Using a Network of Low-cost Particle Sensors to Assess the Impact of Ship Emissions on a Residential Community

ABSTRACT

Shipping emissions are known to have an impact on communities in coastal locations, especially near harbours. This study was carried out to monitor the air quality near the premier cruise ship terminal in Melbourne, over a continuous period of 98 days during the peak cruise ship season in Australia. As these emission plumes are intermittent and fluctuate spatially, a single fixed monitor is not suitable for their detection. To overcome this limitation, seven low-cost KOALA air quality monitors were spatially distributed, 4 at ground level and 3 on the upper balconies of two high-rise apartment blocks. The KOALA monitor measures PM_2.5 and CO concentration in real time and transmits the data through the 3G network to an in-cloud database. The time profile showed numerous very high short-term PM_2.5 concentration spikes coinciding with ship movements, some of them exceeding 200 μg m^-3 for periods of 5-10 min. On average, the PM_2.5 concentration during spike episodes was about 4-5 times over the normal background value of around10 μg m^-3. As they lasted for very short times, these spikes did not contribute significantly to the overall 24-hour average values at any of the locations. However, the number of days when the latter value exceeded the national air quality standard was higher than at the nearest air quality station. We attribute this to the high pollution spikes. While the long-term health effects of elevated PM concentrations are known, there have been very few studies on the effect of short-term exposures to high spikes.