PM2.5 and PM10 concentrations in urban and peri-urban environments of two Pacific Island Countries

Air quality monitoring in most Pacific Island Countries, Territories, and States (PICTS) is minimal, with notable exceptions in Hawai’i and New Caledonia. However, air quality issues are increasingly significant in the region. Existing data on air quality, particularly regarding PM2.5 and PM10, are limited, with studies focusing on Fiji and New Caledonia. Our research provides the first continuous and comparative air quality monitoring in urban and peri-urban areas of Fiji and the Solomon Islands, and it is the first assessment since the introduction of the 2021 World Health Organization (WHO) Air Quality Guidelines (AQG). This study assesses health risks and air pollution trends to inform governmental recommendations. We collected PM2.5, PM10, and weather data from Honiara, Solomon Islands (February 2020–August 2023), and Suva, Fiji (April 2021–August 2023). In Honiara, PM2.5 levels exceeded WHO AQG on 75% of days in urban areas and 51% in peri-urban areas, while PM10 levels
surpassed guidelines on 2% of days in both areas. In Suva, urban areas had a 10% exceedance of PM2.5 guidelines, compared to 13% in peri-urban areas. Annual PM2.5 averages exceeded WHO guidelines every year, with levels in Suva and Honiara exceeding guidelines by 2–4 times. PM10 levels were 1.5 times higher than WHO AQG in urban Honiara and 1.2 times higher in peri-urban areas. These findings highlight the urgent need for governmental action to establish robust air quality standards and long-term monitoring programs in Fiji and the Solomon Islands to mitigate health risks from poor air quality.