Emissions of NOX and particles from manoeuvring ships

Emissions of NO X and particles from manoeuvring ships

Hulda Winnes a,*,Erik Fridell a,b

a

Department of Shipping and Marine Technology,Chalmers University of Technology,SE-41269Göteborg,Sweden

b IVL Swedish Environmental Research Institute and Department of Shipping and Marine Technology,Chalmers University of Technology,Box 5302,SE 400-14Göteborg,Sweden

a r t i c l e

i n f o Keywords:

Manoeuvring ships Marine transport Emissions to air NO X

Particles

a b s t r a c t

Ship exhausts contain high levels of particles and nitrogen oxides due to the heavy fuel oil normally used for combustion and the combustion characteristics of most ship engines.The quantification of exhaust gases during ships’manoeuvring has not received a lot of attention.This work presents results from emission measurements for the main engines onboard two ships and characterises quantities and potential impacts of emissions from manoeuvring.The observed nitrogen oxides levels vary throughout the manoeuvring per-iod but at lower levels than at cruising speed.With a selective catalytic reduction system in operation,however,the situation is reversed.Elevated levels of particle emissions,mea-sured as number concentrations,are detected throughout the manoeuvring.There are also peak concentrations of particles,at both the start-up and the shut-down of the engines.The increase is big enough to suspect a notable impact on air quality in port cities over the short period that manoeuvring at reduced speeds takes place.

Ó2010Elsevier Ltd.All rights reserved.

1.Introduction

PM 2.5,or so called fine particles,are receiving increasing attention as an indicator of air quality due to their role in health risks and since they mainly can be attributed to anthropogenic emissions.Both the EU and the US have,or will have on their agendas,air quality standards regulating the levels of PM 10,PM 2.5and NO 2.The ceiling values differ somewhat between Eur-ope and the US,however,the World Health Organization (WHO)target ceiling value of 10l g/m 3for yearly averages are low-er than both American and European standards for particulate matter (European Parliament –Council,2008;US Environmental Protection Agency,2010).In Europe,more than 50%of the rural background sites reporting PM 2.5,experience annual mean concentrations higher than these targets (EMEP Co-Operative Programme for Monitoring and Evaluation of the Long-Range Transmission of Air Pollutants in Europe,2008).European rural background levels of NO 2average 15–30l g/m 3while urban concentrations exceed the 40l g/m 3annual limit in many large cities all over the world (World Health Organi-zation,2006).

Ship operations during a journey are generally divided into three modes;at berth,manoeuvring and at sea.The majority of global emissions are emitted while the ships are at sea but the share of fuel combusted while a ship is in port can be around 6%mainly due to the production of electricity by auxiliary engines (Entec UK Limited,2002).The emissions from manoeuvring comprise the lowest share of emissions of the three modes but they can have an impact on local air quality in port cities due to the proximity to land.

There are also differences in emission factors between at sea operation and manoeuvring.The Swedish Environmental Research Institute,IVL,database suggests emission factors for NO X of 14.0and 11.2g/kWh and for particulate matter

1361-9209/$-see front matter Ó2010Elsevier Ltd.All rights reserved.doi:10.1016/j.trd.2010.02.003

*Corresponding author.Tel.:+46317721461.

E-mail address:hulda.winnes@chalmers.se (H.Winnes).

Transportation Research Part D 15(2010)204–211

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Transportation Research Part D

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