Poor regulation implications in a low and middle income country based on PAH source apportionment and cancer risk assessment.

Ambient particle-bound polycyclic aromatic hydrocarbons (PAHs) were collected for one year at an urban background site, and spatially and temporally compared to yearly averages in three coastal cities in Lebanon. The samples were quantified using gas chromatography-mass spectrometry (GC-MS) and source apportioned with an optimized robust method using positive matrix factorization (PMF). Three major sources were found to contribute to PAH emissions at the urban background site, namely, traffic (48%), diesel generators (23%), and incineration (29%). The cancer risk was found higher than what was measured at the same site in previous years with an increase of 35%. Improper regulations of the sources (incineration, power plant, diesel generators and traffic) identified in the different sites resulted in PAH intraurban variability. It is essential to study the chemical components of particulate matter (PM) in order to assess toxicity. In particular, particle-bound PAHs and their oxidation products are known for their carcinogenicity as well as their persistence in the atmosphere, which facilitate their transport to new locations. In the absence of law enforcement, unregulated sources and their total contribution to ambient PAHs present a major health risk. This calls for the attention of development funding agencies and their need to implement sustainable "carbon-free" funding strategies in support of urban development of low and middle-income countries (LMICs).