Comparison of published reports on physiological effects of exposure to ozone (O3) suggests that Canadians are more reactive than southern Californians. Responses of subjects and experimental methods were compared in a cooperative investigation of this apparent difference in reactivity. Four Canadians and four Californians were exposed to 0.37 ppm O3 in purified air at 21 degrees C and 50% relative humidity for 2 hours with intermittent light exercise. Exposures to purified air alone served as controls. Responses of subjects were similar to those observed previously: Canadians on the average showed greater clinical and physiological reactivity to exposure than did Californians, who were no more than minimally reactive. Canadians also showed larger increases in erythrocyte fragility following exposure. No methodological differences sufficient to explain different results of previous studies were found. Although other possible explanations have not been ruled out entirely, adaptation of southern Californians to chronic ambient O3 exposure is a rational hypothesis to explain these results.

Acetylcholinesterase↗

PubMedDate not supplied

Physiological effects of acute passive exposure to cigarette smoke.

Effects of passive inhalation of cigarette smoke at levels typically encountered in public buildings have been investigated. Twenty normal male and female nonsmokers (18 to 30 years) were each exposed for two hours on alternate days (in random order) to either room air or room air plus machine-produced cigarette smoke. Exposures were conducted in an unventilated chamber (14.6 m3). Subdivisions of lung volume, maximum expiratory flow-volume curves, single-breath nitrogen washout curves, blood carboxyhemoglobin levels, and heart rates were obtained before, during, and after exposure. A submaximal bicycle ergometer test and a symptom questionnaire were also administered after exposure. Statistical analysis revealed several significant differences between test and control days; the magnitude of the changes was small and of questionable biological significance, however, particularly when account was taken of the number of statistical comparisons made. Despite the relatively small physiological changes, subjective complaints were common-cough, and eye irritation, for example. It is concluded that in normal subjects the magnitude of physiological responses to acute exposures is minimal; thus arguments concerning effects rest on symptomatology and such other factors as the unknown risks of chronic exposure.

Adult↗

PubMedDate not supplied

Effects of ozone exposure: a comparison between oral and nasal breathing.

Mode of inhalation, by nose or by mouth, as a determinant of pulmonary toxicity to acute inhalant exposure has been investigated incompletely. This communication addresses whether there are significant differences in toxic pulmonary responses to acute ozone (O3) exposure between differing modes of inhalation (nasal vs. oral breathing). Changes in the results of pulmonary function tests and symptomatology of healthy young adults were compared following both exclusive nose and exclusive mouth breathing during a 30-min exposure to approximately 0.4 ppm O3 under conditions of moderate continuous exercise. In this single-blind, randomized, crossover study, no significant differences in either the results of pulmonary function tests or in symptomatology were found between the two modes of inhalation.

Adult↗

PubMedDate not supplied

Effects of particulate matter exposure and medication use on asthmatics.

The health risk associated with low-level air pollution exposure is still uncertain. The association between exposure and pulmonary function was assessed with personal sampling. Small, portable multipollutant samplers were used to assess personal exposure to particulate matter. Thirty-six asthmatic subjects participated in the study for up to 20 d in both summer (n = 10 d) and winter (n = 10 d); pulmonary function was assessed at the beginning and end of each sampling day, and medication use was recorded. A within-individual longitudinal analysis of the relationship between pulmonary function and particulate matter revealed an effect of season. In winter, pulmonary function increased as particulate exposure increased, which was explained by a confounding effect of medication use. Therefore, in addition to exposure, season of the year and medication use are factors that must be considered.

Air Pollutants↗

PubMedDate not supplied

Dogs and the elderly: the perfect prescription for companionship.

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Aged↗