An emission inventory of sulfur from anthropogenic sources in Antarctica

Atmos. Chem. Phys., 9, 3397–3408, 2009 www.atmos-chem-phys.net/9/3397/2009/ © Author(s) 2009. This work is distributed under the Creative Commons Attribution 3.0 License. Atmospheric Chemistry and Physics An emission inventory of sulfur from anthropogenic sources in Antarctica S. V. Shirsat and H. F. Graf Department of Geography, University of Cambridge, Cambridge, UK Received: 8 October 2008 – Published in Atmos. Chem. Phys. Discuss.: 21 January 2009 Revised: 14 April 2009 – Accepted: 5 May 2009 – Published: 26 May 2009 Abstract. This paper presents first results of a comprehensive emission inventory of chemical species from anthropogenic activities (power generation, vehicles, ships and aircraft) in Antarctica, covering the 2004–2005 period. The inventory is based on estimated emission rates of fuel consumption provided by some of the Antarctic research stations. Since the emission sources have different modes of operation and use a variety of fuel, the emission flux rate of chemical species is calculated by multiplying the fuel consumption value with the density of fuel and appropriate emission factors. A separate inventory is prepared for each anthropogenic emission source in Antarctica. Depending on the type of operation, emission rates of SO2 , and BC (Black Carbon, from shipping only) have been calculated using the above technique. However, only results of SO2 emissions from each source are presented here. Emission inventory maps of SO2 depicting the track/path taken by each mobile source are shown. The total annual SO2 is 158 Mg from power generation and vehicle operations, 3873 Mg from ships and 56 Mg from aircraft for 2004–2005 and these values undergo strong seasonality following the human activity in Antarctica. Though these figures are small when compared to the emissions at most other regions of the world, they are an indication that human presence in Antarctica leads to at least local pollution. The sources are mainly line and point sources and thus the local pollution potentially is relatively strong. Correspondence to: S. V. Shirsat () 1 Introduction The climate system of Antarctica is very unique and extreme compared to any other region, making it one of the most pristine (Wall, 2005) places on Earth. Chemical species play an important role in the atmosphere, by affecting air-quality, climate, radiative forcing etc. These effects depend on the type and chemical concentration of the species, place of emission in the atmosphere, climatic conditions of a particular region and emission source. Globally, emissions due to anthropogenic activities account for approximately 70 Tg (S) of the total (natural + anthropogenic) 107 Tg (S) emissions of sulphur each year, although a greater uncertainty exists for natural sources (Smith et al., 2000). In the Arctic, critical concentrations of SO2 (5 µg/m3 ) have been exceeded over a large area and pose damage to ecosystems due to anthropogenic activities (nickel smelters) occurring in the nearby Norilsk region and Kola Peninsula (Kashulina et al., 2003; AMAP report, 1998). In Antarctica, due to growth in tourist and scientist visits to various continental and/or peninsular sites, the impact has started to be recognised and is a cause of concern. Tourism in Antarctica started during 1950’s (Roper-Gee, 2003) with the first flight and ship visits to the Peninsular region. However, in recent years the number of tourists visiting Antarctica has increased from approximately 6000 in 1992– 1993 to 26 000 in 2005–2006 (as available from IAATO, International Association of Antarctic Tour Operators), with more than 98% of them being ship-borne (United States Environment Protection Agency, 2001). In recent years, due to the growth of human activity and visits to Antarctica (IAATO, Overview of Antarctic Tourism, 2003–2004), it is necessary to elucidate the contribution of different emission sources towards concentration levels of chemical species. Earlier local investigations by Lugar (1993) revealed that during the 1992–1993 austral summer PM10 levels measured Published by Copernicus Publications on behalf of the European Geosciences Union. 3398 S. V. Shirsat and H. F. Graf: Inventory of sulfur from anthropogenic sources in Antarctica at Central McMurdo were comparable to concentrations found in Santa Fe, New Mexico during 1991. A study conducted during 1992–1995 by Wolff and Cachier (1998) shows that aetholometer readings increased dramatically due to black particle emissions from generators present at Halley research base. Also, Mazzera et al. (2001) in their 1995– 1996, 1996–1997 austral summer study indicate that McMurdo base (located at the Hut Point peninsula on Ross Island) was highly impacted by emissions due to human activities at the base. Studies carried out in the past take into consideration mainly single research station or sources, the only exception being Boutron and Wolff (1989), who suggested sulfur emissions from fuel and waste burning of 70 Mg/year for 1987. Here, we attempt a full survey of contemporary anthropogenic emissions in Antarctica. Global emission inventories like GEIA (Global Emission Inventory Activity), EDGAR (Emission Database for Global Atmospheric Research) etc. have been developed in the past to estimate the contributions of anthropogenic and natural sources towards the levels of different chemical species and greenhouse gases over national/regional/global scales. These databases are of great importance to climate modellers and atmospheric scientists who wish to understand the trends and spatio-temporal distribution of chemical species in the atmosphere and deposition at the surface. Besides this, as pointed by Buron et al. (2005), implications of these emission inventories arise for designing policies oriented towards reduction of emissions, especially from anthropogenic sources. However, so far the “pristine” Antarctic continent has not been included in these inventories. This study presents a comprehensive emission inventory of SO2 emitted due to all anthropogenic activities in Antarctica for the one-year period 2004–2005. Human activities in Antarctica include power/heat generation at the research base, vehicular activity, marine and air-borne traffic. Use of diesel/gas oil in generators leads to the release of chemical species that might affect the air-quality in the vicinity of the bases. Vehicles are used for delivering fuel, support personnel and for carrying out scientific activities across Antarctica. Combustion of fuel in ship engines could lead to release of different pollutants along ship tracks and along coastal regions which might later get transported to elsewhere. Therefore, it becomes necessary to quantify the emissions from shipping operations as they tend to affect the environment especially through radiative forcing (e.g., Lawrence and Crutzen, 1999; Endresen et al., 2003) and are likely to be the most polluting source, particularly when compared to vehicle e (...truncated)