Elemental Composition Of Particulate Matter Research Articles

Long-term effects of elemental composition of particulate matter on inflammatory blood markers in European cohorts

BackgroundEpidemiological studies have associated long-term exposure to ambient particulate matter with increased mortality from cardiovascular and respiratory disorders. Systemic inflammation is a plausible biological mechanism behind this association. However, it is unclear how the chemical composition of PM affects inflammatory responses. ObjectivesTo investigate the association between long-term exposure to elemental components of PM and the inflammatory blood markers high-sensitivity C-reactive protein (hsCRP) and fibrinogen as part of the European ESCAPE and TRANSPHORM multi-center projects. MethodsIn total, 21,558 hsCRP measurements and 17,428 fibrinogen measurements from cross-sections of five and four cohort studies were available, respectively. Residential long-term concentrations of particulate matter <10μm (PM10) and <2.5μm (PM2.5) in diameter and selected elemental components (copper, iron, potassium, nickel, sulfur, silicon, vanadium, zinc) were estimated based on land-use regression models. Associations between components and inflammatory markers were estimated using linear regression models for each cohort separately. Cohort-specific results were combined using random effects meta-analysis. As a sensitivity analysis the models were additionally adjusted for PM mass. ResultsA 5ng/m3 increase in PM2.5 copper and a 500ng/m3 increase in PM10 iron were associated with a 6.3% [0.7; 12.3%] and 3.6% [0.3; 7.1%] increase in hsCRP, respectively. These associations between components and fibrinogen were slightly weaker. A 10ng/m3 increase in PM2.5 zinc was associated with a 1.2% [0.1; 2.4%] increase in fibrinogen; confidence intervals widened when additionally adjusting for PM2.5. ConclusionsLong-term exposure to transition metals within ambient particulate matter, originating from traffic and industry, may be related to chronic systemic inflammation providing a link to long-term health effects of particulate matter.

Cardiac effects of seasonal ambient particulate matter and ozone co-exposure in rats.

BackgroundThe potential for seasonal differences in the physicochemical characteristics of ambient particulate matter (PM) to modify interactive effects with gaseous pollutants has not been thoroughly examined. The purpose of this study was to compare cardiac responses in conscious hypertensive rats co-exposed to concentrated ambient particulates (CAPs) and ozone (O3) in Durham, NC during the summer and winter, and to analyze responses based on particle mass and chemistry.MethodsRats were exposed once for 4 hrs by whole-body inhalation to fine CAPs alone (target concentration: 150 μg/m3), O3 (0.2 ppm) alone, CAPs plus O3, or filtered air during summer 2011 and winter 2012. Telemetered electrocardiographic (ECG) data from implanted biosensors were analyzed for heart rate (HR), ECG parameters, heart rate variability (HRV), and spontaneous arrhythmia. The sensitivity to triggering of arrhythmia was measured in a separate cohort one day after exposure using intravenously administered aconitine. PM elemental composition and organic and elemental carbon fractions were analyzed by high-resolution inductively coupled plasma–mass spectrometry and thermo-optical pyrolytic vaporization, respectively. Particulate sources were inferred from elemental analysis using a chemical mass balance model.ResultsSeasonal differences in CAPs composition were most evident in particle mass concentrations (summer, 171 μg/m3; winter, 85 μg/m3), size (summer, 324 nm; winter, 125 nm), organic:elemental carbon ratios (summer, 16.6; winter, 9.7), and sulfate levels (summer, 49.1 μg/m3; winter, 16.8 μg/m3). Enrichment of metals in winter PM resulted in equivalent summer and winter metal exposure concentrations. Source apportionment analysis showed enrichment for anthropogenic and marine salt sources during winter exposures compared to summer exposures, although only 4% of the total PM mass was attributed to marine salt sources. Single pollutant cardiovascular effects with CAPs and O3 were present during both summer and winter exposures, with evidence for unique effects of co-exposures and associated changes in autonomic tone.ConclusionsThese findings provide evidence for a pronounced effect of season on PM mass, size, composition, and contributing sources, and exposure-induced cardiovascular responses. Although there was inconsistency in biological responses, some cardiovascular responses were evident only in the co-exposure group during both seasons despite variability in PM physicochemical composition. These findings suggest that a single ambient PM metric alone is not sufficient to predict potential for interactive health effects with other air pollutants.Electronic supplementary materialThe online version of this article (doi:10.1186/s12989-015-0087-3) contains supplementary material, which is available to authorized users.

Natural-cause mortality and long-term exposure to particle components: an analysis of 19 European cohorts within the multi-center ESCAPE project.

BackgroundStudies have shown associations between mortality and long-term exposure to particulate matter air pollution. Few cohort studies have estimated the effects of the elemental composition of particulate matter on mortality.ObjectivesOur aim was to study the association between natural-cause mortality and long-term exposure to elemental components of particulate matter.MethodsMortality and confounder data from 19 European cohort studies were used. Residential exposure to eight a priori–selected components of particulate matter (PM) was characterized following a strictly standardized protocol. Annual average concentrations of copper, iron, potassium, nickel, sulfur, silicon, vanadium, and zinc within PM size fractions ≤ 2.5 μm (PM2.5) and ≤ 10 μm (PM10) were estimated using land-use regression models. Cohort-specific statistical analyses of the associations between mortality and air pollution were conducted using Cox proportional hazards models using a common protocol followed by meta-analysis.ResultsThe total study population consisted of 291,816 participants, of whom 25,466 died from a natural cause during follow-up (average time of follow-up, 14.3 years). Hazard ratios were positive for almost all elements and statistically significant for PM2.5 sulfur (1.14; 95% CI: 1.06, 1.23 per 200 ng/m3). In a two-pollutant model, the association with PM2.5 sulfur was robust to adjustment for PM2.5 mass, whereas the association with PM2.5 mass was reduced.ConclusionsLong-term exposure to PM2.5 sulfur was associated with natural-cause mortality. This association was robust to adjustment for other pollutants and PM2.5.CitationBeelen R, Hoek G, Raaschou-Nielsen O, Stafoggia M, Andersen ZJ, Weinmayr G, Hoffmann B, Wolf K, Samoli E, Fischer PH, Nieuwenhuijsen MJ, Xun WW, Katsouyanni K, Dimakopoulou K, Marcon A, Vartiainen E, Lanki T, Yli-Tuomi T, Oftedal B, Schwarze PE, Nafstad P, De Faire U, Pedersen NL, Östenson C-G, Fratiglioni L, Penell J, Korek M, Pershagen G, Eriksen KT, Overvad K, Sørensen M, Eeftens M, Peeters PH, Meliefste K, Wang M, Bueno-de-Mesquita HB, Sugiri D, Krämer U, Heinrich J, de Hoogh K, Key T, Peters A, Hampel R, Concin H, Nagel G, Jaensch A, Ineichen A, Tsai MY, Schaffner E, Probst-Hensch NM, Schindler C, Ragettli MS, Vilier A, Clavel-Chapelon F, Declercq C, Ricceri F, Sacerdote C, Galassi C, Migliore E, Ranzi A, Cesaroni G, Badaloni C, Forastiere F, Katsoulis M, Trichopoulou A, Keuken M, Jedynska A, Kooter IM, Kukkonen J, Sokhi RS, Vineis P, Brunekreef B. 2015. Natural-cause mortality and long-term exposure to particle components: an analysis of 19 European cohorts within the Multi-Center ESCAPE Project. Environ Health Perspect 123:525–533; http://dx.doi.org/10.1289/ehp.1408095

Particulate matter deposited on leaf of five evergreen species in Beijing, China: Source identification and size distribution

Airborne particulate matter (PM) has become a serious problem, and urban plants can play important roles in reducing PM concentrations in the air. The morphology, size, and elemental composition of PM on tree leaves (five evergreen species) from Beijing, China, were obtained, together with number density of PM size fraction, by using scanning electron microscopy (SEM) and energy dispersive X-rays (EDX). The rinse and weigh method was used to characterize PM in three size categories (0.2–2.5 μm, 2.5–10 μm, and 10–100 μm). The results showed that PM up to 2 μm can get into the stomatal cavity, and the most furrowed areas of the leaf surfaces were sites of maximum PM deposition. The leaf-deposited PM mainly comprised C, O, Si, and Fe. The number of particles per leaf per cm2 was 1.95 × 107, and 96% of the particles were less than 2.5 μm. The mass concentration was 148.44 μg/cm2, and PM2.5 comprised only 2.09% by weight while PM larger than 10 μm comprised 79%. Juniperus formosana was most effective at mitigating airborne PM on the leaf scale. Pinus bungeana accumulated the most PM on the tree scale. The results showed that urban plants can play important roles in mitigating urban airborne PM.

Pigments, elemental composition (C, N, P, and Si), and stoichiometry of particulate matter in the naturally iron fertilized region of Kerguelen in the Southern Ocean

Abstract. The particulate matter distribution and phytoplankton community structure of the iron-fertilized Kerguelen region were investigated in early austral spring (October–November 2011) during the KEOPS2 cruise. The iron-fertilized region was characterized by a complex mesoscale circulation resulting in a patchy distribution of particulate matter. Integrated concentrations over 200 m ranged from 72.2 to 317.7 mg m−2 for chlorophyll a 314 to 744 mmol m−2 for biogenic silica (BSi), 1106 to 2268 mmol m−2 for particulate organic carbon, 215 to 436 mmol m−2 for particulate organic nitrogen, and 29.3 to 39.0 mmol m−2 for particulate organic phosphorus. Three distinct high biomass areas were identified: the coastal waters of Kerguelen Islands, the easternmost part of the study area in the polar front zone, and the southeastern Kerguelen Plateau. As expected from previous artificial and natural iron-fertilization experiments, the iron-fertilized areas were characterized by the development of large diatoms revealed by BSi size–fractionation and high performance liquid chromatography (HPLC) pigment signatures, whereas the iron-limited reference area was associated with a low biomass dominated by a mixed (nanoflagellates and diatoms) phytoplankton assemblage. A major difference from most previous artificial iron fertilization studies was the observation of much higher Si : C, Si : N, and Si : P ratios (0.31 ± 0.16, 1.6 ± 0.7 and 20.5 ± 7.9, respectively) in the iron-fertilized areas compared to the iron-limited reference station (0.13, 1.1, and 5.8, respectively). A second difference is the patchy response of the elemental composition of phytoplankton communities to large scale natural iron fertilization. Comparison to the previous KEOPS1 cruise also allowed to address the seasonal dynamics of phytoplankton bloom over the southeastern plateau. From particulate organic carbon (POC), particulate organic nitrogen (PON), and BSi evolutions, we showed that the elemental composition of the particulate matter also varies at the seasonal scale. This temporal evolution followed changes of the phytoplankton community structure as well as major changes in the nutrient stocks progressively leading to silicic acid exhaustion at the end of the productive season. Our observations suggest that the specific response of phytoplankton communities under natural iron fertilization is much more diverse than what has been regularly observed in artificial iron fertilization experiments and that the elemental composition of the bulk particulate matter reflects phytoplankton taxonomic structure rather than being a direct consequence of iron availability.

Elemental composition of particulate matter and the association with lung function.

Negative effects of long-term exposure to particulate matter (PM) on lung function have been shown repeatedly. Spatial differences in the composition and toxicity of PM may explain differences in observed effect sizes between studies. We conducted a multicenter study in 5 European birth cohorts-BAMSE (Sweden), GINIplus and LISAplus (Germany), MAAS (United Kingdom), and PIAMA (The Netherlands)-for which lung function measurements were available for study subjects at the age of 6 or 8 years. Individual annual average residential exposure to copper, iron, potassium, nickel, sulfur, silicon, vanadium, and zinc within PM smaller than 2.5 μm (PM2.5) and smaller than 10 μm (PM10) was estimated using land-use regression models. Associations between air pollution and lung function were analyzed by linear regression within cohorts, adjusting for potential confounders, and then combined by random effects meta-analysis. We observed small reductions in forced expiratory volume in the first second, forced vital capacity, and peak expiratory flow related to exposure to most elemental pollutants, with the most substantial negative associations found for nickel and sulfur. PM10 nickel and PM10 sulfur were associated with decreases in forced expiratory volume in the first second of 1.6% (95% confidence interval = 0.4% to 2.7%) and 2.3% (-0.1% to 4.6%) per increase in exposure of 2 and 200 ng/m, respectively. Associations remained after adjusting for PM mass. However, associations with these elements were not evident in all cohorts, and heterogeneity of associations with exposure to various components was larger than for exposure to PM mass. Although we detected small adverse effects on lung function associated with annual average levels of some of the evaluated elements (particularly nickel and sulfur), lower lung function was more consistently associated with increased PM mass.

Improved methods for elemental analysis of atmospheric aerosols for evaluating human health impacts of aerosols in East Asia

This paper provides improved elemental analysis methods for the characterization of atmospheric particulate matter (PM) samples. With the aim of developing an approach for comprehensive trace element analysis of small mass of PM samples, we coupled an enhanced microwave-assisted acid digestion method with high-resolution magnetic sector inductively coupled plasma-mass spectrometry (SF-ICP-MS). We also propose a rapid and simple method using energy dispersive X-ray fluorescence spectrometry (EDXRF) that has secondary targets and three-dimensional polarization optics for screening elemental composition of PM. We obtained the concentrations of 44 elements ranged from 10−3 to 105 μg/g by SF-ICP-MS, and 16 elements ranged from 101 to 105 μg/g by EDXRF. The analytic results obtained by these two methods agreed well. Comprehensive analysis for a large set of elements was demonstrated by using the improved SF-ICP-MS method, while EDXRF coupled with fundamental parameter (FP) quantification method can analyze several selected elements as fast as 900 s (15 min) per sample with only minimal sample pretreatment. We provide two possible choices of analysis methods for elucidating elemental composition of PM according to the number of samples, target elements, sample amounts, time and cost for analysis required.

Natural cause mortality and exposure to elemental composition of particulate matter: an analysis of 19 European cohorts within the multi-center ESCAPE project

Background Studies have shown associations between mortality and long-term exposure to particle mass air pollution. Studies on the effects of the elemental composition of particulate matter are, however, limited. Aims To study the association between natural cause mortality and long-term exposure to the elemental composition of particulate matter within the multi-center European Study of Cohorts for Air Pollution Effects (ESCAPE) project and the Transport related Air Pollution and Health impacts (TRANSPHORM) project. Methods Data from 19 European cohort studies were used. Residential exposure was characterized following a strictly standardized protocol as annual average concentrations of Copper (Cu), Iron (Fe), Potassium (K), Nickel (Ni), Sulphur (S), Silicon, (Si), Vanadium (V) and Zinc (Zn) within PM size fractions &lt;2.5µm (PM2.5) and &lt;10µm (PM10), estimated using land-use regression (LUR) models. Cohort-specific statistical analyses of the associations between mortality and air pollution were conducted using Cox proportional hazards models using a common protocol followed by meta-analysis. Results The total study population consisted of 322,159 participants, of which 27,208 died from a natural cause during follow-up. Elevated risks were shown for all elements with significantly elevated hazard ratios for: S PM2.5 (1.15 (95% CI: 1.06-1.25) per 200 ng/m3); Si PM2.5 (1.09 (95% CI: 1.01-1.18) per 100 ng/m3); and Ni PM10 (1.10 (95% CI: 1.01-1.21) per 2 ng/m3). No heterogeneity between individual cohort effect estimates was found for these significant associations. Conclusions Long-term exposure to elemental composition of particulate matter was associated with natural cause mortality.

Elemental composition of particulate matter and the association with lung function in 5 European birth cohorts – results of the ESCAPE project

Background Negative effects of long-term exposure to particulate matter (PM) on lung function have been shown repeatedly. We earlier reported a negative association between PM and FEV1 and FVC in c...

Spatial and temporal distribution of PM elemental composition in 20 European areas

Background: Particulate matter (PM) composition is of increasing importance for public health. This is the first European dataset of PM trace elements from harmonized sampling and centralized analysis. Aim: To characterize the spatiotemporal distributions of 26 elements within and between areas across Europe. Methods: Within the framework of ESCAPE (European study of cohorts for air pollution effects), 20 areas were monitored. In each area, an additional 20 sites were chosen to characterize within area spatial variability. PM2.5 &amp; PM10 teflon filters were analyzed by x-ray fluorescence with about 25 elements well detected. Results: Year-round PM2.5 elemental mass gradually increased from north to south with highs in industrial areas. In contrast, coarse PM (PMc, PM10-PM2.5) elemental mass showed a more uniform level across northern/central Europe before a jump in the south. S (primarily as sulfate) is almost entirely in the PM2.5 fraction, while crustal elements (Sr, Ca, Ti, Si, Mg, Fe, Al) are mainly in the coarse fraction. Seasonal analysis comparing within-area median concentrations showed that a minority of elements have similar (R2&gt;0.75) seasonal spatial distributions across Europe (27% for PM2.5, 38% for PMc). Most areas showed wintertime increases of K (PM2.5) from wood burning and Na &amp; Cl (PMc) from road de-icing. Some had increases of Mg &amp; As-maybe coal use. Within areas, many traffic related elements (eg Cu, Fe) had elevated concentrations at street sites compared to urban and regional background sites. For regional pollutants, eg S, the levels were similar regardless of site type. The varying proportions of median levels of PM2.5 &amp; PMc across Europe by element, site type, and season reveals overlapping elemental contributions from different sources. Conclusions: Spatiotemporal distributions differed for most elements and by size fraction. Factor analysis by area would give insight into possible sources and likely provide a more health relevant exposure.

Elemental stoichiometry of marine particulate matter measured by wavelength dispersive X-ray fluorescence (WDXRF) spectroscopy

This paper describes the development of a method for quantitative measurement of the elemental composition of particulate matter (PM) in seawater. This method is based on use of wavelength dispersive X-ray fluorescence (WDXRF) analysing PM harvested on various filter types. As the amount of material is less than a monolayer of cells on the filters we reduced the need for absorption correction. Given the appropriate combination of filters and elements the detection limits are low: &lt;1 µg/filter for carbon (C), nitrogen (N), and &lt;0.1 µg/filter for silicon (Si), phosphorus (P), calcium (Ca) and iron (Fe). The analytical range used was90–750 µgC,23–116 µgN and7–30 µgP, depending on the filters applied. Calibration constants for the elements included in this study were obtained from analysis of known quantities of chemical compounds on filters or silver plates. For carbon and nitrogen we also used comparative measurements ofSynechococcussp. cultures by CHN analyser and WDXRF. We harvested PM from 150 ml to 2000 ml on each filter in three replicates, obtaining less than 5% analytical variability between the replicates. One of the challenges using WDXRF as proposed here is the absorption of X-ray signals by the filter and variability of cell/particle sizes, and, consequentlyly, the variability of harvested PM on various filters. We find that an anodisc filter is best suited for C and N, while polycarbonate filters are best for heavier elements. Here we present analytical details and some data from field experiments related to C, N, P, Si, Ca and Fe in particles from seawater.

Infiltration or indoor sources as determinants of the elemental composition of particulate matter inside a school in Wrocław, Poland?

Children's exposure to air pollution requires a focus on air quality in places where they spend most time, e.g. in schools. Therefore, understanding how indoor elemental concentrations relate the outdoor ones is necessary to create healthy indoor school environment. The aims of this study were to examine the elemental composition of particulate matter (PM1, PM2.5, PM10) in the school and also to investigate to what degree indoor elemental concentrations are affected by outdoor air or generated inside the school. The measurements were performed inside and outside the public school building in the centre of the city. It was observed that concentrations of most elements were higher at school than outside. The dominant elements in PM1 both indoors and outdoors were S, Cl, K, and Zn. PM2.5 and PM10 fractions inside the school were clearly enriched in elements of mineral origin, additionally S, Zn, K and Cl were also present in high concentrations both indoors and outdoors. Results suggested that a significant contribution to indoor Zn, Pb and S concentrations in the PM2.5 fraction was from penetration of outdoor air. 88%, 80% and 90% of the observed total variations in indoor concentrations of Zn, Pb, and S were explained by the linear relationship between indoor and outdoor concentrations. The lack of correlation between indoor and outdoor concentrations obtained for Si, Ca, Ti, Sr indicated that these metals were more likely to originate from indoor sources.

Diurnal Variation and Chemical Characteristics of Atmospheric Aerosol Particles and Their Source Fingerprints at Xiamen Bay

This study investigated the diurnal variation of mass concentration and chemical composition of atmospheric aerosol particles sampled at Xiamen Bay, located on the west bank of the Taiwan Strait. Atmospheric PM10 samples were collected at ten particulate matter (PM) sampling sites at Xiamen Bay, including five sites at the Kinmen Islands and five sites in urban Xiamen, at both daytime and nighttime during the regular and intensive sampling periods. Regular sampling was conducted to collect PM10 with high-volume samplers three times a month from April 2009 to April 2010, while intensive sampling was conducted to collect PM2.5 and PM2.5–10 with dichotomous samplers in the spring and winter of 2009 and 2010. This study further selected ten major emission sources (e.g., stone processing, power plants, soil dusts, and biomass burning) at Xiamen Bay to collect fugitive particulate samples which were then resuspended in a self-designed resuspension chamber to collect PM2.5 and PM2.5–10 with two separate dichotomous samplers for further chemical analysis. The results from PM10 sampling indicated that atmospheric aerosol particles tended to be accumulated in Xiamen Bay all year round, but especially in spring and winter. A significant diurnal variation of PM10 was observed, with higher PM10 concentrations in the daytime during the regular sampling periods. The chemical analysis results showed that the major chemical components of PM10 were SO4 2– , NO3 – , NH4 + , OC, EC, and crustal elements (Ca, Mg, Fe, and Al), which were usually higher in the daytime than at night at Xiamen Bay. The differences were most pronounced at night, where the concentrations of most anthropogenic elements (Ni, Cu, As, and V) were higher than those in the daytime. The elemental composition of PM emitted from stone processing and the cement industry were dominated by crustal elements, particularly Ca, whereas the profile of top-soil mainly contained Al and Ca. The profiles of industrial sources were dominated by secondary inorganic aerosols and EC. Moreover, construction and road dusts contained large amounts of Fe and Al, while biomass burning released large amounts of K, OC, and SO4 2–

Elemental Characterization Of Indoor Breathable Particles at a Portuguese Urban Hospital

Hospitals are a specific indoor environment with highly susceptible individuals for whom indoor air pollution represents additional health risks. Particulate matter (PM) is one of the most health-relevant indoor pollutants due to its association with respiratory and cardiovascular diseases. Particles can also act as a carrier for various harmful organisms present in the air of hospitals, thus leading to airborne transmission of infectious diseases. Thus, the objective of this study was to characterize indoor PM collected in a hospital in consideration of concentration, size distribution, and elemental composition. Emission sources of indoor PM were indentified and risks associated with indoor PM estimated. Sampling was performed at radiology ward of a Portuguese urban hospital where PM10, PM2.5, and PM1 were collected during a period of 4 wk; PM elemental composition was determined by proton-induced x-ray emission (PIXE) analysis. Data showed that indoor PM10 concentrations ranged from 13 to 58.8 μg/m3 and from 10.5 to 41.9 μg/m3 for PM2.5. Fine particles constituted 77% of PM10, indicating that PM2.5 made a significant contribution to indoor air quality at the hospital. PM1 ranged from 9.9 to 35.6 μg/m3, accounting for 93% of PM2.5. PIXE identified 21 elements in PM, including health-hazardous metals (manganese, iron, copper, and vanadium) and carcinogenic elements (nickel, chromium, arsenic, and lead). However, no significant indoor source of PM emissions was identified, while outdoor air was the major contributor of indoor particles. Further, no significant risks existed through PM10 inhalation for population at the respective hospital.

Toxicity and elemental composition of particulate matter from outdoor and indoor air of elementary schools in Munich, Germany

Outdoor particulate matter (PM(10)) is associated with detrimental health effects. However, individual PM(10) exposure occurs mostly indoors. We therefore compared the toxic effects of classroom, outdoor, and residential PM(10). Indoor and outdoor PM(10) was collected from six schools in Munich during teaching hours and in six homes. Particles were analyzed by scanning electron microscopy and X-ray spectroscopy (EDX). Toxicity was evaluated in human primary keratinocytes, lung epithelial cells and after metabolic activation by several human cytochromes P450. We found that PM(10) concentrations during teaching hours were 5.6-times higher than outdoors (117 ± 48 μg/m(3) vs. 21 ± 15 μg/m(3), P < 0.001). Compared to outdoors, indoor PM contained more silicate (36% of particle number), organic (29%, probably originating from human skin), and Ca-carbonate particles (12%, probably originating from paper). Outdoor PM contained more Ca-sulfate particles (38%). Indoor PM at 6 μg/cm(2) (10 μg/ml) caused toxicity in keratinocytes and in cells expressing CYP2B6 and CYP3A4. Toxicity by CYP2B6 was abolished with the reactive oxygen species scavenger N-acetylcysteine. We concluded that outdoor PM(10) and indoor PM(10) from homes were devoid of toxicity. Indoor PM(10) was elevated, chemically different and toxicologically more active than outdoor PM(10). Whether the effects translate into a significant health risk needs to be determined. Until then, we suggest better ventilation as a sensible option. Indoor air PM(10) on an equal weight base is toxicologically more active than outdoor PM(10). In addition, indoor PM(10) concentrations are about six times higher than outdoor air. Thus, ventilation of classrooms with outdoor air will improve air quality and is likely to provide a health benefit. It is also easier than cleaning PM(10) from indoor air, which has proven to be tedious.

In vitro biological effects of airborne PM 2.5 and PM 10 from a semi-desert city on the Mexico–US border

Compelling evidence indicates that exposure to urban airborne particulate matter (PM) affects health. However, how PM components interact with PM-size to cause adverse health effects needs elucidation, especially when considering soil and anthropogenic sources. We studied PM from Mexicali, Mexico, where soil particles contribute importantly to air pollution, expecting to differentiate in vitro effects related to PM-size and composition. PM samples with mean aerodynamic diameters ⩽2.5 μm (PM 2.5) and ⩽10 μm (PM 10) were collected in Mexicali (October 2005–March 2006) from a semi-urban (expected larger participation of soil sources) and an urban (predominately combustion sources) site. Samples were pooled by site and size, analyzed for elemental composition (particle-induced X-ray emission) and tested in vitro for: induction of human erythrocytes membrane disruption (hemolysis) (colorimetrically); inhibition of cell proliferation (ICP) (crystal violet) and TNFα/IL-6 secretion (ELISA) using J774.A1 murine monocytic cells; and DNA degradation using Balb/c3T3 cell naked DNA (electrophoretically). Results of PM elemental composition principal component analysis were used in associating cellular effects. Sixteen elements identified in PM grouped in two principal components: Component 1 ( C 1 ): Mg, Al, Si, P, Cl, K, Ca, Ti, V, Cr, Fe, and Component 2 ( C 2 ): Cu, Zn. Hemolysis was predominately induced by semi-urban-PM 10 ( p < 0.05) and was associated with urban-PM 10 C 1 ( r = 0.62, p = 0.003). Major ICP resulted with semi-urban PM 2.5 ( p < 0.05). TNFα was mainly induced by urban samples regardless of size ( p < 0.05) and associated with urban-PM 2.5 C 2 ( r = 0.48, p = 0.02). Both PM 10 samples induced highest DNA degradation ( p < 0.05), regardless of location. We conclude that PM-size and PM-related soil or anthropogenic elements trigger specific biological-response patterns.

Atmospheric elemental concentration determined by Particle-Induced X-ray Emission at Tlaxcoapan in central Mexico, and its relation to Tula industrial-corridor emissions

Abstract The Tula-Vito-Apasco industrial corridor is considered one of the most contaminated zones in Mexico. In this corridor, at Hidalgo state, is located the Miguel Hidalgo refinery, the biggest in the country. Although ecology agencies monitor criterion contaminants in a routine basis, scarce data are available about elemental composition of particulate matter (PM). The PM 10 elemental composition of Tula vicinity is being analyzed and results of the field study performed in Tlaxcoapan, Hidalgo are presented here. This small agricultural town is located within a 7.5 km from Tula-Vito-Apasco industrial corridor. PM 10 fraction of atmospheric aerosols collected in filters from July to December 2007, was analyzed using Particle Induced X-ray Emission (PIXE) technique, and sixteen elements were detected. Temporal variations were observed during the studied period. Enrichment Factors were moderately high for S, Ca, V, Ni, Cu, Zn and Pb. Rain did not have strong influence but high amounts of sulfur were correlated to high amounts of Ni and V. Comparison of our results with other data from nearby allocations, shows good general agreement. A receptor model with principal component factor analysis (PCFA) and VARIMAX rotation was applied to data in order to estimate source apportionment. Four main sources were identified: soil that contributes to the elemental composition of filters with 26%, refinery and the power plant with 20% and two independent industrial emissions summed 26%. The last three polluting sources indicate that the industrial activities carried out in the corridor have a harmful impact in Tlaxcoapan, Hidalgo.

Concentrations and elemental composition of particulate matter in the Buenos Aires underground system

Total suspended particulate (TSP) samples have been collected at six stations in the C and B lines of the Buenos Aires underground system and, almost simultaneously, at six ground level sites outside and nearby the corresponding underground stations, in the Oct 2005/Oct 2006 period. All these samples were analyzed for mass and elemental Fe, Cu, and Zn concentrations by using the Particle Induced X-ray Emission (PIXE) technique. Mostly, TSP concentrations were found to be between 152 μg m −3 (25% percentile) and 270 μg m −3 (75% percentile) in the platform of the stations, while those in outside ambient air oscillated from 55 μg m −3 (25% percentile) to 137 μg m −3 (75% percentile). Moreover, experimental results indicate that TSP levels are comparable to those measured for other underground systems worldwide. Statistical results demonstrate that subway TSP levels are about 3 times larger on average than those for urban ambient air. The TSP levels inside stations and outdoors are poorly correlated, indicating that TSP levels in the metro system are mainly influenced by internal sources. Regarding metal concentrations, the most enriched element in TSP samples was Fe, the levels of which ranged from 36 (25% percentile) to 86 μg m −3 (75% percentile) in Line C stations, while in Line B ones they varied between 8 μg m −3 (25% percentile) and 46 μg m −3 (75% percentile). As a comparison, Fe concentrations in ambient air oscillated between 0.7 μg m −3 (25% percentile) and 1.2 μg m −3 (75% percentile). Other enriched elements include Cu and Zn. With regard to their sources, Fe and Cu have been related to processes taking place inside the subway system, while Zn has been associated with outdoor vehicular traffic. Additionally, concerns about possible health implications based on comparisons to various indoor air quality limits and available toxicological information are discussed.

Particulate matter and gaseous pollutants in residences in Antwerp, Belgium

This comprehensive study, a first in Flanders, Belgium, aimed at characterizing the residential indoor air quality of subgroups that took part in the European Community Respiratory Health Survey (ECRHS I—1991 and ECHRS II—1996) questionnaire-based asthma and related illnesses studies. This pilot study aimed at the evaluation of particulate matter and various inorganic gaseous compounds in residences in Antwerp. In addition personal exposure to the gaseous compounds of one individual per residence was assessed. The main objective was to obtain some base-line pollutant levels and compare these with studies performed in other cities, to estimate the indoor air quality in residences in Antwerp. Correlations between the various pollutant levels, indoor:outdoor ratios and the micro-environments of each residence were investigated. This paper presents results on indoor and ambient PM 1, PM 2.5 and PM 10 mass concentrations, its elemental composition in terms of K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, Zn, Br, Pb, Al, Si, S and Cl and the water-soluble ionic concentrations in terms of SO 4 2−, NO 3 2−, Cl −, NH 4 + K +, Ca 2+. In addition, indoor, ambient and personal exposure levels of the gases NO 2, SO 2, and O 3 were determined. Elevated indoor:outdoor ratios were found for NO 2 in residences containing gas stoves. In smoker's houses increased PM concentrations of 58 and 43% were found for the fine and coarse fractions respectively. Contrary to the fact that all I/O ratios of the registered elements in each individual house were significantly correlated to each other, no correlation could be established between the I/O ratios of the different houses, thus indicating a unique micro-environment for each residence. Linear relationships between the particulate matter elemental composition, SO 2 and O 3 levels indoors and outdoors could be established. No linear relationships between indoor and outdoor NO 2 and particulate mass concentrations were found.

Particulate matter emission by a vehicle running on unpaved road

The particulate matter (PM) emission from unpaved roads starts with the pulverization of surface material by the force of the vehicle, uplifting and subsequent exposure of road to strong air currents behind the wheels. The objectives of the project were to: demonstrate the utility of a simple technique for collecting suspended airborne PM emitted by vehicle running on an unpaved road, determine the mass balance of airborne PM at different heights, and determine the particle size and elemental composition of PM. We collected dust samples on sticky tapes using a rotorod sampler mounted on a tower across an unpaved road located at the Leyendecker Plant Sciences Research Center, Las Cruces, NM, USA. Dust samples were collected at 1.5, 4.5 and 6m height above the ground surface on the east and west side of the road. One rotorod sampler was also installed at the centre of the road at 6m height. Dust samples from unpaved road were mostly (70%) silt and clay-sized particles and were collected at all heights. The height and width of the PM plume and the amount of clay-sized particles captured on both sides of the road increased with speed and particle captured ranged from 0.05 to 159μm. Dust particles between PM10 and PM2.5 did not correlate with vehicle speed but particles ⩽PM2.5 did. Emission factors estimated for the total suspended PM were 10147gkm−1 at 48kmh−1 and 11062gkm−1 at 64kmh−1 speed, respectively. The predominant elements detected in PM were carbon, aluminum and silica at all heights. Overall, sticky tape method coupled with electron microscopy was a useful technique for a rapid particle size and elemental characterization of airborne PM.