Anna Stella

Principal Component Analysis Application in Polycyclic Aromatic Hydrocarbons "Mussel Watch" Analyses for Source Identification

Abstract This article aims to show how a careful pre-treatment of data can be used to demonstrate various features embedded in a given data set obtained from a “mussel watch” survey, namely site- and source-specific characteristics and weather-related changes, and to provide indications so as to allow comparison with analyses performed on another substrate matrix. Polycyclic aromatic hydrocarbons (PAHs) biomonitored in the aquatic environment by means of caged mussels are compared by site and by season. Moreover, their fingerprints were compared to marine sediments and atmospheric airborne PAHs. The characterization of the sampling stations by means of the multivariate technique called principal component analysis (PCA) allows distinguishing the prevalence of pyrogenic or petrogenic types of pollution and between two kinds of combustibles. This was confirmed by jointly analyzing the percent composition of sea (mussel) and air (filter) samples.

Is the smokers exposure to environmental tobacco smoke negligible

BackgroundVery few studies have evaluated the adverse effect of passive smoking exposure among active smokers, probably due to the unproven assumption that the dose of toxic compounds that a smoker inhales by passive smoke is negligible compared to the dose inhaled by active smoke.MethodsIn a controlled situation of indoor active smoking, we compared daily benzo(a)pyrene (BaP) dose, estimated to be inhaled by smokers due to the mainstream (MS) of cigarettes they have smoked, to the measured environmental tobacco smoke (ETS) they inhaled in an indoor environment. For this aim, we re-examined our previous study on daily personal exposure to BaP of thirty newsagents, according to their smoking habits.ResultsDaily BaP dose due to indoor environmental contamination measured inside newsstands (traffic emission and ETS produced by smoker newsagents) was linearly correlated (p = 0.001 R2 = 0.62) with estimated BaP dose from MS of daily smoked cigarettes. In smoker subjects, the percentage of BaP daily dose due to ETS, in comparison to mainstream dose due to smoked cigarettes, was estimated with 95% confidence interval, between 14.6% and 23% for full flavour cigarettes and between 21% and 34% for full flavour light cigarettes.ConclusionsDuring indoor smoking, ETS contribution to total BaP dose of the same smoker, may be not negligible. Therefore both active and passive smoking exposures should be considered in studies about health of active smokers.

Air Quality Standard for Benzo(a)pyrene (BaP) in Genoa (1994-1995)

Abstract Mean benzo(a)pyrene concentrations were evaluated in four Genoan sampling sites. It was verified the respect of air quality standard recently introduced into Italian legislation (2.5 ng/m3 from 1996 and 1 ng/m3 from 1999). In sites along heavy traffic streets the mean BaP concentrations were about 2 ng/m3; on a buildings roof, 300 metres from a coke oven, the mean BaP concentration was 14 ng/m3.

TREND OF ATMOSPHERIC BENZO[ a ]PYRENE IN ITALY BEFORE THE ADOPTION OF THE EUROPEAN DIRECTIVE ON PAHs

The benzo[a]pyrene temporal trend was investigated in 11 towns where at least five annual means were available. The overall number of stations was 22, of which 12 were traffic-oriented, 6 background and 4 industrial. The trend was generally declining at traffic-oriented sites and roughly stable at background sites. The annual means in 2004 still exceeded the forthcoming European target value of 1 ng/m 3 in two towns (up to 1.9 ng/m 3 ). The background means (up to 1.4 ng/m 3 in 2004) accounted for approximately 40–90% of those at the traffic-oriented sites in the same town. The presence of a coke plant was incompatible with the attainment of the target value, while the adoption of technical measures on a carbon electrode plant was successful in attaining concentrations lower than the target value. In heavy traffic areas in Italy, the attainment of the target value hardly appears feasible under the current conditions of traffic congestion.

Correlations Between PAHs and CO, NO, NO2, O3 along an Urban Street

Abstract Since 1997 to 1999, bimonthly measures of daily PAH concentrations, adsorbed on airborne particulate (PM10) have been carried out in Genoa (Italy), along a canyon street, crossed daily by about 27.000 vehicles. Simultaneous concentrations of CO, NO, NO2 were evaluated in the same sampling site. Ozone concentrations were measured in two sampling stations, far from traffic, and their daily mean was used as a measure of oxidative strength of urban air in Genoa. PAHs correlate positively with CO and NO. Negative correlations were found with NO2 and particularly with O3. Cyclopenta(cd)pyrene was confirmed the most reactive PAH, while benzo(e)pyrene showed a relative stability. Multiple linear regression analyses confirmed that PAH concentration covariates mainly with CO and O3, while NO2 has negligible correlation. According to these results, benzo(a)pyrene concentrations are well predicted (standard error = 0.35 ng/m3), by the following equation: These results suggest that traffic is the main PAH source in the studied site and in urban atmosphere PAHs adsorbed on suspended particulate may be degraded also by oxidation.

Indoor pollution and burning practices in wood stove management

This study evaluates effects of good burning practice and correct installation and management of wood heaters on indoor air pollution in an Italian rural area. The same study attests the role of education in mitigating wood smoke pollution. In August 2007 and winters of 2007 and 2008, in a little mountain village of Liguria Apennines (Italy), indoor and outdoor benzene, toluene, ethylbenzene, and xylene (BTEX) concentrations were measured in nine wood-heated houses. During the first sampling, several mistakes in heating plant installations and management were found in all houses. Indoor BTEX concentrations increased during use of wood burning. Low toluene/benzene ratios were in agreement with wood smoke as main indoor and outdoor pollution source. Other BTEX sources were identified as the indoor use of solvents and paints and incense burning. Results obtained during 2007 were presented and discussed with homeowners. Following this preventive intervention, in the second winter sampling all indoor BTEX concentrations decreased, in spite of the colder outdoor air temperatures. Information provided to families has induced the adoption of effective good practices in stoves and fire management. These results highlight the importance of education, supported by reliable data on air pollution, as an effective method to reduce wood smoke exposures. Implications: Information about burning practices and correct installation and management of wood heaters, supported by reliable data on indoor and outdoor pollution, may help to identify and remove indoor pollution sources. This can be an effective strategy in mitigate wood smoke pollution.

Temporal and spatial variations of polycyclic aromatic hydrocarbon concentrations around a coke oven plant

From 1995 to 2004, in Genoa, Italy, daily concentrations of twelve polycyclic aromatic hydrocarbons (PAHs) were measured in particulate phase (PM10), around a coke oven plant in operation from the 1950s and closed in 2002. The study permitted to identify the coke oven as the main PAH source in Genoa, causing constant exceeding of benzo(a)pyrene (BaP) air quality target (1.0 ng/m3) in the urban area till 1,900 meters distance downwind the plant. For this reason the plant was closed. Distance and daily hours downwind the coke plant were the main sources of variability of toxic BaP equivalent (BaPeq) concentrations and equations that best fitted these variables were experimentally obtained. During full plant activity, annual average BaPeq concentrations, measured in the three sampling sites aligned downwind to the summer prevalent winds, were: 85 ng/m3 at 40 m (site 2, industrial area), 13.2 ng/m3 at 300 m (site 3, residential area) and 5.6 ng/m3 at 575 m (site 4, residential area). Soon after the coke ovens closure (February 2002) BaPeq concentrations (annual average) measured in residential area, decreased drastically: 0.2 ng/m3 at site 3, 0.4 ng/m3 at site 4. Comparing 1998 and 2003 data, BaPeq concentrations decreased 97.6% in site 3 and 92.8% in site 4. Samples collected at site 3, during the longest downwind conditions, provided a reliable PAH profile of fugitive coke oven emissions. This profile was significantly different from the PAH profile, contemporary found at site 5, near the traffic flow. This study demonstrates that risk assessment based only on distance of residences from a coke plant can be heavily inaccurate and confirmed that seasonal variability of BaPeq concentrations and high variability of fugitive emissions of PAHs during coke oven activities require at least one year of frequent and constant monitoring (10-15 samples each month). Implications: Around a coking plant, polycyclic aromatic hydrocarbons (PAHs), concentrations depend mainly on downwind hours and distance. Equations that best fit these variables were experimentally calculated. Fugitive emissions of an old coke oven did not comply with the threshold BAP air concentration proposed by the World Health Organization (WHO), up to 1,900 m distance. The study identified the PAH profile of fugitive emissions of a coke oven, statistically different from the profile of traffic emissions. During its activity, in the Genoa residential area, 575 m away from the plant, 92.8% of found PAHs was due to coke oven emission only. Supplemental Materials: Supplemental materials are available for this article. Go to the publishers online edition of the Journal of the Air & Waste Management Association for information about samples analyses, statistical analyses and regression models figure.

Catalytic Converters and PAH Pollution in Urban Areas

Every organic substance containing carbon and hydrogen yields a large number of polycyclic aromatic hydrocarbons (PAH) during incomplete combustion or pyrolysis or during the formation of petroleum and coal. PAHs are included in a class of chemical compounds characterised by two or more condensed aromatic rings. Several PAHs have been classified by the International Agency for Research on Cancer (IARC) as probable or possible human carcinogens (IARC, 1987). Due to their carcinogenic and mutagenic effects, sixteen PAHs were included in the US EPA priority pollutant list (Yan, Wang et al., 2004); between them, benzo(a)pyrene (BaP), with five condensed aromatic rings, is recognised as the PAH with the highest carcinogenic potency and is considered to be an indicator of the presence of the PAH group in environmental matrices: air, water, soil, food. In fact in every analysed mixture, the BaP concentration fits linearly with the concentrations of other semi volatile PAHs, prevalently adsorbed to airborne particulate matter.