Acoustic / physical factors on noise annoyance

Sound levels, spectrum characteristics, environment and timing are the most commonly investigated factors of annoyance. Some of the other factors that affect annoyance may include regularity of events, maximum sound level, rise time, duration of occasional events, spectral distribution of energy and number and duration of quiet periods (Guski 1997).

3.1.1.1 Sound levels

Sound level is an important factor for evaluation of noise. Many researchers such as Schultz (1978), Kryter (1982), Miedema and Vos (1998), Arana and García (1998), Ali and Tamura (2003), Klæboe et al. (2004), worked on the relationship between annoyance and equivalent continuous sound level, Leq (as cited in Kang, 2007). As a result of numerous studies over the years linking overall sound levels to noise annoyance, European Commission’s Working Group published correlations between day–evening–night sound level Lden and noise annoyance for various environmental transportation noise types (WG-HSEA, 2002). The same working group also published correlation between Lnight and sleep disturbance (WG-HSEA, 2004). The relations are given in Figure 3.1 and Figure 3.2. In Figure 3.1, the solid lines are the estimated curves, and the dashed lines are the polynomial approximations. The figure also shows the 95% confidence intervals (dotted lines) (WG-HSEA, 2002).

Kurra et al. (1999a; 1999b) presented a study on road, railway and aircraft noise levels and annoyance responses. With continuous road traffic and controlled numbers of railway and aircraft traffic, overall annoyance and activity disturbance were investigated. It was found that type of noise source is not highly deterministic for annoyance of reading activity, but that it is deterministic for annoyance of listening activity. Regarding overall annoyance at home, railway noise proved to be the leading noise source especially in Japan. Findings supported the opinion that Leq = 45 dBA is an indoor noise limit which indicates a crossover between the source-specific annoyance lines. Correlation between activity disturbance and noise levels were high.

The annoyance patterns for reading and listening activities were different from one another.

Namba et al. (1996) found that increase in number of acoustics events even with a constant energy summation, Leq, causes the increase in annoyance (as cited in Kang, 2007). As concluded in WG-HSEA (2002) different types of noise, such as aircraft, road traffic, and railway noise, may each have different annoyance relationships even with constant sound level, Lden.

Polynomial approximations (WG-HSEA, 2002):

Road traffic: %A = 1.795*10^-4 (Lden-37)³ + 2.110*10^-2 (Lden-37)²+ 0.5353 (Lden-37) Road traffic: %HA = 9.868*10^-4 (Lden-42)³ - 1.436*10^-2 (Lden-42)²+ 0.5118 (Lden-42)

Figure 3.1 : The percentage annoyed persons (%A) as a function of the noise exposure of the dwelling (Lden) (WG-HSEA, 2002).

Figure 3.2 : Percentages of highly disturbed when exposed to rail and road traffic noise (WG-HSEA, 2004).

3.1.1.2 Spectrum characteristics

Spectrum characteristics of noise have been known to affect evaluation of noise.

Noise that includes tonal components, such as horn noise in traffic, may cause extreme annoyance (Phan et al, 2009).

Torija et al. (2011b), analyzed the relationship between traffic noise annoyance and acoustic indicators of overall indoor sound level. A reduced number of 1/3-octave bands (31.5–125 Hz, 315 Hz, and 630–2500 Hz) was found to be relevant for annoyance of road/railway traffic noise.

Persson Waye K. and Öhrström E. (2002) worked on wind turbine noise annoyance.

Even though noise recordings of different wind turbines had the same equivalent noise levels, annoyance ratings were different. All recordings were analyzed for psycho-acoustic parameters, but none of the psycho-psycho-acoustic parameters (sharpness, loudness, roughness, fluctuation strength or modulation) could explain the differences in annoyance response.

Persson Waye and Rylander (2001) worked on homes exposed to noise from heat pump or ventilation installations and conducted surveys on noise annoyance. It was concluded that sounds that have dominant low frequency components are more annoying and A-weighted evaluation is inefficient in evaluating this. No significant differences in medical or psycho-social symptoms were found between the low-frequency noise exposed subjects and mid-low-frequency noise exposed subjects.

Di et al. (2011) investigated on subjective annoyance of low frequency noise, structure-borne noise from a heat pump, with and without additional sound. Adding frequency-modulated pure tones (15dB, central frequency 2000 Hz) and a modulation frequency (10 Hz) decreased subjective annoyance value.

Sattler and Rott (1996) concluded that elements of traffic (busses, cars, moped, trucks) may have different annoyance rates (as cited in Kang, 2007).

Versfeld and Vos, J. (2002) on the other hand, found that proportion of heavy vehicles in a continuous stream of road vehicles does not affect annoyance in a laboratory listening test.

Paunović et al. (2014) studied the association between noise annoyance and public transport by surveying 5861 adults in the city center of Belgrade. The results showed that the presence of public transport is a predictor of high noise annoyance. The combination of buses and trams at night proved to be the most annoying. The study

demonstrated that the role of public transport on noise annoyance is independent from noise levels.

Ma and Yano (2004) investigated railway and road traffic noises at three noise levels with listening and calculation tasks. The disturbance during listening tests were different but there was not difference for task performance.

3.1.1.3 Environment

Although it was found that background noise has very little effect on overall annoyance (Fields 1998), annoyance in loud and quiet environments was found to have relationships with different socio-acoustic parameters (Paunovic et al., 2009).

On the other hand, Nguyen et al. (2011) concluded that although noise exposure was the same in Hanoi and Ho Chi Minh City, the aircraft annoyance was different because of the lower background noise level in Hanoi.

Rylander and Björkman (2002) researched effects of window orientation in dwellings on road traffic noise annoyance. Dose effect relationships showed that subjects living in flats which only face the street are more annoyed than the subjects which also have a quieter façade.

Öhrström et al. (2006) conducted socio–acoustic surveys to study the health effects of various soundscapes in residential areas. To survey results showed that access to quiet indoor and outdoor sections in dwellings decreased annoyance, improved sleep and contributed to physiological and psychological wellbeing. The study suggests that, LAeq,24h, road traffic noise at the most-exposed side should not exceed 60 dB, even if there is access to a quiet side in the dwelling, in order to protect 80% of people from annoyance.

Viollon et al. (2002) conducted audiovisual tests on listeners’ judgements during different visual settings. The results showed that visual influence was significant and negative for sounds clips without human sounds; urban visual settings were perceived more unpleasant and more stressful. Bangjun, et al. (2003) found that, in the same acoustic environment, noise annoyance is higher if the noise source is visible.

Gidlöf-Gunnarsson & Öhrström (2007) concluded that availability to nearby green areas is important for people’s well-being and daily behavior by reducing long-term

Nang (2011) found that several neighbourhood characteristics such as greenery and sea are able to decrease noise annoyance. Li et al. (2010) concluded that wetland parks and garden parks reduce noise annoyance better than grassy hills.

Morihara et al. (2004) compared the dose–response relationships between railway and road traffic noises in European and Japanese studies and questioned the difference in relationships. Although there are cultural factors, they concluded that distance from the noise source was an important factor in annoyance.

Klaeboe et al. (2000) worked on an integrated approach to assess the combined effects of noise and air pollution on annoyance in Oslo. Result showed that people are more likely to be annoyed by smell at the same air pollution level if traffic noise levels are higher. Similarly, people are more likely to be annoyed by noise at the same noise level if air pollution levels are higher.

3.1.1.4 Time

Seasons such as summer and winter (Recuero et al. 1996, as cited in Kang, 2007) and time of day such as day, evening and night (Vallet et al, 1996 as cited in Kang, 2007) may have an effect in annoyance. Directive 2002/49/EC (The European Parliament and of the Council, 2002) adds a penalty of 5 dB for evening and 10 dB for night, for calculating the day-evening-night level, Lden.

Noise annoyance during night is identified as sleep disturbance and is investigated extensively. Factors which effect sleep disturbance, such as bedroom location (Pirrera et al., 2014), time frames (Pirrera et al., 2014), number of events (Janssen et al., 2014), balcony design (Naish et al., 2012) and noise source types (Lee at al., 2010) have been studied. Health effects were studied under many heading such as objective and subjective sleep quality (Frei et al., 2014), mental health (Sygna et al., 2014), children's behavioral problems (Tiesler et al., 2013) and cardiovascular problems (Fyhri &

Aasvang, 2010; Tonne et al., 2016).

Studies on relatively long-term changes in noise exposure showed interesting results.

Fidell et al. (1998) concluded that a progressive drop of 1.5–3dB near an airport was hardly noticed over a long period. Another study on airports showed an increase of annoyance and an alteration of dose and effect curves over the years (Babisch et al, 2009).

Influence of time patterns on aircraft noise annoyance was investigated by Brooker (2010). It is stated that people benefit from Heathrow’s regular and predictable alternation cycles. Ohshima and Yamada (2009) investigated on the effect of sound duration on the annoyance of helicopter noise. The sound signal durations were time compressed or expanded and results indicated that the effect of duration is significant.