Biomedical subjects

Kiyoung Lee

Publications and source records attributed to Kiyoung Lee.

10 recordsLinked to original sources

PubMed2006

Secondhand smoke and indoor public spaces in Paducah, Kentucky.

INTRODUCTION: Secondhand smoke (SHS) is the third leading cause of preventable death in the United States. It is responsible for an estimated 3,000 lung cancer deaths annually in never-smokers in the US. It also accounts for over 35,000 deaths annually from coronary heart disease in never-smokers. It increases the number and severity of asthmatic attacks in over 300,000 asthmatic children each year, and is associated with Sudden Infant Death Syndrome and middle ear infections, in addition to other illnesses in children. The purpose of this study was to examine indoor air quality in a sample of hospitality venues in Paducah, Kentucky. The relation between indoor air pollution and the presence of on premises smoking was assessed. METHODS: A Personal Aerosol Monitor was used to sample and record the levels of respirable suspended particles in the air. The SidePak uses a built-in sampling pump that draws air through the device and the particulate matter in the air scatters the light from a laser. Based on this light scattering, the device determines to assess the real-time concentration of particles smaller than 2.5 microm in micrograms per cubic meter, or PM2.5. RESULTS: The average PM2.5 concentration in the eleven locations sampled in Paducah, Kentucky, was 177 microg/m3. The average fine particle pollution level in the non-smoking sections tested was 87 microg/m3, which is 29 times higher than the average fine particle pollution level in smoke-free air or 6 times higher than outdoor air in Paducah. The average PM2.5 level across all nine smoking-permitted hospitality locations sampled in Paducah was 200 microg/m3. For a full-time employee in the venues sampled in this study, the average annual PM2.5 exposure would be 46 microg/m3 (assuming exposure to 200 microg/m3 on the job, exposure to zero particles off the job, and a 40-hour work week). The EPA average annual PM2.5 limit is exceeded by 3.1 times due solely to occupational exposure. Of the ten locations visited that permit indoor smoking, the air monitoring was done in the non-smoking section of six of them. These locations included five restaurants and one public government office. The average fine particle pollution level in these non-smoking sections was 87 microg/m3, which is 29 times higher than the average fine particle pollution level in smoke-free air or 6 times higher than outdoor air in Paducah. It is also interesting to note that the average fine particle pollution level in the smoking section of one restaurant was actually less than the average fine particle pollution level in the "no smoking" section of two other restaurants. CONCLUSIONS: The effects of secondhand smoke are substantial and rapid, explaining the relatively large health risks associated with secondhand smoke exposure that have been reported in epidemiological studies. This study shows that physically separating smokers and non-smokers is not an effective way to protect non-smoking patrons from tobacco smoke pollution. "No smoking" sections provided protection to nonsmokers that can be characterized as trivial at best. In fact, patrons in Paducah cannot be certain that their exposure will not be higher in the "no smoking" sections of certain venues when compared to the smoking sections of other venues. It is imperative that physicians and other healthcare providers actively and aggressively lobby local policymakers to pass regulatory and/or public health ordinances, which have been demonstrated to be effective in controlling exposure to secondhand smoke.

Air Pollutants↗

PubMed2005

Occupational hand-arm vibration syndrome in Korea.

OBJECTIVES: It is suspected that there is a large number of patients suffering from hand-arm vibration syndrome (HAVS) in Korea. However, no cases have been reported since 1992. This study was conducted to identify HAVS cases and determine the characteristics of the syndrome. METHODS: In April 2001, the Busan, Ulsan, and Gyeong-Nam Province Occupational Disease Surveillance System (BUGODSS) was established to identify work-related HAVS and other occupational diseases. In the 2 years of this project, occupational physicians from five hospitals in these provinces collected information by way of interviews and questionnaires during mandatory occupational medical examinations. Among the initial 189 suspected HAVS cases, 58 volunteers were given cold-water provocation tests in order to diagnose the vascular component of the disorder. RESULTS: One hundred fifty-four approximately occupational HAVS cases were identified from ca. 21,000 workers. One hundred fifty about of these cases were male. The cases were most often found in workers from the shipbuilding industry, and the grinder was the most common source of vibration exposure. Cases of sensorineural disorder (SD) were more common than cases of vascular disorder (VD). The mean values of the finger skin temperature and its recovery rate at 5 min and 10 min after cold-water provocation were significantly lower in the group with the VD than in the group with the SD. CONCLUSIONS: We identified 154 occupational HAVS cases, although no cases have been reported during the occupational medical examinations mandated by the state. The majority of the cases were in workers that used grinders in the shipbuilding industry. We determined that peripheral VD and peripheral SD can progress independently of each other. We conclude that exposure to hand-transmitted vibration (HTV) and HAVS cases are common in shipbuilding industry in Korea. The recovery rate of finger skin temperature after cold-water provocation is one of the useful methods for diagnosing the vascular component of HAVS.

Adult↗

PubMed2005

Absence of respiratory inflammatory reaction of elemental sulfur using the California Pesticide Illness Database and a mouse model.

Elemental sulfur, a natural substance, is used as a fungicide. Elemental sulfur is the most heavily used agricultural chemical in California. In 2003, annual sulfur usage in California was about 34% of the total weight of pesticide active ingredient used in production agriculture. Even though sulfur is mostly used in dust form, the respiratory health effects of elemental sulfur are not well documented. The purpose of this paper is to address the possible respiratory effect of elemental sulfur using the California Pesticide Illness Database and laboratory experiments with mice. We analyzed the California Pesticide Illness Database between 1991 and 2001. Among 127 reports of definite, probable, and possible illness involving sulfur, 21 cases (16%) were identified as respiratory related. A mouse model was used to examine whether there was an inflammatory or fibrotic response to elemental sulfur. Dust solutions were injected intratracheally into ovalbumin sensitized mice and lung damage was evaluated. Lung inflammatory response was analyzed via total lavage cell counts and differentials, and airway collagen content was analyzed histologically and biochemically. No significant differences from controls were seen in animals exposed to sulfur particles. The findings suggest that acute exposure of elemental sulfur itself may not cause an inflammatory reaction. However, further studies are needed to understand the possible health effects of chronic sulfur exposure and environmental weathering of sulfur dust.

Agricultural Workers' Diseases↗

PubMed2004

Pulmonary function and exercise-associated changes with chronic low-level paraquat exposure.

The present study was undertaken to test the hypothesis that chronic, low-level paraquat exposure causes restrictive lung function with gas transfer impairment. Three hundred thirty-eight Costa Rican farm workers from banana, coffee, and palm oil farms completed a questionnaire, spirometry, and a test of single-breath carbon monoxide diffusing capacity. Subjects 40 years of age or older, without other medical risk factors, completed maximal cardiopulmonary exercise tests. Most (66.6%) were paraquat handlers; 24.8% of handlers and 27.3% of nonhandlers reported current cigarette smoking. In linear regression models, cumulative paraquat exposure was not an independent predictor of VA, carbon monoxide diffusing capacity, peak oxygen uptake, FVC, or oxygen pulse peak. However, the ventilatory equivalent for CO(2), although within normal range, was significantly higher with increased cumulative paraquat exposure. Oxygen desaturation greater than 5% from rest to peak exercise had an odds ratio of 1.7 (95% confidence interval = 0.9-3.0) with the cumulative paraquat exposure index in models adjusted for age, weight, and smoking status. The association of paraquat exposure with ventilatory equivalent and oxygen desaturation suggests that paraquat may be associated with subclinical gas exchange abnormalities, but overall these findings are consistent with no clinically significant increases in interstitial thickening or restrictive lung disease among this population.

Adolescent↗

PubMed2004

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

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

Air Pollutants↗

PubMed2004

Outdoor/Indoor/Personal ozone exposures of children in Nashville, Tennessee.

An ozone (O3) exposure study was conducted in Nashville, TN, using passive O3 samplers to measure six weekly outdoor, indoor, and personal O3 exposure estimates for a group of 10- to 12-yr-old elementary school children. Thirty-six children from two Nashville area communities (Inglewood and Hendersonville) participated in the O3 sampling program, and 99 children provided additional time-activity information by telephone interview. By design, this study coincided with the 1994 Nashville/Middle Tennessee Ozone Study conducted by the Southern Oxidants Study, which provided enhanced continuous ambient O3 monitoring across the Nashville area. Passive sampling estimated weekly average outdoor O3 concentrations from 0.011 to 0.O30 ppm in the urban Inglewood community and from 0.015 to 0.042 ppm in suburban Hendersonville. The maximum 1- and 8-hr ambient concentrations encountered at the Hendersonville continuous monitor exceeded the levels of the 1- and 8-hr metrics for the O3 National Ambient Air Quality Standard. Weekly average personal O3 exposures ranged from 0.0013 to 0.0064 ppm (7-31% of outdoor levels). Personal O3 exposures reflected the proportional amount of time spent in indoor and outdoor environments. Air-conditioned homes displayed very low indoor O3 concentrations, and homes using open windows and fans for ventilation displayed much higher concentrations.

Air Pollutants↗

PubMed2004

Respiratory protection against Mycobacterium tuberculosis: quantitative fit test outcomes for five type N95 filtering-facepiece respirators.

In preparing to fit test a large workforce, a respirator program manager needs to initially choose respirators that will fit the greatest proportion of employees and achieve the best fits. This article discusses our strategy in selecting respirators from an initial array of seven NIOSH-certified Type N95 filtering-facepiece devices for a respiratory protection program against Mycobacterium tuberculosis (M. tb) aerosol. The seven respirators were screened based on manufacturer-provided fit test data, comfort, and cost. From these 7 devices, 5 were chosen for quantitative fit testing on 40 subjects who were a convenience sample from a cohort of approximately 30,000 workers scheduled to undergo fit testing. Across the five brands, medium/regular-size respirators fit from 8% to 95% of the subjects; providing another size of the same brand improved the pass rates slightly. Gender was not found to significantly affect fit test pass rates for any respirator brand. Among test panel members, an Aearo Corporation respirator (TC 84A-2630) and a 3M Company respirator (TC 84A-0006) provided the highest overall pass rates of 98% and 90%, respectively. We selected these two brands for fit testing in the larger worker cohort. To date, these two respirators have provided overall pass rates of 98% (1793/1830) and 88% (50/57), respectively, which are similar to the test panel results. Among 1850 individuals who have been fit tested, 1843 (99.6%) have been successfully fitted with one or the other brand. In a separate analysis, we used the test panel pass rates to estimate the reduction in M. tb infection risk afforded by the medium/regular-size of five filtering-facepiece respirators. We posed a low-exposure versus a high-exposure scenario for health care workers and assumed that respirators could be assigned without conducting fit testing, as proposed by many hospital infection control practitioners. Among those who would pass versus fail the fit test, we assumed an average respirator penetration (primarily due to faceseal leakage) of .04 and 0.3, respectively. The respirator with the highest overall pass rate (95%) reduced M. tb infection risk by 95%, while the respirator with the lowest pass rate (8%) reduced M. tb infection risk by only 70%. To promote the marketing of respirators that will successfully fit the highest proportion of wearers, and to increase protection for workers who might use respirators without the benefit of being fit tested, we recommend that fit testing be part of the NIOSH certification process for negative-pressure air-purifying respirators with tightly fitting facepieces. At a minimum, we recommend that respirator manufacturers generate and provide pass rate data to assist in selecting candidate respirators. In any event, program managers can initially select candidate respirators by comparing quantitative fit tests for a representative sample of their employee population.

Adult↗

PubMed2004

Personal exposures to inorganic and organic dust in manual harvest of California citrus and table grapes.

The aim of this study was to determine characteristics of personal exposure to inorganic and organic dust during manual harvest operations of California citrus and table grapes. Personal exposures to inhalable dust and respirable dust were measured five times over a 4-month period of harvesting season. We analyzed components of the dust samples for mineralogy, respirable quartz, endotoxin, and total and culturable microorganisms. Workers manually harvesting were exposed to a complex mixture of inorganic and organic dust. Exposures for citrus harvest had geometric means of 39.7 mg/m(3) for inhalable dust and 1.14 mg/m(3) for respirable dust. These exposures were significantly higher than those for table grape operations and exceeded the threshold limit value for inhalable dust and respirable quartz. Exposures for table grape operations were lower than the threshold limit value, except inhalable dust exposure during leaf pulling. Considered independently, exposures to inhalable dust and respirable quartz in citrus harvest may be high enough to cause respiratory health effects. The degree of vigorous contact with foliage appeared to be a significant determining factor of exposures in manual harvesting.

Adult↗

PubMed2002

Nitrous acid, nitrogen dioxide, and ozone concentrations in residential environments.

Nitrous acid (HONO) may be generated by heterogeneous reactions of nitrogen dioxide and direct emission from combustion sources. Interactions among nitrogen oxides and ozone are important for outdoor photochemical reactions. However, little is known of indoor HONO levels or the relationship between residential HONO, NO(2), and O(3) concentrations in occupied houses. Six-day integrated indoor and outdoor concentrations of the three pollutants were simultaneously measured in two communities in Southern California using passive samplers. The average indoor HONO concentration was 4.6 ppb, compared to 0.9 ppb for outdoor HONO. Average indoor and outdoor NO(2)concentrations were 28 and 20.1 ppb, respectively. Indoor O(3) concentrations were low (average 14.9 ppb) in comparison to the outdoor levels (average 56.5 ppb). Housing characteristics, including community and presence of a gas range, were significantly associated with indoor NO(2) and HONO concentrations. Indoor HONO levels were closely correlated with indoor NO(2) levels and were about 17% of indoor NO(2) concentrations. Indoor HONO levels were inversely correlated with indoor O(3) levels. The measurements demonstrated the occurrence of substantial residential indoor HONO concentrations and associations among the three indoor air pollutants.

Air Pollution, Indoor↗

PubMedDate not supplied

Identification of agricultural tasks important to cumulative exposures to inhalable and respirable dust in California.

Little data exists on the determinants of agricultural dust exposure, particularly in dry climates. Annual exposure indices to inhalable and respirable dust were constructed by exposure estimates for specific tasks, task duration, and task frequency. The estimates of exposure levels were based on actual field measurements and subjective dust exposure ranking. The task duration and frequency data were obtained by questionnaire from 546 farm operators in California. Annual exposure indices were analyzed to determine which tasks were major contributors to chronic dust exposure. The important tasks were identified by comparisons of the cumulative distribution of exposures for all tasks and the cumulative distribution of exposures with one task deleted. Thirteen and 11 tasks were identified to be important to both inhalable and respirable dust exposures, respectively. Tasks identified to be important to agricultural exposure may be ascribed to exposure duration more than to exposure intensity. Information on task-specific exposure is important for developing control strategies in the agricultural workplace.

Adult↗