Characterization of occupational smoke exposure among wildland firefighters in the midwestern United States.

Wildland firefighters are repeatedly exposed to elevated levels of wildland fire smoke (WFS) while protecting lives and properties from wildland fires. Studies reporting personal exposure concentrations of air pollutants in WFS during fire suppression or prescribed burn activities have been geographically limited to the western and southeastern United States. The objective of this study is to characterize exposure concentrations of air pollutants in WFS emissions among wildland firefighters who conducted prescribed burns in the Midwest. Between 2016 and 2019, a total of 35 firefighters (31 males and 4 females, age of 35.63 ± 9.31 years) were recruited to participate in this study. Personal particulate matter 2.5 (PM2.5) and carbon monoxide (CO) exposure concentrations were measured during prescribed burns. The level of black carbon (BC) in WFS particulates was determined using the light transmission technique, while trace metal composition was analyzed using inductively coupled plasma mass spectrometry (ICP-MS). The results showed geometric means for PM2.5, CO, and BC concentrations were 1.43 ± 0.13 mg/m3, 7.02 ± 0.69 ppm, and 58.79 ± 5.46 µg/m3, respectively. Although no occupational exposure limits (OELs) were exceeded by 8-h time-weighted average (TWA) exposure concentration observed in the firefighters, a total of 28 personal CO exposure concentrations were above the National Institute for Occupational Safety and Health (NIOSH) Recommended Exposure Limit (REL) Ceiling (200 ppm) for CO. PM2.5 and CO concentrations were about 2-7 times higher in the Midwest than the other regions. Firefighters who performed holding had higher CO exposure concentrations compared to firefighters who performed lighting (p < 0.01), while lighters were exposed to higher level of BC in the smoke particulates (p < 0.01), possibly due to the domination of exposure by different combustion sources and stages. The levels of trace metals in WFS particulates were well below the corresponding OELs and no task-related difference was observed except for manganese. Our results suggest that wildland firefighters in the midwestern region have higher WFS exposures while working at prescribed burns compared to those western and southeastern United States.

Urinary mutagenicity and oxidative status of wildland firefighters working at prescribed burns in a Midwestern US forest.

OBJECTIVE: Wildland firefighters (WLFFs) experience repeated exposures to wildland fire smoke (WFS). However, studies about WLFFs remain regionally limited. The objective of this study was to assess the effect of WFS exposure on urinary mutagenicity and cell oxidation among WLFFs who work at prescribed burns in the Midwestern USA. METHODS: A total of 120 spot urine samples was collected from 19 firefighters right before (pre-shift), immediately after (post-shift), and the morning (next-morning) following work shifts on prescribed burn days (burn days) and regular workdays (non-burn days). The levels of urinary mutagenicity, 8-isoprostane, malondialdehyde and oxidised guanine species (Ox-GS) were measured. Linear mixed-effect models were used to determine the difference of cross-shift changes in the concentrations of urinary biomarkers. RESULTS: Post-shift levels of creatinine-corrected urinary mutagenicity and 8-isoprostane were non-significantly higher than pre-shift levels (1.16× and 1.64×; p=0.09 and 0.07) on burn days. Creatinine-corrected Ox-GS levels increased significantly in next-morning samples following WFS exposure (1.62×, p=0.03). A significant difference in cross-shift changes between burn and non-burn days was observed in 8-isoprostane (2.64×, p=0.03) and Ox-GS (3.00×, p=0.02). WLFFs who contained the fire (performed holding tasks) had a higher pre-morning to next-morning change in urinary mutagenicity compared with those who were lighting fires during the prescribed burns (1.56×, p=0.03). CONCLUSIONS: Compared with the other regions, WLFFs who worked in Midwestern forests had an elevated urinary mutagenicity and systemic oxidative changes associated with WFS exposure at prescribed burns.

Urinary mutagenicity and other biomarkers of occupational smoke exposure of wildland firefighters and oxidative stress.

Background: Wildland firefighters conducting prescribed burns are exposed to a complex mixture of pollutants, requiring an integrated measure of exposure. Objective: We used urinary mutagenicity to assess if systemic exposure to mutagens is higher in firefighters after working at prescribed burns versus after non-burn work days. Other biomarkers of exposure and oxidative stress markers were also measured. Methods: Using a repeated measures study design, we collected urine before, immediately after, and the morning after a work shift on prescribed burn and non-burn work days from 12 healthy subjects, and analyzed for malondialdehyde (MDA), 8-isoprostane, 1-hydroxypyrene (OH-pyrene), and mutagenicity in Salmonella YG1041 +S9. Particulate matter (PM2.5) and carbon monoxide (CO) were measured by personal monitoring. Light-absorbing carbon (LAC) of PM2.5 was measured as a surrogate for black carbon exposure. Linear mixed-effect models were used to assess cross-work shift changes in urinary biomarkers. Results: No significant differences occurred in creatinine-adjusted urinary mutagenicity across the work shift between burn days and non-burn days. Firefighters lighting fires had a non-significant, 1.6-fold increase in urinary mutagenicity for burn versus non-burn day exposures. Positive associations were found between cross-work shift changes in creatinine-adjusted urinary mutagenicity and MDA (p = 0.0010), OH-pyrene (p = 0.0001), and mass absorption efficiency which is the LAC/PM2.5 ratio (p = 0.2245), respectively. No significant effect of day type or work task on cross-work shift changes in MDA or 8-isoprostane was observed. Conclusion: Urinary mutagenicity may serve as a suitable measure of occupational smoke exposures among wildland firefighters, especially among those lighting fires for prescribed burns.

Review of the health effects of wildland fire smoke on wildland firefighters and the public.

Each year, the general public and wildland firefighters in the US are exposed to smoke from wildland fires. As part of an effort to characterize health risks of breathing this smoke, a review of the literature was conducted using five major databases, including PubMed and MEDLINE Web of Knowledge, to identify smoke components that present the highest hazard potential, the mechanisms of toxicity, review epidemiological studies for health effects and identify the current gap in knowledge on the health impacts of wildland fire smoke exposure. Respiratory events measured in time series studies as incidences of disease-caused mortality, hospital admissions, emergency room visits and symptoms in asthma and chronic obstructive pulmonary disease patients are the health effects that are most commonly associated with community level exposure to wildland fire smoke. A few recent studies have also determined associations between acute wildland fire smoke exposure and cardiovascular health end-points. These cardiopulmonary effects were mostly observed in association with ambient air concentrations of fine particulate matter (PM2.5). However, research on the health effects of this mixture is currently limited. The health effects of acute exposures beyond susceptible populations and the effects of chronic exposures experienced by the wildland firefighter are largely unknown. Longitudinal studies of wildland firefighters during and/or after the firefighting career could help elucidate some of the unknown health impacts of cumulative exposure to wildland fire smoke, establish occupational exposure limits and help determine the types of exposure controls that may be applicable to the occupation.

Household air pollution: a call for studies into biomarkers of exposure and predictors of respiratory disease.

Household air pollution (HAP) from indoor burning of biomass or coal is a leading global cause of morbidity and mortality, mostly due to its association with acute respiratory infection in children and chronic respiratory and cardiovascular diseases in adults. Interventions that have significantly reduced exposure to HAP improve health outcomes and may reduce mortality. However, we lack robust, specific, and field-ready biomarkers to identify populations at greatest risk and to monitor the effectiveness of interventions. New scientific approaches are urgently needed to develop biomarkers of human exposure that accurately reflect exposure or effect. In this Perspective, we describe the global need for such biomarkers, the aims of biomarker development, and the state of development of tests that have the potential for rapid transition from laboratory bench to field use.

Changes in the concentrations of biochemical indicators of diet and nutritional status of pregnant women across pregnancy trimesters in Trujillo, Peru, 2004-2005.

BACKGROUND: In developing countries, deficiencies in essential micronutrients are common, particularly in pregnant women. Although, biochemical indicators of diet and nutrition are useful to assess nutritional status, few studies have examined such indicators throughout pregnancy in women in developing countries. METHODS: The primary objective of this study was to assess the nutritional status of 78 Peruvian women throughout pregnancy for 16 different nutritional indicators including fat-soluble vitamins and carotenoids, iron-status indicators, and selenium. Venous blood samples from which serum was prepared were collected during trimesters one (n = 78), two (n = 65), three (n = 62), and at term via the umbilical cord (n = 52). Questionnaires were completed to determine the demographic characteristics of subjects. Linear mixed effects models were used to study the associations between each maternal indicator and the demographic characteristics. RESULTS: None of the women were vitamin A and E deficient at any stage of pregnancy and only 1/62 women (1.6%) was selenium deficient during the third trimester. However, 6.4%, 44% and 64% of women had ferritin levels indicative of iron deficiency during the first, second and third trimester, respectively. Statistically significant changes (p ≤ 0.05) throughout pregnancy were noted for 15/16 nutritional indicators for this Peruvian cohort, with little-to-no association with demographic characteristics. Three carotenoids (beta-carotene, beta-cryptoxanthin and trans-lycopene) were significantly associated with education status, while trans-lycopene was associated with age and beta-cryptoxanthin with SES (p < 0.05). Concentrations of retinol, tocopherol, beta-cryptoxanthin, lutein + zeaxanthin and selenium were lower in cord serum compared with maternal serum (p < 0.05). Conversely, levels of iron status indicators (ferritin, transferrin saturation and iron) were higher in cord serum (p < 0.05). CONCLUSION: The increasing prevalence of iron deficiency throughout pregnancy in these Peruvian women was expected. It was surprising though not to find deficiencies in other nutrients. The results highlight the importance of continual monitoring of women throughout pregnancy for iron deficiency which could be caused by increasing fetal needs and/or inadequate iron intake as pregnancy progresses.

Exposure of wildland firefighters to carbon monoxide, fine particles, and levoglucosan.

Wildland firefighters are occupationally exposed to elevated levels of woodsmoke. Eighteen wildland firefighters were monitored for their personal exposure to particulate matter with median aerodynamic diameter of 2.5 microns (PM2.5), levoglucosan (LG), and carbon monoxide (CO) at 30 prescribed burns at the Savannah River Site, South Carolina. Linear mixed effect models were used to investigate the effect on exposure of various factors and to examine whether the firefighters were able to qualitatively estimate their own exposures. Exposure to PM2.5 and CO was higher when firefighters performed 'holding' tasks compared with 'lighting' duties, whereas exposures to CO and LG were higher when burns were in compartments with predominantly pine vegetation (P < 0.05). Exposures to PM2.5 (64-2068 µg m(-3)) and CO (0.02-8.2 p.p.m.) fell within the ranges observed in previous studies. Some recommended shorter term exposure limits for CO were exceeded in a few instances. The very low LG:PM2.5 ratios in some samples suggest that the exposures of wildland firefighters to pollutants at prescribed burns may be substantially impacted by non-woodsmoke sources. The association of the qualitative exposure estimation of the firefighters with actual PM2.5 and CO measurements (P < 0.01) indicates that qualitative estimation may be used to assess exposure in epidemiology studies.

Urinary levoglucosan as a biomarker for woodsmoke exposure in wildland firefighters.

BACKGROUND: Levoglucosan, a sugar anhydride and a combustion breakdown product of cellulose is a dominant organic constituent of particles in woodsmoke. After exposure, levoglucosan is excreted unmetabolized in urine. OBJECTIVE: Urinary levoglucosan was assessed as a biomarker of occupational woodsmoke exposure among wildland firefighters. METHODS: Urine samples were collected from wildland firefighters before and after their work-shifts on days when they worked at prescribed burns. A total of 97 pairs of pre- and post-shift urine samples were collected from 19 firefighters over 10 prescribed burn shifts. The urine samples were analyzed to determine whether there was an increase in the concentration of levoglucosan from pre- to post-shift after the firefighters had worked at the prescribed burns. RESULTS: Overall, there was an increase in both the urinary volume-based and creatinine corrected levoglucosan concentrations from pre- to post-shift (P < 0.05). However, the direction of change in the concentrations was not consistent. There were increases in urinary levoglucosan concentration from pre- to post-shift in 63% of the person-day samples, and in only 58% of the person-day samples for the creatinine corrected concentrations. CONCLUSION: Although there was an overall increase in urinary concentrations of levoglucosan, results suggest that other sources apart from woodsmoke affected the urinary levels of this biomarker in wildland firefighters. Therefore, urinary levoglucosan may not be effective as a biomarker of woodsmoke exposure in this setting.

Using exhaled carbon monoxide and carboxyhemoglobin to evaluate the effectiveness of a chimney stove model in Peru.

BACKGROUND: Measurement of biological indicators of physiological change may be useful in evaluating the effectiveness of stove models, which are intended to reduce indoor smoke exposure and potential health effects. OBJECTIVES: We examined changes in exhaled carbon monoxide (CO), percentage carboxy-hemoglobin, and total hemoglobin in response to the installation of a chimney stove model by the Juntos National Program in Huayatan, Peru in 2008. METHODS: Biomarkers were measured in a convenience sample comprising 35 women who met requirements for participation, and were measured before and three weeks after installation of a chimney stove. The relationships between exposure to indoor smoke and biomarker measurements were also analyzed using simple linear regression models. RESULTS: Exhaled CO reduced from 6.71 ppm (95% CI 5.84-7.71) to 3.14 ppm (95% CI 2.77-3.66) three weeks after stove installation (P < 0.001) while % COHb reduced from 1.76% (95% CI 1.62-1.91) to 1.18% (95% CI 1.12-1.25; P < 0.001). Changes in exhaled CO and % COHb from pre- to post-chimney stove installation were not correlated with corresponding changes in exposure to CO and PM2.5 even though the exposures also reduced after stove installation. CONCLUSION: Exhaled CO and % COHb both showed improvement with reduction in concentration after the installation of the chimney cook stoves, indicating a positive physiological response subsequent to the intervention.

Inflammatory effects of woodsmoke exposure among wildland firefighters working at prescribed burns at the Savannah River Site, SC.

Wildland firefighters in the United States are occupationally exposed to high levels of woodsmoke. Results from experimental studies show that exposure to woodsmoke induces inflammation. A study was conducted to investigate the effect of occupational woodsmoke exposure on inflammatory biomarkers in firefighters working at prescribed burns. Twelve U.S. Forest Service wildland firefighters at the Savannah River Site, South Carolina, volunteered to give blood samples during four prescribed burns between February and March 2011. Twenty-four paired (pre- and post-work shift) blood samples were collected using dried blood spot method to facilitate repeated sample collection. Inflammatory biomarker concentrations in blood samples were measured using the Meso Scale Discovery multi-spot assay system. Concurrent personal PM2.5 and CO monitoring of firefighters was conducted. Linear mixed models were used to test whether cross-work shift differences occurred in the following inflammatory biomarkers: IL-1ß, IL-8, CRP, SAA, ICAM-1, and VCAM-1. IL-8 showed a significant cross-work shift difference as indicated by a post/pre-work shift ratio of 1.70 (95% CL: 1.35, 2.13; p = 0.0012). Concentrations of IL-8, CRP, and ICAM-1 increased in >50% of samples across work shift. Firefighters who lighted fires as opposed to other work tasks had the largest cross-work shift increase in IL-8. A significant cross-work shift increase in IL-8 in blood samples was observed in healthy wildland firefighters working at prescribed burns. Further research is needed to understand the physiological responses underlying the adverse effects of woodsmoke exposure, and the dose-response relationship between woodsmoke exposure and inflammatory responses.

Personal exposure to PM(2.5) and urinary hydroxy-PAH levels in bus drivers exposed to traffic exhaust, in Trujillo, Peru.

Public transport vehicle drivers, especially in highly polluted or trafficked areas, are exposed to high levels of air pollutants. In this study, we assessed the influence of traffic on levels of hydroxy polycyclic aromatic hydrocarbons (OH-PAHs) in commercial bus drivers in Trujillo, Peru, by measuring the within-shift changes in the urinary whole weight and creatinine-corrected concentrations of the PAH metabolites. We measured personal PM(2.5) as a proxy of exposure to traffic emission. Urine samples were collected daily from two bus drivers and three minivan drivers in Trujillo, pre-, mid-, post-work shift and on days when the drivers were off work (total n = 144). Ten OH-PAH metabolites were measured in the urine samples. Drivers were also monitored for exposure to PM(2.5) (n = 41). Daily work shift (mean = 13.1 ± 1.3 hr) integrated PM(2.5) was measured in the breathing zones of the drivers for an average of 10.5 days per driver. The differences across shift in OH-PAH concentrations were not statistically significant except for urinary 2-hydroxyfluorene (2-FLU) (p = 0.04) and 4-hydroxyphenanthrene (4-PHE) (p = 0.01) and creatinine-corrected 4-hydroxyphenanthrene (p = 0.01). Correlation between pairs of hydroxy-PAHs (ρ = 0.50 to 0.93) were highest for mid-shift samples. Concentrations of PM(2.5) (geometric mean = 64 µg/m(3); 95% confidence limits = 52 µg/m(3), 78 µg/m(3)) is similar to those measured in many other studies of traffic exposure. There was significant change across work shift for concentrations of only two of the OH-PAHs (2-FLU and 4-PHE). Results indicate that the drivers may have had limited time for clearance of PAH exposure from the body between work shifts. Comparisons of the concentrations of creatinine-corrected hydroxy-PAH to those reported in other studies indicate that exposure of public transport drivers to PAH could be similar. By following the subjects over multiple days, this study gives an indication of appropriate exposure situations for the use of hydroxy-PAHs and will be beneficial in designing future occupational studies of PAH exposure.

Dietary Behavior and Diet Interventions among Structural Firefighters: A Narrative Review.

Structural firefighters (SFFs) are exposed to multiple occupational hazards that affect dietary behavior and can contribute to increased risks of cancer and cardiovascular disease compared to the United States' general population. Dietary behavior is a feasible modification for positive health outcomes. The objectives of this narrative review are to summarize the diet behavior of SFFs, review findings of diet interventions that positively modify diet behavior, identify research gaps, and suggest recommendations for addressing those gaps. PubMed, MEDLINE, Scopus, and CABI Web of Science were searched between February 2020 and June 2022 for peer-reviewed articles. The inclusion criteria were as follows: (1) study population must include SFFs; (2) investigate diet or diet intervention among SFFs; (3) report results specific to SFFs; and (4) be published in the English language. Thirty-four studies were included. Results indicate that SFFs recognize the importance of a healthy dietary pattern, but do not follow one, and that food choices are often influenced by colleagues. Diet interventions, such as the Mediterranean diet, were observed to have positive health improvements, such as improved lipid levels and lower CVD risk. Team counseling was found to be more effective for adopting healthier diets compared to one-on-one counseling; and general counseling was more effective than no counseling. A gap identified by this review is the lack of information concerning differences in dietary intake, diet quality, and dietary behaviors while on- and off-shift, and throughout the career. Diet is an important risk factor for occupational disease development; therefore, effective, consistent dietary interventions are necessary.

Differences in Fine Particle Exposure and Estimated Pulmonary Ventilation Rate with Respect to Work Tasks of Wildland Firefighters at Prescribed Burns: A Repeated Measures Study.

Wildland firefighters (WLFFs) are exposed to a mixture of chemicals found in wildland fire smoke and emissions from nonwildland-fuel smoke sources such as diesel. We investigated compositional differences in exposure to particulate matter and explored differences in ventilation rate and potential inhaled dose relative to the work tasks of WLFFs. Repeated measures on ten professional and two volunteer firefighters were collected on prescribed burn and nonburn days. Personal monitoring consisted of real-time and gravimetric fine particulate matter (PM2.5), carbon monoxide (CO), and accelerometer measurements to estimate ventilation rate and potential dose of PM2.5. The fine particulate matter was analyzed for levoglucosan (LG) and light absorbing carbon as a surrogate for black carbon (BC). Breathing zone personal exposure concentrations of PM2.5, LG, BC, and CO were higher on burn days (P < 0.05). Differences in exposure concentrations were observed between burn day tasks (P < 0.05) with firefighters managing fire boundaries (holders) being exposed to higher CO and LG concentrations and less BC concentrations than those conducting lighting (lighters). While no statistical difference in PM2.5 exposure measures was observed between the two tasks, holders in the study tended to be exposed to higher PM2.5 concentrations (~1.4×), while lighters tended to have more inhaled amounts of PM2.5 (~1.3×). Our findings demonstrate possible diversity in the sources of particulate matter exposure at the fireline and suggest the potential importance of using dose as a metric of inhalation exposure in occupational or other settings.

A Framework for Interfacing and Partnering with Environmental Justice Communities as a Prelude to Human Health and Hazard Identification in the Vulnerable Census Tracts of Columbus, Ohio.

Columbus, Ohio is one of the more prosperous, well-educated, and progressive cities in the United States. However, it ranks as the second worst life expectancy at birth, has a census tract wealth gap (27-year disparity), and one of the higher infant mortality rates in the country. These data suggest that there are likely several high-risk, vulnerable neighborhoods in Columbus with residents experiencing disparate and adverse outcomes. Illustrative of this fact are studies that have examined the social processes and mechanisms through which neighborhood contexts are at the forefront, including exposures to chemical stressors such as particulate matter (PM2.5) as well as non-chemical stressors including violence, social determinants of health, zoning, and land use policies. It is documented that disparate and adverse outcomes are magnified in the vulnerable neighborhoods on the Near East Side as compared to Columbus city proper, Franklin County and/or the state of Ohio. As such, we developed a nuanced community engagement framework to identify potential environmental hazards associated with adverse pregnancy outcomes in those census tracts. The refined framework uses a blended version of traditional community-based participatory research (CBPR) models and is referred to as E6, Enhancing Environmental Endeavors via e-Equity, Education, and Empowerment.

Lung function changes in wildland firefighters working at prescribed burns.

CONTEXT: Although decline in lung function across workshift has been observed in wildland firefighters, measurements have been restricted to days when they worked at fires. Consequently, such results could have been confounded by normal circadian variation associated with lung function. OBJECTIVES: We investigated the across-shift changes in lung function of wildland firefighters, and the effect of cumulative exposure on lung function during the burn season. MATERIALS AND METHODS: We measured forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), forced expiratory flow from 25% to 75% of FVC (FEF25₋75), and peak expiratory flow (PEF) of wildland firefighters before and after their workshifts. In all, 501 pre-shift and 488 post-shift measurements were collected over 22 prescribed burn days and 43 non-burn days from 24 non-smoking wildland firefighters during the dormant winter burn seasons of 2003 and 2004. We compared changes in the spirometry measures across the workshift on burn days to those observed on non-burn days. We also assessed the effect of cumulative exposure during the burn season on the spirometry measures. RESULTS: There were no significant differences in the across workshift changes on burn days compared to those on non-burn days for all the spirometry measures. However, for a given point in time during the season, each additional day of exposure was estimated to be associated with declines of 24 ml in pre-shift FVC and 24 ml in pre-shift FEV1 (p <0.01). DISCUSSION AND CONCLUSION: Cumulative exposure to woodsmoke was associated with slight decrements in lung function among the wildland firefighters.

Personal PM(2.5) exposure among wildland firefighters working at prescribed forest burns in Southeastern United States.

This study investigated occupational exposure to wood and vegetative smoke in a group of 28 forest firefighters at prescribed forest burns in a southeastern U.S. forest during the winters of 2003-2005. During burn activities, 203 individual person-day PM(2.5) and 149 individual person-day CO samples were collected; during non-burn activities, 37 person-day PM(2.5) samples were collected as controls. Time-activity diaries and post-work shift questionnaires were administered to identify factors influencing smoke exposure and to determine how accurately the firefighters' qualitative assessment estimated their personal level of smoke exposure with discrete responses: "none" or "very little," "low," "moderate," "high," and "very high." An average of 6.7 firefighters were monitored per burn, with samples collected on 30 burn days and 7 non-burn days. Size of burn plots ranged from 1-2745 acres (avg = 687.8). Duration of work shift ranged from 6.8-19.4 hr (avg = 10.3 hr) on burn days. Concentration of PM(2.5) ranged from 5.9-2673 µg/m(3) on burn days. Geometric mean PM(2.5) exposure was 280 µg/m(3) (95% CL = 140, 557 µg/m(3), n = 177) for burn day samples, and 16 µg/m(3) (95% CL = 10, 26 µg/m(3), n = 35) on non-burn days. Average measured PM(2.5) differed across levels of the firefighters' categorical self-assessments of exposure (p < 0.0001): none to very little = 120 µg/m(3) (95% CL = 71, 203 µg/m(3)) and high to very high = 664 µg/m(3) (95% CL = 373, 1185 µg/m(3)); p < 0.0001 on burn days). Time-weighted average PM(2.5) and personal CO averaged over the run times of PM(2.5) pumps were correlated (correlation coefficient estimate, r = 0.79; CLs: 0.72, 0.85). Overall occupational exposures to particulate matter were low, but results indicate that exposure could exceed the ACGIH®-recommended threshold limit value of 3 mg/m(3) for respirable particulate matter in a few extreme situations. Self-assessed exposure levels agreed with measured concentrations of PM(2.5). Correlation analysis shows that either PM(2.5) or CO could be used as a surrogate measure of exposure to woodsmoke at prescribed burns.

Acute cardiovascular responses of wildland firefighters to working at prescribed burn.

Wildland firefighters at prescribed burns are exposed to elevated levels of wildland fire smoke (WFS) while performing physically demanding tasks. WFS exposure has been linked to increases in hospital and emergency admissions for cardiovascular disorders in the general population. However, knowledge about the cardiovascular effect of occupational WFS exposure among wildland firefighters is limited. To provide a better understanding of the effect of this exposure scenario on acute hemodynamic responses, resting systolic/diastolic blood pressure (SBP/DBP) and heart rate (HR) of wildland firefighters were measured before (pre-shift), after (post-shift), and the morning (next morning) immediately following prescribed burn shifts (burn days) and regular work shifts (non-burn days). A total of 38 firefighters (34 males and 4 females) participated in this study and resting BP and HR were recorded on 9 burn days and 7 non-burn days. On burn days, HR significantly increased from pre-to post-shift (13.25 bpm, 95% CI: 7.47 to 19.02 bpm) while SBP significantly decreased in the morning following the prescribed burns compared to pre-shift (-6.25 mmHg, 95% CI: -12.30 to -0.20 mmHg). However, this was due to the decrease of SBP in the firefighters who were hypertensive (-8.46 mmHg, 95% CI: -16.08 to -0.84 mmHg). Significant cross-shift reductions (post-shift/next morning vs. pre-shift) were observed in SBP on burn days compared to non-burn days (-7.01 mmHg, 95% CI: -10.94 to -3.09 mmHg and -8.64 mmHg, 95% CI: -13.81 to -3.47 mmHg, respectively). A significant reduction on burn days was also observed from pre-shift to the following morning for HR compared to non-burn days (-7.28 bpm, 95% CI: -13.50 to -1.06 bpm) while HR significantly increased in pre-to post-shift on burn days compared to non-burn days (10.61 bpm, 95% CI: 5.05 to 16.17 bpm). The decreased BP observed in wildland firefighters might be due to a high level of carbon monoxide exposure and exercise-induced hypotension. The increase in HR immediately after prescribed burns might be attributable to WFS exposure and physical exertion in prescribed burn shifts. The results suggest that wildland firefighting exposure might cause a distinct hemodynamic response, including SBP reduction and HR increment, especially for those who have pre-existing hypertension.

The adverse health effects of waterpipe smoking in adolescents and young adults: A narrative review.

Waterpipe (WP) smoking has rapidly grown in popularity in the United States and other Western countries with the fastest uptake among younger individuals. This growth has been encouraged by the misperception that WP smoke is harmless or less harmful than cigarette smoke. To better understand how WP affects the health of young people, we conducted a narrative review of the literature focusing on the adverse health effects of WP smoking in adolescents and younger adults. We searched scientific literature databases including PubMed, MEDLINE, EMBASE, and ISI Web and selected papers that met the inclusion criteria. Sixty-three papers met the inclusion criteria and were selected for review. Data were abstracted from the selected papers into a standardized table. The evidence demonstrates that WP smoking can cause acute lung infection and injury, and carbon monoxide (CO) poisoning, in adolescents and young adults. It is also associated with adverse subclinical effects in this sub-population, including oral and systemic genotoxicity, lung function decline, and the alteration of vascular and hemodynamic functions. Limited evidence that is available indicates associations with psychological and neurological effects and asthma. No identified publications examined the association between WP use and type 2 diabetes, a condition that is associated with cigarette smoking among young people. WP smoking by younger individuals can result in their hospitalization due to systemic CO poisoning and acute lung disease, and induce subclinical adverse effects in the oral cavity, pulmonary system, and in circulation, that are involved in the pathogenesis of local and systemic chronic diseases.