Provision of shelter for horses kept on summer pasture is rarely considered in welfare guidelines, perhaps because the benefits of shelter in warm conditions are poorly documented scientifically. For cattle, shade is a valued resource during summer and can mitigate the adverse effects of warm weather on well-being and performance. We found in a previous study that horses utilized shelters frequently in summer. A shelter with a roof and closed on three sides (shelter A) was preferred and can reduce insect pressure whereas a shelter with roof and open on three sides was not utilized. However, shelter A restricts the all-round view of a horse, which may be important for horses as flight animals. Therefore, we studied whether a shelter with roof, where only the upper half of the rear wall was closed (shelter B), would be utilized while maintaining insect protection properties and satisfying the horses' sense for security. A third shelter was offered with walls but no roof (shelter C) to evaluate whether the roof itself is an important feature from the horse's perspective. Eight Warmblood horses were tested each for 2?days, kept individually for 24?h in two paddocks with access to shelters A and B, or shelters A and C, respectively. Shelter use was recorded continuously during the night (1800-2400?h, 0200-0600?h) and the following day (0900-1600?h), and insect defensive behaviour (e.g., tail swish) in instantaneous scan samples at 5-min intervals during daytime.
Seven horses used both shelters A and B, but when given the choice between shelters A and C, shelter C was scarcely visited. There was no difference in duration of shelter use between night (105.8???53.6?min) and day (100.8???53.8, P?=?0.829). Daytime shelter use had a significant effect on insect defensive behaviours (P?=?0.027). The probability of performing these behaviours was lowest when horses used shelter A compared to being outside (P?=?0.038).
Horses only utilized shelters with a roof whilst a shelter with roof and closed on three sides had the best potential to lower insect disturbance during daytime in summer.
Notes
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Accumulations of polycyclic aromatic hydrocarbons in a snowpack were studied in an industrial urban area with numerous anthropogenic sources of PAHs. Average PAH loadings stored in the snowpack were determined, plotted on a map of the study area, and arenal distribution approximated by isoloading contours. The loading contours exhibited a marked elongation in the direction of prevailing winds. The unit-area deposition rates observed in the study area exceeded the typical rates reported for other urban areas, and were the highest immediately downwind of a steel plant. PAH levels in snowmelt were well below the freshwater aquatic life toxicity criteria, but exceeded both the WHO drinking water standard and the U.S. EPA carcinogenic criteria at the 10(-5) risk level.
The impact of weather on health is generally overlooked by physicians. Possible reasons for this include lack of training and insufficient awareness of the significant body of research on human biometeorology. The authors argue that, in the absence of clearly demonstrable causal connections, statistical associations between weather phenomena and health problems should be enough to influence clinical practice. Physicians in Germany make use of daily bulletins from the national weather service to advise patients on the management of common health problems that seem to be exacerbated by certain weather conditions. The authors urge Canadian doctors to follow the lead of their European colleagues by increasing their awareness of the relation between weather and health.
Notes
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Action spectrum (AS) describes the relative effectiveness of ultraviolet (UV) radiation in producing biological effects and allows spectral UV irradiance to be weighted in order to compute biologically effective UV radiation (UVBE). The aim of this research was to study the seasonal and latitudinal distribution over Europe of daily UVBE doses responsible for various biological effects on humans and plants. Clear sky UV radiation spectra were computed at 30-min time intervals for the first day of each month of the year for Rome, Potsdam and Trondheim using a radiative transfer model fed with climatological data. Spectral data were weighted using AS for erythema, vitamin D synthesis, cataract and photokeratitis for humans, while the generalised plant damage and the plant damage AS were used for plants. The daily UVBE doses for the above-mentioned biological processes were computed and are analysed in this study. The patterns of variation due to season (for each location) and latitude (for each date) resulted as being specific for each adopted AS. The biological implications of these results are briefly discussed highlighting the importance of a specific UVBE climatology for each biological process.
University of Helsinki, Department of Physics, Division of Atmospheric Sciences, P. O. Box 48, FI-00014 UHEL, Helsinki, Finland. tareq.hussein@helsinki.fi
The daily time-spent in different environments is an important factor in calculation of personal exposure to air pollutants. Despite this importance, the amount of research done on this topic is rather limited, especially in North Europe where the climate is rather cold. In this study, we gathered detailed information via a standard questionnaire to report the residence time and place of 167 subjects (between 2 and 93 years old) lived in Helsinki during three time periods in winter and spring 2009. Subjects spent 81%-92% of their time indoors and up to ~15% of their time outdoors. The daily time-spent in different environments was affected by several factors: ambient temperature, type of day (workday or weekend/holiday), gender, and age. Therefore, the differences occur individually and can be explained by these factors. For example, subjects spent more time at home on weekends than workdays because obviously the majority of our subjects did not have work on weekends. The time-spent at kindergarten/school/work increased with age until retirement. Females spent more time at home than males. After all, the activity pattern found in this study is rather similar to those previously reported in Germany and North America.
The APHEA 2 project investigated short-term health effects of particles in eight European cities. In each city associations between particles with an aerodynamic diameter of less than 10 microm (PM(10)) and black smoke and daily counts of emergency hospital admissions for asthma (0-14 and 15-64 yr), chronic obstructive pulmonary disease (COPD), and all-respiratory disease (65+ yr) controlling for environmental factors and temporal patterns were investigated. Summary PM(10) effect estimates (percentage change in mean number of daily admissions per 10 microg/m(3) increase) were asthma (0-14 yr) 1.2% (95% CI: 0.2, 2.3), asthma (15-64 yr) 1.1% (0.3, 1.8), and COPD plus asthma and all-respiratory (65+ yr) 1.0% (0.4, 1.5) and 0.9% (0.6, 1.3). The combined estimates for Black Smoke tended to be smaller and less precisely estimated than for PM(10). Variability in the sizes of the PM(10) effect estimates between cities was also investigated. In the 65+ groups PM(10) estimates were positively associated with annual mean concentrations of ozone in the cities. For asthma admissions (0-14 yr) a number of city-specific factors, including smoking prevalence, explained some of their variability. This study confirms that particle concentrations in European cities are positively associated with increased numbers of admissions for respiratory diseases and that some of the variation in PM(10) effect estimates between cities can be explained by city characteristics.
Air Health Effects Research Section, Healthy Environments and Consumer Safety Branch, Health Canada, Ottawa, ON, Canada K1A OK9. mietek_szyszkowicz@hc-sc.gc.ca
A variety of environmental factors have been identified as possible triggers for migraine and other headache syndromes.
We analyzed associations between air pollution and emergency department (ED) visits for migraine and headache.
Analysis was based on 56,241 ED visits for migraine and 48,022 ED visits for headache to Edmonton hospitals between 1992 and 2002. A Poisson model of counts hierarchically clustered by day of week, month, and year was applied using generalized linear mixed models. Temperature and relative humidity were included as covariates.
Females accounted for 78.5% of migraine visits and 56.3% of headache visits. An interquartile range (IQR) increase (6.2 microg/m3) in daily average particulate matter of median aerodynamic diameter less than 2.5 microm (PM2.5) was associated with increases in visits of 3.3% for migraine (95% confidence interval [CI]: 0.6-6.0), lagged 2 days, and 3.4% for headache (95% CI: 0.3-6.6), lagged 0 days, among females in the cold season (October-March). PM2.5 was also associated with cold season migraine visits among females at lag 0 and 1 day (P
