Assessment of Occupational Noise Exposure among Groundskeepers in North Carolina Public Universities Jo anne g. Balanay1, gregory D. Kearney2 and adam J. mannarino3 1Assistant Professor, Environmental Health Sciences Program, Department of Health Education and Promotion, East Carolina University, Greenville, NC, USA. 2Assistant Professor, Department of Public Health, East Carolina University, Greenville, NC, USA. 3Alumnus, Department of Public Health, East Carolina University, Greenville, NC, USA. AbstrAct: Groundskeepers may have increased risk to noise-induced hearing loss due to the performance of excessively noisy tasks. This study assessed the exposure of groundskeepers to noise in multiple universities and determined the association between noise exposure and variables (ie, university, month, tool used). Personal noise exposures were monitored during the work shift using noise dosimetry. A sound level meter was used to measure the maximum sound pressure levels from groundskeeping equipment. The mean Occupational Safety and Health Administration (OSHA) and National Institute for Occupational Safety and Health (NIOSH) time-weighted average (TWA) noise exposures were 83.0 ± 9.6 and 88.0 ± 6.7 dBA, respectively. About 52% of the OSHA TWAs and 77% of the NIOSH TWAs exceeded 85 dBA. Riding mower use was associated with high TWA noise exposures and with having OSHA TWAs exceeding 85 and 90 dBA. The maximum sound pressure levels of equipment and tools measured ranged from 76 to 109 dBA, 82% of which were .85 dBA. These findings support that groundskeepers have excessive noise exposures, which may be effectively reduced through careful scheduling of the use of noisy equipment/tools. Keywords: groundskeepers, noise exposure, noise dosimetry, exposure assessment, public universities, occupational noise CitAtiON: Balanay et al. assessment of occupational noise Exposure among COmPEtiNG iNtEREStS: Authors disclose no potential conflicts of interest. groundskeepers in north Carolina Public Universities. Environmental Health Insights 2016:10 83–92 doi: 10.4137/EHi.s39682. CORRESPONdENCE: kearneyg@ecu.edu tYPE: original research COPYRiGht: © the authors, publisher and licensee libertas academica limited. this is an open-access article distributed under the terms of the Creative Commons CC-BY-nC RECEivEd: march 14, 2016. RESUbmittEd: may 12, 2016. ACCEPtEd fOR 3.0 license. PUbliCAtiON: may 12, 2016. P aper subject to independent expert blind peer review. all editorial decisions made ACAdEmiC EditOR: timothy Kelley, Editor in Chief by independent academic editor. Upon submission manuscript was subject to anti- plagiarism scanning. Prior to publication all authors have given signed confirmation of PEER REviEw: Five peer reviewers contributed to the peer review report. reviewers’ agreement to article publication and compliance with all applicable ethical and legal reports totaled 2,591 words, excluding any confidential comments to the academic editor. requirements, including the accuracy of author and contributor information, disclosure of fUNdiNG: this study was supported by grant #5100435 from the national institute competing interests and funding sources, compliance with ethical requirements relating for occupational safety and Health (niosH) through the north Carolina occupational to human and animal study participants, and compliance with any copyright requirements safety and Health Education and research Center. the contents of this article are those of third parties. this journal is a member of the Committee on Publication Ethics (CoPE). of the authors and do not necessarily represent the official views of the NIOSH. The Provenance: the authors were invited to submit this paper. authors confirm that the funder had no influence over the study design, content of the Published by libertas academica. learn more about this journal. article, or selection of this journal. Introduction occupational noise exposure.5 In 2013, the Bureau of Labor Approximately 870,000 groundskeeping and landscaping Statistics reported that nearly 11% of all nonfatal, work-related workers are employed in the United States. Based on the 2014 diseases are NIHL cases.6 data, North Carolina (NC) employed 28,900 of these work- Studies related to the workplace exposure of groundskee- ers, ranking it as the eighth state with the greatest number of pers to noise are limited. A study comparing NIHL between employment in this particular work sector.1 Workers in this landscapers and carpenters was previously conducted,7 but their occupation perform various tasks, including mowing, trim- noise exposures were not evaluated. The operation of ground- ming, sod laying, raking, planting, and installing concrete skeeping/landscaping equipment (eg, riding and push lawn landscape structures (eg, patios, pathways) and irrigation sys- mowers, chippers, shredders, stump grinders, chainsaws, edg- tems.1,2 Power equipment and tools are used to a great extent ers, leaf blowers) without using hearing protection equipment in many of these tasks. has been identified to contribute to NIHL.8 Limited docu- Noise is an important occupational hazard in various ments addressing worker health and safety in the landscaping occupations, including the groundskeeping sector. The U.S. industries are available but mainly focus on the safety hazards Occupational Safety and Health Administration (OSHA) and prevention of injuries from operating-related equipment estimates that about 30 million U.S. workers are exposed and tools.8,9 Noise exposures of certain occupations, such as each year to excessive noise at work. Consequently, noise- construction,10–13 agriculture,14–17 and forestry,18,19 have been induced hearing loss (NIHL) has been one of the most com- studied more extensively in the published literature, and may mon occupational diseases in the past 25 years.3 According be similar to those of groundskeepers because of the similarity to the National Institute for Occupational Safety and Health in some of their tasks and tools. Additional information is (NIOSH), worker compensation costs due to NIHL in the beneficial in further understanding the noise exposures of United States were estimated at $242 million each year.4 An groundskeepers and the contributing factors and may be used estimated 16% of adult hearing loss worldwide is attributed to to tailor strategies for noise exposure reduction specifically EnvironmEntal HEaltH insigHts 2016:10 83 Balanay et al for groundskeepers. In a recent pilot study, which is the represents the median noise level, and the L10 represents the only published study to our knowledge on such work group high-end distribution of noise levels. The calibration of dosim- on noise exposure, groundskeepers employed in a university eters was performed daily before and after monitoring. were found to be excessively exposed to noise.20 The purpose Each monitoring day, information about tools and equip- of this study was to expand on the pilot study by assessing the ment utilized during the work shift, when they were used (ie, occupational noise exposure of groundskeepers employed in specific time during the day), and work break times were col- three public universities in NC, and by evaluating the asso- lected from monitored participants using activity cards. The ciation between noise exposure and certain variables, such as information from each activity card was matched to the cor- university, month, and tool used, as these may contribute to responding noise dosimeter data as previously described.20 differences in the groundskeepers’ noise exposures. Month as source noise measurement. The measurement of a variable may assess the seasonality of noise exposures; dif- the maximum sound pressure levels (SPLs) from different ferent universities may have different landscaping features that groundskeeping tools and equipment as noise sources using a may affect the type of tasks performed by workers, and have sound level meter, including the calibration of the sound level different policies affecting worker noise exposures; and certain meter, has been previously described.20 The maximum SPL equipment and tools may be more associated with higher noise was obtained per tool or equipment operating at full throttle exposures than others due to the noise they produce and the for one to three minutes. Information (eg, brand, model, type) duration of time they are used. on the measured tools and equipment was noted. data analysis. Frequencies and percentages for cat- Methods egorical measures were summarized, while means and stan- Participant recruitment. Full-time groundskeepers dard deviations for continuous measures were determined. employed at three public universities (UnivA, UnivB, and ANOVA and nonpaired t-tests were used to compare mean UnivC) in NC were recruited to participate in the study. eight-hour TWA and one-minute noise exposure levels by Approval to conduct the study was obtained from the East university, month of monitoring, and use of a specific tool or Carolina University Institutional Review Board. During equipment. Pearson chi-square test was used to evaluate dif- recruitment, groundskeepers were provided information ferences in 85- and 90-dBA exceedence percentages among about the study, and were informed that they can choose not universities and monitoring months. Logistic regression was to participate without being penalized. Informed consent was used in calculating odds ratios (OR) to evaluate the associa- obtained prior to the conduct of noise monitoring. Personal tion between tools used and having noise exposure exceeding identifiers from data collected in this study were removed (ie, 85 or 90 dBA. The Statistical Package for the Social Sciences de-identified) prior to data analysis to eliminate the linkage (SPSS version 22; SPSS Institute) was used to analyze data. between participants and their corresponding data. P , 0.05 was considered statistically significant. This study Noise dosimetry. Monitoring for personal noise expo- involved human participants and has complied with the prin- sure of groundskeepers using noise dosimeters has been pre- ciples of the Declaration of Helsinki. viously described.20 Each noise-monitoring exercise covered the full work shift (typically 8–10 hours). Noise dosimetry was results conducted for 45 monitoring days from June to August 2014, Noise exposure levels. A total of 176 TWA samples and from April to June 2015. were obtained from all three universities (UnivA, UnivB, and The noise dosimeters simultaneously used two noise met- UnivC). The length of monitoring periods had an average of rics (OSHA hearing conservation and NIOSH) as previously 523 ± 72 minutes. Groundskeepers from UnivA comprised described.20 As each noise metric differs in terms of criterion 46.0% (n = 81) of TWAs obtained, UnivB comprised 28.4% level, exchange rate, threshold level, and time-weighting (n = 50), and UnivC comprised 25.6% (n = 45). The ground- response, both noise metrics were used to determine the work- skeepers’ eight-hour TWA noise exposure levels by university ers’ noise exposure acceptability in terms of the OSHA action using the OSHA and NIOSH metrics are shown in Table 1. level of 85 dBA (to which time-weighted averages (TWAs) All universities (n = 176) had an overall mean OSHA and obtained using the OSHA metric were compared) and the NIOSH TWA of 83.0 and 88.0 dBA, respectively. UnivB NIOSH REL of 85 dBA (to which TWAs from the NIOSH had the highest mean OSHA TWA (84.4 ± 10.1 dBA), while metric were compared). Each dosimeter was equipped with UnivA had the lowest (82.2 ± 9.2 dBA). The mean OSHA 2 data channels; channel 1 was set to the OSHA metric and TWAs were not significantly different (P = 0.46) among channel 2 to the NIOSH metric. The eight-hour TWAs for the universities. The mean OSHA TWAs of all universi- both noise metrics were acquired. The one-minute averages ties were below the OSHA action limit of 85 dBA, while for the full shift were also obtained using the OSHA metric, the mean NIOSH TWAs exceeded the NIOSH REL of and were analyzed by determining the 90th, 50th, and 10th 85 dBA (Table 1). Similarly, when compared to the OSHA percentiles (L90, L50, and L10, respectively) overall and by uni- metric data, UnivB also had the highest mean NIOSH TWA versity. The L90 represents the background noise level, the L50 (89.2 ± 7.3 dBA), but UnivC had the lowest (86.9 ± 6.1 dBA). 84 EnvironmEntal HEaltH insigHts 2016:10 Assessment of occupational noise exposure among groundskeepers in NC Public Universities table 1. Eight-hour tWa noise exposure level (dBa) using two noise metrics by university. UNivERSitY N OShA NiOSh mEAN (± Sd) miN mAx mEAN (± Sd) miN mAx all 176 83.0 (± 9.6) 50.9 100.00 88.0 (± 6.7) 67.2 102.9 Univa 81 82.2 (± 9.2) 50.9 100.0 87.8 (± 6.6) 67.2 102.9 UnivB 50 84.4 (± 10.1) 56.3 95.5 89.2 (± 7.3) 68.8 98.7 UnivC 45 82.9 (± 9.7) 51.3 95.2 86.9 (± 6.1) 68.9 95.2 The mean NIOSH TWAs were not significantly different one-minute readings by university. The 90th percentile (L90) (P = 0.23) among the universities. of all one-minute noise readings was above 72.5 dBA; the 50th Table 2 compares both OSHA and NIOSH TWA lev- percentile (L50) was above 87.2 dBA; and the 10th percentile els, and the exceedence percentages under each noise metric. (L10) was above 97.0 dBA. Groundskeepers were monitored Exceedence percentage is defined as the percentage of TWA for noise from April to August. samples exceeding 85 and 90 dBA. The overall and university- The eight-hour TWA noise exposures of groundskeep- specific mean NIOSH TWAs are significantly higher than ers by month are shown in Table 4 using both noise metrics. those of the mean OSHA TWAs (P , 0.01 to P = 0.02), April has the highest mean OSHA TWA (87.3 ± 3.3 dBA), which may be attributed to the difference in the exchange while both April and August have the highest mean NIOSH rates used by each noise metric in calculating the TWAs. The TWA (93.1 dBA); July has both the lowest mean OSHA mean of the paired differences is 5.0 ± 3.8 dBA. Overall, more (79.5 ± 12.7 dBA) and NIOSH (86.3 ± 9.0 dBA) TWAs. How- than half of the OSHA (52.3%) and NIOSH TWAs (76.7%) ever, the differences in the mean OSHA TWAs (P = 0.20) exceeded 85 dBA (Table 2). UnivB had the highest percent- and NIOSH TWAs (P = 0.12) by month are not statistically ages of OSHA TWAs exceeding both 85 and 90 dBA (66.0% significant. The percentages of OSHA TWAs .85 dBA by and 28.0%, respectively), which were significantly higher month ranged from 40.9% to 70.0%, while those of NIOSH (P = 0.02) than those of UnivA, which has the lowest percent- TWAs .85 dBA ranged from 50.0% to 100%, with April ages of OSHA TWAs exceeding both 85 and 90 dBA (45.7% having the highest percentages in both noise metrics. and 13.6%, respectively). However, UnivB’s exceedence per- The groundskeepers identified the tools and equipment centages were not significantly different (P = 0.09) from those they used throughout the entire monitoring day. Table 5 com- of UnivC. On the other hand, using the NIOSH noise met- pares the mean TWA noise exposures between groundskee- ric, UnivB also had the highest exceedence percentages of pers who did and did not use a specific equipment or tool. NIOSH TWAs .85 (82.0%) and .90 dBA (62.0%), while The riding mower is the most reported equipment used by UnivC had the lowest exceedence percentage .85 (71.1%) and the groundskeepers (n = 75, 42.6%), followed by leaf blower .90 dBA (40.0%). (n = 52, 29.5%) and weed eater (n = 35, 19.9%). Both the mean Using the OSHA metric, 92,126 minutes of noise moni- OSHA (87.6 ± 4.7 dBA) and NIOSH TWAs (90.6 ± 3.5 dBA) toring were conducted from all 176 TWA samples (Table 3). of groundskeepers who used riding mowers during the moni- Of these minutes of monitoring, 28.2% were .85 dBA and toring day are significantly higher (P , 0.01) than those who 21.9% . 90 dBA. The mean one-minute SPL for all universities did not (79.5 and 86.0 dBA, respectively; Table 5). Moreover, was 85.6 ± 9.4 dBA, which exceeded the OSHA action limit the use of riding mower also showed a significant association of 85 dBA. UnivB (87.6 ± 10.1 dBA) has the highest average with having OSHA TWAs exceeding 85 dBA (OR = 5.97, one-minute noise levels, followed by UnivC (85.3 ± 8.0 dBA), P , 0.01) and 90 dBA (OR = 2.58, P = 0.01), and with having and both exceeded the OSHA 85-dBA action limit (Table 3). NIOSH TWAs exceeding 85 dBA (OR = 10.26, P , 0.01) and There is a significant difference (P , 0.01) among the mean 90 dBA (OR = 3.03, P , 0.01). The OSHA TWAs of riding table 2. Eight-hour tWa noise exposure levels (dBa) and exceedence percentages using two noise metrics by university. UNivERSitY n twA, mEAN (± Sd) ExCEEdENCE PERCENtAGE OShA NiOSh OShA NiOSh .85 dbA .90 dbA .85 dbA .90 dbA all 176 83.0 (± 9.6) 88.0 (± 6.7) 52.3 20.5 76.7 47.2 Univa 81 82.2 (± 9.2) 87.8 (± 6.6) 45.7 13.6 76.5 42.0 UnivB 50 84.4 (± 10.1) 89.2 (± 7.3) 66.0 28.0 82.0 62.0 UnivC 45 82.9 (± 9.7) 86.9 (± 6.1) 48.9 24.4 71.1 40.0 EnvironmEntal HEaltH insigHts 2016:10 85 Balanay et al table 3. one-minute osHa noise readings by university (dBa). UNivERSitY COUNta mEAN Sd mAx % .85 dbA % .90 dbA l10 l50 l90 all 92,126 85.6 9.4 131.4 28.2 21.9 97.0 87.2 72.5 Univa 41,829 84.6 9.6 131.4 22.7 17.2 97.2 83.9 72.2 UnivB 24,888 87.6 10.1 126.5 30.9 25.8 98.0 90.3 72.4 UnivC 25,409 85.3 8.0 123.9 34.7 25.7 93.8 88.1 73.2 Note: anumber of monitoring minutes obtained using osHa noise metric. mower users ranged from 68.2 to 95.5 dBA, 76.0% of which tools were involved in tasks, such as pruning, mulching, and are .85 dBA and 29.3% are .90 dBA. Individual noise expo- watering, or were monitored during rainy days. Other tools sure profiles (Figs. 1 and 2) of two workers who used a rid- that were commonly identified include low-noise equipment/ ing mower demonstrate each of their minute-by-minute noise tools (eg, hand clipper, electric lift/bucket truck), although exposures throughout their full work shift. Figure 1 shows the some noisier equipment were also identified (eg, air compres- noise exposure profile of the groundskeeper with the high- sor, walk-behind mower, tractor, riding blower, road blower, est eight-hour OSHA TWA exposure (95.5 dBA) among the drill, sledge hammer). riding mower users. This worker was using a riding mower sPLs from noise sources. Table 6 shows the maximum for approximately seven hours (6:30 am–2:30 pm with inter- SPLs measured from groundskeeping equipment and tools. mittent breaks) and was exposed during use to one-minute The STIHL MS261 chainsaw has the highest maximum average noise levels between 95 and 100 dBA. Figure 2 demon- SPL measured at full throttle (108.6 dBA), followed by the strates the noise exposure profile of a groundskeeper who STIHL BR 600 leaf blower (105.9 dBA) and wood chip- had one of the lowest eight-hour OSHA TWA (75.5 dBA) per (105.7 dBA). Maximum SPLs measured from all hand- among the riding mower users. This worker was using a rid- held tools and equipment were .85 dBA (85.5–108.6 dBA). ing mower for approximately two hours (12:00–2:00 pm) con- Among the 22 ride-on equipment measured, 68.2% (n = 15) tinuously, exposing him to one-minute average noise levels had maximum SPLs $85 dBA (85.0–100.8 dBA); the rest generally between 85 and 95 dBA, while no other noisy tools had maximum SPLs ranging from 75.5 to 84.2 dBA, and were used for the rest of the work day. Among the universities, include cart, backhoe, front-end loaders, sweeper truck, UnivB had the highest percentage (64.0%) of reported use and hook lift. All eight riding mowers have measured SPLs of riding mower, followed by UnivC (37.8%) and UnivA .85 dBA (88.2–95.9 dBA). A front-end loader (Mini- (32.1%). More than half of the OSHA TWAs of groundskee- Cat 908) with enclosed cab and closed windows/door was pers who used leaf blowers (57.7%) and weed eaters (57.1%) measured to have the lowest SPLs (75.5 dBA), followed exceeded 85 dBA. by a sweeper truck with enclosed cab and closed windows In contrast, both the mean OSHA (74.5 ± 12.1 dBA) (76.1 dBA) and the Toro Workman 3200 cart with open and NIOSH TWAs (82.6 ± 9.0 dBA) of groundskeepers cab (77.9 dBA). SPLs measured from all ride-on equipment who used sprays tanks are significantly lower (P = 0.02 and with enclosed cab, either with open or closed windows or P = 0.03, respectively) than those who did not (83.3 and door, were ,85 dBA (75.5–84.2 dBA). Most of the open- 88.2 dBA, respectively; Table 5). Moreover, those who used cab ride-on equipment (except the Toro Workman cart) had equipment/tools categorized as others had significantly lower SPLs $85 dBA (Table 6). These maximum SPLs measured (P , 0.01) mean OSHA (77.4 ± 12.9 dBA) and NIOSH will be useful in estimating the possible worst-case scenario TWAs (84.3 ± 8.8 dBA) than those who did not (84.3 and of a worker’s noise exposure, depending on the duration of 88.9 dBA, respectively; Table 5). Those who used other equipment or tool use. table 4. Eight-hour tWa noise exposure levels (dBa) using two noise metrics by month. mONth n OShA NiOSh mEAN (± Sd) miN mAx mEAN (± Sd) miN mAx all months 176 83.0 (± 9.6) 50.9 100.00 88.0 (± 6.7) 67.2 102.9 april 10 87.3 (± 3.3) 82.8 93.0 93.1 (± 3.3) 88.6 98.7 may 67 84.0 (± 9.8) 56.3 95.5 88.1 (± 6.6) 68.8 98.2 June 75 82.5 (± 8.8) 51.3 92.8 87.7 (± 6.1) 68.9 95.6 July 22 79.5 (± 12.7) 50.9 100.0 86.3 (± 9.0) 67.2 102.9 august 2 85.9 (± 7.5) 82.8 93.0 93.1 (± 3.3) 88.6 98.7 86 EnvironmEntal HEaltH insigHts 2016:10 Assessment of occupational noise exposure among groundskeepers in NC Public Universities table 5. TWA noise exposure level (dBA) using two noise metrics by the use of specific equipment or tool. EqUiPmENt/tOOl USE N OShA NiOSh mEAN (± Sd) P-vAlUE* mEAN (± Sd) P-vAlUE* riding mower Yes 75 87.6 (± 4.7) ,0.01 90.6 (± 3.5) ,0.01 no 101 79.5 (± 10.8) 86.0 (± 7.8) Push mower Yes 7 84.1 (± 4.8) 0.76 89.3 (± 3.2) 0.61 no 169 82.9 (± 9.7) 87.9 (± 6.8) Weed eater/grass trimmer Yes 35 85.8 (± 5.4) 0.05 90.1 (± 4.0) 0.03 no 141 82.3 (± 10.3) 87.5 (± 7.1) leaf blower Yes 52 84.4 (± 7.5) 0.21 88.8 (± 5.2) 0.27 no 124 82.4 (± 10.3) 87.6 (± 7.2) Hedge trimmer Yes 16 85.8 (± 5.7) 0.23 91.1 (± 4.4) 0.05 no 160 82.7 (± 9.9) 87.7 (± 6.8) Edger Yes 18 83.1 (± 7.9) 0.95 88.4 (± 5.7) 0.79 no 158 83.0 (± 9.8) 87.9 (± 6.8) transport Yes 21 80.6 (± 11.1) 0.23 85.9 (± 7.3) 0.12 no 155 83.3 (± 9.4) 88.3 (± 6.6) spray tank Yes 7 74.5 (± 12.1) 0.02 82.6 (± 9.0) 0.03 no 169 83.3 (± 9.3) 88.2 (± 6.5) Water wagon Yes 2 83.9 (± 0.8) 0.89 87.9 (± 0.6) 0.99 no 174 83.0 (± 9.6) 88.0 (± 6.7) Forklift Yes 1 90.1 (± 0.0) 0.46 94.3 (± 0.0) 0.35 no 175 82.9 (± 9.6) 88.0 (± 6.7) Backhoe Yes 1 95.2 (± 0.0) 0.20 84.9 (± 0.0) 0.65 no 175 82.9 (± 9.6) 88.0 (± 6.7) Chainsaw Yes 11 81.7 (± 7.9) 0.65 89.4 (± 6.7) 0.47 no 165 83.1 (± 9.7) 87.9 (± 6.7) Front loader Yes 4 84.5 (± 3.1) 0.75 88.6 (± 4.2) 0.85 no 172 82.9 (± 9.7) 88.0 (± 6.7) skid steer Yes 4 84.3 (± 7.5) 0.79 86.5 (± 2.1) 0.65 no 172 83.0 (± 9.6) 88.0 (± 6.8) Chipper Yes 4 87.9 (± 2.8) 0.30 96.0 (± 3.1) 0.02 no 172 82.9 (± 9.7) 87.8 (± 6.6) roll off truck Yes 3 79.6 (± 8.1) 0.54 86.6 (± 7.3) 0.72 no 173 83.0 (± 9.6) 88.0 (± 6.7) others Yes 34 77.4 (± 12.9) ,0.01 84.3 (± 8.8) ,0.01 no 142 84.3 (± 8.1) 88.9 (± 5.8) discussion noise exposure in a university setting.20 This indicates that Groundskeepers in this study were exposed to excessive the noise exposures of groundskeepers in different universi- noise levels that exceed the OSHA action level and NIOSH ties may be comparable, which is consistent with our findings, exposure limit, while a large percentage of noise measure- showing no significant differences in average TWA noise ments exceeded 85 dBA, increasing the groundkeepers’ risk exposures by university. However, the tools used were found to NIHL. Noise levels measured from majority of the tools to be significant contributors to noise exposures. Similarly, and equipment commonly used by groundskeepers were Neitzel et al suggested that tools in use and general activi- .85 dBA, and include the riding mower, leaf blower, weed ties are important predictors of exposure.10 TWAs obtained eater (ie, grass trimmer), edger, and hedge trimmer. These using the OSHA and NIOSH noise metrics were shown to findings are similar to those in a pilot study on groundskeepers’ be significantly different. However, the differences are lower EnvironmEntal HEaltH insigHts 2016:10 87 Balanay et al 110 105 Riding mower Riding mower Riding mower 100 95 90 85 80 75 70 6:00 AM 7:00 AM 8:00 AM 9:00 AM 10:00 AM 11:00 AM 12:00 AM 1:00 PM 2:00 PM Time OSHA NIOSH figure 1. Noise exposure profile of a UnivB groundskeeper with eight-hour OSHA TWA = 95.5 dBa (ie, highest tWa among the riding mower users). compared to other similar studies.10,21–23 Considering that the similarities in some tools used and tasks performed, have been degree of difference is related to the degree of variability in studied more extensively in the literature.10–13 In comparison, noise within the work day,10 this indicates that the ground- the overall percentages of the groundskeepers’ OSHA TWAs skeepers were more likely exposed to noise levels of low vari- exceeding 85 and 90 dBA in this study are higher (52% and ability. This may suggest that groundskeepers more likely use 21%, respectively) compared to those in the construction a single equipment throughout the day (as demonstrated by industry (40% and 13%, respectively).10 Although workers in the noise exposure profile of the groundskeeper operating a groundskeeping and construction may share similar equip- riding mower for his entire work shift), or they use various ment/tools (eg, blower, backhoe, loader, forklift, bulldozer, equipment that produce similar noise levels (eg, weed eater, truck, tractor), the main sources of noise exposure in con- blower, and edger) during the work day. Among the OSHA struction are vastly different, which are pneumatic tools (eg, TWAs of groundskeepers who used a riding mower only for jackhammer, chipping guns) and heavy equipment (eg, back- the entire shift, majority (93%) had ,5 dB difference and hoes, bulldozers, roller compactor, front-end loaders, grad- about half (54%) had ,3 dB difference compared to their cor- ers).10,24–26 Although used occasionally, these major noise responding NIOSH TWAs. Similarly, Seshagiri found small sources in construction are not the common equipment and difference between TWAs generated based on 3- and 5-dB tools among groundskeepers. This may have contributed to the exchange rates in truck drivers who were exposed to constant differences in noise exposures between the two industries. vehicle engine noise sources.22 A pilot study identified the riding mower as one of the Noise exposures of workers in the construction industry, most commonly used equipment by groundskeepers,20 but its a sector that may be comparable to groundskeeping due to association with excessive noise exposure was not established. 100 Riding mower 95 90 85 80 75 70 6:00 AM 7:00 AM 8:00 AM 9:00 AM 10:00 AM 11:00 AM 12:00 AM 1:00 PM 2:00 PM Time OSHA NIOSH figure 2. Noise exposure profile of a UnivB groundskeeper with eight-hour OSHA TWA = 75.5 dBa (ie, one of lowest tWas among the riding mower users). 88 EnvironmEntal HEaltH insigHts 2016:10 Sound level, dB Sound level, dB Assessment of occupational noise exposure among groundskeepers in NC Public Universities table 6. maximum sPls of tools and equipment used by groundskeepers. tOOlS ANd EqUiPmENt USEda bRANd/mOdEl SPl (dbA) UNivERSitY hand-held Equipment/tool Edger Echo BrD-280 99.2 Univa stihl FC110 99.9 UnivB stihl FC70C 98.0 UnivC stihl (unknown) 105.5 UnivC leaf blowerb stihl Br 600 102.5 Univa 105.9 UnivB stihl Br 500 94.8 Univa 96.4 UnivC stihl Br 380 102.5 UnivC Weed eater/grass trimmer stihl Fs 90r 98.0 Univa stihl Fs110 101.5 UnivB Chainsaw Echo Cs-530 105.0 Univa stihl ms261 108.6 UnivB Hedge trimmer Echo sHC-240 98.3 Univa Push mower Exmark Commercial 30” 92.4 Univa toro Commercial 21” 85.5 Univa Walk-behind mower Exmark turf tracer HP 97.0 Univa stump grinder vermeer 95.3 UnivB Ride-On Equipment riding mowerc groundsmaster 4700-D 95.9 Univa groundsmaster 580-D 94.1 Univa groundsmaster 345 94.0 Univa groundsmaster 328-D 93.5 Univa ventrac 4200 92.4 UnivB toro groundsmaster 3280-D 88.7 UnivC toro Z master Professional 7000 88.3 UnivC John Deere 997 88.2 UnivB reel mowerc John Deere 7700 91.0 UnivB John Deere 2653B 88.0 UnivB Cart Kubotad 83.3 UnivB toro workman 3200c 77.9 UnivC Backhoe JCB 215E series 3 80.6d Univa 84.2e Univa Front End loader Caterpillar it14g 78.2d Univa Caterpillar mini-Cat 908 75.5d Univa 81.0e Univa sweeper truck isuzu nPr 5.2 l 76.1d Univa 80.8e Univa multipurpose tractorc ventrac 4200 100.8 Univa tractorc John Deere 2155 95.9 Univa multipurpose utility vehiclec Dingo 320-D 93.8 Univa Forkliftc Case 586E 92.9 Univa Hook liftd international 4700 t-444E 80.0 Univa skid steerc Caterpillar 246 85.0 Univa Stationary Equipment Wood chipper vermeer BC1000 Xl 105.7 Univa 102.0 UnivB Notes: aoperated at full throttle; bBack pack type; copen cab; dEnclosed cab, closed windows/door; eEnclosed cab, open window/door. EnvironmEntal HEaltH insigHts 2016:10 89 Balanay et al In this study, the use of riding mower was identified as a .85 dBA, but only one had a hearing conservation program. contributing factor to increased noise exposure. Riding mower Employers, managers, and employees in university work- use was shown to be associated both with high TWA noise place settings must be made fully aware of the extent of the exposures and high exceedence percentages (both for exceed- groundskeepers’ noise exposures in these settings, as well ing 85 and 90 dBA). UnivB was found to have the highest as the preventive measures that are available to reduce the mean OSHA and NIOSH TWA exposures and the high- worker’s risk to NIHL. est percentages of OSHA and NIOSH TWAs above 85 and The OSHA standard states that “feasible administrative 90 dBA. Interestingly, UnivB was also reported to have the or engineering controls shall be utilized” when employees are highest percentage of riding mower use among the universities exposed to noise exceeding the OSHA PEL of 90 dBA, and studied, which may have attributed to this university’s high that “if such controls fail” to reduce noise exposure within the TWAs and exceedence percentages. No other studies in the OSHA PEL, “personal protective equipment shall be pro- literature have identified the riding mower as a major source vided and used”.30 OSHA also provides recommendations to of noise among workers. However, Mallick et al identified the protect workers from construction noise, some of which may grass trimmer as a major source of noise exposure (with SPLs be applicable to reducing noise exposure among groundskee- ranging from 100 to 105 dBA) among roadside maintenance pers.30 Balanay et al described recommended noise source workers.27 Previous SPL measurements for lawn mowers control and noise exposure reduction measures specifically (87–99 dBA)28,29 were found to be comparable to those for groundskeepers, including engineering and administrative obtained in this study (88–96 dBA). controls, and hearing protection.20 The use of riding mower is shown to be associated with Engineering controls include the purchase or renting of high TWA noise exposures. However, there are several mea- less noisy tools and equipment through the participation of sures that can be implemented to reduce the groundskeeper’s universities in the NIOSH Buy Quiet Program,31 retrofitting noise exposure to acceptable levels, even when a riding mower ride-on equipment with enclosed cabs, and regular equipment is used. This can be achieved by reducing the operation time maintenance.20 Many of these engineering control strategies (eg, two hours or less instead of eight hours) and by using rid- are recommended in controlling noise in other industries, ing mowers that produce lower SPLs (eg, ,90 dBA). Hav- such as construction.32,33 ing TWA noise exposures of ,85 dBA while using a riding Retrofitting the cabs of ride-on equipment with enclo- mower was shown to be achievable as demonstrated in noise sure is one important strategy for reducing noise exposure of exposure profiles of a few monitored groundskeepers. For operators. Similar to a pilot study,20 this study confirmed that example, a UnivC worker mowed for 15 minutes, used spray majority of the open-cab ride-on equipment (eg, riding mow- tank for three hours and used no other tools for the rest of ers, tractor, forklift) produce SPLs $85 dBA, and that closed- the shift, resulting on a TWA of 68.2 dBA; a UnivA worker cab ride-on equipment had measured SPLs #80 dBA. Similar mowed for four hours (with the highest one-minute average results were found in studies that compared open-cab with noise levels between 75 and 85 dBA) and a truck for two hours, closed-cab agricultural equipment.15,34 Moreover, it is recom- resulting in a TWA of 73.4 dBA; a UnivB worker mowed for mended that windows and doors of existing enclosed cabs on two hours and used no other tools for the rest of the shift, ride-on equipment be completely closed when in use.20 resulting in a TWA of 75.5 dBA. However, when reducing Regular maintenance of equipment and tools to reduce the operation time for riding mowers, it is important to ensure worksite noise is also recommended in many industries, par- that the rest of the shift does not involve the operation of other ticularly in construction,12,32,33 and may also apply to ground- similar noisy equipment. Otherwise, this will likely result in skeeping. Proper maintenance of equipment was identified as an unacceptable noise exposure, as demonstrated by a UnivB one of the least expensive and most rewarding noise-control worker who mowed for four hours but used a weed eater (with practices in reducing construction noise, and includes lubricat- the highest one-minute average noise levels between 95 and ing and cleaning parts, keeping saw blades sharpened, install- 100 dBA) for an additional two hours, resulting in a TWA of ing mufflers, changing seals, and replacing worn and/or loose 95 dBA. Moreover, less noisy models of riding mowers must bearings and other parts immediately and as necessary.12,32 be obtained when purchasing new equipment, while mow- University facilities managers should ensure that a regular ers with very high SPLs (ie, $95 dBA) must be discarded. maintenance program exists for riding mowers and other This preventive measure may also apply to other noisy tools equipment, and that the maintenance schedule be followed by and equipment. everyone to keep noise levels from these tools and equipment With this study demonstrating the excessive exposure to a minimum. of groundskeepers to noise, it is essential for universities Administrative controls to reduce noise exposure of to establish an effective hearing conservation program to groundskeepers include limiting the duration of use for noisy reduce the workers’ risk to NIHL, as stated by the OSHA tools/equipment, posting noise level signs on noisy equipment/ occupational noise exposure standard.30 All three universities tools and around the workplace, keeping sufficient distance monitored in this study had measured TWA noise exposures between groundskeepers simultaneously operating noisy 90 EnvironmEntal HEaltH insigHts 2016:10 Assessment of occupational noise exposure among groundskeepers in NC Public Universities equipment, and spending work breaks indoors where exposure exposures may not be representative of groundskeepers in to noise is low.20 Posting signs with expected SPLs around the different work scenarios, such as in governmental and com- workplace and on the equipment may serve as a reminder for mercial settings, because of varying factors (eg, tool and employees to wear the needed hearing protection.12,35 More- equipment type and condition, the frequency of equipment/ over, workers operating noisy equipment must have a distance tool use, and groundskeeper activities). Thus, these factors of at least 50 feet from each other, since a study has shown must be further investigated to determine their relationship that noise exposure can further be exacerbated when multiple to the groundskeepers’ noise exposures. Additionally, more weed trimmers are utilized in a common area.27 Additionally, research is warranted to further investigate the contribu- a noise-monitoring program must be regularly conducted to tory factors to noise exposure and to hearing protection use identify workers who need to be enrolled in the university’s among groundskeepers. This includes investigating worker hearing conservation program. demographics (eg, race and ethnicity), worker knowledge, Published data on the occupational noise exposure of attitudes and perception on noise exposure and hearing loss, groundskeepers are very limited. This study is the first of its employer-provided health and safety training received by kind to characterize the noise exposures of groundskeepers in workers, and hearing protection device use by groundskee- multiple universities, which is considered a strength of this pers, and the relationship of these contributory factors to research study. The involvement of multiple sites may improve worker noise exposure. the representativeness of the study results for public universi- ties in NC. Study findings may be used as baseline data in Acknowledgments developing a hearing conservation program in academic insti- The authors thank all the personnel involved from the Facili- tutions for groundskeepers. However, one study limitation ties Offices and the Environmental Health and Safety Offices is that some of the activity cards obtained from monitored of each university for their assistance in participant recruit- groundskeepers were incomplete, wherein some did not spec- ment and noise monitoring, and the groundskeepers moni- ify the time of the day when they used a tool or equipment, tored for their participation. and some failed to identify all the tools and equipment they operated throughout their work day. Other limitations include Author contributions the small number of source noise measurements for equipment Conceived and designed the experiments: GDK, JAGB. and tools, and lack of information on the use of hearing pro- Analyzed the data: JAGB, GDK, AJM. Wrote the first tection among groundskeepers. draft of the manuscript: JAGB. Contributed to the writing of the manuscript: JAGB, GDK, AJM. Agreed with manu- conclusions script results and conclusions: GDK, JAGB, AJM. Jointly Groundskeepers are occupationally exposed to noise levels developed the structure and arguments for the paper: JAGB, exceeding the OSHA and NIOSH exposure limits. About GDK. Made critical revisions and approved the final version: 52% of the OSHA TWA noise exposures were above the JAGB, GDK, AJM. All the authors reviewed and approved OSHA action limit of 85 dBA, at which an effective hearing the final manuscript. conservation program is required. Although groundskeepers and their supervisors are aware that they are exposed to noise refereNces from equipment, they may not appreciate the extent of their 1. Bureau of Labor Statistics (BLS). Occupational Employment Statistics: Occupa- noise exposure and its related risk and, thus, may not realize tional Employment and Wages, May 2014: 37-3011 Landscaping and Groundskeep- the necessity of a hearing conservation program to reduce the ing Workers. Washington, DC: U.S. Department of Labor; 2015. Available at: http://www.bls.gov/oes/current/oes373011.htm. Accessed January 23, 2016. NIHL risk among university groundskeepers. 2. Occupational Safety and Health Administration (OSHA). Safety and Health No significant differences were found in the mean Topics: Landscaping and Horticultural Services. Washington, DC: OSHA, U.S. TWA exposure levels by university and by month when the Department of Labor; 2015. Available at: https://www.osha.gov/SLTC/land-scaping/index.html. Accessed January 23, 2016. noise monitoring was conducted. However, the use of certain 3. Occupational Safety and Health Administration (OSHA). Safety and Health equipment and tools was shown to be associated with high Topics: Occupational Noise Exposure. Washington, DC: OSHA, U.S. Department of Labor; 2015. Available at: https://www.osha.gov/SLTC/noisehearingconser- noise exposure levels. Therefore, it is important to ensure vation/. 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