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At least 19 recordsLinked to original sources
PubMedDate not supplied

Longitudinal distribution of ozone absorption in the lung: effects of nitrogen dioxide, sulfur dioxide, and ozone exposures.

Investigators used an ozone bolus inhalation method to study the effects of continuous exposure to ozone, nitrogen dioxide, and sulfur dioxide on ozone absorption in the conducting airways of human lungs. Healthy, young nonsmokers (6 males, 6 females) were exposed on separate days for 2 h to air containing 0.36 ppm nitrogen dioxide, 0.75 ppm nitrogen dioxide, 0.36 ppm sulfur dioxide, or 0.36 ppm ozone. Every 30 min, the subject interrupted exposure for approximately 5 min, during which he or she orally inhaled five ozone boluses-each in a separate breath. Investigators targeted penetration of the boluses distal to the lips in the 70-130-ml range, which corresponded to the lower conducting airways. The authors computed the change in absorption resulting from exposure (delta lambda) by comparing the amount of each ozone bolus that was absorbed with a corresponding value obtained prior to exposure. Results indicated that ozone exposure caused delta lambda to decrease relative to air exposure (p < .01), whereas both nitrogen dioxide and sulfur dioxide exposures caused an increase in delta lambda that was not significantly different from air exposure. This resulted, at least in part, to an artifact caused by preexposure to ozone boluses. The authors concluded that exposure of the lower conducting airways to nitrogen dioxide or sulfur dioxide increased their capacity to absorb ozone because more of the biochemical substrates that are normally oxidized by ozone were made available. During continuous ozone exposure, this excess of substrate is depleted and the absorption of ozone boluses decreases.

Absorption↗
PubMed1975

Long-term exposure to sulfur dioxide, sulfuric acid mist, fly ash, and their mixtures. Results of Studies in Monkeys and guinea pigs.

Groups of cynomolgus monkeys and guinea pigs were exposed to mixtures of sulfur dioxide, fly ash, and sulfuric acid mist. The exposure concentrations varied between 0.1 and 5.0 ppm for sulfur dioxide, 0.1 and 1 mg/cu m for sulfuric acid mist, while a concentration of approximately 0.5 mg/cu m was used for fly ash. The duration of exposure was 52 weeks for guinea-pigs and 78 weeks for monkeys. Pulmonary function tests and serum biochemical and hematological analyses were conducted prior to and periodically during the exposure period. At the termination of exposure, the lungs were examined microscopically. Analysis of the data revealed that in groups exposed to the mixtures of pollutants, sulfuric acid mist was responsible for the effects observed. No synergistic action between the pollutants was detected.

Aerosols↗
PubMed1990

[The effect of quiet breathing of nitrogen dioxide and sulfur dioxide on the sensitivity of the respiratory tract to hyperventilation of sulfur dioxide].

In 14 patients with an oversensitive bronchial system (non-smokers), we investigated the question as to whether quiet breathing in a nitrogen dioxide or sulphur dioxide atmosphere would modify the sensitivity of the airways to sulphur dioxide. On three consecutive days, over a period of 30 minutes at rest, the patients breathed either filtered air or an atmosphere containing 0.25 ppm nitrogen dioxide, or 0.5 ppm sulphur dioxide. There then followed isocapnic hyperventilation of 0.75 ppm sulphur dioxide in increasing ventilation steps of 3 minutes duration each. On three other experimental days, in 7 patients, a stepwise hyperventilation of filtered air was carried out. Quiet breathing of nitrogen dioxide or sulphur dioxide resulted in no obstruction of the airways. The ventilation required to achieve a doubling of the specific airway resistance (PV100SRaw) during hyperventilation of sulphur dioxide was, on average, 46.5, 37.7 and 45.4 l/min after inhalation of filtered air, nitrogen dioxide and sulphur dioxide, respectively. Following nitrogen dioxide, PV100SRaw was significantly smaller (p less than 0.01 than following filtered air or sulphur dioxide. During hyperventilation of filtered air, the average PV100SRaw was 58.2, 51.8 and 55.7 l/min, respectively. We conclude that in non-smokers with an hypersensitive bronchial system, the inhalation of nitrogen dioxide can bring about an increase in the obstructive reaction to sulphur dioxide, without itself leading to an obstruction of the airways; in contrast, sulphur dioxide does not modify the degree of sensitivity.

Adult↗
PubMed1982

Bronchoconstrictor responses to sulfur dioxide or sulfur dioxide plus sodium chloride droplets in allergic, nonasthmatic adolescent.

Eight atopic adolescent subjects without diagnosis of clinical asthma but with signs of hyperactive airways were studied. The subjects were exposed for 30 min at rest followed by 10 min during moderate exercise on a treadmill to the following: (1) filtered air, (2) 1 mg/m3 NaCl droplet aerosol, (3) 1 ppm SO2 and NaCl droplet aerosol, or (4) 1 ppm SO2. All exposures were at 75% relative humidity and 22 degrees C. Exposures to either SO2 mode produced statistically significant changes in pulmonary function, whereas sham exposures to air on NaCl did not. These results are similar to those seen earlier in a group of extrinsic asthmatic adolescent subjects and are three to 22 times greater than changes we saw in a group of normal adolescent subjects. The changes seen after inhalation of SO2 were not statistically different from those seen after inhalation of SO2 and NaCl droplet aerosol. Our results indicate that inhalation of 1 ppm SO2 by a group of atopic adolescents can produce exercise-induced bronchospasm at a level of exercise that has no effect by itself.

Adolescent↗
PubMed2005

Expression of apoptosis-related genes in livers from rats exposed to sulfur dioxide.

Sulfur dioxide (SO2) is a ubiquitous air pollutant that is present in low concentrations in the urban air, and in higher concentrations in the working environment. In the present study, male Wistar rats were housed in exposure chambers and treated with 14.00+/-1.01, 28.00+/-1.77 and 56.00+/-3.44 mg/m3 SO2 for 6 h/day for 7 days, while control rats were exposed to filtered air in the same condition. The mRNA and protein levels of three apoptosis-related genes (p53 and bax were promoters of apoptosis, whereas bcl-2 was apoptotic suppressor) were analyzed in livers using a real-time reverse transcription-polymerase chain reaction (real-time RT-PCR) assay and immunohistochemistry method. The results showed that mRNA levels of p53 and bax were increased in a dose-dependent manner and at the concentrations of 28.00 and 56.00 mg/m3SO2 the increases were significant (for p53: 1.30-fold at 28 mg/m3 and 3.43-fold at 56 mg/m3, for bax: 1.63-fold at 28 mg/m3 and 2.17-fold at 56 mg/m3, respectively), while mRNA levels of bcl-2 were decreased significantly (0.63-fold at 28 mg/m3 and 0.45-fold at 56 mg/m3) in livers of rats exposed to SO2. Dose-dependent increases of p53 and bax proteins in the livers were observed after SO2 inhalation, while decrease of bcl-2 protein levels was obtained using immunohistochemistry method. These results lead to a conclusion that SO2 exposure could change the expression of apoptosis-related genes, and it suggests that SO2 can induce apoptosis in liver of rat and may have relations with some apoptosis-related diseases. It is critical for our understanding of the mechanisms of SO2 toxicity and helpful for the therapeutic intervention to elucidate the expression pattern of those factors involved in apoptosis signaling pathway after SO2 inhalation.

Air Pollutants↗
PubMed1985

Passive colorimetric dosimeter tubes for ammonia, carbon monoxide, carbon dioxide, hydrogen sulfide, nitrogen dioxide and sulfur dioxide.

Colorimetric, stain length, personal dosimeters operating by gas diffusion have been developed to determine worker exposure for up to an eight-hour period for several inorganic airborne contaminants in the range of their Threshold Limit Values. Length of stain, colorimetric dosimeters have been made for the detection of ammonia (NH3), carbon monoxide (CO), carbon dioxide (CO2), hydrogen sulfide (H2S), nitrogen dioxide (NO2), and sulfur dioxide (SO2) in air. For each gas detection system, the sampler depends on the transfer of the gas by diffusion into a glass tube containing a colorimetric length of stain indicator. The stain length developed in a given period of time is compared to a calibration chart to determine, on the spot, the average gas concentration to which the dosimeter has been exposed. These dosimeters are known by the trade name Vapor Gard.

Air Pollutants, Occupational↗
PubMed2004

Interpersonal and daily variability of personal exposures to nitrogen dioxide and sulfur dioxide.

Chronic exposure is often assessed using a single measurement per individual or group. However, daily levels of personal exposure can vary greatly. Chronic exposure classification by a single measurement could be significantly affected by the interpersonal and daily variations of exposures. The purpose of this study is to determine the effect of using a single personal exposure measurement on estimating long-term exposure. This study used measurements of consecutive 14 daily personal exposures to nitrogen dioxide (NO(2)) and sulfur dioxide (SO(2)) of 50 individuals in Yeochun, Korea. The daily personal exposures were measured by passive samplers. Personal exposure to NO(2) was associated with gas cooking, and personal exposure to SO(2) was associated with ambient air pollution. Mixed effects models indicated that daily variability was greater than interpersonal variability for both the pollutants. Effectiveness of using single-day personal measurements for long-term population mean exposure was supported by relatively consistent daily population averages, but multiple-day measurements might be warranted for characterizing individual exposures or high-end population exposures such as the 95th percentile. Although classification of high and low exposure groups by 1-day exposure and by 14-day exposure produced similar group totals, 20% of individual NO(2) exposures and 31% of individual SO(2) exposures were misclassified using 1-day exposures. Average values of 1-day exposure and 14-day exposure were significantly different, but the difference decreased by an increase in the number of measurements for the short-term exposure. The findings were similar for both NO(2) and SO(2), although the two air pollutants have different sources and behaviors.

Air Pollutants↗
PubMed1981

Exposures of human volunteers to a controlled atmospheric mixture of ozone, sulfur dioxide and sulfuric acid.

Nineteen human volunteers with normal pulmonary function and no history of asthma were exposed on two separate days to clean air and to an atmospheric mixture containing ozone (O3), 0.37 ppm, sulfur dioxide (SO2), 0.37 ppm, and sulfuric acid aerosol (B2SO4), 100 micrograms/m3. Subjects were exposed under carefully controlled conditions for two hours. During this period, the subjects alternately exercised for 15 minutes, at a level calculated to double minute ventilation, and rested for 15 minutes. The experimental goal was to determine whether the presence of the copollutants, H2SO4 and SO2, would significantly enhance the irritant potential of ozone, or cause decrements in pulmonary function on the order of 10 - 20 percent. Statistical analysis of the group averaged data suggested that the mixture may have been slightly more irritating to the subjects than was O3 alone. A large percentage of the subjects exhibited small decrements in pulmonary function. The group averaged FEV1.0 (forced expiratory volume in one second) on the exposure day was depressed 3.7 percent from the control value. One might expect O3 alone to depress FEV1.0 by about 2.8 percent under similar exposure conditions.

Adult↗
PubMedDate not supplied

Chamber exposures of children to mixed ozone, sulfur dioxide, and sulfuric acid.

To help assess acute health effects of summer air pollution in the eastern United States, we simulated ambient "acid summer haze" as closely as was practical in a laboratory chamber. We exposed young volunteers who were thought to be sensitive to this pollutant mixture on the basis of previous epidemiologic evidence. Specifically, we exposed 41 subjects aged 9-12 y to mixed ozone (0.10 ppm), sulfur dioxide (0.10 ppm), and 0.6-microm sulfuric acid aerosol (100 +/- 40 microg/m3, mean +/- standard deviation) for 4 h, during which there was intermittent exercise. Fifteen subjects were healthy, and 26 had allergy or mild asthma. The entire group responded nonsignificantly (p > .05) to pollution exposure (relative to clean air), as determined by spirometry, symptoms, and overall discomfort level during exercise. Subjects with allergy/asthma showed a positive association (p = .01) between symptoms and acid dose; in healthy subjects, that association was negative (p = .08). In these chamber-exposure studies, we noted less of an effect than was reported in previous epidemiologic studies of children exposed to ambient "acid summer haze."

Air Pollutants↗
PubMed2000

Outdoor air concentrations of nitrogen dioxide and sulfur dioxide and prevalence of wheezing in school children.

We report analysis of data on outdoor air pollution and respiratory symptoms in children collected in the Czech part of the international Small Area Variations in Air pollution and Health (SAVIAH) Project, a methodological study designed to test the use of geographical information systems (GIS) in studies of environmental exposures and health at small area level. We collected the following data in two districts of Prague: (1) individual data on 3,680 children (response rate 88%) by questionnaires; (2) census-based socio-demographic data for small geographical units; (3) concentrations of nitrogen dioxide (NO2) and sulfur dioxide (SO2) measured by passive samplers in three 2-week surveys at 80 and 50 locations, respectively. We integrated all data into a geographical information system. Modeling of NO2 and SO2 allowed estimation of exposure to outdoor NO2 and SO2 at school and at home for each child. We examined the associations between air pollution and prevalence of wheezing or whistling in the chest in the last 12 months by logistic regression at individual level, weighted least squares regression at small area (ecological) level and multilevel modeling. The results varied by the level of analysis and method of exposure estimation. In multilevel analyses using individual data, odds ratios per 10 microg/m3 increase in concentrations were 1.16 (95% CI = 0.95-1.42) for NO2, and 1.08 (95% CI = 0.97-1.21) for SO2. While mapping of spatial distribution of NO2 and SO2 in the study area appeared valid, the interpolation from outdoor to personal exposures requires consideration.

Air Pollutants↗
PubMed2005

Feasibility study of preparation and certification of reference materials for nitrogen dioxide and sulfur dioxide in diffusive samplers.

This paper presents the results of a feasability study for the preparation and certification of reference materials (RMs) for nitrogen dioxide (NO(2)) and sulfur dioxide (SO(2)) in diffusive samplers. RMs for NO(2) were prepared by exposure to gas mixtures in a chamber while the RMs for SO(2) were prepared by liquid spiking. Certification of RMs for NO(2) was found feasible with a certified uncertainty of 5.8% and a proposed shelf life of 5 years. The uncertainty was calculated with contribution from the homogeneity of preparation, stability and transport of the CRMs and from an external verification of the certified value. To reach 5.8% of uncertainty, the contribution of the differences between the results of analysis by ion chromatography and colorimetry must be eliminated. It is proposed to solve this by pre-extracting the samplers with water before analysis. The results of this study indicate that the samplers are stable for at least two years before and after exposure when stored in a refrigerator. By contrast, the certification of RMs for SO(2) was found to not be feasible due to instability problems. This instability was attributed to reaction of sulfate on the walls of the samplers. Alternatively, the preparation of RMs by simultaneous exposure to SO(2) and NO(2) has been tested. Satisfying homogeneities has been reached both for NO(2) and SO(2).

Air Pollutants↗
PubMed2002

Performances and application of a passive sampling method for the simultaneous determination of nitrogen dioxide and sulfur dioxide in ambient air.

The performances and applicability of a diffusion tube sampler for the simultaneous measurements of NO2 and SO2 in ambient air were evaluated. SO2 and NO2 are collected by the passive sampler using triethanolamine as trapping agent and are determined as sulphate and nitrite with ion chromatography. The detection limit (2.3 microg m(-3) of NO2 and 4.2 microg m(-3) of SO2 for two weeks sampling) is adequate for the determination of concentrations in urban and industrial areas. Precision of the method as RSD is in mean 5% for NO2 and 12% for SO2 at the concentration levels in urban areas. Calibration of the method was performed in the field conditions by comparison between the responses of sampler and the concentrations measured by the continuous monitors. High degree of linearity (correlation coefficients > 0.8) is found between the passive sampler tube and the continuous monitor data for both NO2 and SO2. To reduce the wind velocity influence on passive sampling of diffusion tubes, a protective shelter was tested in this study. The overall uncertainty of one measure for the optimised method is estimated at 5 microg m(-3) for NO2 and 6 microg m(-3) for SO2. Suitability of this passive sampling method for air pollution monitoring in urban areas was demonstrated by the results shown in this paper on a campaign carried out in the French agglomeration.

Air Pollutants↗