Determination of Selected Indoor and Outdoor Air Pollutants in the Central Business District of Nairobi City, Kenya
Loading...
Date
2013-10-16
Authors
Kipkorir, Bartilol Simion
Journal Title
Journal ISSN
Volume Title
Publisher
Abstract
The atmosphere is a complex environment that coexist gas species, solid particles
and liquid droplets. When these substances are in amounts that could be harmful to
the' health or comfort of humans and animals or which could cause damage to
plants and materials, air pollution is said to occur. Some of the well known effects
associated to air pollution include pulmonary and cardiovascular diseases, reduced
visibility, acidification of soils and waters and accelerated decay of building
materials and paints. Air pollution studies, for a long time concentrated on outdoor
measurements, but recent findings show that indoor concentrations are greater than
five times the corresponding outdoor levels and therefore making it ranked as one
of the top five environmental hazards to human health considering that most urban
people spend 90% of their time indoors. In Kenya, most air pollution
measurements concentrated on outdoor environment with very little on indoor air
pollution reported. The present study determined and compared indoor and
outdoor levels of particulate matter (PM 10), heavy metals (Pb, Zn, Mn, Cu,) in
PMlO and noxious gases (S02, NO, N02, and CO) in Nairobi central business
district from March - November 2007. The PMlO were sampled using a Gent
aerosol sampler and the heavy metals in the particulate matter determined by Xray
fluorescence technique. Gases were collected and analysed using direct reading
gas sensors. Statistical analysis of PMlO results show that 53% indoor
measurements had higher concentration levels compared to corresponding
outdoors (I/O ratio >1.0). The mean average concentrations were 377.0 ±
197.7!lg/M3 and 280.1 ± 122.5!lg/M3 for indoor and outdoor respectively.
However, indoor/outdoor ratio analyses for heavy metals indicate higher
concentrations in outdoors compared to corresponding indoors (I/O ratio=0.9).
Noxious gases' ratios had indoor concentrations greater than outdoor suggesting
indoor levels being influenced by indoor activities. Correlation analyses of PMlO,
heavy metals and gases between regions indicate significant positive and negative
relationships (P > 0.050) suggesting differences in activities in the regions. Most
concentration levels of PMlO and heavy metals surpass the set maximum
concentration limits while gases were within. It is hoped that the Ministry of
Nairobi Metropolitan and interested stakeholders use this baseline data to come up
with measures to mitigate emission of air pollutants in Nairobi city as envisioned
in the Nairobi Metropolitan vision 2030 blueprint; "A World Class African
Metropolis" .
Description
Department of Chemistry, 95p. 2013