Physical science research needed to evaluate the viability and risks of marine cloud brightening.

Marine cloud brightening (MCB) is the deliberate injection of aerosol particles into shallow marine clouds to increase their reflection of solar radiation and reduce the amount of energy absorbed by the climate system. From the physical science perspective, the consensus of a broad international group of scientists is that the viability of MCB will ultimately depend on whether observations and models can robustly assess the scale-up of local-to-global brightening in today's climate and identify strategies that will ensure an equitable geographical distribution of the benefits and risks associated with projected regional changes in temperature and precipitation. To address the physical science knowledge gaps required to assess the societal implications of MCB, we propose a substantial and targeted program of research-field and laboratory experiments, monitoring, and numerical modeling across a range of scales.

Mortality of older construction and craft workers employed at Department of Energy (DOE) nuclear sites: Follow-up through 2021.

BACKGROUND: To determine if construction and trades workers formerly employed at US Department of Energy (DOE) nuclear weapons sites are at significant risk for occupational diseases, we studied the mortality experience of participants in the Building Trades National Medical Screening Program (BTMed). METHODS: The cohort included 26,922 participants enrolled between 1998 and 2021 and 8367 deaths. Standardized mortality ratios were calculated based on US death rates. Cox models compared construction workers (n = 22,747; 7487 deaths) to two nonconstruction subpopulations: administrative, scientific and security workers (n = 1894; 330 deaths), and all other nonconstruction workers (n = 2218; 550 deaths). RESULTS: Mortality was elevated for all causes, all cancers, cancers of the trachea, bronchus, lung, kidneys, and lymphatic and hematopoietic system, mesothelioma, chronic obstructive pulmonary disease (COPD), asbestosis, transportation injuries, and other injuries, particularly accidental poisonings. There were 167 deaths from coronavirus disease 2019 (COVID-19), which was lower than expected using US death rates. Overall cause-specific mortality was significantly higher among construction workers than for internal comparison groups. CONCLUSIONS: Construction workers employed at DOE sites have a significantly increased risk for occupational illnesses. Apart from COVID-19 deaths, this update: (1) found that mortality among construction workers is significantly elevated compared to the US population and significantly higher than in the internal comparison populations, and (2) confirmed excess risk for these workers for first employment after 1990. Cancer mortality risks are similar to the cancers identified for DOE compensation from radiation exposures. The high lung cancer risk supports the value of early lung cancer detection. Continued medical surveillance is important.

Depression Negatively Impacts Dyadic Quality of Life Following Neuro-ICU Admission: A Prospective Study of Cognitively Intact Patients and Caregivers.

BACKGROUND: Admission to a neurological intensive care unit (Neuro-ICU) can increase risk for depressive and anxiety symptoms for both patients and caregivers. To better understand the long-term mental health impact of a Neuro-ICU admission, we examined the dyadic interdependence between depression and anxiety at Neuro-ICU admission with 3-month quality of life (QoL) for patients and caregivers in a longitudinal, observational cohort study. METHOD: We assessed depressive and anxiety symptoms (Hospital Anxiety and Depression Scale; HADS) reported by neurologically intact patients (n = 72) and their caregivers (n = 72) within 2 weeks of Neuro-ICU admission (baseline) and 3-months post-discharge (follow-up). We examined the longitudinal association between dyadic depression and anxiety at Neuro-ICU admission and 3-month QoL (World Health Organization; QOL-BREF) across four domains (Physical, Psychological, Social relationships, and Environmental QoL) in separate actor-partner interdependence models (APIM) for patients and caregivers. RESULTS: In the overall models, patients' own baseline depression levels were negatively associated with their own 3-month QoL in all domains (ß = - 0.53 to - 0.64, p < 0.001), and for caregivers, only in the psychological (ß = - 0.73, p < .001) and social relationships (ß = - 0.56, p < .001) domains. No actor effects were found for one's own baseline anxiety impacting one's own 3-month QoL. Partner effects for one's own depression were significant for caregivers on patients' 3-month psychological (ß = - 0.26, p < .02) and environmental (ß = - 0.29, p < .03) QoL, as well as for patients on caregiver's 3-month psychological QoL (ß = 0.25, p < .02). No partner effects were significant in association with baseline anxiety and 3-month QoL in both patients and caregivers. CONCLUSION: Neuro-ICU patients' and caregivers' baseline depression has significant negative impacts on their own long-term QoL. Caregivers demonstrate significant negative impacts on patient long-term QoL in domains related to emotional distress and caregiver burden. Early identification of mental health symptoms, especially depression, during Neuro-ICU admission may provide an intervention opportunity to improve QoL post-discharge for both dyad members.

Social support, resource utilization, and well-being: a survey of adolescent parents in Washington, DC.

BACKGROUND: Adolescent parents experience worse health and socioeconomic outcomes compared to older parents. Little is known about the factors that can lead to better health and well-being among teen-headed families. A city-wide collaborative conducted a comprehensive well-being assessment of expectant and parenting teens in Washington, DC. METHODS: An online, anonymous survey was conducted with adolescent parents in Washington, DC, using convenience sampling. The survey consisted of 66 questions adapted from validated scales of quality of life and well-being. Descriptive statistics were used to describe the data overall, by subgroups of mother and father, and by subgroups of parent age. Spearman's correlations were utilized to demonstrate associations of social supports with well-being metrics. RESULTS: A total of 107 adolescent and young adult parents from Washington, DC, completed the survey; 80% of respondents identified as mothers and 20% as fathers. Younger adolescent parents rated their physical health better compared to older adolescent and young adult parents. Adolescent parents reported accessing various governmental and community-based resources in the preceding 6 months. The most used resources were supplemental food programs, with 35% receiving Supplemental Nutrition Assistance Program benefits and 24% receiving support from the Special Supplemental Nutrition Program for Women, Infants and Children. There was no significant difference in health-related well-being metrics among those who did and did not receive resources. Having higher self-reported social support was positively correlated with higher self-rated physical health, mental health, and well-being, as well as experiencing positive emotions, and was negatively correlated with experiencing negative emotions. CONCLUSION: This snapshot of the well-being of expectant and parenting teens in Washington, DC, showed overall positive physical, mental, and emotional health. Greater social support was correlated with better outcomes in these areas. Future work will leverage the multidisciplinary collaborative to translate these findings into policies and programs that meet the needs of this population.

Multi-campaign ship and aircraft observations of marine cloud condensation nuclei and droplet concentrations.

In-situ marine cloud droplet number concentrations (CDNCs), cloud condensation nuclei (CCN), and CCN proxies, based on particle sizes and optical properties, are accumulated from seven field campaigns: ACTIVATE; NAAMES; CAMP2EX; ORACLES; SOCRATES; MARCUS; and CAPRICORN2. Each campaign involves aircraft measurements, ship-based measurements, or both. Measurements collected over the North and Central Atlantic, Indo-Pacific, and Southern Oceans, represent a range of clean to polluted conditions in various climate regimes. With the extensive range of environmental conditions sampled, this data collection is ideal for testing satellite remote detection methods of CDNC and CCN in marine environments. Remote measurement methods are vital to expanding the available data in these difficult-to-reach regions of the Earth and improving our understanding of aerosol-cloud interactions. The data collection includes particle composition and continental tracers to identify potential contributing CCN sources. Several of these campaigns include High Spectral Resolution Lidar (HSRL) and polarimetric imaging measurements and retrievals that will be the basis for the next generation of space-based remote sensors and, thus, can be utilized as satellite surrogates.

Restrictive spirometry pattern among construction trade workers.

BACKGROUND: Spirometry-based studies of occupational lung disease have mostly focused on obstructive or mixed obstructive/restrictive outcomes. We wanted to determine if restrictive spirometry pattern (RSP) is associated with occupation and increased mortality. METHODS: Study participants included 18,145 workers with demographic and smoking data and repeatable spirometry. The mortality analysis cohort included 15,445 workers with known vital status and cause of death through December 31, 2016. Stratified analyses explored RSP prevalence by demographic and clinical variables and trade. Log-binomial regression models explored RSP risk factors while controlling for important confounders such as smoking, obesity, and comorbidities. Cox regression models explored mortality risk by spirometry category. RESULTS: Prevalence of RSP was very high (28.6%). Mortality hazard ratios for RSP were 1.50 for all causes, 1.86 for cardiovascular diseases, 2.31 for respiratory diseases, and 1.66 for lung cancer. All construction trades except painters, machinists, and roofers had significantly elevated risk for RSP compared to our internal reference group. RSP was significantly associated with both parenchymal and pleural changes seen by chest X-ray. CONCLUSIONS: Construction trade workers are at significantly increased risk for RSP independent of obesity. Individuals with RSP are at increased risk for all-cause mortality as well as mortality attributable to respiratory diseases, cardiovascular diseases, and lung cancer. RSP deserves greater attention in occupational medicine and epidemiology.

How much have adverse occupational health outcomes among construction workers improved over time? Evidence from 25 years of medical screening.

BACKGROUND: Construction workers have always had a high risk of occupational illnesses. We used 25 years of data from a medical screening program serving older construction workers to determine how much health outcomes have improved over the past 60 years. METHODS: We investigated changes in relative risk for chest radiographs consistent with pneumoconiosis, COPD by spirometry, lung cancer mortality, and audiometry-assessed hearing impairment among workers participating in a medical screening program. Results were stratified by decade of first construction employment: before 1960, 1960-1969, 1970-1979, 1980-1989, and after 1990. Poisson and Cox regression analyses assessed relative risk by decade adjusted for age, sex, smoking, and years of construction trade work. RESULTS: Subjects were 94% male and, on average, 60 years old with 25 years of construction work. When compared to workers employed before 1960, those first employed after 1990 experienced the following reductions in model-adjusted relative risks: chronic obstructive pulmonary disease, 32%; all pneumoconiosis, 68%; parenchymal abnormalities, 35%; pleural abnormalities, 71%; hearing impairment, 20%; and lung cancer mortality, 48%. Risks started to decline in the 1960s with greatest reductions among workers first employed after 1970. CONCLUSIONS: This study demonstrates the positive impact that adoption of occupational health protections have had over the past 60 years. The greatest risk reductions were observed for outcomes with strong regulatory and legal incentives to reduce exposures and associated risks, such as those associated with inhalation hazards (asbestos and silica), while lowest improvement was for hearing impairment, for which little regulatory enforcement and few prevention incentives have been adopted.

Hearing impairment and tinnitus among older construction workers employed at DOE facilities.

BACKGROUND: Few studies have defined the risk of hearing impairment and tinnitus after retirement. This report measures hearing impairment and tinnitus prevalence among older construction trades workers. METHODS: The study cohort included 21,340 participants in a national medical screening program (www.btmed.org). Audiometric hearing impairment was classified according to the Global Burden of Disease Study. Tinnitus was determined by self-report. An internal subcohort of nonconstruction trades workers served as a reference group. Stratified analyses and multivariate analyses were used to measure the prevalence of hearing impairment and tinnitus by age, sex, and job category. RESULTS: Prevalence of any hearing impairment was 55.2% (males, 57.7%; females, 26.8%) and increased rapidly with age. Construction trades workers were 40% more likely to have hearing impairment than the reference group. The overall prevalence of tinnitus was 46.52% and followed patterns similar to hearing impairment. Workers with hearing impairment were more likely to also have tinnitus, but tinnitus was frequently reported in the absence of measured hearing impairment. CONCLUSIONS: Hearing impairment and tinnitus prevalence were much higher in this study than in previous research. A significant reason for the difference is that BTMed follows participants after they have retired. To draw conclusions about the risk for work-related chronic diseases and disorders it is important to monitor workers through their lifetimes. Also, tinnitus by itself should be given greater significance. These findings reinforce the need to promote noise reduction and hearing conservation in construction.

Solid organic-coated ammonium sulfate particles at high relative humidity in the summertime Arctic atmosphere.

SignificancePhysical and chemical properties of individual atmospheric particles determine their climate impacts. Hygroscopic inorganic salt particles mixed with trace amounts of organic material are predicted to be liquid under typical tropospheric conditions in the summertime Arctic. Yet, we unexpectedly observed a significant concentration of solid particles composed of ammonium sulfate with an organic coating under conditions of high relative humidity and low temperature. These particle properties are consistent with marine biogenic-derived new particle formation and growth, with particle collision hypothesized to result in the solid phase. This particle source is predicted to have increasing relevance in the context of declining Arctic sea ice and increasing open water, with impacts on clouds, and therefore climate.

COPD risk among older construction workers-Updated analyses 2020.

BACKGROUND: A 2010 study of construction workers participating in medical screening programs at the Department of Energy (DOE) nuclear facilities demonstrated increased chronic obstructive pulmonary disease (COPD) risk. The current study of a larger worker cohort allowed for a more nuanced analysis of COPD risk, including for employment beginning after the mid-1990s. METHODS: Study participants included 17,941 workers with demographic and smoking data and spirometry with a minimum of three recorded expiratory efforts and reproducibility of forced vital capacity (FVC) and forced expiratory volume in 1 s (FEV1 ) of 0.2 L or less. COPD was defined as a FEV1 /FVC ratio below the lower limit of normal using established prediction equations without use of bronchodilation. Stratified analyses explored COPD prevalence by demographic variables and trade. Logistic regression analyses assessed risks by trade and time periods of trade and DOE site work, controlling for age, gender, race/ethnicity, body mass index, and smoking. RESULTS: Overall COPD prevalence was 13.4% and 67.4% of cases were classified as moderate to severe. Compared to nonconstruction workers, construction trade workers were at significantly increased risk of all COPD (OR = 1.34, 95% CI = 1.29-1.79) and even more so for severe COPD (OR = 1.61, 95% CI = 1.32-1.96). The highest risk trades were cement masons/bricklayers (OR = 2.36; 95% CI = 1.71-3.26) and roofers (OR = 2.22; 95% CI = 1.48-3.32). Risk among workers employed after 1995 was elevated but not statistically significant. CONCLUSIONS: Construction workers are at increased COPD risk. Results support the prevention of both smoking and occupational exposures to reduce these risks. While the number of participants employed after 1995 was small, patterns of risk were consistent with findings in the overall cohort.

Lung cancer mortality among construction workers: implications for early detection.

OBJECTIVES: This study examined predictors of lung cancer mortality, beyond age and smoking, among construction workers employed at US Department of Energy (DOE) sites to better define eligibility for low-dose CT (LDCT) lung cancer screening. METHODS: Predictive models were based on 17 069 workers and 352 lung cancer deaths. Risk factors included age, gender, race/ethnicity, cigarette smoking, years of trade or DOE work, body mass index (BMI), chest X-ray results, spirometry results, respiratory symptoms, beryllium sensitisation and personal history of cancer. Competing risk Cox models were used to obtain HRs and to predict 5-year risks. RESULTS: Factors beyond age and smoking included in the final predictive model were chest X-ray changes, abnormal lung function, chronic obstructive pulmonary disease (COPD), respiratory symptoms, BMI, personal history of cancer and having worked 5 or more years at a DOE site or in construction. Risk-based LDCT eligibility demonstrated improved sensitivity, specificity and positive predictive value compared with current US Preventive Services Task Force guidelines. The risk of lung cancer death from 5 years of work in the construction industry or at a DOE site was comparable with the risk from a personal cancer history, a family history of cancer or a diagnosis of COPD. LDCT eligibility criteria used for DOE construction workers, which includes factors beyond age and smoking, identified 86% of participants who eventually would die from lung cancer compared with 51% based on age and smoking alone. CONCLUSIONS: Results support inclusion of risk from occupational exposures and non-malignant respiratory clinical findings in LDCT clinical guidelines.

Factors driving the seasonal and hourly variability of sea-spray aerosol number in the North Atlantic.

Four North Atlantic Aerosol and Marine Ecosystems Study (NAAMES) field campaigns from winter 2015 through spring 2018 sampled an extensive set of oceanographic and atmospheric parameters during the annual phytoplankton bloom cycle. This unique dataset provides four seasons of open-ocean observations of wind speed, sea surface temperature (SST), seawater particle attenuation at 660 nm (cp,660, a measure of ocean particulate organic carbon), bacterial production rates, and sea-spray aerosol size distributions and number concentrations (NSSA). The NAAMES measurements show moderate to strong correlations (0.56 < R < 0.70) between NSSA and local wind speeds in the marine boundary layer on hourly timescales, but this relationship weakens in the campaign averages that represent each season, in part because of the reduction in range of wind speed by multiday averaging. NSSA correlates weakly with seawater cp,660 (R = 0.36, P << 0.01), but the correlation with cp,660, is improved (R = 0.51, P < 0.05) for periods of low wind speeds. In addition, NAAMES measurements provide observational dependence of SSA mode diameter (dm) on SST, with dm increasing to larger sizes at higher SST (R = 0.60, P << 0.01) on hourly timescales. These results imply that climate models using bimodal SSA parameterizations to wind speed rather than a single SSA mode that varies with SST may overestimate SSA number concentrations (hence cloud condensation nuclei) by a factor of 4 to 7 and may underestimate SSA scattering (hence direct radiative effects) by a factor of 2 to 5, in addition to overpredicting variability in SSA scattering from wind speed by a factor of 5.

Mortality of older construction and craft workers employed at department of energy nuclear sites: Follow-up through 2016.

BACKGROUND: To determine if construction and trades workers employed at U.S. Department of Energy (DOE) nuclear sites facilities are at significant risk for diseases associated with occupational exposures, we compared the mortality experience of participants in the Building Trades National Medical Screening Program (BTMed) to that of the US population. METHODS: The cohort includes 24,086 BTMed participants enrolled between 1998 and 2016 and 5203 deaths. Cause-specific standardized mortality ratios were calculated based on US death rates. RESULTS: Mortality was elevated for all causes, all cancers, cancers of the trachea, bronchus, and lung and lymphatic and hematopoietic system, mesothelioma, chronic obstructive pulmonary disease, asbestosis, transportation injuries, and other injuries, particularly those caused by accidental poisoning, suggesting a possible effect of the opioid epidemic. CONCLUSIONS: Apart from other injuries, mortality patterns were very similar to those reported in the past in this population. Construction workers employed at DOE sites have a significantly increased risk for occupational illnesses. Risks are associated with employment during all time periods covered including possibly after 1990. The cancer risks closely match the cancers identified for DOE compensation from radiation exposures. The high risk of lung cancer supports the value of early lung cancer detection. Continued medical surveillance is important.

Early detection of lung cancer in a population at high risk due to occupation and smoking.

OBJECTIVE: The US National Comprehensive Cancer Network (NCCN) recommends two pathways for eligibility for Early Lung Cancer Detection (ELCD) programmes. Option 2 includes individuals with occupational exposures to lung carcinogens, in combination with a lesser requirement on smoking. Our objective was to determine if this algorithm resulted in a similar prevalence of lung cancer as has been found using smoking risk alone, and if so to present an approach for lung cancer screening in high-risk worker populations. METHODS: We enrolled 1260 former workers meeting NCCN criteria, with modifications to account for occupational exposures in an ELCD programme. RESULTS: At baseline, 1.6% had a lung cancer diagnosed, a rate similar to the National Lung Cancer Screening Trial (NLST). Among NLST participants, 59% were current smokers at the time of baseline scan or had quit smoking fewer than 15 years prior to baseline; all had a minimum of 30 pack-years of smoking. Among our population, only 24.5% were current smokers and 40.1% of our participants had smoked fewer than 30 pack-years; only 43.5% would meet entry criteria for the NLST. The most likely explanation for the high prevalence of screen-detected lung cancers in the face of a reduced risk from smoking is the addition of occupational risk factors for lung cancer. CONCLUSION: Occupational exposures to lung carcinogens should be incorporated into criteria used for ELCD programmes, using the algorithm developed by NCCN or with an individualised risk assessment; current risk assessment tools can be modified to incorporate occupational risk.

Hearing loss among older construction workers: Updated analyses.

BACKGROUND: A prior study of this construction worker population found significant noise-associated hearing loss. This follow-up study included a much larger study population and consideration of additional risk factors. METHODS: Data included audiometry, clinical chemistry, personal history, and work history. Qualitative exposure metrics for noise and solvents were developed. Analyses compared construction workers to an internal reference group with lower exposures and an external worker population with low noise exposure. RESULTS: Among participants (n = 19 127) an overall prevalence of hearing loss of 58% was observed, with significantly increased prevalence across all construction trades. Construction workers had significantly increased risk of hearing loss compared to reference populations, with increasing risk by work duration. Noise exposure, solvent exposure, hypertension, and smoking were significant risk factors in multivariate models. CONCLUSIONS: Results support a causal relationship between construction trades work and hearing loss. Prevention should focus on reducing exposure to noise, solvents, and cigarette smoke.

Substantial Seasonal Contribution of Observed Biogenic Sulfate Particles to Cloud Condensation Nuclei.

Biogenic sources contribute to cloud condensation nuclei (CCN) in the clean marine atmosphere, but few measurements exist to constrain climate model simulations of their importance. The chemical composition of individual atmospheric aerosol particles showed two types of sulfate-containing particles in clean marine air masses in addition to mass-based Estimated Salt particles. Both types of sulfate particles lack combustion tracers and correlate, for some conditions, to atmospheric or seawater dimethyl sulfide (DMS) concentrations, which means their source was largely biogenic. The first type is identified as New Sulfate because their large sulfate mass fraction (63% sulfate) and association with entrainment conditions means they could have formed by nucleation in the free troposphere. The second type is Added Sulfate particles (38% sulfate), because they are preexisting particles onto which additional sulfate condensed. New Sulfate particles accounted for 31% (7 cm-3) and 33% (36 cm-3) CCN at 0.1% supersaturation in late-autumn and late-spring, respectively, whereas sea spray provided 55% (13 cm-3) in late-autumn but only 4% (4 cm-3) in late-spring. Our results show a clear seasonal difference in the marine CCN budget, which illustrates how important phytoplankton-produced DMS emissions are for CCN in the North Atlantic.

Longitudinal decline in lung function among older construction workers.

BACKGROUND: Occupational exposures to vapours, gasses, dusts and fumes (VGDF) and chest X-ray abnormalities by the International Labour Office (ILO) classification system are associated with reduced lung function, with the majority of published studies being cross-sectional. We examined the effects of VGDF exposures, as well as ILO parenchymal changes, pleural plaque and diffuse pleural thickening (DPT) on reduction in lung function in a longitudinal study. METHODS: Chest radiographs and spirometry for 3150 ageing construction workers enrolled in a medical screening programme with a baseline and at least one follow-up examination were studied. Indices for VGDF exposure, parenchymal changes, pleural plaque and DPT severity were developed and used in longitudinal mixed models of lung function. RESULTS: Smoking and VGDF exposure were associated with decreased FEV1 and FVC at baseline as well as accelerated rates of annual decline. High VGDF exposure was associated with a yearly decline of -19.5 mL for FEV1 and -15.7 mL for FVC. Parenchymal abnormalities, pleural plaque and DPT were more strongly associated with reduced FVC. An increase of one unit in the pleural plaque severity index resulted in approximately -5.3 mL loss of FVC and -3.3 mL loss of FEV1, with a possible non-linear effect of plaque on FEV1. CONCLUSIONS: Increasing pleural plaque severity was associated with progressively greater loss of FVC and FEV1, supporting a causal association. VGDF exposures were associated with reduced FVC and FEV1 at baseline as well as accelerated annual loss of lung function.

Impact of Secondary Prevention in an Occupational High-Risk Group.

BACKGROUND: A study of medical outcomes among 6857 elderly construction workers who received an initial and at least one periodic follow-up examination as a result of participating in a medical screening program was undertaken. METHODS: We compared results from the initial examination to follow-up examinations delivered at least 3 years after the initial examination for the following outcomes: body mass index (BMI); total serum cholesterol; nonhigh-density lipoprotein (non-HDL) cholesterol; hemoglobin A1c, hypertension; current cigarette smoking; and 10-year cardiovascular disease (CVD) risk scores. RESULTS: Statistically significant improvements (P < 0.05) were observed for all measures except BMI. CONCLUSIONS: Participation in a periodic medical screening program for elderly construction workers is associated with a favorable impact on common health outcomes. When presented with a program designed for them, blue-collar workers are motivated to seek improvements in their health status.

A case-control study of airways obstruction among construction workers.

BACKGROUND: While smoking is the major cause of chronic obstructive pulmonary disease (COPD), occupational exposures to vapors, gases, dusts, and fumes (VGDF) increase COPD risk. This case-control study estimated the risk of COPD attributable to occupational exposures among construction workers. METHODS: The study population included 834 cases and 1243 controls participating in a national medical screening program for older construction workers between 1997 and 2013. Qualitative exposure indices were developed based on lifetime work and exposure histories. RESULTS: Approximately 18% (95% CI = 2-24%) of COPD risk can be attributed to construction-related exposures, which are additive to the risk contributed by smoking. A measure of all VGDF exposures combined was a strong predictor of COPD risk. CONCLUSIONS: Construction workers are at increased risk of COPD as a result of broad and complex effects of many exposures acting independently or interactively. Control methods should be implemented to prevent worker exposures, and smoking cessation should be promoted.