitic and (intermediate and/or advanced) argillic stages, while IOCG deposits typically evolve through sodic(–calcic), potassic and carbonate-rich stages, and at deeper levels, generally lack sericitic and argillic alteration. The common association of porphyry and IOCG Cu–Au deposits with potassic, oxidized intermediate to felsic granitoids, together with their contrasting fluid compositions, alteration styles and parageneses suggest that they should be considered as part of the broad family of intrusion-related systems but that they are typically not directly related to each other