Air quality impacts of Tokyo’s on-road diesel emission regulations

https://doi.org/10.1016/j.trd.2008.02.004Get rights and content

Abstract

In October 2003, the Tokyo Metropolitan Government began regulating emissions from diesel-powered trucks and buses under a local in-use particulate emission standard. This paper uses an empirically based emissions modeling approach to estimate the effect of Tokyo’s regulations on emissions of particulate matter and nitrogen oxides. Results indicate that Tokyo’s regulations cut exhaust particulate emissions from diesel-powered trucks and buses registered in Tokyo by 17% and 31% in 2003 and 2004 through the promotion of diesel particulate filters and oxidation catalysts and by accelerating fleet turnover. Modest emission reductions were also observed for nitrogen oxides. The model suggests that the bulk of emission reductions – 70% for particulate matter, and 30% for nitrogen oxides – after 2002 directly tied to environmental policies are attributable to Tokyo’s local regulations rather than national emission control policies.

Introduction

Since the mid-1980s, Japan has struggled with arguably the developed world’s worst problem with pollution from on-road diesel vehicles due to the density of its cities, preferential pricing and taxation policies for diesel fuel adopted in the 1970s, and weak restrictions on emissions of particulate matter from new and in-use vehicles. Beginning around 1985, air quality began to decline in many Japanese cities as diesel trucks became more prevalent in goods movement, threatening progress the central government made in the 1970s controlling emissions from stationary sources and light-duty passenger vehicles. Bucking trends in much of the developed world, ambient concentrations of nitrogen oxides (NOx) and suspended particulate matter (SPM) worsened in urban areas during the 1980s, with the central government being forced to delay its targets for compliance with ambient air quality standards in 1985, 1988, and once again in 2000.

Japan’s central government reacted in 1989 by adopting its first comprehensive diesel emissions policy, establishing emission standards for diesel particulates from new trucks and buses, requiring the sale of 500 parts per million (ppm) sulfur diesel fuel by 1997, and implementing regulations mandating the early retirement of older diesel trucks and buses in urban areas. While significant, those regulations failed to reverse the slide in air quality: by 1998, only 55% of the roadside monitoring stations in the extended Tokyo metropolitan region were in compliance with central ambient air quality standards for nitrogen dioxide (NO2) originally targeted for 1976, with only 11% of stations complying with SPM standards (Environment Agency, 1999).

On August 27th, 1999, Japan’s laissez faire policy toward diesel pollution came to an abrupt end when the Tokyo Metropolitan Government (TMG), led by controversial Governor Shintaro Ishihara, announced “Operation No Diesel”, a local policy pushing for tougher regulation of on-road diesel emissions. The cornerstone of Tokyo’s diesel policy was a local in-use particulate emission standard requiring the installation of either diesel particulate filters (DPF) or diesel oxidation catalysts (DOC) on all diesel-powered trucks, buses, and special purpose vehicles1 in operation for more than seven years and used within city limits.

The implementation of Tokyo’s in-use standard was correlated with significant improvements in local air quality. Roadside concentrations of SPM fell by over 20% between 2002 and 2004, with the percentage of stations complying with national ambient air quality standards jumping from 0% to 97% (Tokyo Bureau of Environment, 2005). Ueno et al. (2004) found that per kilometer emissions of primary particulate matter from diesel trucks and buses decreased by more than 40% from 2001 to 2003 in Tokyo.

This paper estimates the contribution of Tokyo’s local in-use emission standard, in the form of reduced emissions of particulate matter and NOx from trucks, buses, and special purpose vehicles, to these air quality improvements. To do so, we introduce a simple emissions model capable of disaggregating the impact of local regulations from intervening variables such as central emission control policies and exogenous changes in transport demand.

Section snippets

Air quality improvements in Tokyo

Under “Operation No Diesel”, TMG issued new diesel emission regulations that in October 2003 retroactively enforced the central government’s particulate emission standards for model year 1998 vehicles on in-use medium and heavy-duty vehicles. Owners of affected vehicles could comply with Tokyo’s regulations through one of three means: installing a TMG-certified DPF or DOC, replacing vehicles that had been in use for more than seven years with a newer diesel-powered vehicle, or purchasing a

Japan’s diesel emissions regulations

Three primary motor vehicle emission regulations – two central, and one local – likely contributed to the substantial improvement in Tokyo’s air quality from 2002 to 2004. The first were tighter emission standards for NOx and particulate matter adopted in December 1989 by Japan’s Environment Agency. These requirements were introduced in two phases: “short-term” (tanki) standards enforced in 1994 for heavy-duty vehicles, and “long-range” (chouki) standards introduced in 1998 (Japanese Ministry

Emissions modeling procedure

Each of these policy instruments likely contributed to the recently observed air quality improvements in Tokyo. For this study, we have adapted a model previously used by Japan’s Environment Agency to construct national motor vehicle emissions inventories (Nomura Research Institute, 1998) to estimate the specific contribution of Tokyo’s in-use emission standard.

The model estimates a fleet average annual emission factor (EF) for four vehicle types – light and heavy commercial vehicles, buses,

Estimating emission reductions attributable to Tokyo’s in-use standard

The emission reductions seen in Fig. 5, Fig. 6 are driven by three major trends – a reduction in particulate and NOx emission factors for new vehicles over time, a decrease in the mean vehicle age due to accelerated fleet turnover, and the spread of DPF and DOC retrofits since 2002 – along with two less important changes: reductions in vehicle kilometers traveled by light and heavy commercial vehicles, and the falling incidence of diesel engines in light and medium-duty trucks.

The first three

Interpretation of model results

Table 5, Table 6 illustrate the air quality impact of Tokyo’s in-use particulate standard by showing emission reductions attributable to each local and central regulatory instrument from 2001 to 2004. To facilitate comparison, all emission reductions are calculated relative to a hypothetical “no-regulation” case corresponding to emission levels in the absence of local and central emission regulations after 1993.

Absent central and local regulations, the model predicts that particulate emissions

Acknowledgements

The authors would like to thank the staff of the Tokyo Bureau of Environment, in particular Teruyuki Ohno, Masa Ohara, Yuko Nishida, and Toshiko Chiba, for their aid in collecting the data necessary for this paper. Thanks goes as well to Duc Wong for her help in preparing this manuscript. This research was conducted with the generous financial support of the Japan US Educational Commission, the Japan Fund, the Stanford Center for East Asian Studies, the UPS Foundation, and the Shorenstein Asia

References (24)

  • Automobile Inspection and Registration Association, 1996–2005a. Jidousha hoyuu sharyousuu, hatsu tourokunen betsu...
  • Automobile Inspection and Registration Association, 1996–2005b. Jidousha hoyuu sharyousuu, shobunbetsu (Motor vehicle...
  • Environment Agency, 1999. Heisei 10 nendo ippan kankyou taiki sokutei kyoku sokutei kekka (Monitoring results for...
  • Japan Automobile Dealers Association, 1999–2004a. Jidousha touroku toukei jouhou, shinshahen (Motor vehicle...
  • Japan Automobile Dealers Association, 1999–2004b. Jidousha touroku toukei jouhou, chuukohen (Motor vehicle registration...
  • Japan Clean Air Program, 2000. Dhiizeru kihaisha taisaku no taikishitsu he no eikyou hyouka houkokusho (Air quality...
  • Japanese Ministry of Land, Infrastructure, and Transport, 2001–2005. Jidousha unsou toukei chousa nenpyou (Annual...
  • Japanese Ministry of Land, Infrastructure, and Transport, 2005. Rikuun toukei youran (Survey of land transport...
  • Japanese Ministry of the Environment, 2002. Heisei 13 nendo ippan kankyou taiki sokutei kyoku sokutei kekka (Monitoring...
  • Japanese Ministry of Transport, 1996–2000. Jidousha unsou toukei chousa nenpyou (Annual survey of motor vehicle...
  • N. Nishikawa

    NOx kisei ni tsuite

    Kankyou to Kougai

    (1993)
  • Nomura Research Institute, 1998. Jidousha haishutsu gasu gentani oyobi souryou ni kan suru chousa (Survey of motor...
  • Cited by (6)

    • Evaluation of ginkgo as a biomonitor of airborne polycyclic aromatic hydrocarbons

      2012, Atmospheric Environment
      Citation Excerpt :

      The second objective of the present study was to evaluate the effects of the on-road diesel emission regulations introduced by the Tokyo Metropolitan Government in October 2003, through long-term (five-year) monitoring using ginkgo trees. Diesel vehicles that do not meet the new particulate matter (PM) standard can be replaced or retrofitted with a particulate control device (Tokyo Metropolitan Government, 2006; Rutherford and Ortolano, 2008). Although the effects of the regulations on black carbon, PM, and oxides of nitrogen were reported (Kondo et al., 2006; Rutherford and Ortolano, 2008), the effects on PAHs are not well understood.

    • Road traffic flow and air pollution concentrations: evidence from Japan

      2024, International Journal of Economic Policy Studies
    • Urban air pollution control policies and strategies: a systematic review

      2021, Journal of Environmental Health Science and Engineering
    • The analysis of subsidy and reward policies for alternative fuel vehicles

      2010, EVS 2010 - Sustainable Mobility Revolution: 25th World Battery, Hybrid and Fuel Cell Electric Vehicle Symposium and Exhibition
    View full text