Measuring SO<sub>2</sub> ship emissions with an ultraviolet imaging camera

Abstract

Abstract.Over the last few years fast-sampling ultraviolet (UV) imaging cameras have been developed for use in measuring SO 2 emissions from industrial sources (e.g. power plants; typical emission rates ∼ 1-10 kg s −1 ) and natural sources (e.g. volcanoes; typical emission rates ∼ 10-100 kg s −1 ). Generally, measurements have been made from sources rich in SO 2 with high concentrations and emission rates. In this work, for the first time, a UV camera has been used to measure the much lower concentrations and emission rates of SO 2 (typical emission rates ∼ 0.01-0.1 kg s −1 ) in the plumes from moving and stationary ships. Some innovations and trade-offs have been made so that estimates of the emission rates and path concentrations can be retrieved in real time. Field experiments were conducted at Kongsfjord in Ny Ålesund, Svalbard, where SO 2 emissions from cruise ships were made, and at the port of Rotterdam, Netherlands, measuring emissions from more than 10 different container and cargo ships. In all cases SO 2 path concentrations could be estimated and emission rates determined by measuring ship plume speeds simultaneously using the camera, or by using surface wind speed data from an independent source. Accuracies were compromised in some cases because of the presence of particulates in some ship emissions and the restriction of single-filter UV imagery, a requirement for fastsampling (> 10 Hz) from a single camera. Despite the ease of use and ability to determine SO 2 emission rates from the UV camera system, the limitation in accuracy and precision suggest that the system may only be used under rather ideal circumstances and that currently the technology needs further development to serve as a method to monitor ship emissions for regulatory purposes. A dual-camera system or a single, dual-filter camera is required in order to properly correct for the effects of particulates in ship plumes.

Field test of available methods to measure remotely SO<sub>x</sub> and NO<sub>x</sub> emissions from ships

“…This leads to the conclusion that the UV camera most likely overestimates the emission rate values. The measurements of ship emissions of SO 2 performed with the UV camera in this and other campaigns are further discussed by Prata (2014).…”

“…A new approach based on UV imaging has been tested by the Norwegian NILU institute (Prata and Bernardo, 2008;Prata, 2014). The SO 2 imaging camera (UVGasCam) exploits a strong absorption feature of the SO 2 molecule in the UV region (between 280-320 nm) and is composed by a highly sensitive (between 280-320 nm) CCD array (1344 × 1024 pixels) manufactured by Hamamatsu Photonics and a UV transparent lens objective.…”

First estimates of fumarolic SO 2 fluxes from Putana volcano, Chile, using an ultraviolet imaging camera

“…A precursor of this UV camera has recently been used to show that SO 2 cameras are, besides useful for monitoring volcanic and stack emissions, able to measure SO 2 fluxes from ships (Prata, 2014). A detailed overview of the instrumental parameters of the Envicam-2 is given in Kern et al (2015), Table 1 where the authors present an intercomparison of seven state-of-the-art SO 2 cameras gathered during the first Plume Imaging Workshop at Mt.…”

“…UV cameras have been used to monitor SO 2 emissions from volcanoes (typical fluxes~10-100 kg s −1 ; Burton et al, 2015, and references therein), power plants (~1-10 kg s − 1 ; McElhoe and Conner, 1986;Ajtai, 2012) and ships (~0.002-0.1 kg s −1 ; Prata, 2014). So far, the only fumarole field observations using UV cameras were made by Tamburello et al (2011a) at the La Fossa crater, Vulcano Island.…”

Characterising vertical turbulent dispersion by observing artificially released SO<sub>2</sub> puffs with UV cameras

“…To date, SO 2 cameras have been used mostly to monitor SO 2 15 emissions from volcanoes , power plants ( McElhoe and Conner, 1986;Smekens et al, 2015) and ships (Prata, 2014). While each individual camera measures only 2D distributions of SO 2 column concentrations, a combination of several such cameras should allow a tomographic reconstruction of the 3D SO 2 distribution.…”