摘要：Air quality is a serious and worsening problem in the rapidly growing cities of sub-Saharan
Africa (SSA). However, the lack of ambient monitoring data, and particularly urban
roadside concentrations for particulate matter in SSA cities severely hinders our
ability to describe temporal and spatial patterns of concentrations, characterize
exposure–response relationships for key health outcomes, estimate disease burdens,
and promote policy initiatives to address air quality. As part of a collaborative
transportation planning exercise between Columbia University and the University
of Nairobi, air monitoring was carried out in February 2006 in Nairobi, Kenya.
The objective of the monitoring was to collect pilot data on air concentrations
(PM2.5 and black carbon) encountered while driving in the Nairobi metropolitan area,
and to compare those data to simultaneous 'urban background' concentrations
measured in Nairobi but away from roadways. For both the background and roadway
monitoring, we used portable air sampling systems that collect integrated filter
samples. Results from this pilot study found that roadway concentrations of
PM2.5 were approximately 20-fold higher than those from the urban background site,
whereas black carbon concentrations differed by 10-fold. If confirmed by more
extensive sampling, these data would underscore the need for air quality and
transportation planning and management directed at mitigating roadway pollution.
