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Monitoring restorative effects of physical activities in self-selected indoor and outdoor environments (fitness centers versus forests). A quasi-experimental study (N = 269) compared the physical and psychological benefits of exercise performed in urban fitness centers and in the urban forest. A questionnaire was distributed in four fitness centers and at four forest sites. Ratings of the restorative effects of physical activity on that specific occasion were elicited with respect to four criteria: participants were asked 1) to what extent they felt stressed before and after exercising, and 2) whether they suffered less from everyday hassles, 3) felt mentally more balanced afterward than before and, 4) whether their physical well-being had increased. Further questions addressed the duration and mode of travel to the exercise environment and attitudes towards the environment. Subjective perception of air quality at the site was assessed, and respondents rated whether air quality was an important factor in choosing the location of exercise. Independent of the location, exercising achieved substantial restorative outcomes. Feelings of everyday hassles and improvement in mental balance were more pronounced after exercise in the forest; increases in perceived physical well being and stress reduction were higher indoors. People exercising in the forest judged air quality to be better, were more reluctant to leave the exercise environment, and looked forward to their next session. Medical practitioners, health advisors and urban planners should take note that forests may support repeated exercise with positive health outcomes to a greater degree than other environments. [ABSTRACT FROM AUTHOR]

We used inert melamin particles that are very well defined in size (diameters: 0.5, 1.9, 6.8 µm) to study the effects of ambient particles of <10 µm (PM[sub 10]) on phagocytosis. Dose-response functions were found between the amount of added melamin particle mass and the toxicity. Fine particles (0.5 µm) were more toxic at low and medium amounts of mass per cell added than the larger particles (1.9, 6.8 µm). However, with regard to particle numbers applied per cell, toxicity is reversed, with the largest particles being the most toxic. In the whole dose range tested, the melamin particles used did not stimulate cells to produce oxidative radicals or tumor necrosis factor-α (TNFα). Flow cytometric analyses visualized the time-dependent melamin particle uptake, which was inhibited by polyinosinic acid (Poly-I), suggesting that phagocytosis is mediated by scavenger-type receptors. Cells exposed to an aqueous PM[sub 10] extract, which also had a dose-dependent toxic potential, were stimulated to produce oxidative radicals, measured as NO[sub 2][sup -], and TNFα. Combined exposures with the PM[sub 10] extract followed by the inert melamin particles show that the PM[sub 10] extract inhibits inert particle uptake by alveolar macrophages. It is proposed that ambient PM[sub 10], besides being toxic for alveolar macrophages, stimulates them to produce oxidative radicals and the proinflammotry cytokine TNFα. Moreover, it inhibits their particle uptake potential. Thus PM[sub 10] appears to promote inflammation and reduce defense. [ABSTRACT FROM AUTHOR]

Abstract: Daily PM2.5 and PM10 samples were taken from April 1998 to March 1999 at urban kerbside, urban background, near-city, and rural sites in Switzerland. The samples were analysed for mass, water soluble ions, trace elements, as well as elemental and organic carbon. The present paper focuses on the variation of element concentration between different site types and on the chemical mass closure of atmospheric particulate matter. Information on emission sources of trace elements is obtained by evaluation of the element abundances at sites that represent different pollution levels. The abundances of Ba, Ca, Ce, Cu, Fe, La, Mo, Mn, Pb, Sb, and Rh are gradually decreasing from urban kerbside to urban background, near-city and rural sites, indicating that road traffic is a main source of these elements. On the other hand, the abundances of Al, As, Cd, K, and V are similar for the different site types, which implies that emission sources are either spatially uniformly distributed (e.g. mineral dust), or there are no important regional emission sources and the ambient concentration of these elements might be dominated by long-range transport. When performing a mass closure, the annual average of the sum of aerosol chemical components was 22–27% for PM10 and 8–15% for PM2.5 lower than the PM mass. A drying procedure applied to a subset of PM10 samples and model calculations for PM2.5 samples according to their inorganic composition were used to estimate the contribution of retained water to the unaccounted mass at 50% RH. The obtained average water content was 10.6% for PM10 and 13–23% for PM2.5, clearly indicating that water is a major contributor to the unaccounted mass. Furthermore, a pronounced seasonal variation was observed with relatively lower water content in the colder season, indicating that the inorganic salts were mainly crystalline in winter, whereas they were probably dissolved during the rest of the year. [Copyright &y& Elsevier]