Night noise guidelines for Europe - WHO/Europe - World Health ...

EXECUTIVE SUMMARY XV
From source to source the number of separate events varies considerably. Road
traffic noise is characterized by relatively low levels per event and high numbers,
while air and rail traffic are characterized by high levels per event and low numbers.
For two typical situations estimates have been made and presented in
graphical form. The first is an average urban road (600 motor vehicles per night,
which corresponds roughly to a 24-hour use of 8000 motor vehicles, or 3 million
per year, the lower boundary the END sets) and the second case is for an
average situation of air traffic exposure (8 flights per night, nearly 3000 per
year).
Fig. 3 shows how effects increase with an increase of L night, outside values for the
typical road traffic situation (urban road). A large number of events lead to high
levels of awakening once the threshold of L Amax, inside is exceeded. To illustrate
this in practical terms: values over 60 dB L night, outside occur at less then 5 metres
from the centre of the road.
In Fig. 4 the same graph is presented for the typical airport situation. Due to a lower
number of events there are fewer awakenings than in the road traffic case (Fig. 3),
but the same or more health effects. In these examples the worst case figures can be
factors higher: the maximum number of awakenings for an L night,outside of 60–65 dB
is around 300 per year.
% incease/ % population
50
40
30
20
Average motility
Awakenings
Infarcts
100
80
60
40
Number awakenings/year
Fig. 3
Effects
of road traffic
noise at night *
10
Highly sleep disturbed
20
0
20-25 25-30 30-35 35-40 40-45 45-50 50-55 55-60 60-65
0
*Average motility and infarcts are expressed in percent increase (compared to baseline number); the number of
highly sleep disturbed people is expressed as a percent of the population; awakenings are expressed in number of
additional awakenings per year.
A recent study suggests that high background levels of noise (from motorways) with
a low number of separate events can cause high levels of average motility.
Therefore, by using the L night,outside as a single indicator, a relation between effects
and indicator can be established. For some effects, however, the relation can be