Correlation between particulate matter concentrations and meteorological parameters at a site in Ile-Ife, Nigeria

INTRODUCTION The earth's atmosphere has served man as a means of sustaining air to breathe and as a medium for disposing waste from various activities. Pollutants such as dust, fumes, gas, mist, odour, smoke, or vapour occur in varying quantities, characteristics and residence time and have the potential to alter the state of the atmosphere (Flagan and Seinfeld, 1988). The actual composition of the atmosphere varies with geographical location, elevation and season of the year (Muhammad, 2007). Atmospheric accumulation of pollutants may also have significant impact on the climate and weather processes and modification. One of the most frequently encountered pollutants is particulate matter which consist of suspended mixture of solids and liquid droplets materials. Particulate Matter (PM) are introduced into the atmosphere from a variety of anthropogenic and natural sources (Miranda and Tomaz, 2008). The primary sources of the particulate matter are dust storms, fugitive dust from tilling, roadways and construction, windblown soils, forest fires, bush and wood burning and traffic exhaust while s e c o n d a r y s o u r c e s i nvo l ve ch e m i c a l transformation of the primary pollutants through complex photochemical reactions and gas-toparticle conversion of precursors such as SO , NO and Volatile Organic Compounds (VOCs) under favourable meteorological conditions (Fraser 1999). Incineration of domestic waste constitutes further sources to atmospheric particulate matter. In urban area, the principal sources of air pollution are from activities which involve generation of fuel and its utilisation to achieve services necessary for promoting good and enviable standard of living. The concentration of particulate matter varies and it is majorly influenced by weather pattern, wind speed and direction, relative humidity, precipitation and topography (Ghim, , 2001). Study of large scale potential influence of meteorological conditions on atmospheric particulate matter requires the knowledge of physiochemical composition, sizes, distribution in time, space and atmospheric residence time of the particulates (IPCC, 2001). Meteorological conditions also determine the behaviour and fate of atmospheric particulates after been released from the source. Physical sizes depend on the 2