Respiratory Health Indicators Research Articles

Change of air quality knowledge, perceptions, attitudes, and practices during and post-wildfires in the United States

Amid worsening climate change, the recurrent wildfires have substantially worsened air quality in the Western United States (U.S.). Understanding the knowledge, attitudes, perception, and practices (KAPP) over time in response to natural disasters such as wildfires is crucial for public health interventions and disaster preparedness. This is the first study to investigate the change in air quality KAPP over time in response to natural disasters. Previous studies have only assessed KAPP at a fixed time point. Using a two-wave panel survey (during and post-wildfires), we assessed the association between KAPP and respiratory health indicators as well as the changes over time in 212 participants in the U.S. Between the two waves, we found a significant 8% increase in knowledge, which was mainly driven by participants in areas unaffected by the wildfires. In addition, we found differential associations between KAPP and respiratory health indicators between areas affected and unaffected by the wildfires. These findings suggest that experiencing wildfires may affect KAPP and more longitudinal studies are warranted, particularly during periodic air quality crises.

A panel study on the acute respiratory effects of ambient particles of different sizes on children in Shanghai

Objective: To explore the association between size-fractionated particle number concentrations (PNC) and respiratory health in children. Methods: From November 2018 to June 2019, there were 65 children aged 6-9 years from an elementary school in shanghai recruited in this panel study with three rounds of follow-up. The forced vital capacity (FVC), forced expiratory volume in the first second (FEV1), and exhaled nitric oxide (FeNO) levels were measured and buccal mucosa samples of children were collected at each follow-up visit. The level of PNC, temperature and humidity of the elementary school was monitored from 3 days before each physical examination to the end of the physical examination. The linear mixed effects model was used to analyze the association between PNC and indicators of respiratory health in children. Results: Linear mixed effects model analysis revealed that, at lag 2 day, an interquartile range increase in PNC for particles measuring 0.25-0.40 μm was associated with the absolute changes in FVC, FEV1 and abundance-based coverage estimator (ACE) about -60.15 ml (95%CI:-88.97 ml, -31.32 ml), -34.26 ml (95%CI:-63.22 ml, -5.31 ml), -6.00 (95%CI:-9.15, -2.84) and percentage change in FeNO about 12.10% (95%CI: 3.05%, 21.95%), respectively. These adverse health effects increased with the decrease of particle size. Conclusion: The short-term exposure to particulate matter is associated with reduced lung function, buccal microbe diversity and higher airway inflammation level among children. These adverse health effects may increase with the decrease of particle size.

Analysis of respiratory kinematics: a method to characterize breaths from motion signals

Objective. Breathing motion (respiratory kinematics) can be characterized by the interval and depth of each breath, and by magnitude-synchrony relationships between locations. Such characteristics and their breath-by-breath variability might be useful indicators of respiratory health. To enable breath-by-breath characterization of respiratory kinematics, we developed a method to detect breaths using motion sensors. Approach. In 34 volunteers who underwent maximal exercise testing, we used 8 motion sensors to record upper rib, lower rib and abdominal kinematics at 3 exercise stages (rest, lactate threshold and exhaustion). We recorded volumetric air flow signals using clinical exercise laboratory equipment and synchronized them with kinematic signals. Using instantaneous phase landmarks from the analytic representation of kinematic and flow signals, we identified individual breaths and derived respiratory rate (RR) signals at 1 Hz. To evaluate the fidelity of kinematics-derived RR, we calculated bias, limits of agreement, and cross-correlation coefficients (CCC) relative to flow-derived RR. To identify coupling between kinematics and flow, we calculated the Shannon entropy of the relative frequency with which flow landmarks were distributed over the phase of the kinematic cycle. Main Results. We found good agreement in the kinematics-derived and flow-derived RR signals [bias (95% limit of agreement) = 0.1 (± 7) breaths/minute; CCC median (IQR) = 0.80 (0.48–0.91)]. In individual signals, kinematics and flow were well-coupled (entropy 0.9–1.4 across sensors), but the relationship varied within (by exercise stage) and between individuals. The final result was that the flow landmarks did not consistently localize to any particular phase of the kinematic signals (entropy 2.2–3.0 across sensors). Significance. The Analysis of Respiratory Kinematics method can yield highly resolved respiratory rate signals by separating individual breaths. This method will facilitate characterization of clinically significant breathing motion patterns on a breath-by-breath basis. The relationship between respiratory kinematics and flow is much more complex than expected, varying between and within individuals.

Associations between Second-Hand Tobacco Smoke Exposure and Cardiorespiratory Fitness, Physical Activity, and Respiratory Health in Children.

Background: Cardiorespiratory fitness (CRF) and physical activity (PA) are associated with a plethora of positive health effects. Many UK children fail to meet the recommended level of PA, with an observed decline in CRF levels over recent decades. Second-hand tobacco smoke (SHS) is responsible for a significant proportion of the worldwide burden of disease, but little is understood regarding the impact of SHS exposure on CRF and PA in children. The aim of this study was to test the associations between SHS exposure and CRF, PA, and respiratory health in children. Method: Children (9–11 years) from UK primary schools in deprived areas participated (n = 104, 38 smoking households). Surveys determined household smoking, and exhaled carbon monoxide was used to indicate children’s recent SHS exposure. CRF (VO2peak) was assessed via maximal treadmill protocol using breath-by-breath analysis. Fractional exhaled nitric oxide and spirometry were utilised as indicators of respiratory health. Results: Linear regression models demonstrated that SHS exposure was negatively associated with allometrically scaled VO2peak (B = −3.8, p = 0.030) but not PA or respiratory health. Conclusion: The results indicate that SHS is detrimental to children’s CRF; given that approximately one-third of children are regularly exposed to SHS, this important finding has implications for both public health and the sport and exercise sciences.

Maternal stress and depression are associated with respiratory phenotypes in urban children

Prenatal and early-life exposure to maternal stress and depression is linked to development of recurrent wheezing in young children. We sought to determine whether maternal stress and depression in early life are associated with nonatopic wheezing phenotype in urban children. The Urban Environment and Childhood Asthma Study examined a birth cohort of children at high risk for asthma in low-income neighborhoods. Prenatal and postnatal (through age 3 years) maternal stress and depression scores were compared with respiratory phenotypes through age 10 years (multinomial regression), self-reported colds (linear regression), and detection of respiratory viruses (Poisson regression). Scores for maternal depression, and, to a lesser extent, maternal perceived stress, were positively related to multiple wheezing phenotypes. In particular, cumulative measures of maternal depression in the first 3 years were related to the moderate-wheeze-low-atopy phenotype (odds ratio, 1.13; [1.05, 1.21]; P< .01). Considering indicators of respiratory health that were used to identify the phenotypes, there were multiple positive associations between early-life scores for maternal stress and depression and increased wheezing illnesses, but no consistent relationships with lung function and some inverse relationships with allergic sensitization. Cumulative maternal stress and depression scores were associated with cumulative number of respiratory illnesses through age 3 years. Among high-risk, urban children, maternal stress and depression in early life were positively associated with respiratory illnesses and a moderate-wheeze-low-atopy phenotype. These results suggest that treating stress and depression in expectant and new mothers could reduce viral respiratory illnesses and recurrent wheeze during the preschool years and some forms of childhood asthma.

A long-term multi-parametric monitoring study: Indoor air quality (IAQ) and the sources of the pollutants, prevalence of sick building syndrome (SBS) symptoms, and respiratory health indicators

Poor indoor air quality (IAQ) can cause several respiratory diseases and symptoms. In this study, IAQ of 121 homes located in 3 different towns of Çanakkale, Turkey was monitored throughout a year. Target air pollutants were particulate matter, volatile organic compounds (VOCs), bioaerosols, and Carbon dioxide (CO2), as well as air temperature and humidity. Moreover, pulmonary functions of the occupants were measured on a monthly basis. Also, occurrence of sick building syndrome (SBS) symptoms and other health related data were gathered from the occupants by a detailed questionnaire. The SBS is a situation related to indoor air pollution in which the occupants of a building experience health or comfort related adverse effects that appear to be associated directly to the time spent in the “sick” building. Results of this study showed that the highest indoor air pollutant levels were observed in Çan town and the lowest levels were observed in Central town. Indoor levels of bioaerosols, particulate matter, benzene, Cladosporium spp., and Penicillium spp. as well as pulmonary functions of the occupants showed statistically significant differences between the locations of the homes (p < 0.001). Factor analysis implied that both indoor and outdoor originated sources contributed to IAQ. Even though the predominant SBS symptoms varied seasonally and spatially among the study sites, fatigue, cold-flu like symptoms, and difficulty in concentration occurred frequently. Correlations were found among the occurrence of SBS symptoms, measured IAQ parameters, and personal factors (p < 0.05). Performing more studies from the health and IAQ points of view improve public awareness.

A comprehensive assessment of ambient air quality in Çanakkale city: Emission inventory, air quality monitoring, source apportionment, and respiratory health indicators

This comprehensive study aims to examine the relationships between ambient air quality (AAQ) and respiratory health of the participants residing in three different towns of Çanakkale city, Turkey between August 2013 and 2014. AAQ measurements for bioaerosols, volatile organic compounds (VOCs), total particulate matter (PM) count, carbon dioxide (CO2), and carbon monoxide (CO) were performed and monthly pulmonary function test (PFT) was applied to volunteer participants residing in the study sites (n = 121) for one year. Additionally, concentrations of air pollutants for PM2.5/PM10, sulfur dioxide (SO2), nitrogen oxides, and ozone were gathered from AAQ monitoring stations. To estimate the contributions of the emission sources and their effects on human health in the region, an emission inventory was also prepared in the region and AERMOD modelling system was applied for the year of 2013. Accordingly, the industry was the most polluting sector for NOx and SO2, while road traffic and residential heating were the most polluting sectors for CO and PM10. Factor analysis revealed that organics, combustion, bioaerosol propagation, and ozone accumulation contributed to AAQ, in agreement with AQ modelling results. Çan had the worst air quality (industrialized site), which affected the respiratory health indicators of the participants. Generalized linear model estimated that PF of the participants varied according to the residing district, gender, suffering from asthma, and lifelong smoking or environmental tobacco smoke exposure (p < 0.05). Also, PF of the participants were linked with VOCs levels in the Central town, total PM count in Lapseki, and ozone levels in Çan (p < 0.05).

An Acoustic Analysis of Formants between Frequently Smoking Subjects and Non-smoking Subjects

Smoking is one of the factors that affect the respiratory health of human. A system of respiratory health indicators is needed to prevent the negative effects of smoking at an early stage. The relation between respiratory and vocal coordination can be analysed by measuring the formant frequencies, which indicate the spectral shaping of the human vocal tract. In this study, two groups of subjects with and without smoking habits were studied in terms of their formant frequencies. The results showed that there were statistical significance differences in the four formant frequencies between the two groups. The differences might be due to the changes in the elasticity of the oral cavity, which were affected by the smoke produced from cigarettes. Therefore, we conclude that a smoking person can be identified by the characteristics of their formant frequencies.

Interventions for management of respiratory disease in young people with cerebral palsy: A systematic review.

Respiratory disease is a leading cause of hospitalizations and deaths in young people with cerebral palsy (CP). It is insidious and multifactorial. Clinical management can be complex. This systematic review describes effects of interventions for the prevention and management of respiratory disease in young people with CP. Nine databases (Cochrane, CINAHL, Embase, EMCare, MEDLINE, PEDro, OpenGrey, ScienceDirect, and SpeechBITE) were searched. Eligibility criteria were as follows: the population included at least 50% individuals with CP aged under 26years, the intervention was for chronic respiratory illness, the outcomes were any measurable indicators of respiratory health or morbidity; the study design could be any original study reporting effects of an intervention on measurable outcomes, and the study was published January 1998 or later. The American Academy for Cerebral Palsy and Developmental Medicine methodology guided study appraisal and synthesis. The review was registered with PROSPERO (reference number CRD42018086314). The search yielded 3,347 papers; 37 papers (reporting 34 studies) of these met the eligibility criteria. They included 582 participants with CP (ranging from 1 to 77 across studies) with ages from 5months to 25years. Interventions were diverse and included: airway clearance techniques, exercise, positioning, mealtime management, salivary management, upper airway interventions, antibiotics, gastro-intestinal interventions, and spinal surgery. There were no interventions aimed at prevention of respiratory disease in this population. Research designs were classified as Levels 2 (n=3), 3 (n=2), 4 (n=25), and 5 (n=4). Evidence for most respiratory interventions for young people with CP is absent or weak. No controlled trials demonstrated significant effects on respiratory morbidity, owing to their scarcity, weak designs, and inadequate power. There is an urgent need for well-designed prospective controlled studies investigating prevention and management of respiratory disease in young people with CP.

Catalyzing Action on First Nations Respiratory Health Using Community-based Participatory Research: Integrated Knowledge Translation through Strategic Symposia

Assess, Redress, Re-assess: Addressing Disparities in Respiratory Health Among First Nations is an ongoing community-based participatory research initiative involving two First Nations communities in Saskatchewan. The initiative’s rationale is grounded in the ethos of transformative community-based participatory research and facilitated through integrated knowledge translation with the aim of building community capacity. The initiative’s goal was to engage community members to actively participate in all research phases, from the development of the research questions to dissemination of results and evaluation of community-chosen interventions that evolved from the results. After baseline assessment of predictors and indicators of respiratory health, a program of integrated knowledge translation was adopted. As part of this program, a community-researcher collaboration was put in place that produced two knowledge translation symposia. The two symposia have brought together First Nations community members, interdisciplinary researchers, federal and provincial policy makers, and multiple Aboriginal organizational stakeholders. The symposia provided a pathway for knowledge synthesis and sharing to ultimately integrate knowledge into practice and enable First Nations’ community capacity building in addressing and redressing critical respiratory health issues. This article delineates the processes involved in developing this model of integrated knowledge translation and highlights the continuing engagement with the participating communities supported by Knowledge Translation (KT) Symposia.

Assessment of Respiratory Health Indicators among Agricultural Workers Exposed to Pesticides: A Cross Sectional Study from Palestine

Pesticides are toxic chemicals commonly used in agriculture. No previous studies have been carried out to assess the respiratory health indicators among agricultural workers who are being continuously exposed to pesticides. So, this pilot study aims to determine the respiratory health effects of occupational exposure to pesticides for those workers in Palestine. A cross-sectional study was conducted in one district in Palestine as a pilot study. Lung function tests (LFTs) are measured using a spirometer. Forced spirometry was used to measure the forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC), the FEV1/FVC ratios and prevalence of restrictive and obstructive lung diseases of the two groups were investigated and compared. A total of 98 workers were screened. Their mean age was 41.9 ± 13 years while the mean duration of exposure to agricultural chemicals was 27.8 ± 7.2 years. According to the type of lung status, 92% of the workers showed lung diseases, 80% were restrictive lung disease, 12% were obstructive lung disease and 8% of workers were normal. The mean FEV1 of the sample was 2.6 ± 0.8 compared with normal reference value of 3.9 ±0.6 [ P-value =0.010]. On the other hand, the mean FVC for the study sample was 3.2±1.4 compared with the normal reference value of 5 ± 0.6 [P-value =0.023]. The ratio of these two parameters was 85.4 ± 15.5 compared with a normal reference ratio of 79 ± 2.7 [ P-value=0.6 ].In this study, we concluded that agricultural workers who are exposed to pesticides suffer from variety of diseases that pose a serious risk to public health, mainly on the lung disease (mainly restrictive lung diseases).

Lessons learned from the application of BEES-C: Systematic assessment of study quality of epidemiologic research on BPA, neurodevelopment, and respiratory health

Epidemiologic studies evaluating associations between biomarkers of exposure to short-lived chemicals and health endpoints in humans face special challenges. Perhaps the most critical challenges are the need to determine the type and optimal number of samples, and the proper timing of specimen collection. Further, as many short-lived chemicals are ubiquitous in the environment, utmost care is required to avoid sample contamination. A separate set of challenges is associated with appropriate interpretation and reporting of results from multiple simultaneous analyses, which are becoming increasingly feasible. The Biomonitoring, Environmental Epidemiology, and Short-Lived Chemicals (BEES-C) instrument is specifically designed to evaluate the quality of epidemiologic studies that measure biomarkers of chemicals with short physiologic half-lives. The instrument provides systematic guidance for evaluating 14 different aspects of study quality divided into three broad categories: 1) biomarker selection and measurement, 2) strategy and execution of exposure assessment, and 3) general considerations of study design and reporting. We evaluated the utility of the BEES-C instrument using epidemiologic studies of exposure to bisphenol A and its association with neurodevelopmental and respiratory health indicators. Each BEES-C element was assessed with respect to needed modifications and concordance among reviewers using professional, scientific judgment. Based on this first use of the BEES-C instrument, we found that most of its elements were effective in comparing the quality of available studies, with reviews generally concordant and justifications consistent. However, we note that certain elements would be improved with slight adjustments and that one of the elements appeared redundant and should be removed.

Content-based classification of breath sound with enhanced features

Since breath sound (BS) contains important indicators of respiratory health and disease, analysis and detection of BS has become an important topic, with diagnostic and assessment of treatment capabilities. In this paper, the identification and classification of respiratory disorders based on the enhanced perceptual and cepstral feature set (PerCepD) is proposed. The hybrid PerCepD feature can capture the time-frequency characteristics of BS very well. Thus, it is very effective for the exploration and classification of normal and pathological BS related data. The classification models based on support vector machine (SVM) and artificial neural network (ANN) have been adopted to achieve automatic detection from BS data. The high detection accuracy results validate the performance of the proposed feature sets and classification model. The experimental results also demonstrate that the high accuracy of the pathological BS data can provide reliable diagnostic suggestions for breath disorders, such as flu, pneumonia and bronchitis.

Assessment of the association between predictions from a wildfire smoke forecasting system and respiratory health indicators

Background: Exposure to wildfire smoke has been associated with increases in measures of respiratory health. Forecasts of smoke exposure can provide prospective information to support public health...

Evaluation of a Wildfire Smoke Forecasting System as a Tool for Public Health Protection

Background: Exposure to wildfire smoke has been associated with cardiopulmonary health impacts. Climate change will increase the severity and frequency of smoke events, suggesting a need for enhanced public health protection. Forecasts of smoke exposure can facilitate public health responses.Objectives: We evaluated the utility of a wildfire smoke forecasting system (BlueSky) for public health protection by comparing its forecasts with observations and assessing their associations with population-level indicators of respiratory health in British Columbia, Canada.Methods: We compared BlueSky PM2.5 forecasts with PM2.5 measurements from air quality monitors, and BlueSky smoke plume forecasts with plume tracings from National Oceanic and Atmospheric Administration Hazard Mapping System remote sensing data. Daily counts of the asthma drug salbutamol sulfate dispensations and asthma-related physician visits were aggregated for each geographic local health area (LHA). Daily continuous measures of PM2.5 and binary measures of smoke plume presence, either forecasted or observed, were assigned to each LHA. Poisson regression was used to estimate the association between exposure measures and health indicators.Results: We found modest agreement between forecasts and observations, which was improved during intense fire periods. A 30-μg/m3 increase in BlueSky PM2.5 was associated with an 8% increase in salbutamol dispensations and a 5% increase in asthma-related physician visits. BlueSky plume coverage was associated with 5% and 6% increases in the two health indicators, respectively. The effects were similar for observed smoke, and generally stronger in very smoky areas.Conclusions: BlueSky forecasts showed modest agreement with retrospective measures of smoke and were predictive of respiratory health indicators, suggesting they can provide useful information for public health protection.Citation: Yao J, Brauer M, Henderson SB. 2013. Evaluation of a wildfire smoke forecasting system as a tool for public health protection. Environ Health Perspect 121:1142–1147; http://dx.doi.org/10.1289/ehp.1306768

Contribution of smoking and air pollution exposure in urban areas to social differences in respiratory health

BackgroundSocio-economic status, smoking, and exposure to increased levels of environmental air pollution are associated with adverse effects on respiratory health. We assessed the contribution of occupational exposures, smoking and outdoor air pollution as competing factors for the association between socio-economic status and respiratory health indicators in a cohort of women from the Ruhr area aged 55 at the time of investigation between 1985 and 1990.MethodsData of 1251 women with spirometry and complete questionnaire information about respiratory diseases, smoking and potential confounders were used in the analyses. Exposure to large-scale air pollution was assessed with data from monitoring stations. Exposure to small-scale air pollution was assessed as traffic-related exposure by distance to the nearest major road. Socio-economic status was defined by educational level. Multiple regression models were used to estimate the contribution of occupational exposures, smoking and outdoor air pollution to social differences in respiratory health.ResultsWomen with less than 10 years of school education in comparison to more than 10 years of school education were more often occupationally exposed (16.4% vs. 10.1%), smoked more often (20.3% vs. 13.9%), and lived more often close to major roads (26.0% vs. 22.9%). Long-term exposure to increased levels of PM10 was significantly associated with lower school education. Women with low school education were more likely to suffer from respiratory symptoms and had reduced lung function. In the multivariate analysis the associations between education and respiratory health attenuated after adjusting for occupational exposure, smoking and outdoor air pollution. The crude odds ratio for the association between the lung function indicator FEV1 less than 80% of predicted value and educational level (<10 years vs. >10 years of school education) was 1.83 (95% CI: 1.22–2.74). This changed to 1.56 (95% CI: 1.03–2.37) after adjusting for occupational exposure, smoking and outdoor air pollution.ConclusionWe found an association between socio-economic status and respiratory health. This can partly be explained by living conditions indicated by occupational exposure, smoking behaviour and ambient air pollution. A relevant part of the social differences in respiratory health, however, remained unexplained.

Does respiratory health contribute to the effects of long-term air pollution exposure on cardiovascular mortality?

BackgroundThere is growing epidemiological evidence that short-term and long-term exposure to high levels of air pollution may increase cardiovascular morbidity and mortality. In addition, epidemiological studies have shown an association between air pollution exposure and respiratory health. To what extent the association between cardiovascular mortality and air pollution is driven by the impact of air pollution on respiratory health is unknown. The aim of this study was to investigate whether respiratory health at baseline contributes to the effects of long-term exposure to high levels of air pollution on cardiovascular mortality in a cohort of elderly women.MethodWe analyzed data from 4750 women, aged 55 at the baseline investigation in the years 1985–1994. 2593 of these women had their lung function tested by spirometry. Respiratory diseases and symptoms were asked by questionnaire. Ambient air pollution exposure was assessed by the concentrations of NO2 and total suspended particles at fixed monitoring sites and by the distance of residency to a major road. A mortality follow-up of these women was conducted between 2001 and 2003. For the statistical analysis, Cox' regression was used.ResultsWomen with impaired lung function or pre-existing respiratory diseases had a higher risk of dying from cardiovascular causes. The impact of impaired lung function declined over time. The risk ratio (RR) of women with forced expiratory volume in one second (FEV1) of less than 80% predicted to die from cardiovascular causes was RR = 3.79 (95%CI: 1.64–8.74) at 5 years survival time and RR = 1.35 (95%CI: 0.66–2.77) at 12 years. The association between air pollution levels and cardiovascular death rate was strong and statistically significant. However, this association did only change marginally when including indicators of respiratory health into the regression analysis. Furthermore, no interaction between air pollution and respiratory health on cardiovascular mortality indicating a higher risk of those with impaired respiratory health could be detected.ConclusionRespiratory health is a predictor for cardiovascular mortality. In women followed about 15 years after the baseline investigation at age 55 years long-term air pollution exposure and impaired respiratory health were independently associated with increased cardiovascular mortality.

Fundamentals of Respiratory Sounds and Analysis

Breath sounds have long been important indicators of respiratory health and disease. Acoustical monitoring of respiratory sounds has been used by researchers for various diagnostic purposes. A few dec

The effects of intervention with local electrostatic air cleaners on airborne dust and the health of office employees

The aim of this intervention study was to identify any health improvements in the upper and lower airways of office workers after the installation of local electrostatic air cleaners. Eighty persons with airways symptoms were recruited and randomly assigned to an intervention or control group. Half of the air cleaners had a non-functioning electrostatic unit. Both participants and field researchers were blinded to the group status. Subjective symptoms were recorded using a questionnaire, and indexes calculated for general, irritation and skin symptoms. Objective respiratory health indicators were recorded, with acoustic rhinometry and peak expiratory flow (PEF) meters. In the intervention group there was a decrease in mean dust concentration from 65 to 35 microg/m(3), and a reduction from 57 to 47 microg/m(3) in the control group (P < 0.05 for difference in decline). The reduction was observed for all particles sizes. The irritation and general symptom indices decreased in both groups, but there was no improvement in the intervention group, compared with the control group. Median PEF increased 3 ml/s in the intervention group, and decreased 4 ml/s in the control group. The adjusted odds ratio for an increase above the 70th percentile was 5.7 (95% CI 1.0-32). Electrostatic air cleaners can reduce the dust concentration effectively in the office environment. Small, medium and large sized particles can be reduced by approximately 50%, relatively most effectively for the respirable particles. However, the air cleaners tested in this study produced an annoying fan noise. Cleaning efficiency and noise data should be given consideration before installation. This experimental field study suggests that office workers with airways symptoms may benefit from installation of local electrostatic air cleaners.

Respiratory health effects of long-term exposure to different chromium species in stainless steel production.

The aim of this study was to determine whether occupational exposure to chromite, trivalent chromium (Cr(3+)) or hexavalent chromium (Cr(6+)) causes respiratory diseases, an excess of respiratory symptoms, a decrease in pulmonary function or signs of pneumoconiosis among workers in stainless steel production. Altogether, 203 exposed workers and 81 referents with an average employment of 23 years were investigated for indicators of respiratory health on two occasions, in 1993 and in 1998. Data collection with a self-administered questionnaire, flow volume spirometry, measurement of diffusing capacity, chest radiography and laboratory tests were carried out by a mobile research unit. Exposure to different chromium species and other metals was monitored regularly and studied separately. No adverse respiratory health effects were observed in the group exposed to Cr(6+), either in comparison with the control group in the first cross-sectional study or during the additional 5 year follow-up. Among the Cr (3+) exposed people, the production of phlegm, shortness of breath and breathlessness on exertion were significantly more frequent than in the control group, but the frequency of the symptoms did not increase during the follow-up; no differences were observed in the lung function tests and the radiographic findings did not progress. In the chromite group, the prevalence of breathlessness on exertion was higher than in the control group. However, in the follow-up, the occurrence of symptoms did not differ from 1993 to 1998. In the first study, most parameters of lung function were lower among the smokers in the chromite group than among the smoking controls, but in 1998 the difference was less marked. An average exposure time of 23 years in modern ferrochromium and stainless steel production and low exposure to dusts and fumes containing Cr(6+), Cr(3+), nickel and molybdenum do not lead to respiratory changes detectable by lung function tests or radiography. The workers exposed to Cr(3+) had more respiratory symptoms than those in the control group. The workers in the chromite mine had lower lung function test results than the control group due to earlier exposure to higher dust concentrations.