The impact of closure of coal-fired power stations on aerosol concentrations in the Sydney Basin

Abstract

Abstract Measurements of total PM2.5 from February 1998 to February 2017 were undertaken at Richmond, Australia and elemental composition was determined using Ion Beam Analysis. Using positive matrix factorisation seven source fingerprints were identified; soil dust Soil (4.1% ± 0.6%), industrial sulfur with aged sea spray IndSaged (16% ± 1%), fresh sea salt Sea (4.8% ± 0.7%), secondary sulfate 2ndryS (24% ± 1%), Smoke (31% ± 1%), industrial metals Indmetals (1.9% ± 0.9%) and vehicle emissions Auto (18% ± 1%). Back trajectory analysis showed that 27% of the measurements recorded at least one crossing with a coal-fired power station. During the study period a reduction in the SO2 emissions was seen and three coal-fired power stations were closed; one each to the north, west and north-east (central coast) of the sampling site. The central coast region had the major impact at this site (with 50% and 67% of back trajectory crossing reported overall and summer, respectively). One of the central coast coal-fired power stations, Munmorah, closed in July 2012, followed by the closure of a western power station Wallerawang and a northern power station Redbank in the second half of 2014. When the difference in the average of the four years before the closure of Munmorah was compared against the average of the four years after the closure, a 32% reduction in the mean of secondary sulfate fingerprint was observed (from 1.47 μg/m3 to 1.00 μg/m3) and about 27% was attributed to the reduction in emissions from the coal-fired power stations and 5% due to the reduction in releases from other sources.