levels of environmental noise and perceived health implications in bus termini nairobi central business district
Loading...
Date
2018-06
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
Environmental noise is noise emanating from all other sources except the industrial
workplace, main sources include road, rail and air traffic, industries, construction,
public works and social activities. WHO and NEMA provides permissible
environmental noise level standard to be 75 and 60 dB (A) respectively. Noise pollution
has been linked to many adverse health effects and there is limited documentation to
this effect within the CBD termini of Nairobi.The aim of this study was to assess noise
levels and it’s perceived health effects across bus termini in Central Business District of
Nairobi City. Using a cross-sectional study design and fishers et al (1983) to determine
the sample size, a random sample of 422 community members working within nine bus
termini for more than 8 hours a day were approached and recruited in the study. Noise
levels were measured using Calibrated sound level meter (Model # 8926). A selfadministered semi-structured questionnaire was used to collect data to identify
perceived health risks of noise and safety practices across bus termini. Univariate Chisquare test of independence was used to test the association between noise levels and
reported health implications. The response rate was 94.7% (n= 397). The study revealed
that 66.8% of respondents (n=265) had awareness on effects of excessive noise
exposure as compared to 33.2% (n=132).This study revealed that a higher proportion of
respondents spending more than 3 days a week working at the bus termini visited the
doctor for a perceived noise induced hearing problem. As such there was a significant
association between the number of days spend working at the bus termini in a week and
visiting a doctor for a noise induced hearing problem (χ2=16.52, df=2; p<0.001). In this
study, the leading acute perceived health effects of excessive noise were reported to be
sleep disturbance at 24.17% (n=152), hearing impairment at 23.05% (n=145),
exhaustion at 13.04% (n=82), high blood pressure at 12.72% (n=80) and annoyance at
10.18% (n=64). This study revealed a high concentration of noise levels ranging
between 88.14 to115.04dB(A) at Tuskys, St Peters Clavers, Central, Latema and Ronald
Ngala bus termini as compared to Ngara and Railways bus termini which reported low
concentration of noise levels ranging 85.45 to 93.63dB(A). There was a variation in
maximum mean noise levels across the day, in the morning the maximum noise level
was 93.65dB recorded at Old Nation Bus Terminus, at midday the maximum noise level
was 94.28 dB recorded at Tuskys Bus Terminus while in the evening maximum mean
noise level was 118.44 dB as recorded at Moi Lane Bus Terminus. This study revealed
a significant association (χ2=27.663; df=8; p<0.001) between a respondent visiting a
doctor for a perceived noise induced hearing problem and bus termini in which they are
located. Hence a high proportion of respondents who visited the doctor for a perceived
noise induced hearing problem were from bus termini that recorded high noise levels.
This study revealed that safety practices most likely to be utilized across all
occupational groups include; working few hours in the noisy environment (χ2=7.746;
df=2; p<0.021); closing windows and doors to eliminate noise (χ2=3.89; df=2; p<0.05)
and walking away from noise (χ2=5.29; df=2; p<0.024). However, a higher proportion
of respondents across all the occupational groups reported not using personal protective
equipment. In conclusion, this study has demonstrated that noise levels in Nairobi are
beyond the permissible levels as per NEMA standards 60 dB(A) and WHO ( 75dB(A)
standards. Location of bus termini close to each other contributes to the significant
generation of noise. Consequently, the authorities should spread out bus termini to
reduce high concentration of noise levels at single hotspots in the city. In addition, the
public transport routes should be designed in a manner such that they do not terminate
at one point in the city.