Environmental Engineering Reference
In-Depth Information
Fig. 7
Unit pollutant load from
road surface
20
16
15
10
8
7
5
4.3
2.6
1.96
1.35
1.41
0
Public Works
Research Institute
(surveyed in
1974)
JIWET
(surveyed
in 1993-95)
This Research
History of Unit Load in Japan
In Japan, national research institutes
[5]
and nonprofit foundations
[6]
have sur-
veyed pollution loads from road surface. The data sets summarized in Fig.
7
cannot
simply be compared with each other because the sites of the survey differed, but a
decreasing trend over the years is shown. This was possibly attributable to reduc-
tions in dust fall from the atmosphere due to successful environmental policies,
exhaust gas restrictions and road cleaning.
Conclusion
In this study, a basic and large-scale survey was conducted on pollutant loads from
roads. The results of the study are summarized as follows.
1. In four cities of Japan, pollutant loads from road were surveyed at 24 points in
each residential, commercial and industrial district by using a newly developed
mobile sprinkling equipment. The amounts of pollutants were measured for
those discharged just by spraying water and those discharged only after the road
surface was scrubbed with a brush separately to understand the potential of the
road surface for a non-point source.
2. The measurements suggested that the unit loads of BOD, COD
Mn
and SS were
the largest in commercial districts and were almost the same in industrial and
residential districts, but with smaller values.
