McLaren, RobertPritchard-Oh, Austin Michael2023-08-042023-08-042023-08-04https://hdl.handle.net/10315/41292Sulfur dioxide (SO2), particle sulfate (p-SO4-2), and total sulfur (SOx) were evaluated at York University, in Toronto, Canada, using a ThermoFisher SO2 analyzer and an Aerodyne Aerosol Mass Spectrometer. These measurements were compared with a dataset from 2002-2020, which demonstrated a downward trend in atmospheric sulfur. Toronto’s atmospheric sulfur decline has plateaued in recent years. Current mean SO2 was 0.37 ppb, p-SO4-2 was 0.60 μg/m3, and SOx was 1.6 μg/m3. There were no significant seasonal or daytime/nighttime differences. The effects of pollutant transport and major contributors to Toronto’s sulfur were determined. Major contributors to SO2 included Hamilton metal refineries, Greater Toronto Area chemical production facilities, the Nanticoke petroleum refinery, and vehicle emissions. Major contributors to p-SO4-2 are Sarnia petroleum and chemical production, Sudbury metal refineries, and long-range transport from the Ohio River Valley. A field study mass-balance determination of Sarnia’s SO2 emissions was estimated at 0.18 tonnes/hr (4,300 kg/day).Author owns copyright, except where explicitly noted. Please contact the author directly with licensing requests.Atmospheric chemistryEnvironmental scienceAnalytical chemistryElectronic Thesis or Dissertation2023-08-04AtmosphereAtmospheric chemistryAnalytical chemistryEnvironmentSulfurSulphurSulfateSulphateParticle sulfateSO2SO4SOxTorontoYork UniversityPollutionChange in sulfurPollutant transportLong rangeShort rangeSarniaOhio River ValleyPetroleum emissionsAerodyneAMSAerosol mass spectrometerThermo FisherSO2 fluorescence