A total of 130 children were evaluated by fitting doseBadges to individual children. The daily sound exposures (DSEs) measured were:
• 82 (63.0%) received DSEs of less than 50%
• 24 children (18.5%) received DSEs between 50-100%
• 24 children (18.5%) received DSEs greater than 100%
(100% is the maximum permitted DSE for an adult worker and young children are likely to be more susceptible to the adverse affects of noise than adults).
An evaluation of the A-frequency weighted time-average levels taken over 2-3 hour sessions (LAeq 2-3 h) measured by the doseBadges on children was carried out. Of the 130 children:
• 18 children (14.0%) recorded time-average levels (LAeq 2-3 h) of less than 75 dB
• 51 children (39.0%) recorded time-average levels (LAeq 2-3 h) between 75-85 dB
• 37 children (28.5%) recorded time-average levels (LAeq 2-3 h) between 85-90 dB
• 24 children (18.5%) recorded time-average levels (LAeq 2-3 h) greater than 90 dB
Peak levels (Lpeak)
• 110 children recorded at least one exceedance over 140 dB* 8.2.2 Staff exposure to noise
A total of 28 staff were evaluated by fitting doseBadges or personal sound exposure meters to individuals staff members. The daily sound exposures (DSEs) measured were:
*
Due to the limitations of the doseBadges, further information on the numbers of exceedances, when they occurred or to the actual peak levels obtained could not be determined. However, from experience, exceedances are likely to have occurred several times or more in one session.
• 23 staff members (82.0%) received DSEs less than 50%
• 4 staff members (14.0%) received DSEs between 50-100%
• 1 staff member received a DSE greater than 100% Peak levels (Lpeak)
• 11 staff members recorded peak sound levels in excess of 140dB*.
8.3 All day centres
8.3.1 Children’s exposure to noise
A total of 61 children were evaluated by fitting doseBadges for the time they were present in the centre. The daily sound exposures (DSEs ) were measured:
• 19 children (31.0%) received a DSEs of less than 50%
• 16 children (26.0 )received DSEs between 50-100%
• 26 children (43.0%) received DSEs greater than 100% (100% is the maximum permitted DSE for an adult worker)
Peak levels (Lpeak)
• 55 children recorded at least one exceedance over 140 dB*
An evaluation of the time-average sound pressure levels taken over 6-9 hour periods (LAeq 6-9 h) measured by the doseBadges on children was carried out. Of the 61 children:
• 2 children (3.0%) recorded time-average levels of less than 75 dB
• 27 children (44.0%) recorded time-average levels between 75-85 dB
• 24 children (39.0%) recorded time-average levels between 85-90 dB
8.3.2 Staff exposure to noise
A total of 45 staff were evaluated by fitting doseBadges or Personal Sound Exposure meters to individuals staff members. The daily sound exposures (DSEs) were measured:
• 31 members (69.0%) received DSE s less than 50%
• 9 staff members (20.0%) received DSEs between 50-100%
• 5 staff members (11.0%) received DSEs greater than 100% Peak levels (Lpeak)
• 19 staff members recorded at least one exceedance over 140 dB*
A typical time history from a staff member wearing a personal sound exposure meter is shown in Figure 8-1.
Figure 8-1 Time history of personal exposure to noise of a staff member. (Time given in 24 hour clock i.e. 13h = 1pm)
30 40 50 60 70 80 90 100 110 09h 10h 11h 12h 13h 14h 15h 10 second time – average level ( L Aeq 10 s dB) Time *
Due to the limitations of the doseBadges, further information on the numbers of exceedances, when they occurred or to the actual peak levels obtained could not be determined. However, from experience, exceedances are likely to have occurred several times or more in one session.
8.3.3 Discussion of daily sound exposure results
The numbers of children and teachers monitored depended very much on the availability of the doseBadges and the ages of the children. As most teachers preferred the light-weight doseBadges to the heavier and more bulky personal sound exposure meters, efforts were made to gain a fair representation of teachers and children in each centre with the doseBadges available. Infants 2 years of age and under were not monitored as this was not permitted by the approval given by the ethics committee, so available doseBadges were used on teaching staff. When compared to all day centres, higher numbers of children could be monitored in sessional centres because two sessions are held in a single day. This enabled 2 children to be monitored with a single doseBadge. In addition, staff numbers in sessional centres were fewer than all day
centres due to higher permitted staff to children ratios. In all day centres, individual children were monitored throughout the time they attended. This varied considerably with some children attending for a full 8-hour day. All day centres have higher staff-to- children ratios than sessional centres, so there was always a higher number of staff present in all day centres. This explains the reasons why there are differences in numbers of children and teachers monitored in both categories.
In the latter part of the sampling programme, the receipt of a successful research grant enabled the purchase of seven more doseBadges giving a total of 17 units. Fitting of doseBadges was time-consuming as the children, whose parents had given informed consent, had to be located, and the badges fitted under supervision. In addition, a number of dummy badges were also fitted to any other children who wanted them.
One hundred and ten of 130 children in sessional centres and 55 of 61 children in all day centres recorded peak levels (Lpeak) exceeding 140 dB on at least one occasion. Of all the children monitored in both sessional and all day centres, this equates to 86% recording peak levels in excess of 140 dB. Unfortunately the earlier model of doseBadges was not able to give more information as to the number of exceedances, when they occurred and to what levels they reached. It would have been useful to know at what times the exceedances were occurring so as to relate back to the events
exceedances. However, striking the badge against playground equipment is likely to also give false exceedances. As peak levels above 140 dB are known to cause hearing damage, it is critical that the extent of this exposure be investigated further.
In general the higher the exposure time to noise, the greater the potential risk. Therefore those children in all day centres, especially those who spend long hours in childcare, are at greater risk from the adverse effects of noise occurring in childcare centres. As would be expected, the DSEs are considerably higher in all day centres. Forty three percent of the children monitored in all day centres received a DSE in excess of 100% whereas 18.5% of the children monitored in sessional centres received a DSE in excess of 100%. .
It is serious cause for concern that, when considering the total number of children monitored (i.e. 191 children in both sessional and all day centres), 50 (26%) of these children received DSEs in excess of 100%, the maximum permitted for adults in the workplace. This cannot be ignored despite the limitations associated with this form of monitoring.
A thorough evaluation is needed to determine the reasons. Child participants (wearing doseBadges) who were observed to be active, exuberant, and playing vigorously, often received the highest levels as would be expected. Their own voices along with the knocking of the badges against equipment etc certainly contributed to noise and dose levels recorded. Screaming near the badge will add significant contributions to the levels l recorded. It is not generally the sound of one's own voice that will cause hearing damage, as the ear’s protective mechanisms (the muscles of the aural reflex) are activated, but the sound from other sources such as the voices of other children, especially those close by may well contribute to hearing loss. There is, however, good evidence that someone screaming and yelling will cause hearing damage to their own hearing over an extended period of time. Opera singers are at higher risk of damage from their own voices.1
It wasn’t possible to measure the full exposures for all the staff in all day centres, as many were rostered different hours from day to day. If is of concern that 5 of the 40
staff members recorded DSEs in excess of 100% and therefore in excess of the maximum noise dose permitted in the workplace.
While daily exposure rates are clearly of less concern for the sessional centres due to less contact time with children, it was nevertheless of concern that in one of these centres a DSE of 133% was recorded on a member of staff.