Evaluation of airborne particulate matter and metals data in personal,indoor and outdoor environments using ED-XRF and ICP-MS and co-located duplicate samples

Factors and sources affecting measurement uncertainty associated with monitoring metals in airborne particulate matter (PM) were investigated as part of the Windsor, Ontario Exposure Assessment Study (WOEAS). The assessment was made using co-located duplicate samples and a comparison of two analytical approaches: ED-XRF and ICP-MS. Sampling variability was estimated using relative percent difference (RPD) of co-located duplicate samples. The comparison of ICP-MS and ED-XRF results yields very good correlations (R² ≥ 0.7) for elements present at concentrations that pass both ICP-MS and ED-XRF detection limits (e.g. Fe, Mn, Zn, Pb and Cu). PM concentration ranges (median, sample number) of 24-h indoor PM₁₀ and personal PM₁₀ filters, and outdoor PM_2.5 filters were determined to be 2.2–40.7 (11.0, n = 48) μg m^?3, 8.0–48.3 (11.9, n = 48) μg m^?3, and 17.1–42.3 (21.6, n = 18) μg m^?3, respectively. The gravimetric analytical results reveal that the variations in PM mass measurements for same-day sampling are insignificant compared to temporal or spatial variations: 92%, 100% and 96% of indoor, outdoor and personal duplicate samples, respectively, pass the quality criteria (RPD ≤ 20%). Uncertainties associated with ED-XRF elemental measurements of S, Ca, Mn, Fe and Zn for 24-h filter samples are low: 78%–100% of the duplicate samples passed the quality criteria. In the case of 24-h filter samples using ICP-MS, more elements passed the quality criteria due to the lower detection limits. These were: Li, Na, K, Ca, Si, Al, V, Fe, Mn, Co, Cu, Mo, Ag, Zn, Pb, As, Mg, Sb, Sn, Sr, Th, Ti, Tl, and U. Low air concentrations of metals (near or below instrumental detection limits) and/or inadvertent introduction of metal contamination are the main causes for excluding elements based on the pass/fail criteria. Uncertainty associated with elemental measurements must be assessed on an element-by-element basis.     

Characterisation of particulate exposure during fireworks displays

Little is known about the level and content of exposure to fine particles (PM_2.5) among persons who attend fireworks displays and those who live nearby. An evaluation of the levels of PM_2.5 and their elemental content was carried out during the nine launches of the 2007 Montréal International Fireworks Competition. For each event, a prediction of the location of the firework plume was obtained from the Canadian Meteorological Centre (CMC) of the Meteorological Service of Canada. PM_2.5 was measured continuously with a photometer (Sidepak?, TSI) within the predicted plume location (“predicted sites”), and integrated samples were collected using portable personal samplers. An additional sampler was located on a nearby roof (“fixed site”). The elemental composition of the collected PM_2.5 samples from the “predicted sites” was determined using both a non-destructive energy dispersive ED-XRF method and an ICP-MS method with a near-total microwave-assisted acid digestion. The elemental composition of the “fixed site” samples was determined by the ICP-MS with the near-total digestion method. The highest PM_2.5 levels reached nearly 10 000 μg m^?3, roughly 1000 times background levels. Elements such as K, Cl, Al, Mg and Ti were markedly higher in plume-exposed filters. This study shows that 1) persons in the plume and in close proximity to the launch site may be exposed to extremely high levels of PM_2.5 for the duration of the display and, 2) that the plume contains specific elements for which little is known of their acute cardio-respiratory toxicity.     

Airborne molds and mycotoxins associated with handling of corn silage and oilseed cakes in agricultural environment

In agricultural areas, the contamination of feedstuffs with molds and mycotoxins presents major environmental and health concerns. During cattle feeding, fungi and mycotoxins were monitored in corn silage, oilseed cakes and bioaerosols collected in Normandy. Most of the corn silages were found to be contaminated by deoxynivalenol (mean concentration: 1883 μg kg^?1) while a few of oilseed cakes were contaminated by alternariol, fumonisin B₁ or gliotoxin. In ambient bioaerosols, the values for fungi per cubic meter of air varied from 4.3 × 10² to 6.2 × 10⁵ cfu m^?3. Seasonal variations were observed with some species like Aspergillus fumigatus which significantly decreased between the 2 seasons (P = 0.0186) while the Penicillium roqueforti group significantly increased during the second season (P = 0.0156). In the personal bioaerosols, the values for fungi per cubic meter of air varied from 3.3 10³ to 1.7 10⁶ cfu m^?3 and the number of A. fumigatus spores significantly decreased between the 2 seasons (P = 0.0488). Gliotoxin, an immunosuppressive mycotoxin, was quantified in 3 personal filters at 3.73 μg m^?3, 1.09 μg m^?3 and 2.97 μg m^?3.     

Discriminating the regional and urban contributions in the North-Western Mediterranean: PM levels and composition

Simultaneous measurements of the PM concentration levels and chemical composition of atmospheric aerosols at a regional background (RB) and an urban background (UB) site, located in the same geographic region, allowed for the determination of their urban and regional contributions. In the specific case of the North-Western region of the Mediterranean the RB amount has been quantified in 18, 13 and 12 μg m^?3 for PM₁₀, PM_2.5 and PM₁, respectively, whereas the UB contribution reached 22, 13 and 8 μg m^?3, respectively. The UB contributions in the Western Mediterranean are much higher than those observed in other European regions; especially concerning the coarse fraction. The high loads of road dust in the urban areas across the Mediterranean may account for these large differences.The urban contributions are extremely enriched in Ca, Fe, Sb, Sn, Cu, Zn, being the main tracers of the road dust, with concentrations up to 6–8 times higher than those at the RB. Elemental carbon and nitrate are mainly derived from direct vehicular emissions. Some industrial tracers (Mn, Pb, Bi) are also enriched in the urban area. The evaluation of the Cu/Sb, Cu/Zn, Cu/Cd and Cu/Pb ratios and the high enrichment of these trace elements versus the Upper Crustal Composition average values corroborates the importance of the road-traffic emissions in the study area, also influencing the RB.The supplementary results from a suburban site in the Balearic Islands and the evaluation of the V/Ni ratios evidence the strong signature of fuel-oil combustion processes, which is a general characteristic of the Mediterranean aerosols.     

Characterisation of PM10 emissions from woodstove combustion of common woods grown in Portugal

A series of source tests was performed to evaluate the chemical composition of particle emissions from the woodstove combustion of four prevalent Portuguese species of woods: Pinus pinaster (maritime pine), Eucalyptus globulus (eucalyptus), Quercus suber (cork oak) and Acacia longifolia (golden wattle). Analyses included water-soluble ions, metals, radionuclides, organic and elemental carbon (OC and EC), humic-like substances (HULIS), cellulose and approximately l80 organic compounds. Particle (PM₁₀) emission factors from eucalyptus and oak were higher than those from pine and acacia. The carbonaceous matter represented 44–63% of the particulate mass emitted during the combustion process, regardless of species burned. The major organic components of smoke particles, for all the wood species studied, with the exception of the golden wattle (0.07–1.9% w/w), were anhydrosugars (0.2–17% w/w). Conflicting with what was expected, only small amounts of cellulose were found in wood smoke. As for HULIS, average particle mass concentrations ranged from 1.5% to 3.0%. The golden wattle wood smoke presented much higher concentrations of ions and metal species than the emissions from the other wood types. The results of the analysis of radionuclides revealed that the ²²⁶Ra was the naturally occurring radionuclide more enriched in PM₁₀. The chromatographically resolved organics included n-alkanes, n-alkenes, PAH, oxygenated PAH, n-alkanals, ketones, n-alkanols, terpenoids, triterpenoids, phenolic compounds, phytosterols, alcohols, n-alkanoic acids, n-di-acids, unsaturated acids and alkyl ester acids.     

Variable emissions of microbial volatile organic compounds (MVOCs) from root-associated fungi isolated from Scots pine

Soils emit a large variety of volatile organic compounds. In natural ecosystems, measurements of microbial volatile organic compound (MVOC) exchange rates between soil and atmosphere are difficult due to e.g. the spatial heterogeneity of the belowground organisms, and due to the many potential sources for the same compounds. We measured in laboratory conditions the MVOC emission rates and spectra of eight typical fungi occurring in boreal forest soils. The studied species are decomposers (Gymnopilus penetrans, Ophiostoma abietinum), ectomycorrhizal (Cenococcum geophilum, Piloderma olivaceum, Suillus variegatus, Tomentellopsis submollis) and endophytic fungi (Meliniomyces variabilis, Phialocephala fortinii). The MVOC emissions contained altogether 21 known and 6 unidentified compounds whose emission rates were >0.1 μg g(DW)^?1 h^?1. The most abundant compounds were the short-chain carbonyl compounds (acetone and acetaldehyde). The greatest carbonyl emissions were measured from P. olivaceum (1.9 mg acetone g(DW)^?1 h^?1) and P. fortinii (0.114 mg acetaldehyde g(DW)^?1 h^?1). Terpenoid emissions (isoprene, mono- and sesquiterpenes) were detected from some fungal cultures, but in relatively small amounts. We conclude that soil micro-organisms can potentially be responsible for significant emissions of volatiles, especially short-chain oxygenated compounds, to the below-canopy atmosphere.     

PM2.5 and PM10: The influence of sugarcane burning on potential cancer risk

In Brazil, sugarcane fields are often burned to facilitate manual harvesting, and this burning causes environmental pollution from the large amounts of soot released into the atmosphere. This material contains numerous organic compounds such as PAHs. In this study, the concentrations of PAHs in two particulate-matter fractions (PM_2.5 and PM₁₀) in the city of Araraquara (SE Brazil, with around 200,000 inhabitants and surrounded by sugarcane plantations) were determined during the sugarcane harvest (HV) and non-harvest (NHV) seasons in 2008 and 2009. The sampling strategy included four campaigns, with 60 samples in the NHV season and 220 samples in the HV season. The PM_2.5 and PM₁₀ fractions were collected using a dichotomous sampler (10 L min^?1, 24 h) with Teflon? filters. The filter sets were extracted (ultrasonic bath with hexane/acetone (1:1 v/v)) and analyzed by HPLC/Fluorescence. The median concentration for total PAHs (PM_2.5 in 2009) was 0.99 ng m^?3 (NHV) and 3.3 ng m^?3 (HV). In the HV season, the total concentration of carcinogenic PAHs (benz(a)anthracene, benzo(b)fluoranthene, benzo(k)fluoranthene, and benzo(a)pyrene) was 5 times higher than in the NHV season. B(a)P median concentrations were 0.017 ng m^?3 and 0.12 ng m^?3 for the NHV and HV seasons, respectively. The potential cancer risk associated with exposure through inhalation of these compounds was estimated based on the benzo[a]pyrene toxic equivalence (BaP_eq), where the overall toxicity of a PAH mixture is defined by the concentration of each compound multiplied by its relative toxic equivalence factor (TEF). BaP_eq median (2008 and 2009 years) ranged between 0.65 and 1.0 ng m^?3 and 1.2–1.4 ng m^?3 for the NHV and HV seasons, respectively. Considering that the maximum permissible BaP_eq in ambient air is 1 ng m^?3, related to the increased carcinogenic risk, our data suggest that the level of human exposure to PAHs in cities surrounded by sugarcane crops where the burning process is used is cause for concern.     

A simplified approach to the indirect evaluation of the chemical composition of atmospheric aerosols from PM mass concentrations

The present work shows a straightforward procedure to indirectly estimate the chemical composition at a given site only from the determination of the PM concentrations, and the classification of the days according to the main meteorological scenarios. A previous study based on the mean chemical composition associated to the main meteorological scenarios is required.This experiment has been carried out with data from two monitoring sites in the North-Western Mediterranean, one regional and one suburban background. At both sites, one-year datasets on chemical PM₁₀ composition were obtained. Based on these datasets, the mean PM₁₀ compositions according to the most relevant meteorological situations were calculated for both locations. After that, the reconstruction of the chemical composition for all the days with available PM₁₀ concentrations was completed. Subsequently, the estimated PM₁₀ composition was compared with that determined experimentally. The comparison between the rebuilt and the experimental results was very satisfactory in the case of the regional background site, and relatively replaced in the other case. Furthermore, the validation of the method at the regional background site has been conducted from the reconstruction of a 4-year data base, and subsequent comparison with the experimental chemical composition.Our results show that it is possible to attain a good approach to the chemical composition at regional background sites, where local emission sources are negligible. Conversely, when the local sources rise in importance, i.e., at a suburban background site, the approach is suitable only for those components with a more regional origin and/or those from long range transport of air masses.     

An urban emissions inventory for South America and its application in numerical modeling of atmospheric chemical composition at local and regional scales

This work describes the development of an urban vehicle emissions inventory for South America, based on the analysis and aggregation of available inventories for major cities, with emphasis on its application in regional atmospheric chemistry modeling. Due to the limited number of available local inventories, urban emissions were extrapolated based on the correlation between city vehicle density and mobile source emissions of carbon monoxide (CO) and nitrogen oxides (NOx). Emissions were geographically distributed using a methodology that delimits urban areas using high spatial resolution remote sensing products. This numerical algorithm enabled a more precise representation of urban centers. The derived regional inventory was evaluated by analyzing the performance of a chemical weather forecast model in relation to observations of CO, NOx and O₃ in two different urban areas, São Paulo and Belo Horizonte. The gas mixing ratios simulated using the proposed regional inventory show good agreement with observations, consistently representing their hourly and daily variability. These results show that the integration of municipal inventories in a regional emissions map and their precise distribution in fine scale resolutions are important tools in regional atmospheric chemistry modeling.     

A field study on residues of four insecticides used in strawberry protection

Abstract

In 1986 strawberry plots were treated with dimethoate, malathion, permethrin and cypermethrin at 80% bloom of primary flowers. In 1987 the plots were sprayed with dimethoate, malathion and permethrin at 30% bloom. Residue analysis of these insecticides on the flowers were analyzed using solvent extraction and gas liquid chromatography. Residue analysis at 0 to 18 days on flowers and fruit showed an exponential decrease. Organophosphates tended to degrade more quickly than synthetic pyrethroids. The results are discussed in the context of an integrated pest management program.