Autor(es):
Slezakova, Klara 
; Pires, J. C. M. ; Castro, Dionísia ; Alvim-Ferraz, Maria da Conceição M. ; Delerue-Matos, Cristina ; Morais, S. ; Pereira, Maria do Carmo
Data: 2013
Identificador Persistente: http://hdl.handle.net/10400.22/3356
Origem: Repositório Científico do Instituto Politécnico do Porto
Assunto(s): Polycyclic aromatic hydrocarbons (PAHs); Health risks; Traffic emissions; Cluster analysis (CA); Principal component analysis (PCA); Linear regression models
Descrição
This study aimed to characterize air pollution and
the associated carcinogenic risks of polycyclic aromatic
hydrocarbon (PAHs) at an urban site, to identify possible
emission sources of PAHs using several statistical methodologies,
and to analyze the influence of other air pollutants
and meteorological variables on PAH concentrations.The air
quality and meteorological data were collected in Oporto,
the second largest city of Portugal. Eighteen PAHs (the 16
PAHs considered by United States Environment Protection
Agency (USEPA) as priority pollutants, dibenzo[a,l]pyrene,
and benzo[j]fluoranthene) were collected daily for 24 h in
air (gas phase and in particles) during 40 consecutive days
in November and December 2008 by constant low-flow
samplers and using polytetrafluoroethylene (PTFE) membrane
filters for particulate (PM10 and PM2.5 bound) PAHs
and pre-cleaned polyurethane foam plugs for gaseous compounds.
The other monitored air pollutants were SO2, PM10,
NO2, CO, and O3; the meteorological variables were temperature,
relative humidity, wind speed, total precipitation,
and solar radiation. Benzo[a]pyrene reached a mean concentration
of 2.02 ngm−3, surpassing the EU annual limit
value. The target carcinogenic risks were equal than the
health-based guideline level set by USEPA (10−6) at the
studied site, with the cancer risks of eight PAHs reaching
senior levels of 9.98×10−7 in PM10 and 1.06×10−6 in air.
The applied statistical methods, correlation matrix, cluster
analysis, and principal component analysis, were in
agreement in the grouping of the PAHs. The groups
were formed according to their chemical structure (number
of rings), phase distribution, and emission sources.
PAH diagnostic ratios were also calculated to evaluate
the main emission sources. Diesel vehicular emissions
were the major source of PAHs at the studied site.
Besides that source, emissions from residential heating
and oil refinery were identified to contribute to PAH
levels at the respective area. Additionally, principal
component regression indicated that SO2, NO2, PM10,
CO, and solar radiation had positive correlation with
PAHs concentrations, while O3, temperature, relative
humidity, and wind speed were negatively correlated.
