FTIR analysis and evaluation of carcinogenic and mutagenic risks of nitro-polycyclic aromatic hydrocarbons in PM1.0.

Nitro-polycyclic aromatic hydrocarbons (NPAHs) represent a group of organic compounds of significant interest due to their presence in airborne particulates of urban centers, wide distribution in the environment, and mutagenic and carcinogenic properties. These compounds, associated with atmospheric particles of size < 1 µm, have been reported as a major risk to human health. This study aims at identifying the spectral features of NPAHs (1-nitropyrene, 2-nitrofluorene, and 6-nitrochrysene) in emissivity and transmittance spectra of samples of particulate matter < 1 µm (PM1.0) using infrared spectrometry. Carcinogenic and mutagenic risks of the studied NPAHs associated with PM1.0 samples were also determined for two sampling sites: Canoas and Sapucaia do Sul. The results showed that NPAH standard spectra can effectively identify NPAHs in PM1.0 samples. The transmittance and emissivity sample spectra showed broader bands and lower relative intensity than the standard NPAH spectra. The carcinogenic risk and the total mutagenic risk were calculated using the toxic equivalent factors and mutagenic potency factors, respectively. Canoas showed the highest total carcinogenic risk, while Sapucaia do Sul had the highest mutagenic risk. The seasonal analysis suggested that in the study area the ambient air is more toxic during the cold periods. These findings might of significant importance for the decision and policy making authorities.

Assessment of nitro-polycyclic aromatic hydrocarbons in PM1 near an area of heavy-duty traffic.

The objective of this research was to evaluate nitro-polycyclic aromatic hydrocarbons (NPAHs) associated with ultrafine airborne particles (PM1) in areas affected by vehicles in the metropolitan area of Porto Alegre (MAPA), RS, Brazil. Extraction, isolation/derivatization, and subsequently gas chromatography with electron capture detection (GC/ECD) were the techniques used to extract and determine NPAHs (1-nitronaphthalene, 2-nitrofluorene,3-nitrofluoranthene,1-nitropyrene, and 6-nitrochrysene) associated with PM1 Airborne particles (PM1) were collected using PTFE filters in a PM162M automatic sampler. The analytical method was validated by the Standard Reference Material - SRM 1649 b - from the National Institute of Standards and Technology (NIST, USA). The results were consistent with the certified values. 3-NFlt and 6-NChr reached highest concentrations of 0.047 ng·m(-3) and 0.0284 ng·m(-3), respectively, in Sapucaia do Sul and Canoas. Seasonal variation showed higher NPAH concentrations in cold days. The NPAHs associated with PM1 were correlated with the pollutants nitrogen oxides and NPAHs with meteorological variables: temperature and wind speed. The results indicated that vehicles with diesel engines were influential. This was confirmed by the study of the ratios NPAHs/PAHs, 1-NPyr/Pyr, and 6-NChr/Chr.