Research Trend & Results

Research and study for planning future measures forroadside atmospheric environment
KADOYU Katsunori, HeadDOHI Manabu, Senior Researcher
KANDA Taro, Researcher
Road Environment Division, Environment Department
Roadside atmospheric environment, NO2, SPM, PM2.5

道路端における沿道濃度
NO2濃度[ppb], SPM・PM2.5濃度[μg/m3]

y=x

100

新長期規制に適合する貨物車普及率はworld-highest level’s newlong-term
regulation introduced
未だ約4割。
in 2005.
(As of End-Mar. 2012)(2012年3月末時点)

878,769 , 15%

1,550,773 ,26%

ポスト新長期規制
Post
new long-term
新長期規制
Newlong-term
新短期規制
Newshort-term

1,131,679 ,19%

長期規制
Long-term
Short-term
短期規制759,044 , 13%

Beforeshort-term
短期規制以前Figure 2. Share of freight cars conforming to exhaustemission regulations by years
14,000Estimatedemissions in surrounding areas of
一般国道同士の交差点周辺における推定intersections between national highways

12,000354

10,000
5,342

8,000
6,000
4,000

211

8,198

12,09047%減
Reductionby 47%

Reductionby
光触媒による
photocatalyst

削減効果

Reductionby measures
交通流対策にfor traffic flow

よる削減効果Reduction
by single
単体規制によregulation
る削減効果

NOx排出量NOx
emissions

6,385

2,000
70%減
Reductionby 70%080

世界最高水準である
freightcars conforms to the807,774 , 13%削減
効果
Reduction

Concentration at Roadside (Edges)
NO2 Concentration [ppb],
SPM ·PM2.5 Concentration [μm/m3]

120

Only
about 40% of ownership of
2005年に導入された

853,259 , 14%

削減効果
Reduction

Autumn & WinterSurveys on National highways (4 lanes)
一般国道(4車線)における秋季・冬季調査

3. Provisional calculation of future transitions inroadside atmospheric environment
Although the automobile exhaust emission control has
been tightened so far, it will take more than ten years until
the cars conforming to this regulation spread across thecountry because the regulation is applied only to new cars.
For this reason, the environmental burden is expected tobe reduced further by replacing the existing cars with newones in the future. (See Figure 2. )NILIM calculated future transitions in environmental
burden in the surrounding areas of intersections based oneffects of measures. One example of calculation results isshown in Figure 3. This indicates that the environmental
burden will reduce substantially by 2020 and its main
factor is a spread of cars conforming to exhaust emission
control across the country.

NOx emissions [g/day]

1. Introduction
In recent years, roadside atmospheric environment isimproving significantly by tightened automobile exhaustemission control based on the Air Pollution Control Act
and the Road Trucking Vehicle Act, restriction on use ofdiesel cars and introduction of post-setup PM reduction
device at once in metropolitan area based on theAutomobile NOx/PM Act, and improvement of traffic
flow and trial introduction of purifying air technique by
the road administrator, and so on. On the other hand,some roadside automobile exhaust monitoring stations
mainly in traffic-intensive intersections are not satisfying
the environmental standard for NO2 concentrations in theatmosphere as of the year 2010.
NILIM is now conducting a research and study forcorrectly understanding the current situation of roadsideatmospheric environment and its future transition in order
to abstract roadside atmospheric environmental measures
to be implemented predominantly from now on.
2. Study for understanding the current situation ofroadside atmospheric environment
NILIM is conducting a seasonal survey of NO2, SPM,and PM2.5 at the edge and hinterland (about 200m fromthe edge) of roadsides and highways which daily traffic
volume is tens of thousands cars. See Figure 1 for an
example of survey results. The figure shows while theNO2 concentration at the edge of the roads is about twice
as much as that at the hinterland, the concentrations ofSPM and PM2.5 are shifting with almost at the same level
both at the edge and the hinterland of the roads.

NOx排出量 [g/日](Keywords)

2010年
2010
2010
(平成22年)

2015年
2015(平成27年)

3,672
2020年
2020
(平成32年)

604020NO2SPM
PM2.5002040
6080 100 120
Concentration
at Roadside (Hinterlands)
背後地における沿道濃度
33NO2 Concentration[ppb], SPM·PM2 Concentration[μm/m]
NO2濃度[ppb],SPM・PM
2.5濃度[μg/m ]Figure 1. Results of roadside atmospheric study

Figure 3. Estimation of NOx emissions in surrounding
areas of intersections
4. Future direction
According to these study results, we think future
measures for roadside atmospheric environment should
specialize only in NOx physically, and be concentrated
on spreading the cars conforming to more tightened
exhaust emission regulation across the country promptly.