10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Between Two Oceans: Auckland’s Urban Aerosol
GUY COULSON, Gustavo Olivares, Sally Gray, Oliver Wilson, National Inst of Water & Atmospheric Research, New Zealand
Abstract Number: 603 Working Group: Aerosol Transport and Transformation
Abstract Auckland, the largest city in New Zealand, is unique in being the largest city in the World to be almost completely surrounded by ocean and hence have no up or downwind sources of pollution. The city lies on a narrow isthmus between the Pacific Ocean and the Tasman Sea. Because of the lack of outside sources, average urban background concentrations of between 1000 and 4000 particles/cm3 are common away from major sources with very steep concentration gradients approaching sources such as roads (Pattinson et al., 2014). Consequently, Auckland’s typical urban aerosol tends to be similar to other cities in character but with lower concentrations (Coulson et al 2015).
The Aerosol Tropospheric Chemistry in Urban Auckland (ATChU) experiment aimed to track the changes in aerosols and aerosol precursors as they move from open-ocean (clean background) across the city (polluted) and out into ocean again. Auckland has two prevailing wind directions WSW from the Tasman and ENE from the Pacific, so a transect along this line will almost always be in the prevailing wind direction. The experiment measured various aerosol parameters including composition, Black Carbon, particle number and size distributions along with gaseous pollutants simultaneously at three points across Urban Auckland, one on the upwind coastal urban edge, one in central Auckland and one on the downwind coastal urban edge for a period of approximately one month during March and April 2015.
Results from the west coast site have a similar character to the central Auckland site but with lower concentrations and a noticeable marine influence, whilst the east coast site has a more marine character with some urban influence. This presentation will examine results from the ATChU campaign with an emphasis on looking for the urban influence in a marine setting.
1. Pattinson, W., I. Longley and S. Kingham, Atmospheric Environment Volume 94, Pages 782-792(2014). 2. Guy Coulson, Gustavo Olivares and Nick Talbot. (2016) Aerosol Size Distributions in Auckland. Air Quality and Climate Change Volume 50 No.1. February 2016
Acknowledgements: Thanks to Melita Keywood and Paul Selleck at CSIRO for measurements of chemical composition. This work was funded by NIWA under the Strategic Science Investment Fund - Impacts of Atmospheric Pollution Programme.