Elemental Characterization and Source Apportionment of Fine Particulate Matter (PM2.5) in Industrial and Non-Industrial Areas of Lagos State, Nigeria

IFECHUKWUDE CHIEDU, Faith Oyibo, Federal Institute of Industrial Research Lagos, Nigeria.

     Abstract Number: 93
     Working Group: Source Apportionment

Abstract
Air pollution is initiated by substances in the air caused by natural emissions or by anthropogenic (originated by humans) activities. Some particulates come from natural sources such as evaporated sea spray, windborne pollen and entrained soil dust. Particulates from natural sources tend to be coarse. Almost all fine particulates are generated as a result of combustion processes, including the combustion of fossil fuels for steam generation, heating and household cooking, agricultural field burning, diesel-fuelled engine combustion, and various industrial processes. Particulate matter (PM) which can be inhaled into the human respiratory system is related to most serious health effect including pulmonary and cardiovascular illness.

The fine particulate matter (PM_2.5) was collected using Casella Cel-712 Microdust Pro Real-time Dust Monitor with polyurethane foam (PUF) and a glass fibre filter (GFF).The sampler was placed at heights of 1.5m above ground level and within the human breathing zone. The glass fibre filter (GFF) was used to collect the fine particulate matter. The sampler was connected to a pump with a flow rate of 2L/min for a sampling period of 8 hours/day. Based on the field study conducted, the concentrations of PM_2.5 at the different locations vary with respect to anthropogenic sources. The PM_2.5 levels obtained ranged from 14.00 to 32.67µg/m3during wet season and 18.67 to 34.67µg/m3during dry season. Trace elements were determined using Atomic Absorption Spectrophotometer.

The elements: Pb, Cd, Cr, Cu and Ni, in the fine fraction (PM_2.5) is a signature of anthropogenic sources. Principal Component Analysis (PCA) studies explained two common contributing sources of fine particulates (PM_2.5) such as entrained soil and combustion. Correlation matrix which reflects the association between elements and the similarity of their pollution sources was also determined and some of the elements were strongly correlated while some were not.