Understanding the Relationship Between Vocal Function Disorders and Air Pollution Particulate Matter in Central Valley California (original) (raw)
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Indigenous Farmworkers and Vocal Function Disorders
The Central Valley of California is a broad basin between two mountain ranges that captures dust in the fall, fog in the winter, pollen in the spring and chemicals in the summer heat. This environment has been identified as a catch basin for smog and air pollution. Speech-language pathologists practicing in the Central Valley are confronted with complications of allergy and irritation that may impair progress of recovery for their patients. Indigenous farmworkers are a specific population with a higher exposure to damaging particulate matter than any other employed in the region. These indigenous Mexican farmworkers use seven main native language dialects of the Spanish language with at least 23 dialects which have been recorded across the culture (State population data regarding Japanese, Hispanic, Hmong and other cultures revealed more dense populations in the agricultural zones. It is proposed that the diagnoses of vocal function referrals located from within this environment be differentiated and classified so that they may be compared to the air quality scales in the geographic regions represented by medical professional respondents from the Central California's San Joaquin Valley Air Pollution Control District (SJVAPCD). According to the National Center for Farmworker Health (NCFH, 2011), these hometown networks, the highest concentration is in the Central Valley, and according to California Rural Legal Assistance these workers are the least apt to be counted in a census or to apply for healthcare assistance because of the fear of deportation (Simas, J., 2010).
Evidence suggests that airborne transmission of infectious respiratory aerosol plays an important role for the SARS-CoV-2 virus. This work characterized respiratory aerosol emissions from a panel of healthy individuals of varying age and sex while talking and singing in a controlled laboratory setting. Particle number concentrations between 0.25 and 33 μm were measured from 63 participants aged 12−61 years with concurrent monitoring of voice volume and exhaled CO 2 levels. On average, singing produced 77% (95% CI: 42,109%) more aerosol than talking, adults produced 62% (CI: 27,98%) more aerosol than minors, and males produced 34% (CI: 0,70%) more aerosol than females. After accounting for participant voice volume and exhaled CO 2 (both of which were positively correlated with aerosol emissions) in linear models, the age and sex differences were attenuated and no longer statistically significant. These results support further investigation of voice volume and CO 2 as indicators of infection risk indoors.
Comparison of Aerosol Emissions during Specific Speech Tasks
Journal of Voice
The study of aerosols and droplets emitted from the oral cavity has become increasingly important throughout the COVID-19 pandemic. Studies show particulates emitted while speaking were generally much smaller compared to coughing or sneezing. However, recent investigations revealed that they are large enough to carry respiratory contagions. Although studies have shown that particulate emissions do indeed occur during speech, to date, there is little information about the relative contribution of different speech sounds in producing particle emissions. This study compares airborne aerosol generation in participants producing isolated speech sounds: fricative consonants, plosive consonants, and vowel sounds. While participants produced isolated speech tasks, a planar beam of laser light, a high-speed camera, and image software calculated the number of particulates detected overtime. This study compares airborne aerosols emitted by human participants at a distance of 2.54 cm between the laser sheet and the mouth and reveals statistically significant increases in particulate counts over ambient dust distribution for all speech sounds. Vowel sounds were statistically greater than consonants, suggesting that mouth opening, as opposed to place of vocal tract constriction or manner of sound production, might be the primary influence in the degree to which particulates become aerosolized during speech. Results of this research will inform boundary conditions for computation models of aerosolized particulates during speech.
Journal of thoracic disease, 2015
Outdoor air pollution is one of the leading contributors to adverse respiratory health outcomes in urban areas around the world. Children are highly sensitive to the adverse effects of air pollution due to their rapidly growing lungs, incomplete immune and metabolic functions, patterns of ventilation and high levels of outdoor activity. The Children's Health Study (CHS) is a continuing series of longitudinal studies that first began in 1993 and has focused on demonstrating the chronic impacts of air pollution on respiratory illnesses from early childhood through adolescence. A large body of evidence from the CHS has documented that exposures to both regional ambient air and traffic-related pollutants are associated with increased asthma prevalence, new-onset asthma, risk of bronchitis and wheezing, deficits of lung function growth, and airway inflammation. These associations may be modulated by key genes involved in oxidative-nitrosative stress pathways via gene-environment inte...
Characterizing respiratory aerosol emissions during sustained phonation
Journal of Exposure Science & Environmental Epidemiology
To elucidate the role of phonation frequency (i.e., pitch) and intensity of speech on respiratory aerosol emissions during sustained phonations. METHODS: Respiratory aerosol emissions are measured in 40 (24 males and 16 females) healthy, non-trained singers phonating the phoneme /a/ at seven specific frequencies at varying vocal intensity levels. RESULTS: Increasing frequency of phonation was positively correlated with particle production (r = 0.28, p < 0.001). Particle production rate was also positively correlated (r = 0.37, p < 0.001) with the vocal intensity of phonation, confirming previously reported findings. The primary mode (particle diameter~0.6 μm) and width of the particle number size distribution were independent of frequency and vocal intensity. Regression models of the particle production rate using frequency, vocal intensity, and the individual subject as predictor variables only produced goodness of fit of adjusted R 2 = 40% (p < 0.001). Finally, it is proposed that superemitters be defined as statistical outliers, which resulted in the identification of one superemitter in the sample of 40 participants. SIGNIFICANCE: The results suggest there remain unexplored effects (e.g., biomechanical, environmental, behavioral, etc.) that contribute to the high variability in respiratory particle production rates, which ranged from 0.2 particles/s to 142 particles/s across all trials. This is evidenced as well by changes in the distribution of participant particle production that transitions to a more bimodal distribution (second mode at particle diameter~2 μm) at higher frequencies and vocal intensity levels.
Voice Disorders in the General Population: Prevalence, Risk Factors, and Occupational Impact
The Laryngoscope, 2005
Objectives: Epidemiologic studies of the prevalence and risk factors of voice disorders in the general adult population are rare. The purpose of this investigation was to 1) determine the prevalence of voice disorders, 2) identify variables associated with increased risk of voice disorders, and 3) establish the functional impact of voice disorders on the general population. Study Design: Cross-sectional telephone survey. Methods: A random sample (n ؍ 1,326) of adults in Iowa and Utah was interviewed using a questionnaire that addressed three areas related to voice disorders: prevalence, potential risk factors, and occupational consequences/effects. Results: The lifetime prevalence of a voice disorder was 29.9%, with 6.6% of participants reporting a current voice disorder. Stepwise logistic regression identified specific factors that uniquely contributed to increased odds of reporting a chronic voice disorder including sex (women), age (40 -59 years), voice use patterns and demands, esophageal reflux, chemical exposures, and frequent cold/sinus infections. However, tobacco or alcohol use did not independently increase the odds of reporting of a chronic voice disorder. Voice disorders adversely impacted job performance and attendance, with 4.3% of participants indicating that their voice had limited or rendered them unable to do certain tasks in their current job. Furthermore, 7.2% of employed respondents reported that they were absent from work 1 or more days in the past year because of their voice, and 2% reported more than 4 days of voice-related absence. Conclusions: The results of this large epidemiologic study provide valuable information regarding the prevalence of voice disorders, factors that contribute to voice disorder vulnerability, and the functional impact of voice problems on the general population.
Air Pollution and Respiratory Morbidity among Adults in Southern California
American Journal of Epidemiology, 1993
This paper reports trie results of an investigation of the acute effects of air pollution in 321 nonsmoking adults residing in Southern California. Previous eptdemiologic investigations of effects of acute exposure to ozone have focused on groups who may not be representative of the general public, such as asthmatics or student nurses. For this study, participants recorded the daily incidence of several respiratory symptoms over a 6-month period between 1978 and 1979. The authors examined the impact of ambient concentrations of ozone, paniculate sulfates, and other air pollutants on the incidence of respiratory morbidity, measured as either upper or lower respiratory tract symptoms. Using a logistic regression model, the authors found a significant association between the incidence of lower respiratory tract symptoms and 1-hour daily maximum ozone levels (odds ratio (OR) = 1.22, 95% confidence interval (Cl) 1.11-1.34, for a 10 parts per hundred million (pphm) change), 7-hour average ozone levels (OR = 1.32, 95% Cl 1.14-1.52), and ambient sulfates (OR = 1.30, 95% Cl 1.09-1.54, for a ^0-ng| m 3 change), but no association was found with coefficient of haze, a more general measure of particulates. The existence of a gas stove in the home was also associated with lower respiratory tract symptoms (OR = 1.23, 95% Cl 1.03-1.47). The effects of ozone were greater in the subpopulation without a residential air conditioner. In addition, ozone appears to have had a greater effect among individuals with a preexisting respiratory infection.
Journal of Voice, 2005
Calcium carbonate (CaCO 3) particles, the main component of chalk, are an important pollutant in the Brazilian school environment. However, there are few reports of the effect of this pollutant in the vocal folds and its influence in voice disorder in the literature. Methods: Thirty rats (Wistar), randomly divided into two groups, the control group and the experimental group, were submitted to air or to CaCO 3 inhalation, respectively, during 15, 30, and 90 days. Then, the larynx region was dissected and embedded in paraffin, and 5-µm sections were obtained for microscopic analysis. Results: No histopathological alteration was found on the vocal folds in the control group. In the experimental group, a moderate chronic inflammatory infiltrate, characterized by macrophage cells, was found in the vocal folds after 30 and 90 days of the CaCO 3 inhalation. Conclusions: This study suggests that the inhalation of pollutant particles, such as CaCO 3 , induces inflammatory alterations in the larynx; this can affect the vibration of the vocal folds, which influence vocal function.
CHEST Journal, 2006
To determine whether increased exposure to particulate matter air pollution (PM), measured with personal, residential, or central site monitoring, was associated with pulmonary function decrements in either adults with COPD or children with asthma. Participants: We studied 57 adults with or without COPD and 17 children aged 6 to 13 years with physician-diagnosed asthma in Seattle during a 3-year panel study. Study design and measurements: Indoor and outdoor PM measurements were made at subjects' homes. The subjects wore personal exposure monitors for 10 consecutive 24-h periods, and PM was also measured at a central outdoor location. We assessed the within-subject effect of particulate exposure on FEV 1 and peak expiratory flow (PEF) in adults, and maximal midexpiratory flow (MMEF), PEF, FEV 1 , and symptoms in children. Results: FEV 1 decrements were associated with 1-day lagged central site PM < 2.5 m in diameter (PM 2.5) in adult subjects with COPD. In children not receiving antiinflammatory medication, same day indoor, outdoor, and central site exposures to PM 2.5 were associated with decrements in MMEF, PEF, and FEV 1. Associations with PM 2.5 and lung function decrements were also observed for 1-day lagged indoor (MMEF, PEF, FEV 1) and personal (PEF only) exposures. Antiinflammatory medication use in children significantly attenuated the PM effect on airflow rates and volumes. Conclusions: This study found consistent decrements in MMEF in children with asthma who were not receiving medications. It is notable that effects were observed even though PM exposures were low for an urban area. These findings suggest the need for future larger studies of PM effects in this susceptible population that repeatedly measure spirometry to include MMEF and potentially more sensitive markers of airway inflammation such as exhaled breath condensate and exhaled nitric oxide.