Marine aerosol in Aotearoa New Zealand: implications for air quality, climate change and public health

Particulates emitted from the ocean’s surface such as sea salt and byproducts of marine biogenic activity form atmospheric aerosols. Aerosols are important for climate change because they have offset some of the historical warming caused by greenhouse gases. Aerosols are also significant for human health: they are small enough to be inhaled and contribute to respiratory problems and other illnesses. Marine aerosol is the primary source of natural aerosol present in urban areas of Aotearoa New Zealand and, as part of the natural aerosol background, cannot be managed. Here, we review the production and presence of marine aerosols in New Zealand’s air, and the implications for human health and climate change. Because marine aerosol is sensitive to physical changes in climate such as sea surface temperature and winds, production is likely to be affected by climate change. Overall, marine aerosol is unlikely to become a smaller contributor to urban atmospheric aerosol loading in New Zealand towns and cities under future climate change scenarios. Continued assessment of anthropogenic aerosols will be necessary to ensure that air quality targets are met.