Dust exposure, eye redness, eye cytology and mucous membrane irritation in a tobacco industry

Meandered and muddled: a systematic review on the impact of air pollution on ocular health

From the years 1970-2023, a systematic overview of the diverse consequences of particulate matter on eye health and a disease classification according to acute, chronic, and genetic are presented using the PubMed, Research Gate, Google Scholar, and Science Direct databases. Various studies on medical aspects correlate with the eye and health. However, from an application perspective, there is limited research on the ocular surface and air pollution. The main objective of the study is to uncover the relationship between eye health and air pollution, particularly particulate matter, along with other external factors acting as aggravators. The secondary goal of the work is to examine the existing models for mimicking human eyes. The study is followed by a questionnaire survey in a workshop, in which the exposure-based investigation was tagged based on their activity. This paper establishes a relationship between particulate matter and its influence on human health, leading to numerous eye diseases like dry eyes, conjunctivitis, myopia, glaucoma, and trachoma. The results of the questionnaire survey indicate that about 68% of the people working in the workshop are symptomatic with tears, blurred vision, and mood swings, while 32% of the people were asymptomatic. Although there are approaches for conducting experiments, the evaluation is not well defined; empirical and numerical solutions for particle deposition on the eye are needed. There prevails a broad gap in the arena of ocular deposition modeling.

The effect of smoking on ocular surface and tear film based on clinical examination and optical coherence tomography

Purpose:

Smoking is a global health problem with a high burden of smokers in India and the world as well. Smoking is a known eye irritant that may have a significant effect on the anterior ocular surface. Hence, the present study was aimed to investigate the effect of smoking on dry eye parameters, ocular surface, and central corneal thickness (CCT) and to compare the results with nonsmokers.

Methods:

In this cross-sectional study, 40 (80 eyes) smokers and 40 (80 eyes) age-matched nonsmokers were included. The severity of ocular surface disease symptoms was assessed by the Ocular Surface Disease Index (OSDI) tool. All participants underwent a series of measurements, that is, the Schirmer’s II test score and tear breakup time (TBUT). Tear meniscus height (TMH) and CCT were measured using anterior segment optical coherence tomography (OCT).

Results:

The mean value of all dry eye parameters was statistically different among the group of smokers and nonsmokers. The mean score of symptomatic assessment (OSDI) was observed to be significantly higher in smokers than in nonsmokers (P < 0.0001), and dry eye parameters, that is, Schirmer’s score (P = 0.0127), TMH (P < 0.0001), and TBUT (P < 0.0001) were significantly lower among smokers than nonsmokers. There was no significant difference in CCT between smokers and nonsmokers (P = 0.06).

Conclusion:

Cigarette smoking has deteriorating effects on the ocular surface. Exposure to smoking was found to be associated with dryness of the eye. Further studies are needed on a molecular basis.

Dose - response relationship between noise exposure and the risk of occupational injury

Many workers worldwide experience fatality and disability caused by occupational injuries. This study examined the relationship between noise exposure and occupational injuries at factories in Korea. A total of 1790 factories located in northern Gyeonggi Province, Korea was evaluated. The time-weighted average levels of dust and noise exposure were taken from Workplace Exposure Assessment data. Apart occupational injuries, sports events, traffic accidents, and other accidents occurring outside workplaces were excluded. The incidences of occupational injury in each factory were calculated by data from the Korea Workers' Compensation and Welfare Services. Workplaces were classified according to the incidence of any occupational injuries (incident or nonincident workplaces, respectively). Workplace dust exposure was classified as <1 or ≥ 1 mg/m³ , and noise exposure as <80, 80-89, or >90 dB. Workplaces with high noise exposure were significantly associated with being incident workplaces, whereas workplaces with high dust exposure were not. The odds ratios (95% confidence intervals) derived from a logistic regression model were 1.68 (1.27-2.24) and 3.42 (2.26-5.17) at 80-89 dB and ≥ 90 dB versus <80 dB. These associations remained significant when in a separate analysis according to high or low dust exposure level. Noise exposure increases the risk of occupational injury in the workplace. Furthermore, the risk of occupational injury increases with noise exposure level in a dose-response relationship. Therefore, strategies for reducing noise exposure level are required to decrease the risk of occupational injury.

The effect of smoking on the ocular surface and the precorneal tear film

BACKGROUND

Smoking, both active and passive, creates a plethora of health-related problems, which primarily affect the cardiovascular and respiratory systems. There is very little evidence on the effects of tobacco smoke on the eye, especially regarding anterior ocular surface related pathology. This study was undertaken to determine the effects of smoking on the ocular surface and the tear film in smokers.

METHODS

A total of 51 (102 eyes) smokers and 50 (100 eyes) age-and gender-matched healthy non-smokers were included in this study. The ocular surface was evaluated by measuring tear film break-up time, surface staining with fluorescein, and corneal and conjunctival sensitivities, and by completing the Schirmer's II test. Data was analysed using Statistical Package for Social Sciences (SPSS) version 11.5. A p value less than 0.05 was considered statistically significant.

RESULTS

The smoker group had significantly lower tear film break-up time, and corneal and conjunctival sensitivity than the nonsmoker group. Punctate staining was significantly higher in the smoker group than the non-smoker group. There was no statistically significant difference in Schirmer's II test results between the smoker and non-smoker group.

CONCLUSION

Smoking caused adverse effects on the precorneal tear film and there was strong association between smoking and tear film instability. Although a causative relationship could not be determined, there is a need for further longitudinal studies.

A multicentric case-control study on the impact of air pollution on eyes in a metropolitan city of India

PURPOSE

To study the effect of exposure to high level of air pollution on ocular surface health.

MATERIALS AND METHODS

A total of 520 subjects volunteered to participate in this study. All volunteers were required to give a detailed history and were subjected to ophthalmic examination under slit lamp, visual acuity test, tear film break-up time (BUT) and Schrimer's test.

RESULTS

Significantly high number of subjects in study group complained of ophthalmic symptoms compared to control group. Sevent eight per cent subjects in the study group had symptoms such as redness, watering, irritation, strain or photophobia whereas this number was 45% in control group. Schirmer's test showed a significantly low value of 22.75±8.91 mm in study group as compared to 30.30±7.92 mm in control group (P<0.001). Average tear break-up time in study group was significantly low (P<0.05) with a value of 11.17±2.92 seconds compared to 12.13 ± 3.24 seconds in control group.

CONCLUSION

Results of our study indicate that people traveling in highly polluted areas and exposed to high level of air pollutants are likely to suffer from significantly high incidence of subclinical ocular surface disorders.

Assessment of Upper Respiratory Tract and Ocular Irritative Effects of Volatile Chemicals in Humans

Accurate assessment of upper respiratory tract and ocular irritation is critical for identifying and remedying problems related to overexposure to volatile chemicals, as well as for establishing parameters of irritation useful for regulatory purposes. This article (a) describes the basic anatomy and physiology of the human upper respiratory tract and ocular mucosae, (b) discusses how airborne chemicals induce irritative sensations, and (c) reviews practical means employed for assessing such phenomena, including psychophysical (e.g., threshold and suprathreshold perceptual measures), physiological (e.g., cardiovascular responses), electrophysiological (e.g., event-related potentials), and imaging (e.g., magnetic resonance imaging) techniques. Although traditionally animal models have been used as the first step in assessing such irritation, they are not addressed here since (a) there are numerous reviews available on this topic and (b) many rodents and rabbits are obligate nose breathers whose nasal passages differ considerably from those of humans, potentially limiting generalization of animal-based data to humans. A major goal of this compendium is to inform the reader of procedures for assessing irritation in humans and to provide information of value in the continued interpretation and development of empirical databases upon which future reasoned regulatory health decisions can be made.

Effects of smoking on tear film and ocular surface

This study was performed to evaluate the changes of tear film and ocular surface caused by smoking. Symptom scoring, tear film break-up time (BUT), basal tear secretion test, corneal sensitivity test, keratoepitheliopathy scoring, and conjunctival impression cytology were performed in 29 smokers (58 eyes) and 26 non-smokers (52 eyes). Tear film BUT, basal tear secretion, corneal sensitivity, and squamous metaplasia were 7.71+/-2.66 sec, 6.29+/-2.85 mm, 53.69+/-5.69 mm, and 2.45+/-1.26 in smokers and 9.62+/-3.14 sec, 10.04+/-3.87 mm, 56.46+/-4.79 mm, and 1.12+/-0.83 in non-smokers, respectively (p<0.05). Symptom score, keratoepitheliopathy score, and goblet cell density were not significantly different between the two groups. Tear film BUT was shorter, basal tear secretion and corneal sensitivity were lower, and squamous metaplasia was higher in heavy smokers than in light smokers. In conclusion, smoking deteriorates the tear film and ocular surface with decreased quantity and quality of tear film, decreased corneal sensitivity, and squamous metaplasia, and this deterioration is related to the amount of smoking.

Respiratory effects of experimental exposure to office dust

The aim of this experiment was to test if healthy persons respond to exposures to normal office dust with objective or subjective effects in a dose-related way. If they did, the importance of their personal characteristics should be investigated. This paper presents the results related to respiratory effects caused by exposures to office dust. The experiment compared the responses of 24 healthy non-sensitive adult subjects with no known hyperreactivity to exposure to normal office dust in the air at 136 and 390 microg/m3 with their responses in clean air. The exposure duration was 5.25 h in a climate chamber under controlled conditions. The dust had no major identifiable specific reactive compounds. There were no direct effects of dust exposures on nasal lavages or rhinometry. The overall indications of the experiment are that healthy subjects without any hypersensitive reactions seem to respond to exposure to house dust without specific reactive components. The only effect indicated was on eosinophil cationic protein in nasal lavages and peak flow. A delayed effect on peak expiratory flow was observed the day after the exposure. Other effects were seen but in opposite direction of expectations. Several deviations from the original design of the experiment prevent any definitive conclusions from being made from these findings before they have been confirmed in future experiments to come.

PRACTICAL IMPLICATIONS

Reflecting the exploratory status of the study its major implication is to point at possible future hypotheses. The study implies that office dust may have an effect on occupants' lung function even at concentrations found in normal indoor environments. The influences of a multitude of response modifying variables were tested but no consistent pattern was found. The study does therefore not identify a specific risk group but suggests that among normal non-sensitized subjects most of the traditional risk factors can be rejected as single responsible risk factor.

The effects of chronic smoking on the ocular surface and tear characteristics: a clinical, histological and biochemical study

PURPOSE

To investigate the effects of chronic smoking on the ocular surface and tear characteristics.

METHODS

The Schirmer I-test, tear film break-up time, rose Bengal staining scores, impression cytology, tear lysozyme concentration, eye irritation symptoms, and eye irritation indices were determined for 44 eyes in 44 healthy, chronic smokers who had smoked six or more cigarettes per day for the previous year. Thirty-seven eyes in 37 healthy, non-smokers were assessed in the same masked manner for comparison. Cytological specimens were obtained from the temporal interpalpebral bulbar conjunctiva by 'impression' technique. Goblet cells were counted in the specimens obtained and squamous metaplasia was graded following epithelial cell morphology assessment.

RESULTS

In chronic smokers, we found decreased tear film break-up time (p=0.022) and tear lysozyme concentration (p=0.013), and increased Schirmer I-test values (p=0.047), squamous metaplasia scores (p=0.016), eye irritation scores (p<0.001) and eye irritation indices (p=0.013), as compared with the control group. There were no statistically significant differences in goblet cell counts (p=0.710) or rose Bengal staining scores (p=0.827).

CONCLUSION

These findings suggest that chronic smoking has a negative effect on the ocular surface and affects some tear characteristics. The chronic ocular irritative effects of cigarette smoking may lead to defects in ocular surface defence.

Hyperresponsiveness to tobacco dust extract in sensitized guinea pig trachea

The role of pre-existing airway inflammation in the pathogenesis of occupational airway disease is poorly understood. Previously we studied an extract of tobacco dust (TDE) and determined that it causes concentration dependent contractions of nonsensitized guinea pig trachea (GPT). In the present study animals were sensitized using Ovalbumin (OA) and subsequently challenged with an aerosol of 2.5% OA on day 21. A control group of nonsensitized GPs were divided into rings in which the epithelium was retained (EPI+) or removed (EPI-). Concentration related contractions of sensitized and nonsensitized GPTs were elicited with TDE. Sensitized GPTs demonstrated a greater contractile response to TDE than did nonsensitized GPTs. In nonsensitized animals the EPI- GPTs demonstrated a lesser response to TDE than did the EPI+. Similar findings were demonstrated in sensitized GPTs with and without epithelium. When epithelium was removed, sensitized and nonsensitized GPTs behaved similarly. Moreover, sensitized GPTs without epithelium and nonsensitized with epithelium responded similarly. These findings suggest that presensitization with an unrelated antigen enhances the response to an occupational agent and that in sensitized animals at least part of the enhanced response is mediated by the epithelial layer.

Impact of environmental pollution on the eye

PURPOSE

To study the effect of environmental toxins on the ocular surface in persons travelling through highly polluted areas of the metropolis of Delhi.

METHODS

A total of 500 apparently healthy volunteers recruited from the metropolis of Delhi were examined to establish the frequency of ocular surface disorders. All subjects underwent a slit-lamp examination, tear break-up time (BUT) test, Rose Bengal test, Schirmer's test and tear lysozyme level test.

RESULTS

Subjects in the study group had significantly higher levels of ophthalmic symptoms compared to the control group. In all, 105 (42%) and 125 (50%) subjects in the study group compared to 50 (20%) and 65 (26%) in the control group complained of redness and irritation (p < 0.05). There was no significant difference in visual acuity (VA) between the two groups, with best corrected VA being 6/9 or better in 92% of the study group and 96% of the control group. The average (+/-standard deviation) Schirmer's test result was 13.42+/-6.67 mm in the study group compared to 15.95+/-6.14 mm in the control group. This difference was statistically significant. The BUT was also significantly lower in the study group (12.97+/-6.12 seconds) compared to the control group (19.23+/-5.70 seconds) (p < 0.001). The Rose Bengal test and tear lysozyme activity did not show any significant difference between the two groups.

CONCLUSION

According to our study, environmental conditions appear to have a very significant effect on the ocular surface. There were very high levels of subclinical ocular surface changes among persons travelling in highly polluted areas.

Respiratory findings in tobacco workers

OBJECTIVES

To screen for respiratory symptoms and lung function impairment in workers occupationally exposed to tobacco dust in a tobacco-processing plant.

PARTICIPANTS

One hundred twenty-one tobacco workers (97 women and 24 men) were included in the study. In addition, a group of 98 control workers (73 women and 25 men) were studied.

METHODS

Acute and chronic respiratory symptoms were recorded in all tobacco workers. Lung function was measured by recording the maximum expiratory flow-volume curves on which FVC, FEV(1), and flow rates at 50% of FVC (FEF(50)) and the last 25% of FVC (FEF(25)) were read.

RESULTS

There was a high prevalence of chronic respiratory symptoms among these workers, and this prevalence was significantly higher in exposed female workers than in female or male control workers (p < 0.01 and p < 0.05, respectively). Occupational asthma was recorded in 6 female tobacco workers (6.2%) and in none of the control subjects (p < 0.05). None of the male workers were found to have occupational asthma. There was also a high prevalence of acute symptoms that were noted during the work shift (particularly for nose and throat dryness, as well as eye irritation). Among these tobacco workers, the odds ratios for respiratory symptoms were frequently significant for employment and smoking among male tobacco workers but were not significant in general for female tobacco workers. The ventilatory capacity data in tobacco workers showed statistically significant reductions in FEV(1), FEF(50), and FEF(25) in relation to predicted values. These reductions were demonstrated in smokers as well as in nonsmokers. Regression analysis suggested that there were significant changes according to employment status for FVC, FEV(1), and FEF(25) in female tobacco workers. Measurements of ventilatory capacity during the course of the work shift in 38 female tobacco workers demonstrated significant mean acute reductions in FEV(1) (-5.7%), in FEF(50) (-15.7%), and in FEF(25) (-23.4%).

CONCLUSIONS

Our data indicate that tobacco workers may develop respiratory disorders related to tobacco dust in their work environment.

Human volunteer study with PGME: eye irritation during vapour exposure

The objective of this study was to establish the possible occurrence of eye irritation and subjective symptoms in human volunteers exposed to propylene glycol monomethyl ether (PGME) vapour at concentrations of 0, 100 and 150 ppm. Testing was conducted in 12 healthy male volunteers using a repeated measures design. Each subject was exposed for 2.5 h to each of the three exposure conditions that were spaced 7 days apart. The exposure sequences were counterbalanced and the exposure to the test substance and the effect measurements were conducted in a double-blind fashion. During all exposure sessions, 20 ppm diethyl ether was used as a 'masking agent' for vapour exposure. Measurements of pre- and post exposure eye redness, corneal thickness, tear film break-up time, conjunctival epithelial damage, blinking frequency, and subjective ratings on discomfort were used to evaluate the possible irritating effects of PGME. The results indicated no significant treatment effects for any of the objective parameters. Results of the subjective ratings indicated very slight effects on the eyes in the 150 ppm PGME condition only. No significant effects of treatment were found for the remaining questions concerning the perceived intensity of the smell in the room, the (un)pleasantness of the smell, the perceived effects on the skin, effects on the throat, shivering, muscle aching, and intestinal cramps. In conclusion, the results of the present study indicated minimal subjective eye effects at 150 ppm only, and no impact on the objective measures of eye irritation at either of the two exposure levels. It was concluded that the no adverse effect concentration for eye irritation due to PGME vapour was at least 150 ppm.

Effects in the eyes caused by exposure to office dust

This Danish Office Dust Experiment compares the responses of 24 normal non-sensitive adult subjects to exposure to normal office dust in the air at 136 and 390 micrograms/m3 (median) and to their responses in clean air. The exposure duration was 5 1/4 h in a climate chamber under controlled conditions. The dust had no major identifiable specific reactive compounds. The overall conclusion is that healthy subjects without any hypersensitive reactions seem to respond to exposure to the house dust. The effects observed were all found in interaction with response modifying factors. The effects were a decrease in inflammatory cells in tear fluids, increased epithelium defects, and a decrease in break-up time. No effect was seen on eye reddening, or eye sensitivity to CO2. As no specific hypotheses could be specified before the study for the observed interactions, no definitive conclusions can be made. Furthermore, it seemed that there was no consistency in the interacting factors after the exposure and the next morning. A tentative analysis of the effects of the importance of personal characteristics showed that only a minority within the subject group may respond to the exposure. However, no common set of sensitivity measures could be defined for these responders.

Respiratory health of cigar factory workers

OBJECTIVES

To determine whether occupational exposure to raw tobacco causes respiratory or allergic diseases, an excess of respiratory symptoms, a decrease in lung function, or parenchymal changes in chest radiography among Finnish cigar workers.

METHODS

This cross sectional study included all Finnish cigar workers (n = 106) exposed to raw tobacco and also a group of unexposed matched referents. Data were collected with a self administered questionnaire, flow volume spirometry, measurements of diffusing capacity of the lung for carbon monoxide, chest radiography and skin prick tests. A questionnaire was also sent to former workers of the factory.

RESULTS

There were no significant differences between the groups in the prevalence of respiratory symptoms and chest radiography findings. Nine of 102 tobacco workers had pulmonary fibrosis of at least 1/0 (according to the International Labour Organisation (ILO) 1980 classification) and the corresponding figure was five for the referents. The tobacco workers tended to have a low forced vital capacity (FVC), and they had impaired forced expiratory volume in 1 second and lower means of the maximal expiratory flow at 25% of the FVC significantly more often than the referents. Diffusing capacity tended to be lower among the referents. The referents more often had atopy and earlier atopic diseases than the exposed workers. These results indicate the possibility of selection among the exposed workers.

CONCLUSIONS

No excess of prevalence of respiratory symptoms in the tobacco workers was found. According to the questionnaire episodes of allergic alveolitis may have occurred in the cigar factory workers. However, in the absence of impairments in lung function and radiological changes it was not possible to distinguish humidifier fever and allergic alveolitis. In exposure conditions that include humidification of the air humidifier, fever and allergic alveolitis constitute a risk for tobacco workers. No effects were shown of exposure to tobacco dust on lung function.

The association between cigarette smoking and ocular diseases

Tobacco smoke is composed of as many as 4,000 active compounds, most of them toxic on either acute or long-term exposure. Many of them are also poisonous to ocular tissues, affecting the eye mainly through ischemic or oxidative mechanisms. The list of ophthalmologic disorders associated with cigarette smoking continues to grow. Most chronic ocular diseases, with the possible exception of diabetic retinopathy and primary open-angle glaucoma, appear to be associated with smoking. Both cataract development and age-related macular degeneration, the leading causes of severe visual impairment and blindness, are directly accelerated by smoking. Other common ocular disorders, such as retinal ischemia, anterior ischemic optic neuropathy, and Graves ophthalmopathy, are also significantly linked to this harmful habit. Tobacco smoking is the direct cause of tobacco-alcohol amblyopia, a once common but now rare disease characterized by severe visual loss, which is probably a result of toxic optic nerve damage. Cigarette smoking is highly irritating to the conjunctival mucosa, also affecting the eyes of nonsmokers by passive exposure (secondhand smoking). The dangerous effects of smoking are transmitted through the placenta, and offspring of smoking mothers are prone to develop strabismus. Efforts should be directed toward augmenting the campaign against tobacco smoking by adding the increased risk of blindness to the better-known arguments against smoking. We should urge our patients to quit smoking, and we must make them keenly aware of the afflictions that can develop when smoke gets in our eyes.

Experimental exposure to methyl tertiary-butyl ether. II. Acute effects in humans

Methyl tertiary-butyl ether (MTBE) is widely used in gasoline as an oxygenate and octane enhancer. Acute effects, such as headache, nausea, and nasal and ocular irritation, have been associated with the exposure to gasoline containing MTBE. The aim of this study was to assess acute health effects up to the Swedish occupational exposure limit value, both with objective methods and a questionnaire. Ten healthy male volunteers were exposed to MTBE vapor for 2 h at three levels (5, 25, and 50 ppm), during light physical work (50 W). All subjects rated the degree of irritative symptoms, discomfort, and CNS effects before, during, and after all three exposure occasions using a questionnaire. Answers were given on a 100-mm visual analog scale, graded from "not at all" to "almost unbearable." Ocular (redness, tear film break-up time, self-reported tear film break-up time, conjunctival epithelial damage, and blinking frequency) and nasal (mouth and nasal peak expiratory flow, acoustic rhinometry, biochemical inflammatory markers, and cells in nasal lavage) measurements were performed mainly at the highest exposure level. The ratings of solvent smell increased dramatically (ratings up to 50% of the scale) as the volunteers entered the chamber and declined slowly with time (p < 0.05, repeated-measures ANOVA). All other questions were rated from "not at all" to "hardly at all" (0-10% of the scale) with no significant relation to exposure. The eye measurements showed no effects of MTBE exposure. Blockage index, a measure of nasal airway resistance calculated from the peak expiratory flows, increased significantly after exposure; however, the effect was not related to exposure level. In addition, a nonsignificant tendency of decreased nasal volume was seen in the acoustic rhinometry measurements, but with no clear dose-effect relationship. In conclusion, our study suggests no or minimal acute effects of MTBE vapor upon short-term exposure at relatively high levels.

Automatic quantitative measurement of ocular hyperemia

Evaluation of ocular hyperemia has been an important assessment in research studies of effects of contact lenses, medications, and pollutants on the eye. Hyperemia has been difficult to quantitate objectively. The purpose of this study was to validate a computer based image analysis system to quantitate hyperemia automatically and objectively in pixelated images of the external eye using two measures, the percent of the red color, RR, and the fraction of pixels which are blood vessels, VA. Validation was against an established photographic reference scale of ocular hyperemia and against the clinical pharmacologic effects of 0.5% dapiprazole hydrochloride, known to increase hyperemia, and 2.5% phenylephrine hydrochloride, known to decrease hyperemia. Color transparencies from the reference scale were converted to digital images. Temporal and nasal regions of the external eye were imaged directly to magnetic disk before and after pharmacologic intervention. Custom software automatically excluded unwanted regions, and quantitative image analysis produced RR and VA. RR and VA were each correlated with the reference scale. For each region and for each pharmacologic intervention, the mean RR and the mean VA, respectively, were compared at time zero and at a mean elapsed time of 713 +/- 47 s. RR and VA consistently increased as the hyperemia in the reference scale increased. Pearson correlation coefficients were 0.98 and 0.99, respectively, (p < 0.01). At 713 +/- 47 s after each pharmacologic intervention, RR and VA increased and decreased as expected (p < 0.001). Thus, this study successfully validated the methodology against expert clinical judgment and was able to measure automatically and objectively clinical changes in ocular hyperemia.

Irritation effects from experimental exposure to n-butyl acetate

The irritation produced by acute exposure to n-butyl acetate in human subjects without any history of occupational solvent exposure was studied in three experiments. Exposure levels tested in the different experiments were 350, 700, 1,050, and 1,400 mg/m3 in 20 min sessions, 70 and 1,400 mg/m3 in 20 min sessions, and 70 and 700 mg/m3 in 4 h sessions. Rating scales, various measures of eye irritation, and pulmonary functions were used to evaluate the irritation produced by the exposures in different parts of the study. The results indicate only very slight irritation from the exposures as revealed by categorical ratings, magnitude estimation, and some of the clinical measures of eye irritation and pulmonary functions, such as eye redness, lipid layer thickness, and bronchial responsiveness. These essentially negative results indicate the need to explore and develop the utility of new/different methods of quantifying irritative effects of exposure to various substances.

Pollution: the nose and sinuses

The nose and sinuses are constantly exposed to the huge quantities of gases needed to maintain life. Not only is the human nose well-equipped to warm and humidify this inhaled air, but it is also uniquely able to clean much of it. Any material other than physiologic amounts of oxygen, nitrogen, carbon dioxide, and water that accompanies the airstream can be considered a pollutant, and this pollutant could potentially injure the individual. The following discussion will review the defense mechanisms that allow the nose and sinuses to protect the lower airways. The effects of pollutants on the respiratory mucosa will then be described, including some recent trends in those effects. These trends include specific population consequences of indoor and outdoor air pollution, and changes in risk for individuals in several occupations. Throughout these discussions, specific areas that would benefit from further research will be mentioned.

Critical review: the health significance of environmental odor pollution

Environmental odor pollution problems generate a significant fraction of the publicly initiated complaints received by air pollution control districts. Such complaints can trigger a variety of enforcement activities under existing state and local statutes. However, because of the frequently transient timing of exposures, odor sources often elude successful abatement. Furthermore, because of the predominantly subjective nature of associated health complaints, air pollution control authorities may predicate their enforcement activities upon a judgment of the public health impact of the odor source. Noxious environmental odors may trigger symptoms by a variety of physiologic mechanisms, including exacerbation of underlying medical conditions, innate odor aversions, aversive conditioning phenomena, stress-induced illness, and possible pheromonal reactions. Whereas relatively consistent patterns of subjective symptoms have been reported among individuals who live near environmental odor sources, documentation of objective correlates to such symptoms would require as-yet unproven research tools. Therefore, given our current state of knowledge, any differential regulatory response to environmental odor pollution, which is based upon the distinction between community "annoyance reactions" and "health effects," is a matter of legal--not scientific--interpretation.

Assessment of changes in eye redness by a photographic method and the relation to sensory eye irritation

The purpose of the present study was to evaluate the relation between photographically assessed changes in eye redness and sensory eye irritation in 17 patients suffering from hayfever, provoked by increasing doses of birch pollen in the eye. Pre- and post-exposure diapositives were compared in a randomized and double blind design by a panel of five members. By evaluating the photographs we found a high reproducibility between panel members and for repeated evaluation by the individual panel member. Furthermore, we found that the photographic method was more sensitive for measurements of changes in eye redness than the observations normally performed during such conjunctival provocation tests. The correlations of the objective findings with the symptoms reported were good at high pollen doses, but at lower doses of birch pollen (about half the effective dose) a decreased eye redness was observed. We found that sensory irritation (often expressed as dryness) measured simultaneously by questionnaires, in general occurred before any increased eye redness. The study indicates that photographic measurement of eye redness is reproducible, sensitive, unbiased and therefore a useful tool in environmental studies. Furthermore we demonstrated that the relation between eye redness and eye irritation is interestingly biphasic and may need further clarification.