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Biomedical subjects

T Lindvall

Publications and source records attributed to T Lindvall.

At least 19 recordsLinked to original sources
PubMed1992

Environmentally induced changes in sensory sensitivities.

For studying changes in the sensory sensitivities, psychophysical methods offer a variety of models. The psychophysical approach also holds for applications on indoor air quality. The human senses can be used for characterizing environments in terms of effects on health and comfort, and have been used by the WHO for determining recommended exposure limits. The use of psychophysical methods for air pollution applications is illustrated by two studies on effects on sensory functions in smokers and passive smokers. Olfactory as well as auditory effects were found. Furthermore, methodological findings are presented, such as obtaining information on detectability and perceived intensity in the very same estimation procedure. The results also demonstrate the need for calibrating scales with regard to individual scaling behavior in perceived intensity measurements as well as the capability of the master scale principle for performing such a calibration.

Air Pollution, Indoor↗
PubMed1988

Ambient nitrogen dioxide concentrations increase bronchial responsiveness in subjects with mild asthma.

Twenty subjects with mild asthma were exposed at rest in a body plethysmograph, to NO2 at 0, 260, 510 and 1,000 micrograms.m3, for 30 min on four separate days. Bronchial responsiveness (histamine inhalation test) was measured after each exposure session. Airway resistance (Raw), thoracic gas volume (TGV) and specific airway resistance (sRaw) were measured before, during and after exposure, and the breathing pattern was monitored during the whole session. Bronchial responsiveness increased significantly after 30 min exposure to 510 micrograms.m3 NO2 (p less than 0.01). There were also tendencies to an increased bronchial responsiveness after exposure to 260 and 1,000 micron.m3 NO2, but these changes were not statistically significant. Effects on airway resistance and breathing pattern were not demonstrated by exposure to 0-1,000 micrograms.m3 NO2. We conclude that short-term NO2 exposure at about 500 micrograms.m3 slightly affects human bronchial responsiveness in subjects with mild asthma.

Adult↗
PubMed1986

Impaired odor perception in tank cleaners.

The olfactory perception of 20 men (tank cleaners) exposed to petroleum products (while cleaning oil tanks) was examined. Office workers and watchmen were used as referents (N = 20 + 20). They were matched with regard to sex, age, and smoking habits. Odor detection thresholds and the perceived odor intensity of four odorous stimuli, pyridine, dimethyl disulfide (DMDS), n-butanol, and heating oil vapor (gas phase of heating oil heated to +40 degrees C), were determined. The results suggested that the tank cleaners had higher absolute odor thresholds for n-butanol and oil vapor than the referents. The psychophysical function of the tank cleaners and referents differed for all the tested substances in respect to odor intensity. The tank cleaners displayed an odor deficit analogous to the hearing loss known as "loudness recruitment," ie, normal perception of strong stimuli but impaired perception of weak stimuli. This odor deficit was therefore named "odor intensity recruitment" and seems, in tank cleaners, to be associated with occupational exposure to oil vapor.

Adult↗
PubMed1985

Health effects of nitrogen dioxide and oxidants.

The document is an evaluation of the health effects of nitrogen dioxide (NO2) and ozone (O3) intended to serve as a basis for establishing Swedish air quality standards. The specific effects of nitrogen dioxide and ozone are reviewed on the basis of published studies on animals, tissues and cells, controlled studies on humans, and epidemiologic studies. The focus is on the importance of the gases in relation to sensitive groups, outdoor-indoor exposure relationships, the question of short- or long-term limit values, and their combined effects with other pollutants. The minimum adverse effect level for human short-term exposure is assessed to be 900 micrograms/m3 for nitrogen dioxide and 200 micrograms/m3 for ozone; for sensitive persons these values should possibly be even lower. Large safety factors should be added to these values before they are used for air pollution control purposes.

Air Pollutants↗
PubMed1985

Recommendations for air quality standards for nitrogen dioxide and ozone.

The acute health effects of nitrogen dioxide and ozone critical to the general population are summarized. For long-term exposures to the former in the outdoor environment a six-month average limit value of 80 micrograms/m3 is recommended for the wintertime. When "new" residential areas are planned or when the limit value is used as an air quality standard for the nonindustrial indoor environment, the adequate six-months' average limit value for the winter would be 50 micrograms/m3. For short-term exposures to nitrogen dioxide outdoors a limit value of 320 micrograms/m3 (1-h average) is recommended, not to be exceeded more than 12 h per year, each time during a maximum of 2 h. This value should apply only to "old" residential areas in which nitrogen dioxide pollution cannot be reduced without large economical and practical consequences. The value 190 micrograms/m3 (1-h average), not to be exceeded more than 12 h per year, should apply to most residential areas, to recreational areas, and to all nonindustrial indoor environments. For short-term exposures to photochemical oxidants, as represented by ozone in nonindustrial outdoor environments, the acceptable short-term limit value should be 120 micrograms/m3 (1-h average), not to be exceeded more than 12 h per year. An additional 1-h outdoor ceiling value of 200 micrograms/m3 is recommended, not to be exceeded. For the nonindustrial indoor environment a 1-h ceiling value of 100 micrograms/m3 is recommended, not to be exceeded.

Air Pollutants↗
PubMed1985

Effects of short-term exposure to ambient nitrogen dioxide concentrations on human bronchial reactivity and lung function.

Eight normal and 8 asthmatic subjects were exposed to NO2 in a modified body box for plethysmography during 20 min at 0,230,460 and 910 micrograms/m3 on 4 separate days. Bronchial reactivity (histamine inhalation test) was measured after exposure to air alone and to 910 micrograms/m3NO2. Airway resistance (Raw), thoracic gas volume (TGV) and specific airway resistance (SRaw) were measured before, during and after exposure. The bronchial reactivity of the asthmatic subjects increased significantly (p = 0.04) by 20 min exposure to 910 micrograms/m3 NO2. In the non-asthmatic group the airway resistance increased significantly (p = 0.03) after 20 min exposure to 460 micrograms/m3 NO2 and decreased significantly (p = 0.01) after 20 min exposure to 910 micrograms/m3 NO2. In the asthmatic group the trend in airway resistance was the same but not statistically significant. In the latter group TGV was significantly decreased (p = 0.02) during exposure to 910 micrograms/m3 NO2. Short term NO2-exposure in concentrations even below 1000 micrograms/m3 seems to have effects on human bronchial reactivity and lung function.

Adolescent↗
PubMed1978

Olfactory self- and cross-adaptation: effects of time of adaptation on perceived odor intensity.

The time-course of self- and cross-adaptation of the olfactory system was investigated for two constant concentrations of three odorous substances. The substances (hydrogen sulfide, dimethyl disulfide, and pyridine) were matched, in a pilot experiment, with regard to perceived odor intensity. The time of adaptation was controlled by the number of inhalations (1-10). A two-step scaling method, involving cross-modality matching and numerical scaling of the matching continuum, was used for measuring perceived odor intensity during adaptation. The results show that the time-course function for self-adaptation seems to be an exponential function for two of the substances (H2S, DMDS), while for the third (pyridine) the form of the function is less distinct. Cross-adaptation between substances was found for the high concentrations, while for the low concentrations, hydrogen sulfide and dimethyl disulfide gave rise to pronounced cross-facilitation. The latter effect increased with time of adaptation.

Adaptation, Physiological↗