SEASONAL VARIATIONS AND INFLUENCE OF TWO CLIMATIC PARAMETERS ON AMBIENT
CONCENTRATIONS OF CARBON MONOXIDE AND PARTICULATE MATTER AT TIN CAN
PORT, LAGOS, NIGERIA
Abstract
Shipping activities are a major source of air pollution in port cities
with the expected high population of port workers and related workforce
being chronically exposed to air pollutants such as carbon monoxide (CO)
and suspended particulate matters (SPM: PM 10). These two priority air
pollutants in addition to relative humidity (RH) and wind speed were
monitored every month over a period of four years at Tin Can, Apapa
Lagos, being the location of the busiest port in Nigeria. Results
indicate that the highest monthly mean concentrations recorded
throughout the study were 3.31 ppm and 258.6 µg/m 3 for CO and PM 10
respectively. While the value of CO was within the recommended threshold
limits by the World Health Organization (WHO) and the Federal Ministry
of Environment (FMEnv), the PM 10 exceeded the WHO specified limit of 50
µg/m 3 for a-24 h period of exposure. The ambient concentrations of the
two air pollutants were higher in the dry season than their
concentrations in rainy season. However, a significant seasonal
variation was observed in the ambient concentrations of PM 10.
Regression analysis shows that wind speed contributes significantly
(p<0.05) to the detectable concentration of CO while RH had no
significant influence on CO availability in the study area. Conversely,
RH significantly influenced the concentration of PM 10 with a direct
positive correlation between the climatic index and particulate matter
while wind speed had no significant influence on suspended particles.
The study established that there is no risk of acute human exposure to
the air pollutants in the ports area. In spite of the low ambient
concentrations recorded during the study, chronic exposure of workers or
residents in port areas has its long-term health implications. Further
study is required to monitor the indoor concentrations of these
pollutants, which were possibly dispersed by wind from the lagoon and
the ocean.