Abstract
PM2.5 has been a problem for inhabitants throughout the whole world. To reduce this, there is a need to know the amount that is present in the atmosphere. The quantification of PM2.5 will help to determine the type of remedies for air quality. One of the methods used for quantification is the use of low-cost sensors which are easy to use, high temporal resolution, and small to handle. The aim of this study is to apply low-cost optical sensors to determine the PM2.5 during the dry (Harmattan) season at two sites in Akure, Ondo State, Nigeria. The results showed that PM2.5 at a site (Site-B) ranged between 14.4 and 590.4 µg/m3, while that at another site (Site-C) ranged between 14.5 and 737.2 µg/m3. The mean values (75.7 and 87.5 µg/m3 at the Site-B and the Site-C, respectively) were significantly beyond the standard limits of WHO and NESREA. Shorter timescales peaks within a few hours were frequently observed especially at the Site C during daytime, likely due to the local emissions of PM2.5 due to combustion activities. The higher-density multi-points observations are highly recommended to understand sources, behavior, and health effects of PM2.5 in regional city in South-West Africa.