*4.2.1 Population characteristics*

In total, the respondents are defined by 116 (56%) men and 91 (44%) women aged between 18 and 65 years.

In Germany, the majority of personnel is formed by men (35%), while in Latvia, the majority is dominated by female workers (30%) (see **Figure 2**)*.*

The age distribution shows that the Latvian emergency personnel in general are composed of a rather young team in the age range of 18–30 years (18–25 years = 57.1%, 26–30 years = 30.5%), and in return, the German personnel show a wider range of age distribution, which majorly is observed to be between 18 and 40 years (18–25 years = 46.1%, 26–30 years = 22.5%, 31–40 years = 16.7%). Consequently, the emergency workers in Germany are older compared to the Latvian emergency workers (see **Figure 3**).

Relating the personnel's age and years of employment, a correlation is apparent. The vast majority of the young Latvian workers have been working for 1–5 years (84.8%) and then an abrupt decrease of employment time by approximately 80% is seen, while the investigated German ambulance service also has its peak employment time at 1–5 years (54.9%) but then gradually decreases by 50% (see **Figure 4**)*.*

According to the amount of shifts per week and the density of emergency occurrence, both countries have four shifts of 12 h during a 7-day working week and parallels are seen for the average amount of trips that are set at approximately six non-signal and five signal trips for both countries.

Evaluating the amount of hours the worker is exposed to noise during trips, the German ambulance service personnel are approximately 1.5 h (63 min) longer exposed to noises from signal and 0.71 h (43 min) longer exposed to non-signal noises during a 12-h shift. Comparing both countries for their total emergency

**13**

**Figure 4.**

*comparison.*

**Figure 3.**

*Influence of Noise in Ambulance Vehicles on Emergency Service Personnel*

*The distribution in absolute numbers of survey population by age, Latvia and Germany in comparison.*

*The distribution in absolute numbers of survey population by years of employment, Latvia and Germany in* 

*DOI: http://dx.doi.org/10.5772/intechopen.91898*

**Figure 2.** *The percentage of survey population by gender.*

*Influence of Noise in Ambulance Vehicles on Emergency Service Personnel DOI: http://dx.doi.org/10.5772/intechopen.91898*

*Noise and Environment*

http://www.visidati.lv or in printed version.

Latvian emergency workers (see **Figure 3**).

non-signal and five signal trips for both countries.

*4.2.1 Population characteristics*

aged between 18 and 65 years.

Latvian emergency workers answered fourteen questions in an electronic form at

In total, the respondents are defined by 116 (56%) men and 91 (44%) women

The age distribution shows that the Latvian emergency personnel in general are composed of a rather young team in the age range of 18–30 years

(18–25 years = 57.1%, 26–30 years = 30.5%), and in return, the German personnel show a wider range of age distribution, which majorly is observed to be between 18 and 40 years (18–25 years = 46.1%, 26–30 years = 22.5%, 31–40 years = 16.7%). Consequently, the emergency workers in Germany are older compared to the

Relating the personnel's age and years of employment, a correlation is apparent. The vast majority of the young Latvian workers have been working for 1–5 years (84.8%) and then an abrupt decrease of employment time by approximately 80% is seen, while the investigated German ambulance service also has its peak employment time at 1–5 years (54.9%) but then gradually decreases by 50% (see **Figure 4**)*.* According to the amount of shifts per week and the density of emergency occurrence, both countries have four shifts of 12 h during a 7-day working week and parallels are seen for the average amount of trips that are set at approximately six

Evaluating the amount of hours the worker is exposed to noise during trips, the German ambulance service personnel are approximately 1.5 h (63 min) longer exposed to noises from signal and 0.71 h (43 min) longer exposed to non-signal noises during a 12-h shift. Comparing both countries for their total emergency

the majority is dominated by female workers (30%) (see **Figure 2**)*.*

In Germany, the majority of personnel is formed by men (35%), while in Latvia,

**12**

**Figure 2.**

*The percentage of survey population by gender.*

**Figure 3.** *The distribution in absolute numbers of survey population by age, Latvia and Germany in comparison.*

#### **Figure 4.**

*The distribution in absolute numbers of survey population by years of employment, Latvia and Germany in comparison.*

#### *Noise and Environment*

trip-related noise exposure during a 12-h shift, German personnel are in total 68% exposed to noise and Latvian personnel in total 53% (see **Figure 5**).

The time that the worker is not sitting in the car and presented to the evaluated noise is categorised as "other" in **Figure 5**, which stands for the time, e.g., in the hospital, patient house or guardhouse. It is impossible to measure these noise levels; nonetheless, it should be taken into consideration, since presentation to noise is ubiquitous and affecting the body.

## *4.2.2 Symptom prevalence*

In the questionnaire, respondents were allowed to choose more than one symptom and indeed, most respondents indicated more than one symptom. In comparison, Germans assigned 1–2 fitting symptoms and Latvians choose 2–3 (see **Figure 6**).

For both countries, a common pattern of complaints and also highest incidences were found in following two symptoms: difficulties of understanding during background noises (Germany 30.2%, *N* = 42 and Latvia 26.6%, *N* = 46) and tinnitus (Germany 38.8%, *N* = 52 and Latvia 23.8%, *N* = 41).

Other similarities but with lower frequency are given for hyperacusis (Germany 6%, *N* = 6 and Latvia 5.8%, *N* = 10), pain or pressure in the ear (Germany 13.4%, *N* = 18 and Latvia 13.4%, *N* = 23) and difficulties understanding speech, particularly women and children (Germany 7.9%, *N* = 11 and Latvia 10.4%, *N* = 18).

Comparing main differences, Latvian emergency workers show a much higher incidence of symptoms such as vertigo (23.8%, *N* = 41), changes in sound perception (7.5%, *N* = 13), difficulties in determination of sound direction (5.8%, *N* = 10) and difficulties using the phone due to poor understanding of the partner (13.3%, *N* = 23).

German emergency personnel showed higher prevalence only for difficulties understanding electronic audio devices such as TV and radio and thus the need to increase the volume (20.9%, *N* = 28).

Concluding, Latvian emergency personnel clearly dominate in 8 from 10 auditory symptoms with higher absolute number.

For a closer accurate evaluation risks for NIHL, also an average noise exposure during free time was requested giving a defined range from 1 (low noise exposure) to 10 (high noise exposure). Both indicated an average free time exposure to noise at 5.

#### **Figure 5.**

*Time of exposure of the survey population to signal and non-signal trips during a 12-h shift. \*Others include the time during the 12-h shift outside the emergency car.*

**15**

*4.2.3 Statistical data*

*Germany and Latvia in comparison.*

**Figure 6.**

**5. Discussion**

Statistical investigations for relations according to the study showed that there is no significant relation between countries, age, gender or length of employment towards symptoms (*p* > 0.05) and thus cannot be attributed to the general population.

*Prevalence of chronic hearing symptoms for each country of the survey population in absolute number,* 

When persons with normal hearing are exposed to high noise levels over a prolonged period of time and by this reaching or exceeding the limit of permissible noise level exposure equivalent of 85 dB(A) during 8 h, a shift of hearing threshold may result. Under a threshold shift is meant an average deterioration of hearing of 10 dB(A) or more in the frequency ranges of 2000, 3000 and 4000 Hz in both ears,

defined by Occupational Safety and Health Act (OSHA).

*Influence of Noise in Ambulance Vehicles on Emergency Service Personnel*

*DOI: http://dx.doi.org/10.5772/intechopen.91898*

*Influence of Noise in Ambulance Vehicles on Emergency Service Personnel DOI: http://dx.doi.org/10.5772/intechopen.91898*

#### **Figure 6.**

*Noise and Environment*

ubiquitous and affecting the body.

(Germany 38.8%, *N* = 52 and Latvia 23.8%, *N* = 41).

*4.2.2 Symptom prevalence*

(13.3%, *N* = 23).

noise at 5.

increase the volume (20.9%, *N* = 28).

tory symptoms with higher absolute number.

**14**

**Figure 5.**

*the time during the 12-h shift outside the emergency car.*

*Time of exposure of the survey population to signal and non-signal trips during a 12-h shift. \*Others include* 

trip-related noise exposure during a 12-h shift, German personnel are in total 68%

The time that the worker is not sitting in the car and presented to the evaluated noise is categorised as "other" in **Figure 5**, which stands for the time, e.g., in the hospital, patient house or guardhouse. It is impossible to measure these noise levels; nonetheless, it should be taken into consideration, since presentation to noise is

In the questionnaire, respondents were allowed to choose more than one symptom and indeed, most respondents indicated more than one symptom. In comparison, Germans assigned 1–2 fitting symptoms and Latvians choose 2–3 (see **Figure 6**). For both countries, a common pattern of complaints and also highest incidences were found in following two symptoms: difficulties of understanding during background noises (Germany 30.2%, *N* = 42 and Latvia 26.6%, *N* = 46) and tinnitus

Other similarities but with lower frequency are given for hyperacusis (Germany 6%, *N* = 6 and Latvia 5.8%, *N* = 10), pain or pressure in the ear (Germany 13.4%, *N* = 18 and Latvia 13.4%, *N* = 23) and difficulties understanding speech, particularly women and children (Germany 7.9%, *N* = 11 and Latvia 10.4%, *N* = 18).

Comparing main differences, Latvian emergency workers show a much higher incidence of symptoms such as vertigo (23.8%, *N* = 41), changes in sound perception (7.5%, *N* = 13), difficulties in determination of sound direction (5.8%, *N* = 10) and difficulties using the phone due to poor understanding of the partner

German emergency personnel showed higher prevalence only for difficulties understanding electronic audio devices such as TV and radio and thus the need to

Concluding, Latvian emergency personnel clearly dominate in 8 from 10 audi-

For a closer accurate evaluation risks for NIHL, also an average noise exposure during free time was requested giving a defined range from 1 (low noise exposure) to 10 (high noise exposure). Both indicated an average free time exposure to

exposed to noise and Latvian personnel in total 53% (see **Figure 5**).

*Prevalence of chronic hearing symptoms for each country of the survey population in absolute number, Germany and Latvia in comparison.*

#### *4.2.3 Statistical data*

Statistical investigations for relations according to the study showed that there is no significant relation between countries, age, gender or length of employment towards symptoms (*p* > 0.05) and thus cannot be attributed to the general population.

#### **5. Discussion**

When persons with normal hearing are exposed to high noise levels over a prolonged period of time and by this reaching or exceeding the limit of permissible noise level exposure equivalent of 85 dB(A) during 8 h, a shift of hearing threshold may result. Under a threshold shift is meant an average deterioration of hearing of 10 dB(A) or more in the frequency ranges of 2000, 3000 and 4000 Hz in both ears, defined by Occupational Safety and Health Act (OSHA).

This deterioration of hearing can be of a temporary nature (TTS), or in opposite at continuous exposition can result to a permanent threshold shift (PTS) and hearing loss.

The amount of hearing loss results from the sound pressure level, the duration of exposure, the frequency of noise and the individual predispositions.

The study focuses on the distribution of symptoms that determine the current state and assess the future trend of NIHL risks. The Latvian ambulance service personnel are exposed up to 5.2 dB(A) (non-signal) and 2.4 dB(A) (with signal) louder noise than German personnel. Both countries demonstrate an exposure to hazardous noise level of approximately 85–90 dB(A) during signal trips, which reaches and partly exceeds the exposure limits of 85 dB(A).

Sound measurements of this study show that during non-signal trips, the noise pressure level varies depending on speed by 2–6 dB(A). The faster the speed level, the greater the noise level. During signal trips, for Latvians, the increase in noise level is by 2–4 dB(A) depending on speed level seen, but for Germans, the noise level stays almost constant at different speed levels.

However, during a 12-h shift, the Latvian survey population is exposed for approximately 2 h to signal trips with an average noise level of approximately 87 dB(A) and the German survey population approximately 3 h to signal trips with an average noise level of 85 dB(A).

Referring to OSHA regulations, both countries are not exceeding the limit of permissible noise level exposure equivalent. Thus, the exposure to noise during emergency trips with signal is considered to be safe for the auditory system.

Nonetheless, especially the Latvian emergency personnel indicate a great dominance for auditory changes, as clearly shown in my study data.

Possible explanations for the contrary facts may be found when considering the sirens of the ambulance vehicles. The frequencies of ringtones that can be selected in Latvian cars are usually higher and thus more harmful to the hearing system. Also the majority of streets are in rather poor condition, which increases the noise level by its vibrations. Furthermore, accumulations of numerous unrecovered TTS by short and extreme fluctuations of noise level may also trigger NIHL. Moreover, the natural limitations of the study need to be taken into account. Firstly non-job-related noise exposure such as listening to a walkman loudly for long time or being a member of an orchestra and giving a concert has a great impact on hearing, which limits the accuracy of the study. Secondly, during the last 5 years, both ambulance services invested enormously into new cars and equipment. Thus, the symptoms can be a result from the older cars, where presumably the noise level must have been presented far louder.

#### **5.1 Preventive measures**

Personal:


**17**

*Influence of Noise in Ambulance Vehicles on Emergency Service Personnel*

• Intelligent planning of the duty roster to provide rest from loud noise

• Audiogram check-ups to make the personnel more aware of the auditory

• Keeping the noise level and its exposure during leisure time safe

• Acoustic insulation and sound proofing to doors, walls and ceilings

• Fixing all loose equipment in the cabin for safety reasons but also noise

• Positioning of sirens as far away as possible from the personnel, e.g., front of

1.NIHL is one of the oldest and most common occupationally induced health

2.Common pattern and highest prevalence for auditory symptoms for both

• Difficulties understanding electronic audio devices such as TV and radio

3.The Latvian ambulance service personnel have a higher risk of developing NIHL reasoned by high frequency of sound melody of the sirens and exposure to higher sound level during signal trips, caused by poor street condi-

4.For both countries, the noise level is remarkably elevated during signal trips

5.Speed level influences the noise level during trips without signal by 2–6 dB(A). The higher the speed, the higher the noise level during non-signal trips.

6.During emergency trips with signal use, the noise level is reaching and partly

7.Education of the ambulance workers and management about preventive measures, the importance of NIHL development and risk as well as regular audi-

• Difficulties of understanding during background noises

Latvian and German ambulance services are:

and thus the need to increase the volume

*DOI: http://dx.doi.org/10.5772/intechopen.91898*

exposure

status

Vehicle:

reduction

the spoiler

issues worldwide.

• Tinnitus

• Vertigo

tions.

compared to non-signal trips.

ometry check-ups are needed.

exceeding the safety limits of 80–85 dB(A).

**6. Conclusion**

*Influence of Noise in Ambulance Vehicles on Emergency Service Personnel DOI: http://dx.doi.org/10.5772/intechopen.91898*


Vehicle:

*Noise and Environment*

hearing loss.

This deterioration of hearing can be of a temporary nature (TTS), or in opposite at continuous exposition can result to a permanent threshold shift (PTS) and

The amount of hearing loss results from the sound pressure level, the duration

The study focuses on the distribution of symptoms that determine the current state and assess the future trend of NIHL risks. The Latvian ambulance service personnel are exposed up to 5.2 dB(A) (non-signal) and 2.4 dB(A) (with signal) louder noise than German personnel. Both countries demonstrate an exposure to hazardous noise level of approximately 85–90 dB(A) during signal trips, which

Sound measurements of this study show that during non-signal trips, the noise pressure level varies depending on speed by 2–6 dB(A). The faster the speed level, the greater the noise level. During signal trips, for Latvians, the increase in noise level is by 2–4 dB(A) depending on speed level seen, but for Germans, the noise

However, during a 12-h shift, the Latvian survey population is exposed for approximately 2 h to signal trips with an average noise level of approximately 87 dB(A) and the German survey population approximately 3 h to signal trips with

Referring to OSHA regulations, both countries are not exceeding the limit

Nonetheless, especially the Latvian emergency personnel indicate a great domi-

Possible explanations for the contrary facts may be found when considering the sirens of the ambulance vehicles. The frequencies of ringtones that can be selected in Latvian cars are usually higher and thus more harmful to the hearing system. Also the majority of streets are in rather poor condition, which increases the noise level by its vibrations. Furthermore, accumulations of numerous unrecovered TTS by short and extreme fluctuations of noise level may also trigger NIHL. Moreover, the natural limitations of the study need to be taken into account. Firstly non-job-related noise exposure such as listening to a walkman loudly for long time or being a member of an orchestra and giving a concert has a great impact on hearing, which limits the accuracy of the study. Secondly, during the last 5 years, both ambulance services invested enormously into new cars and equipment. Thus, the symptoms can be a result from the older cars, where

of permissible noise level exposure equivalent. Thus, the exposure to noise during emergency trips with signal is considered to be safe for the

nance for auditory changes, as clearly shown in my study data.

presumably the noise level must have been presented far louder.

• Personal protective devices (e.g., filter-type earplugs)

• Education of both workers and the management staff in order to prevent

• Planning and organisation to avoid streets of bad quality, which produce excessive noise or need of prolonged signal use due to a crowded traffic

• Regular medical examinations of workers

of exposure, the frequency of noise and the individual predispositions.

reaches and partly exceeds the exposure limits of 85 dB(A).

level stays almost constant at different speed levels.

an average noise level of 85 dB(A).

auditory system.

**5.1 Preventive measures**

Personal:

NIHL

**16**

