Urban Airborne Particulate Matter Research Articles

Lnc-Clic5 as a sponge for miR-212–5p to inhibit cow barn PM2.5-induced apoptosis in rat alveolar macrophages

Particulate matter 2.5 (PM2.5) is a highly hazardous airborne particulate matter that poses a significant risk to humans and animals. Urban airborne particulate matter contributes to the increased incidence and mortality of respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD), in humans. However, the specific mechanism by which PM2.5 affects animals in barn environments is yet to be elucidated. In this study, we investigated the effect of exposure to cow barn PM2.5 on rat alveolar macrophages (NR8383) and found that it induced apoptosis via the miR-212–5p/RASSF1 pathway. We found that lnc-Clic5 expression was downregulated in NR8383 cells exposed to cow barn PM2.5. Lnc-Clic5 plays a competitive endogenous RNA (ceRNA) regulatory role by sponging miR-212–5p to attenuate the regulation of RASSF1. Moreover, lnc-Clic5 overexpression inhibited NR8383 apoptosis by targeting the miR-212–5p/RASSF1 pathway. Co-treatment with miR-212–5p and lnc-Clic5 in the presence of cow barn PM2.5 revealed that lnc-Clic5 reversed NR8383 cell apoptosis induced by PM2.5 when miR-212–5p was overexpressed. These findings contribute to the study of ncRNAs and ceRNAs regulating PM2.5-induced apoptosis in animal farms, provide therapeutic targets for lung macrophage apoptosis, and may be useful for further evaluating the toxicological effects of PM2.5 in farmhouses on the respiratory systems of humans and animals.

Investigation of the Immunogenic Properties of Ovalbumin Modified by Urban Airborne Particulate Matter

Exposure to air particulate matter (PM) is linked to the blood oxidative stress and systemic inflammation. The aim of this study was to elucidate whether oxidative PM modification of ovalbumin (OVA), the major antioxidant serum protein, may alter its antigenicity and/or immunogenicity. Ovalbumin was exposed via dialysis to the standard urban PM (SRM 1648a) or to PM with removed organic content (encoded as LAP). Both structural changes and biological properties of PM-modified OVA were measured. T lymphocytes and dendritic cells (the major antigen-presenting cells) isolated from C57BL/6 and OT-II (323–339 epitope) OVA-specific T cell receptor (TCR)-transgenic mice were used to test the effect of PM on OVA immunogenicity. The immunogenicity of both SRM 1648a and LAP-modified OVA was significantly higher than that of control OVA, as measured by the epitope-specific T cell proliferation and interferon γ production by the stimulated cells. This effect was associated with mild oxidative changes in the carrier molecule outside the structure of the OVA epitope and with increased resistance to proteolysis of PM-modified OVA. Interestingly, dendritic cells showed enhanced capacity for the uptake of proteins when the cells were cultured with PM-modified OVA. Our results suggest that the enhanced immunogenicity of PM-modified OVA is not associated with altered antigenicity or antigen presentation. However, it may result from slower degradation and longer persistence of modified antigens in dendritic cells. Whether this phenomenon is associated with enhanced risk prevalence of autoimmune diseases observed in the areas with high urban PM pollution needs to be explained.

Sr-Nd-Hf isotopic analysis of reference materials and natural and anthropogenic particulate matter sources: Implications for accurately tracing North African dust in complex urban atmospheres.

We present novel chemical separation protocols for isotopic analysis of low mass aliquots (0.3mg and 25mg) of several reference materials and real-world samples of relevance to urban airborne particulate matter (PM) investigations. A high-yielding gravity flow column chromatography scheme was developed for facile and quantitative separation of Sr, Nd, and Hf prior to multi collector - inductively coupled plasma - mass spectrometry (MC-ICP-MS). Because we are interested in isolating and accurately quantitating individual anthropogenic and natural aerosol sources in complex industrial/metropolitan atmospheric environments, laboratory protocols were optimized using National Institute of Standards and Technology Standard Reference Material (SRM) 1648a (urban atmospheric PM), SRM 1633b (coal fly ash), and European Commission standards BCR-723 (vehicular road dust), and BCR-2 (basalt rock standard). Sr, Nd, and Hf procedural blanks from column chromatography were low (averaging only 37pg, 17pg, 11pg, respectively) and recoveries were high (averaging 95%, 82%, and 92%, respectively). A volume-adjustment protocol was established using isotope reference solutions SRM 987 (SrCO3), JNdi (Nd2O3), and in-house Hf standards to dilute the dried samples prior to MC-ICP-MS based on projected uncertainties for low sample masses. 87Sr/86Sr, 143Nd/144Nd, and 176Hf/177Hf isotopic ratios in SRM 1648a, BCR-723, and SRM 1633b are reported for the first time that can serve as provisional reference values. The novel method was used to characterize isotopic ratios and elemental abundances in two anthropogenic urban aerosol sources, namely motor vehicles and petroleum refining using airborne fine PM collected in a vehicular tunnel and fluidized-bed catalytic cracking catalysts, respectively. Two other important mineral-rich urban PM sources, namely soil (i.e., resuspended crustal material) and concrete/cement dust (i.e., construction activity) were also characterized. These are the first isotopic measurements in these environmental compartments and were compared with literature data for long-range transported North African dust, which is a prominent summertime PM source in urban regions in southeastern United States. We demonstrate the capability of coupled Sr-Nd-Hf isotopes to uniquely trace different mineral dust sources with overlapping elemental composition (Sahara-Sahel region, local soil, and concrete/cement) and accurately isolate various urban PM sources demonstrating the superiority of isotopic markers over elemental tracers.

Lung cell toxicity of co-exposure to airborne particulate matter and extremely low-frequency magnetic field

Although the toxic effects of urban airborne particulate matter (PM) have been known on lung cells, there is less attention to co-exposure to PM and extremely low frequency magnetic (ELF-MF) in occupational settings. The present study investigated the influences of PM and ELF-MF co-exposure on toxicity in human lung cells (A549). In this case, total PM (TPM) was evaluated according to NIOSH-0500. The TPM SiO2 and metal contents were determined based on NIOSH-7602 and 7302, respectively. Besides, 900 mG ELF-MF exposure was simulated based on field measurements. The toxicity mechanisms were assessed by examining malondialdehyde, glutathione ratio, gene expression, and DNA strand breaks. Also, the toxicity indicators of the TPM samples were MDA generation, glutathione depletion, and DNA damage, and their impacts were analysed at doses below the LD50 (4 µg). In addition, gene expression of OGG1 and MTH1 was upregulated after TPM exposure at the lowest dose (2 µg). But ITPA was upregulated in the presence of ELF-MF. The co-exposure to TPM and ELF-MF decreased oxidative stress and DNA damage levels compared to a single exposure to TPM. Although the ELF-MF reduced toxicity in response to TPM, this reduction was not lower than the unexposed cells.

Variations in Reactive Oxygen Species Generation by Urban Airborne Particulate Matter in Lung Epithelial Cells-Impact of Inorganic Fraction.

Air pollution is associated with numerous negative effects on human health. The toxicity of organic components of air pollution is well-recognized, while the impact of their inorganic counterparts in the overall toxicity is still a matter of various discussions. The influence of airborne particulate matter (PM) and their inorganic components on biological function of human alveolar-like epithelial cells (A549) was investigated in vitro. A novel treatment protocol based on covering culture plates with PM allowed increasing the studied pollutant concentrations and prolonging their incubation time without cell exposure on physical suffocation and mechanical disturbance. PM decreased the viability of A549 cells and disrupted their mitochondrial membrane potential and calcium homeostasis. For the first time, the difference in the reactive oxygen species (ROS) profiles generated by organic and inorganic counterparts of PM was shown. Singlet oxygen generation was observed only after treatment of cells with inorganic fraction of PM, while hydrogen peroxide, hydroxyl radical, and superoxide anion radical were induced after exposure of A549 cells to both PM and their inorganic fraction.

Application of k0-INAA Method in Preliminary Characterization of KRISS Urban Airborne Particulate Matter Certified Reference Material

We report comprehensive elemental composition studies on the average urban airborne particulate matters (PMs) collected in the Greater Seoul area, Korea, in 2019 to identify regional and chronological characteristics of the sample as a candidate for certified reference material (CRM), using k0-based single comparator instrumental neutron activation analysis (k0-INAA). The method was successfully validated by comparing the analysis result of a similar matrix CRM (SRM 1648a urban particulate matter) of National Institute of Standards and Technology, USA, with corresponding certified values. The same methodology was applied to determine various elements in candidate environmental materials for future CRM development, including the urban PMs and incineration ashes, to investigate the possibility of using k0-INAA for certification of relevant reference materials. In total, 46 elements in the urban PM sample were analyzed and their concentration levels were compared with the urban PMs collected in the 1970s in St. Louis, USA. Urban PMs of Korea Research Institute of Standards and Science in 2019 contain significantly lower levels of hazardous elements, such as As, Cd, Cr, Hg, and Pb, as compared to those of the 1970s, which can be attributed to the reduced air pollution by environmental regulation and technological innovation. The potential major source of urban airborne PMs was also discussed.

Hazard assessment of air pollutants: The transforming ability of complex pollutant mixtures in the Bhas 42 cell model.

The use of in vitro alternative methods is a promising approach to characterize the hazardous properties of environmental chemical mixtures, including urban airborne particulate matter (PM). The aim of this study was to examine seasonal differences in the toxic and transforming potential of PM samples, by using the in vitro cell transformation assay in Bhas 42 cells for the prediction of potential carcinogenic effects. Bhas 42 cells are already initiated, and the v-Ha-ras transfection, together with genetic modification following the immortalization process, makes them a valuable model to study the late steps of cellular transformation leading to the acquisition of the malignant phenotype. Exposure to organic extracts of PM1 and PM2.5 induced dose-related effects. The transforming and cytotoxic properties are related to the amount of PM collected during the sampling campaign and associated with the concentrations of polycyclic aromatic hydrocarbons (PAHs) in the samples. All the samples induced cell transformation following prolonged exposure of 2 weeks. Our results support the utility of the in vitro top-down approach to characterise the toxicity of real mixtures, thereby supporting regulators in the decision-making process. The results also identify the need for appropriate assay selection within the in vitro testing strategy to address the complexity of the final adverse outcomes.

Bioaccessibility and exposure assessment of trace metals from urban airborne particulate matter (PM10 and PM2.5) in simulated digestive fluid

We describe a batch-extraction with simulated digestive fluid (salivary fluid, gastric fluid and intestinal fluid) to estimate the bioaccessibility of inhaled trace metals (TMs) in particulate matter less than 10 and 2.5 μm in aerodynamic diameter (PM10 and PM2.5). Concentrations of the assayed TMs (As, Cd, Cr, Ni, Mn, Cu, Zn, Sb, Hg and Pb) were determined in PM10 and PM2.5 samples by inductively coupled plasma-mass spectrometry. The TMs with the largest soluble fractions for airborne PM collected from winter and summer in saliva were Mn and Sb, respectively; in seasons this became Co in gastric fluid and Cu in intestinal fluid. Clearly, bioaccessibility is strongly dependent on particle size, the component of simulated digestive fluids (e.g., pH, digestive enzymes pepsin and trypsin), and the chemical properties of metal ions. The particle size and seasonal variation affected the inhaled bioaccessible fraction of PM-bound TMs during mucociliary clearance, which transported PM from the tracheal and the bronchial region to the digestive system. This study provides direct evidence for TMs in airborne PM being bioaccessible TMs are likely to possess an enhanced digestive toxic potential due to airborne PM pollution.

Milan winter fine particulate matter (wPM2.5) induces IL-6 and IL-8 synthesis in human bronchial BEAS-2B cells, but specifically impairs IL-8 release

Inflammatory responses have an important role in the onset of many lung diseases associated with urban airborne particulate matter (PM). Here we investigate effects and mechanisms linked to PM-induced expression and release of two main interleukins, IL-6 and IL-8, in human bronchial epithelial BEAS-2B cells. The cells were exposed to well characterized Milan city PM, winter PM2.5 (wPM2.5) and summer PM10 (sPM10), representing combustion and non-combustion sources, respectively. Both wPM2.5 and sPM10 increased mRNA-synthesis and intracellular protein levels of IL-6 and IL-8. Exposure to sPM10 also resulted in continuous and time-dependent increases in release of IL-6 and IL-8 for up to 48 h. By comparison, in wPM2.5-exposed cells IL-8 release was not significantly augmented, while extracellular IL-6 levels were increased but remained constant beyond 24 h exposure. Moreover, wPM2.5 also reduced the lipopolysaccharide (LPS)-increased release of IL-8. No cytotoxicity or significant adsorption of cytokines to wPM2.5 were observed. Immunofluorescence microscopy revealed an accumulation of IL-8 in intracellular vesicles and alterations in actin filament organization in wPM2.5 exposed cells, suggesting that the trafficking of vesicles carrying interleukins to the plasma membrane might be inhibited. Thus, wPM2.5 appeared to impair cytokine release in BEAS-2B cells, in particular of IL-8, possibly by damaging cytoskeletal function involved in protein secretion.

Combustion-Related Organic Species in Temporally Resolved Urban Airborne Particulate Matter.

Accurate characterization of the chemical composition of particulate matter (PM) is essential for improved understanding of source attribution and resultant health impacts. To explore this we conducted ambient monitoring of a suite of 15 combustion-related organic species in temporally resolved PM 2.5 samples during an ongoing animal exposure study in a near source environment in Detroit, MI. All of the 15 species detected were above the method detection limit in 8 hour samples. This study focused on two molecular classes: Polycyclic Aromatic Hydrocarbons (PAHs) and Hopanes measured in samples. Of the 12 PAHs studied, benzo[b]fluoranthene (169 pg m-3), benzo[g,h,i]perylene (124 pg m-3), and benzo[e]pyrene (118, pg m-3) exhibited the three highest mean concentrations while 17α(H),21β(H)-Hopane (189 pg m-3) and 17α(H),21β(H)-30-Norhopane (145 pg m-3) had the highest mean concentrations of the 3 Hopanes analyzed in samples. Ratios of individual compound concentrations to total compound concentrations (∑ 15 compounds) showed the greatest daily variation for 17α(H),21β(H)-Hopane (11-28%) and 17α(H),21β(H)-30-Norhopane (8-20%). Diagnostic PAH concentration ratios ([IP]/[IP + BP] (range 0.30 - 0.45), [BaP]/[BaP+BeP] (range 0.26 - 0.44), [BaP]/[BP] (range 0.41 - 0.82), [Bb]/[Bk] (range 2.07 - 2.66), in samples reflected impacts froma mixture of combustion sources consistent with greater prevalence of petroleum combustion source emissions (gasoline, diesel, kerosene, and crude oil) compared to coal or wood combustion emissions impacts at this urban site. Results from this study demonstrate that short duration sampling for organic speciation provides temporally relevant exposure information.

Stroke Damage Is Exacerbated by Nano-Size Particulate Matter in a Mouse Model.

This study examines the effects of nano-size particulate matter (nPM) exposure in the setting of murine reperfused stroke. Particulate matter is a potent source of inflammation and oxidative stress. These processes are known to influence stroke progression through recruitment of marginally viable penumbral tissue into the ischemic core. nPM was collected in an urban area in central Los Angeles, impacted primarily by traffic emissions. Re-aerosolized nPM or filtered air was then administered to mice through whole body exposure chambers for forty-five cumulative hours. Exposed mice then underwent middle cerebral artery occlusion/ reperfusion. Following cerebral ischemia/ reperfusion, mice exposed to nPM exhibited significantly larger infarct volumes and less favorable neurological deficit scores when compared to mice exposed to filtered air. Mice exposed to nPM also demonstrated increases in markers of inflammation and oxidative stress in the region of the ischemic core. The findings suggest a detrimental effect of urban airborne particulate matter exposure in the setting of acute ischemic stroke.

Estimated Exposure Risks from Carcinogenic Nitrosamines in Urban Airborne Particulate Matter.

Organic nitrogen (ON) compounds are present in atmospheric particulate matter (PM), but compared to their inorganic, hydrocarbon, and oxygenated counterparts, they are difficult to characterize due to their low concentrations in complex matrices. Nitrosamines are a class of ON compounds known to be highly carcinogenic and include species formed from nicotine degradation, but there are no detailed estimates of their abundance in ambient air. We use a highly sensitive analytical method, which is capable of separating over 700 ON compounds, to determine daily variability in nicotine, and 8 nonspecific and 4 tobacco-specific nitrosamines in ambient PM from central London over two periods in winter and summer. The average total nitrosamine concentration was 5.2 ng m(-3), substantially exceeding a current public recommendation of 0.3 ng m(-3) on a daily basis. The lifetime cancer risk from nitrosamines in urban PM exceeded the U.S. Environmental Protection Agency guideline of 1 excess cancer case per 1 million population exposed after 1 h of exposure to observed concentrations per day over the duration of an adult lifetime. A clear relationship between ambient nitrosamines and total PM2.5 was observed with 1.9 ng m(-3) ± 2.6 ng m(-3) (total nitrosamine) per 10 μg m(-3) PM2.5.

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.

Air pollution effects on the gut microbiota

Global incidence rates for inflammatory bowel disease (IBD) have gradually risen over the past 20 years. Genome-wide association studies (GWAS) have identified over 160 genetic loci associated with IBD; however, inherited factors only account for a partial contribution to the disease risk. We have recently shown that urban airborne particulate matter (PM) ingested via contaminated food can alter gut microbiome and immune function under normal and inflammatory conditions. In this addendum, we will discuss how PM can modify the gut microbial form and function, provide evidence on changes seen in intestinal barrier, and suggest a working hypothesis of how pollutants affect the gastrointestinal tract. The significance of the work presented could lead to identifying airborne pollutants as potential risk factors and thus provide better patient care management.

Genotoxicity of polycyclic aromatic hydrocarbons and nitro-derived in respirable airborne particulate matter collected from urban areas of Rio de Janeiro (Brazil).

Air pollution toxic effects are mainly attributed to small inhalable particulates with an aerodynamic diameter of less than 2.5 µm (PM 2.5). Our objective was to investigate mutagenic and clastogenic activity in PM samples collected in Rio de Janeiro. Samples were collected using a high-volume sampler at three sites: with low traffic and (2) and (3) with a heavy traffic. Six polycyclic aromatic hydrocarbons (PAHs) were quantified by gas chromatography/mass spectrometry (GC/MS). Salmonella typhimurium TA98 and the derivative strains YG1021 and YG1024 were used in mutagenicity assays in the presence of organic extracts (10–50 µg/ plate) with and without exogenous metabolization. Allium cepa test was performed to evaluate possible cytotoxic and clastogenic activities. The highest PM 2.5 µm (132.73 µm/m3) and PAH values (1.22 ng/m3 for benzo(a)pyrene) were detected at site 3. High mutagenic frameshift responses in absence and presence of metabolic activation were detected at site 3. The participation of nitroarenes and dinitroarenes was detected in the total mutagenicity of the extracts studied. The cytotoxic effect and the abnormalities detected by Allium cepa test can be attributed to the PAH nitroderivatives in the organic extracts. Evaluation of the genotoxicity of urban airborne particulate matter is important as a basis for decision making by regulatory authorities.

On the magnetic characterization and quantification of the superparamagnetic fraction of traffic-related urban airborne PM in Rome, Italy

The magnetic properties of traffic-related airborne particulate matter (PM) in the city of Rome, Italy, have been previously analyzed and interpreted as suitable proxies to discriminate between different vehicular sources. In this study, we carried out a new set of measurements and analyses specifically devoted to the identification and evaluation of the contribution of ultrafine superparamagnetic (SP) particles to the overall magnetic assemblage of traffic-related PM in Rome. In particular, the presence and the concentration of SP particles have been estimated on powders collected from disk brakes and gasoline exhaust pipes of circulating vehicles and from Quercus ilex leaves grown along high-traffic roads, measuring their hysteresis parameters in a range of temperatures from 293 K to 10 K and measuring the time decay of their saturation remanent magnetization (MRS) at room temperature. The SP fraction contributes for the 10–15% to the overall room temperature MRS and causes the observed changes in the hysteresis properties measured upon cooling down to 10 K. In all the analyzed samples the SP fraction is associated to a generally prevailing population of larger ferrimagnetic multidomain (MD) particles and we suppose that in traffic-related PM the SP fraction mainly occurs as coating of MD particles and originated by localized stress in the oxidized outer shell surrounding the unoxidized core of magnetite-like grains. Under this hypothesis, the estimate of SP content in traffic-related PM cannot be considered a robust proxy to estimate the overall concentration of nanometric particles.

Monitoring of Pd in airborne particulates by solid sampling high-resolution continuum source electrothermal atomic absorption spectrometry

An analytical method has been developed for determination of palladium in PM2.5 fractions of urban airborne particulate matter by solid sampling high-resolution continuum source electrothermal atomic absorption spectrometry. For the optimization of the experimental conditions, a road dust certified reference material (BCR-723) was used. The influence of pyrolysis and atomization temperatures, the amount of sample introduced into the graphite furnace and the addition of acids, surfactants and modifiers on the analytical signal of Pd were investigated. The limit of detection, calculated based on three times the standard deviations of analytical signals obtained during the atomization of 10 blank filter pieces, was 0.07pg/m3. Since the amount of solid certified reference material introduced into the graphite furnace was about 50–2000 times lower than those required in order to obtain the certified value, the precision was relatively poor. This analytical method was applied for investigation of urban airborne particulate matter collected onto quartz fiber filters by high-volume aerosol samplers in the city center of Istanbul (Turkey) and Budapest (Hungary). The measured Pd concentrations changed in the range of 0.22–0.64 and 0.25–0.86pg/m3 in Istanbul and Budapest, respectively.

Chemical composition of urban airborne particulate matter in Ulaanbaatar

Abstract Atmospheric pollution caused by airborne particulate matter in the winter season in Ulaanbaatar, Mongolia is a very serious problem. However, there is a complete lack of scientific observation data to define the situation prior to any remediation. PM10 and PM2.5 average monthly values obtained by continuous monitoring showed the concentrations of particles of both size categories exceeded 100 μg m −3 during November to February (winter). PM10 particles were sampled with filters in January (i.e. during the heating period) and June (i.e.non-heating period) of 2008 in central Ulaanbaatar. To determine the composition of urban airborne particulate matter we analyzed a range of ionic components, multiple elements including heavy metals, and organic and inorganic carbon (soot). We also measured the stable carbon isotope ratio of the soot. Total carbon (sum of organic carbon and inorganic carbon) accounted for 47% of the mass of the PM10 during the heating period and 33% during the non-heating period, and was the largest component of urban airborne particulate matter in Ulaanbaatar. Stable isotope ratios (δ 13 C) of soot generated during the heating period (−23.4 ± 0.2‰) approximated the ratios for coal used in Ulaanbaatar (−21.3 to −24.4‰), while the ratios during the non-heating period (−27.1 ± 0.4‰) were clearly different from the coal values. In the heating period, a very high correlation was observed between soot and organic carbon, SO 4 2– , NO 3 − , F − , Zn, As, and Pb, and we concluded that they were derived from coal combustion along with soot. In addition, the concentrations and their ratios relative to each other of Al, Fe, Ca, K, Na, Mg, and Mn hardly differed between the heating period and the non-heating period, and it was concluded that they were derived from soil dust.

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.

210Pb and 210Po radionuclides in the urban air of Lodz, Poland

The concentration of two important radionuclides: 210Pb and its decay product 210Po in the urban air in the center of the Polish city of Lodz were measured during the winter and spring seasons of 2008–2009. Urban airborne particulate matter was collected using two methods: an Anderson 9-stage impactor, and a high-volume aerosol sampler type ASS500 working in the frames of the aerosol sampling network in Poland, established for radionuclide monitoring. Average concentrations for 10 months sampling period for 210Pb and 210Po were 0.556 and 0.067 mBq/m3, respectively. However remarkable fluctuations due to meteorological condition were observed: from 0.010 to 0.431 mBq/m3 for 210Po and from 0.167 to 1.847 mBq/m3 for 210Pb. The highest concentrations, almost 60% of the total activities, of both radionuclides were found in the first two fine aerosol fractions with particle diameters below 0.36 μm. The aerosol residence times calculated from the 210Po/210Pb ratio ranged from 7 to 120 days.