Mobile source pollution is one of the major reasons for the deterioration
of air quality in the metropolitan area and the key point which the
environmental protection and traffic authorities focus on. Besides, emitting
the black smoke from diesel vehicles is most series problem blamed by
citizens. In order to improve the emission by diesel vehicles, the Ministry of
Environment (MOENV) has implemented not only, irregular inspections, but
also enhance the control measures for diesel vehicles. For example, assist
Tier-1 to Tier-3 heavy-duty diesel vehicles (HDDVs) to be replaced for new
ones, install air pollution control equipment or repair fuel injection system,
and it has formulated annual targets for achievement. From 2017 to October
2023, MOENV has assisted as many as 83,333 Tier-1 to Tier-3 HDDVs to
improve pollution, the subsidy measures for large diesel vehicles have
reduced TSP by approximate 4,763 metric tons (including PM10 4,193 tons
and PM2.5 3,708 tons), and NOx approximate 64,677 metric tons.
Until October 2023, there are 3,290 Tier-1 to Tier-3 HDDVs have been
eliminated. Among the applications for subsidies, include eliminating Tier-1
to Tier-3 HDDVs and transferring for new vehicles, totaling 3,077 cases.
This project has evaluated the advantages, disadvantages, and
cost-effectiveness of emission reduction of various inspection tools such as
the no-load free acceleration opacity test method, the full-load 80% test to
inspect NOx and NH3 emissions, and OBD diagnostic equipment. Among
them, considering that the control components of OBD monitoring involve
PM and NOx emissions, and OBD diagnostic equipment is the most
cost-effective, it is more appropriate to plan to introduce OBD diagnostic
equipment and include technological inspection tools in the autonomous
management label specifications after tier-5.
During the period of the plan, nationwide correlation test of diesel
emission testing stations has been finished well, only one inspection line was
found to exceed the control range, showing that the quality of testing stations
for diesel vehicles is favorable. Finally, the statistics of the past eight years
shows that through irregular inspection of diesel vehicles, the country-wide
average opacity rate dropped from 0.82m-1 to 0.33m-1, indicating emission by
diesel vehicles has improved year by year.
