Emissions of NOx, SO2, CO, and HCHO from commercial marine shipping during Texas Air Quality Study (TexAQS) 2006

Williams, E. J.; Lerner, B. M.; Murphy, P. C.; Herndon, S. C.; Zahniser, M. S.

doi:10.1029/2009jd012094

Cited by 105 publications

(116 citation statements)

References 23 publications

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“…SO 2 emissions are directly related to F S (e.g. Williams et al, 2009) and primary particulate sulfate is linked to F S and engine load Petzold et al, 2010). However the impacts of fuel quality on some emissions is unknown or there have been relatively few studies performed.…”

Section: Literature Reviewmentioning

confidence: 99%

Black carbon from ships: a review of the effects of ship speed, fuel quality and exhaust gas scrubbing

2012

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Abstract. The International Maritime Organization (IMO) has moved to address the health and climate impact of the emissions from the combustion of low-quality residual fuels within the commercial shipping industry. Fuel sulfur content (F S ) limits and an efficiency design index for future ships are examples of such IMO actions. The impacts of black carbon (BC) emissions from shipping are now under review by the IMO, with a particular focus on the potential impacts of future Arctic shipping.Recognizing that associating impacts with BC emissions requires both ambient and onboard observations, we provide recommendations for the measurement of BC. We also evaluate current insights regarding the effect of ship speed (engine load), fuel quality and exhaust gas scrubbing on BC emissions from ships. Observations demonstrate that BC emission factors (EF BC ) increases 3 to 6 times at very low engine loads (<25 % compared to EF BC at 85-100 % load); absolute BC emissions (per nautical mile of travel) also increase up to 100 % depending on engine load, even with reduced load fuel savings. If fleets were required to operate at lower maximum engine loads, presumably associated with reduced speeds, then engines could be re-tuned, which would reduce BC emissions.Ships operating in the Arctic are likely running at highly variable engine loads (25-100 %) depending on ice conditions and ice breaking requirements. The ships operating at low load may be emitting up to 50 % more BC than they would at their rated load. Such variable load conditions make it difficult to assess the likely emissions rate of BC.Current fuel sulfur regulations have the effect of reducing EF BC by an average of 30 % and potentially up to 80 % regardless of engine load; a removal rate similar to that of scrubbers.Uncertainties among current observations demonstrate there is a need for more information on a) the impact of fuel quality on EF BC using robust measurement methods and b) the efficacy of scrubbers for the removal of particulate matter by size and composition.

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Section: Literature Reviewmentioning

confidence: 99%

Black carbon from ships: a review of the effects of ship speed, fuel quality and exhaust gas scrubbing

2012

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“…These data are compared to actual in situ measurements obtained during the SIRENAS-R campaign (Mellqvist and Berg, 2012) as briefly described in section 1. The in situ measurements are based on measuring the ratio of SO 2 and CO 2 downwind of the ships in a similar way as Williams et al (2009). The combined optical and model data correspond to a SFC of (1.3 ± 0.5) % while the in situ data shows (1.15 ± 0.2) %.…”

Section: So 2 and No X Emissions Versus Modelled Ship Emissionsmentioning

confidence: 99%

“…The optical system is here combined with an in situ system (Mellqvist and Berg, 2012) that measures ratios of the pollutants against CO 2 , and from this the SFC and NO x emission per fuel unit is directly derived (Williams et al, 2009). The disadvantage with the in situ system is that it requires flying directly into the ship plume, at low altitude 50 to 150 m, and the fact that only relative emissions are obtained.…”

Section: Introductionmentioning

confidence: 99%

Ship emissions of SO2 and NO2: DOAS measurements from airborne platforms

et al. 2012

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Abstract.A unique methodology to measure gas fluxes of SO 2 and NO 2 from ships using optical remote sensing is described and demonstrated in a feasibility study. The measurement system is based on Differential Optical Absorption Spectroscopy using reflected skylight from the water surface as light source. A grating spectrometer records spectra around 311 nm and 440 nm, respectively, with the telescope pointed downward at a 30 • angle from the horizon. The mass column values of SO 2 and NO 2 are retrieved from each spectrum and integrated across the plume. A simple geometric approximation is used to calculate the optical path. To obtain the total emission in kg h −1 the resulting total mass across the plume is multiplied with the apparent wind, i.e. a dilution factor corresponding to the vector between the wind and the ship speed. The system was tested in two feasibility studies in the Baltic Sea and Kattegat, from a CASA-212 airplane in 2008 and in the North Sea outside Rotterdam from a Dauphin helicopter in an EU campaign in 2009. In the Baltic Sea the average SO 2 emission out of 22 ships was (54 ± 13) kg h −1 , and the average NO 2 emission was (33 ± 8) kg h −1 , out of 13 ships. In the North Sea the average SO 2 emission out of 21 ships was (42 ± 11) kg h −1 , NO 2 was not measured here. The detection limit of the system made it possible to detect SO 2 in the ship plumes in 60 % of the measurements when the described method was used.A comparison exercise was carried out by conducting airborne optical measurements on a passenger ferry in parallel with onboard measurements. The comparison shows agreement of (−30 ± 14) % and (−41 ± 11) %, respectively, for two days, with equal measurement precision of about 20 %. This gives an idea of the measurement uncertainty caused by errors in the simple geometric approximation for the optical light path neglecting scattering of the light in ocean waves and direct and multiple scattering in the exhaust plume under various conditions. A tentative error budget indicates uncertainties within 30-45 % but for a reliable error analysis the optical light path needs to be modelled.A ship emission model, FMI-STEAM, has been compared to the optical measurements showing an 18 % overestimation and a correlation coefficient (R 2 ) of 0.6. It is shown that a combination of the optical method with modelled power consumption can estimate the sulphur fuel content within 40 %, which would be sufficient to detect the difference between ships running at 1 % and at 0.1 %, limits applicable within the IMO regulated areas.

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“…NO x measurements were made with a two-channel O 3 -NO chemiluminescence detector (Williams et al, 2009). Only the NO observations from the NO x instruments were used in this study.…”

Section: No X and Hno 3 Measurementsmentioning

confidence: 99%

Nitrous acid formation in a snow-free wintertime polluted rural area

et al. 2018

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Abstract. Nitrous acid (HONO) photolysis is an important source of hydroxyl radicals (OH) in the lower atmosphere, in particular in winter when other OH sources are less efficient. The nighttime formation of HONO and its photolysis in the early morning have long been recognized as an important contributor to the OH budget in polluted environments. Over the past few decades it has become clear that the formation of HONO during the day is an even larger contributor to the OH budget and additionally provides a pathway to recycle NO x . Despite the recognition of this unidentified HONO daytime source, the precise chemical mechanism remains elusive. A number of mechanisms have been proposed, including gas-phase, aerosol, and ground surface processes, to explain the elevated levels of daytime HONO. To identify the likely HONO formation mechanisms in a wintertime polluted rural environment we present LP-DOAS observations of HONO, NO 2 , and O 3 on three absorption paths that cover altitude intervals from 2 to 31, 45, and 68 m above ground level (a.g.l.) during the UBWOS 2012 experiment in the Uintah Basin, Utah, USA. Daytime HONO mixing ratios in the 2-31 m height interval were, on average, 78 ppt, which is lower than HONO levels measured in most polluted urban environments with similar NO 2 mixing ratios of 1-2 ppb. HONO surface fluxes at 19 m a.g.l., calculated using the HONO gradients from the LP-DOAS and measured eddy diffusivity coefficient, show clear upward fluxes. The hourly average vertical HONO flux during sunny days followed solar irradiance, with a maximum of (4.9 ± 0.2) × 10 10 molec. cm −2 s −1 at noontime. A photostationary state analysis of the HONO budget shows that the surface flux closes the HONO budget, accounting for 63 ± 32 % of the unidentified HONO daytime source throughout the day and 90 ± 30 % near noontime. This is also supported by 1-D chemistry and transport model calculations that include the measured surface flux, thus clearly identifying chemistry at the ground as the missing daytime HONO source in this environment. Comparison between HONO surface flux, solar radiation, NO 2 and HNO 3 mixing ratios, and results from 1-D model runs suggest that, under high NO x conditions, HONO formation mechanisms related to solar radiation and NO 2 mixing ratios, such as photo-enhanced conversion of NO 2 on the ground, are most likely the source of daytime HONO. Under moderate to low NO 2 conditions, photolysis of HNO 3 on the ground seems to be the main source of HONO.

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Emissions of NO_x, SO₂, CO, and HCHO from commercial marine shipping during Texas Air Quality Study (TexAQS) 2006

Cited by 105 publications

References 23 publications

Black carbon from ships: a review of the effects of ship speed, fuel quality and exhaust gas scrubbing

Black carbon from ships: a review of the effects of ship speed, fuel quality and exhaust gas scrubbing

Ship emissions of SO<sub>2</sub> and NO<sub>2</sub>: DOAS measurements from airborne platforms

Nitrous acid formation in a snow-free wintertime polluted rural area

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Emissions of NOx, SO2, CO, and HCHO from commercial marine shipping during Texas Air Quality Study (TexAQS) 2006

Cited by 105 publications

References 23 publications

Black carbon from ships: a review of the effects of ship speed, fuel quality and exhaust gas scrubbing

Black carbon from ships: a review of the effects of ship speed, fuel quality and exhaust gas scrubbing

Ship emissions of SO&lt;sub&gt;2&lt;/sub&gt; and NO&lt;sub&gt;2&lt;/sub&gt;: DOAS measurements from airborne platforms

Nitrous acid formation in a snow-free wintertime polluted rural area

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Emissions of NO_x, SO₂, CO, and HCHO from commercial marine shipping during Texas Air Quality Study (TexAQS) 2006

Ship emissions of SO<sub>2</sub> and NO<sub>2</sub>: DOAS measurements from airborne platforms