Inter-annual trends of ultrafine particles in urban Europe.

Ultrafine particles (UFP, those with diameters ≤ 100 nm), have been reported to potentially penetrate deeply into the respiratory system, translocate through the alveoli, and affect various organs, potentially correlating with increased mortality. The aim of this study is to assess long-term trends (5-11 years) in mostly urban UFP concentrations based on measurements of particle number size distributions (PNSD). Additionally, concentrations of other pollutants and meteorological variables were evaluated to support the interpretations. PNSD datasets from 12 urban background (UB), 5 traffic (TR), 3 suburban background (SUB) and 1 regional background (RB) sites in 15 European cities and 1 in the USA were evaluated. The non-parametric Theil-Sen's method was used to detect monotonic trends. Meta-analyses were carried out to assess the overall trends and those for different environments. The results showed significant decreases in NO, NO2, BC, CO, and particle concentrations in the Aitken (25-100 nm) and the Accumulation (100-800 nm) modes, suggesting a positive impact of the implementation of EURO 5/V and 6/VI vehicle standards on European air quality. The growing use of Diesel Particle Filters (DPFs) might also have clearly reduced exhaust emissions of BC, PM, and the Aitken and Accumulation mode particles. However, as reported by prior studies, there remains an issue of poor control of Nucleation mode particles (smaller than 25 nm), which are not fully reduced with current DPFs, without emission controls for semi-volatile organic compounds, and might have different origins than road traffic. Thus, contrasting trends for Nucleation mode particles were obtained across the cities studied. This mode also affected the UFP and total PNC trends because of the high proportion of Nucleation mode particles in both concentration ranges. It was also found that the urban temperature increasing trends might have also influenced those of PNC, Nucleation and Aitken modes.

Recommendations for reporting equivalent black carbon (eBC) mass concentrations based on long-term pan-European in-situ observations.

A reliable determination of equivalent black carbon (eBC) mass concentrations derived from filter absorption photometers (FAPs) measurements depends on the appropriate quantification of the mass absorption cross-section (MAC) for converting the absorption coefficient (babs) to eBC. This study investigates the spatial-temporal variability of the MAC obtained from simultaneous elemental carbon (EC) and babs measurements performed at 22 sites. We compared different methodologies for retrieving eBC integrating different options for calculating MAC including: locally derived, median value calculated from 22 sites, and site-specific rolling MAC. The eBC concentrations that underwent correction using these methods were identified as LeBC (local MAC), MeBC (median MAC), and ReBC (Rolling MAC) respectively. Pronounced differences (up to more than 50 %) were observed between eBC as directly provided by FAPs (NeBC; Nominal instrumental MAC) and ReBC due to the differences observed between the experimental and nominal MAC values. The median MAC was 7.8 ± 3.4 m2 g-1 from 12 aethalometers at 880 nm, and 10.6 ± 4.7 m2 g-1 from 10 MAAPs at 637 nm. The experimental MAC showed significant site and seasonal dependencies, with heterogeneous patterns between summer and winter in different regions. In addition, long-term trend analysis revealed statistically significant (s.s.) decreasing trends in EC. Interestingly, we showed that the corresponding corrected eBC trends are not independent of the way eBC is calculated due to the variability of MAC. NeBC and EC decreasing trends were consistent at sites with no significant trend in experimental MAC. Conversely, where MAC showed s.s. trend, the NeBC and EC trends were not consistent while ReBC concentration followed the same pattern as EC. These results underscore the importance of accounting for MAC variations when deriving eBC measurements from FAPs and emphasize the necessity of incorporating EC observations to constrain the uncertainty associated with eBC.

Ambient air particulate total lung deposited surface area (LDSA) levels in urban Europe.

This study aims to picture the phenomenology of urban ambient total lung deposited surface area (LDSA) (including head/throat (HA), tracheobronchial (TB), and alveolar (ALV) regions) based on multiple path particle dosimetry (MPPD) model during 2017-2019 period collected from urban background (UB, n = 15), traffic (TR, n = 6), suburban background (SUB, n = 4), and regional background (RB, n = 1) monitoring sites in Europe (25) and USA (1). Briefly, the spatial-temporal distribution characteristics of the deposition of LDSA, including diel, weekly, and seasonal patterns, were analyzed. Then, the relationship between LDSA and other air quality metrics at each monitoring site was investigated. The result showed that the peak concentrations of LDSA at UB and TR sites are commonly observed in the morning (06:00-8:00 UTC) and late evening (19:00-22:00 UTC), coinciding with traffic rush hours, biomass burning, and atmospheric stagnation periods. The only LDSA night-time peaks are observed on weekends. Due to the variability of emission sources and meteorology, the seasonal variability of the LDSA concentration revealed significant differences (p = 0.01) between the four seasons at all monitoring sites. Meanwhile, the correlations of LDSA with other pollutant metrics suggested that Aitken and accumulation mode particles play a significant role in the total LDSA concentration. The results also indicated that the main proportion of total LDSA is attributed to the ALV fraction (50 %), followed by the TB (34 %) and HA (16 %). Overall, this study provides valuable information of LDSA as a predictor in epidemiological studies and for the first time presenting total LDSA in a variety of European urban environments.

Different approaches to explore the impact of COVID-19 lockdowns on carbonaceous aerosols at a European rural background site.

To prevent the fast spread of COVID-19, worldwide restrictions have been put in place, leading to a reduction in emissions from most anthropogenic sources. In this study, the impact of COVID-19 lockdowns on elemental (EC) and organic (OC) carbon was explored at a European rural background site combining different approaches: - "Horizontal approach (HA)" consists of comparing concentrations of pollutants measured at 4 m a.g.l. during pre-COVID period (2017-2019) to those measured during COVID period (2020-2021); - "Vertical approach (VA)" consists of inspecting the relationship between OC and EC measured at 4 m and those on top (230 m) of a 250 m-tall tower in Czech Republic. The HA showed that the lockdowns did not systematically result in lower concentrations of both carbonaceous fractions unlike NO2 (25 to 36 % lower) and SO2 (10 to 45 % lower). EC was generally lower during the lockdowns (up to 35 %), likely attributed to the traffic restrictions whereas increased OC (up to 50 %) could be attributed to enhanced emissions from the domestic heating and biomass burning during this stay-home period, but also to the enhanced concentration of SOC (up to 98 %). EC and OC were generally higher at 4 m suggesting a greater influence of local sources near the surface. Interestingly, the VA revealed a significantly enhanced correlation between EC and OC measured at 4 m and those at 230 m (R values up to 0.88 and 0.70 during lockdown 1 and 2, respectively), suggesting a stronger influence of aged and long distance transported aerosols during the lockdowns. This study reveals that lockdowns did not necessarily affect aerosol absolute concentrations but it certainly influenced their vertical distribution. Therefore, analyzing the vertical distribution can allow a better characterization of aerosol properties and sources at rural background sites, especially during a period of significantly reduced human activities.

Long-term trends of ultrafine and fine particle number concentrations in New York State: Apportioning between emissions and dispersion.

In the past several decades, a variety of efforts have been made in the United States to improve air quality, and ambient particulate matter (PM) concentrations have been used as a metric to evaluate the efficacy of environmental policies. However, ambient PM concentrations result from a combination of source emission rates and meteorological conditions, which also change over time. Dispersion normalization was recently developed to reduce the influence of atmospheric dispersion and proved an effective approach that enhanced diel/seasonal patterns and thus provides improved source apportionment results for speciated PM mass and particle number concentration (PNC) measurements. In this work, dispersion normalization was incorporated in long-term trend analysis of 11-500 nm PNCs derived from particle number size distributions (PNSDs) measured in Rochester, NY from 2005 to 2019. Before dispersion normalization, a consistent reduction was observed across the measured size range during 2005-2012, while after 2012, the decreasing trends slowed down for accumulation mode PNCs (100-500 nm) and reversed for ultrafine particles (UFPs, 11-100 nm). Through dispersion normalization, we showed that these changes were driven by both emission rates and dispersion. Thus, it is important for future studies to assess the effects of the changing meteorological conditions when evaluating policy effectiveness on controlling PM concentrations. Before and after dispersion normalization, an evident increase in nucleation mode particles was observed during 2015-2019. This increase was possibly enabled by a cleaner atmosphere and will pose new challenges for future source apportionment and accountability studies.

Mass absorption cross-section and absorption enhancement from long term black and elemental carbon measurements: A rural background station in Central Europe.

Black carbon (BC) is a dominant aerosol light absorber, and its brown carbon (BrC) coating can enhance absorption and lead to uncertainties concerning the radiative forcing estimation. This study investigates the mass absorption cross-section of equivalent BC (MACeBC) during a long-term field measurement (2013-2017) at a rural Central European site. The MAC enhancement factor (Eabs) and the contribution of BrC coatings to the absorption coefficient (Babs) were estimated by combining different approaches. The annual mean Babs and MACeBC values decreased slightly over the measurement period associated with change in the submicron aerosol size distribution. Regardless of the wavelength, Babs exhibited clear seasonal and diurnal variations, with higher values in winter when a higher absorption Ångström exponent (1.4) was observed due to the local biomass burning (BB). In contrast, MACeBC did not have a distinct temporal trend at 600 nm (7.84 ± 2.79 m2 g-1), while it showed a seasonal trend at 370 nm with higher values in winter (15.64 ± 4.77 m2 g-1). During this season, Eabs_660 was 1.18 ± 0.27 and did not exhibit any clear wavelength dependence, despite the influence of BB. During the study period, BrC-attributed absorption was observed in 31% of the samples, with a contribution of up to 40% of total Babs. In summer, the Eabs_660 increased to 1.59 ± 0.60, when a larger BC coating could be formed by secondary aerosol fractions. During this season, MACeBC_660 and Eabs_660 showed comparable source profiles that were mainly associated with aged air masses over central Europe, thereby supporting the fact that characteristics of coating materials formed during atmospheric aging are a major factor driving the MACeBC_660 measured at the regional background site. Further field investigations of the composition of BC coatings would help to better understand and estimate uncertainties related to the radiative effect of aerosols.

Elemental and microbiota content in indoor and outdoor air using recuperation unit filters.

This paper presents the results of a twelve-month measurement campaign conducted at a rural single-family house in Poland. The external and internal filters of a recuperator used to mechanically ventilate the building were used to separate the total suspended particles (TSPs), and the concentrations of fifteen elements and abundance of fungi and bacteria were determined. Lower annual mean concentrations were observed indoors, and the concentrations of most elements did not significantly change between seasons. There were some differences between winter and summer, which may have resulted from changes in the ventilation regimes in the house. The number of bacteria was similar outdoors and indoors, while the amounts of fungi were higher indoors (p < 0.05). The order of metal concentrations outdoors agreed well with observations in other countries, while indoors the metal concentrations order indicated the individual characteristics of the building. The species diversity of fungi was higher than that of bacteria, and different species were found indoors and outdoors, while bacteria were typically present both indoors and outdoors. Different TSP sources were identified indoors and outdoors, suggesting limited penetration between the two environments. However, both environments were affected by traffic. Mechanical ventilation systems with built-in filters (such as recuperators) were useful in assessing the air quality within the building, and the changeable recuperation filters offer an approach to assess the air quality in several houses without any additional cost or discomfort to the residents.

Atmospheric aerosol growth rates at different background station types.

Highly time-resolved particle number size distributions (PNSDs) were evaluated during 5 years (2013-2017) at four background stations in the Czech Republic located in different types of environments-urban background (Ústí nad Labem), industrial background (Lom), agricultural background (National Atmospheric Observatory Kosetice), and suburban background (Prague-Suchdol). The PNSD data was used for new particle formation event determination as well as growth rate (GR) and condensation sink (CS) calculations. The differences or similarities of these parameters were evaluated from perspectives of the different pollution load, meteorological condition, and regional or long-range transport. The median growth rate (4 nm h-1) is very similar at all stations, and the most frequent length of growth lasted between 2 and 4 h. Condensation sink reflects the pollution load at the individual station and their connection to the environment type. The highest median, CS = 1.34 × 10-2 s-1, was recorded at the urban station (Ústí nad Labem), and the lowest (CS = 0.85 × 10-2 s-1) was recorded at the agricultural station (National Atmospheric Observatory Kosetice). Conditional probability function polar plots illustrate the influence of source location to GR. These primary potential emission sources involve traffic, operation of a power plant, and domestic heating.

Spatial-temporal variability of aerosol sources based on chemical composition and particle number size distributions in an urban settlement influenced by metallurgical industry.

The Moravian-Silesian region of the Czech Republic with its capital city Ostrava is a European air pollution hot spot for airborne particulate matter (PM). Therefore, the spatiotemporal variability assessment of source contributions to aerosol particles is essential for the successful abatement strategies implementation. Positive Matrix Factorization (PMF) was applied to highly-time resolved PM0.15-1.15 chemical composition (1 h resolution) and particle number size distribution (PNSD, 14 nm - 10 µm) data measured at the suburban (Ostrava-Plesná) and urban (Ostrava-Radvanice) residential receptor sites in parallel during an intensive winter campaign. Diel patterns, meteorological variables, inorganic and organic markers, and associations between the chemical composition factors and PNSD factors were used to identify the pollution sources and their origins (local, urban agglomeration and regional). The source apportionment analysis resolved six and four PM0.15-1.15 sources in Plesná and Radvanice, respectively. In Plesná, local residential combustion sources (coal and biomass combustion) followed by regional combustion sources (residential heating, metallurgical industry) were the main contributors to PM0.15-1.15. In Radvanice, local residential combustion and the metallurgical industry were the most important PM0.15-1.15 sources. Aitken and accumulation mode particles emitted by local residential combustion sources along with common urban sources (residential heating, industry and traffic) were the main contributors to the particle number concentration (PNC) in Plesná. Additionally, accumulation mode particles from local residential combustion sources and regional pollution dominated the particle volume concentration (PVC). In Radvanice, local industrial sources were the major contributors to PNC and local coal combustion was the main contributor to PVC. The source apportionment results from the complementary datasets elucidated the relevance of highly time-resolved parallel measurements at both receptor sites given the specific meteorological conditions produced by the regional orography. These results are in agreement with our previous studies conducted at this site. Graphical abstract.

Characterization of Equivalent Black Carbon at a regional background site in Central Europe: Variability and source apportionment☆.

Characterizing Black Carbon (BC) at regional background areas is important for better understanding its impact on climate forcing and health effects. The variability and sources of Equivalent Black Carbon (EBC) in PM10 (atmospheric particles with aerodynamic diameter smaller than 10 µm) have been investigated during a 5-year measurement period at the National Atmospheric Observatory Kosetice (NAOK), Czech Republic. Ground based measurements were performed from September 2012 to December 2017 with a 7-wavelength aethalometer (AE31, Magee Scientific). The contributions of fossil fuel (EBCff) and biomass burning (EBCbb) were estimated using the aethalometer model. Seasonal, diurnal and weekly variations of EBC were observed that can be related to the sources fluctuations and transport characteristic of pollutants predominantly associated with regional air masses recirculating over the Czech Republic and neighboring countries. The absorption Ångström exponent (α-value) estimated in summer (1.1 ± 0.2) was consistent with reported value for traffic, while the mean highest value (1.5 ± 0.2) was observed in winter due to increased EBCbb accounting for about 50% of the total EBC. This result is in agreement with the strong correlation between EBCbb and biomass burning tracers (levoglucosan and mannosan) in winter. During this season, the concentrations of EBCbb and Delta-C (proxy for biomass burning) reached a maximum in the evening when increasing emissions of wood burning in domestic heating devices (woodstoves/heating system) is expected, especially during the weekend. The diurnal profile of EBCff displays a typical morning peak during the morning traffic rush hour and shows a decreasing concentration during weekends due to lower the traffic emission.

Hourly land-use regression models based on low-cost PM monitor data.

Land-use regression (LUR) models provide location and time specific estimates of exposure to air pollution and thereby improve the sensitivity of health effects models. However, they require pollutant concentrations at multiple locations along with land-use variables. Often, monitoring is performed over short durations using mobile monitoring with research-grade instruments. Low-cost PM monitors provide an alternative approach that increases the spatial and temporal resolution of the air quality data. LUR models were developed to predict hourly PM concentrations across a metropolitan area using PM concentrations measured simultaneously at multiple locations with low-cost monitors. Monitors were placed at 23 sites during the 2015/16 heating season. Monitors were externally calibrated using co-located measurements including a reference instrument (GRIMM particle spectrometer). LUR models for each hour of the day and weekdays/weekend days were developed using the deletion/substitution/addition algorithm. Coefficients of determination for hourly PM predictions ranged from 0.66 and 0.76 (average 0.7). The hourly-resolved LUR model results will be used in epidemiological studies to examine if and how quickly, increases in ambient PM concentrations trigger adverse health events by reducing the exposure misclassification that arises from using less time resolved exposure estimates.

Estimating Hourly Concentrations of PM2.5 across a Metropolitan Area Using Low-Cost Particle Monitors.

There is concern regarding the heterogeneity of exposure to airborne particulate matter (PM) across urban areas leading to negatively biased health effects models. New, low-cost sensors now permit continuous and simultaneous measurements to be made in multiple locations. Measurements of ambient PM were made from October to April 2015-2016 and 2016-2017 to assess the spatial and temporal variability in PM and the relative importance of traffic and wood smoke to outdoor PM concentrations in Rochester, NY, USA. In general, there was moderate spatial inhomogeneity, as indicated by multiple pairwise measures including coefficient of divergence and signed rank tests of the value distributions. Pearson correlation coefficients were often moderate (~50% of units showed correlations >0.5 during the first season), indicating that there was some coherent variation across the area, likely driven by a combination of meteorological conditions (wind speed, direction, and mixed layer heights) and the concentration of PM2.5 being transported into the region. Although the accuracy of these PM sensors is limited, they are sufficiently precise relative to one another and to research grade instruments that they can be useful is assessing the spatial and temporal variations across an area and provide concentration estimates based on higher-quality central site monitoring data.

Markers of lipid oxidative damage in the exhaled breath condensate of nano TiO2 production workers.

Nanoscale titanium dioxide (nanoTiO2) is a commercially important nanomaterial. Animal studies have documented lung injury and inflammation, oxidative stress, cytotoxicity and genotoxicity. Yet, human health data are scarce and quantitative risk assessments and biomonitoring of exposure are lacking. NanoTiO2 is classified by IARC as a group 2B, possible human carcinogen. In our earlier studies we documented an increase in markers of inflammation, as well as DNA and protein oxidative damage, in exhaled breath condensate (EBC) of workers exposed nanoTiO2. This study focuses on biomarkers of lipid oxidation. Several established lipid oxidative markers (malondialdehyde, 4-hydroxy-trans-hexenal, 4-hydroxy-trans-nonenal, 8-isoProstaglandin F2α and aldehydes C6-C12) were studied in EBC and urine of 34 workers and 45 comparable controls. The median particle number concentration in the production line ranged from 1.98 × 104 to 2.32 × 104 particles/cm3 with ∼80% of the particles <100 nm in diameter. Mass concentration varied between 0.40 and 0.65 mg/m3. All 11 markers of lipid oxidation were elevated in production workers relative to the controls (p < 0.001). A significant dose-dependent association was found between exposure to TiO2 and markers of lipid oxidation in the EBC. These markers were not elevated in the urine samples. Lipid oxidation in the EBC of workers exposed to (nano)TiO2 complements our earlier findings on DNA and protein damage. These results are consistent with the oxidative stress hypothesis and suggest lung injury at the molecular level. Further studies should focus on clinical markers of potential disease progression. EBC has reemerged as a sensitive technique for noninvasive monitoring of workers exposed to engineered nanoparticles.

Markers of lipid oxidative damage among office workers exposed intermittently to air pollutants including nanoTiO2 particles.

Nanoscale titanium dioxide (nanoTiO2) is a commercially important nanomaterial used in numerous applications. Experimental studies with nanotitania have documented lung injury and inflammation, oxidative stress, and genotoxicity. Production workers in TiO2 manufacturing with a high proportion of nanoparticles and a mixture of other air pollutants, such as gases and organic aerosols, had increased markers of oxidative stress, including DNA and protein damage, as well as lipid peroxidation in their exhaled breath condensate (EBC) compared to unexposed controls. Office workers were observed to get intermittent exposures to nanoTiO2 during their process monitoring. The aim of this study was to investigate the impact of such short-term exposures on the markers of health effects in office workers relative to production workers from the same factory. Twenty-two office employees were examined. They were occupationally exposed to (nano)TiO2 aerosol during their daily visits of the production area for an average of 14±9 min/day. Median particle number concentration in office workers while in the production area was 2.32×104/cm3. About 80% of the particles were <100 nm in diameter. A panel of biomarkers of lipid oxidation, specifically malondialdehyde (MDA), 4-hydroxy-trans-hexenal (HHE), 4-hydroxy-trans-nonenal (HNE), 8-isoprostaglandin F2α (8-isoprostane), and aldehydes C6-C12, were studied in the EBC and urine of office workers and 14 unexposed controls. Nine markers of lipid oxidation were elevated in the EBC of office employees relative to controls (p<0.05); only 8-isoprostane and C11 were not increased. Significant association was found in the multivariate analysis between their employment in the TiO2 production plant and EBC markers of lipid oxidation. No association was seen with age, lifestyle factors, or environmental air contamination. The EBC markers in office employees reached about 50% of the levels measured in production workers, and the difference between production workers and office employees was highly significant (p<0.001). None of these biomarkers were elevated in urine. The approach presented here seems to be very sensitive and useful for non-invasive monitoring of employees exposed to air pollutants, including gases, organic aerosols, and nanoTiO2, and may prove useful for routine biomonitoring purposes. Among them, aldehydes C6, C8, C9, and C10 appear to be the most sensitive markers of lipid oxidation in similar occupational cohorts. One major challenge with sensitive biomonitoring techniques, however, is their non-specificity and difficulty in interpreting the meaning of their physiological values in the context of chronic disease development and damage-repair kinetics.

Leukotrienes in exhaled breath condensate and fractional exhaled nitric oxide in workers exposed to TiO2 nanoparticles.

Human health data regarding exposure to nanoparticles are extremely scarce and biomonitoring of exposure is lacking in spite of rodent pathological experimental data. Potential markers of the health-effects of engineered nanoparticles were examined in 30 workers exposed to TiO2 aerosol, 22 office employees of the same plant, and 45 unexposed controls. Leukotrienes (LT) B4, C4, E4, and D4 were analysed in the exhaled breath condensate (EBC) and urine via liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS). Fractional exhaled nitric oxide (FeNO) and spirometry was also measured. The median particle number concentration of the aerosol in the production ranged from 1.98 × 10(4) to 2.32 × 10(4) particles cm(-3); about 80% of the particles were <100 nm in diameter. Median total mass concentration varied between 0.4 and 0.65 mg m(-3). All LT levels in workers' EBC were elevated relative to the controls (p < 0.01). LTs in the EBC sample were correlated with titanium levels. Urinary LTs were not elevated in the workers and office employees. Office workers had higher LTB4 in EBC (p < 0.05), and higher levels of FeNO (p < 0.01). FeNO was higher in office employees with allergic diseases and was negatively correlated with smoking (p < 0.01). In spirometry significant impairment in the workers was seen only for %VCIN and %PEF (both p < 0.01). Multiple regression analysis confirmed a significant association between production of TiO2 and all cysteinyl LTs in EBC (p < 0.01) and impaired %VCIN and %PEF (both p < 0.01). LTB4 was also associated with smoking (p < 0.01). LT levels complemented our earlier findings of DNA, protein, and lipid damage in the EBC of workers with nanoTiO2 exposures. Cysteinyl LTs in EBC analysis suggest inflammation and potential fibrotic changes in the lungs; they may be helpful for monitoring the biological effect of (nano)TiO2 on workers. Spirometry was not sensitive enough.

Oxidative stress markers are elevated in exhaled breath condensate of workers exposed to nanoparticles during iron oxide pigment production.

Markers of oxidative stress and inflammation were analysed in the exhaled breath condensate (EBC) and urine samples of 14 workers (mean age 43 ± 7 years) exposed to iron oxide aerosol for an average of 10 ± 4 years and 14 controls (mean age 39 ± 4 years) by liquid chromatography-electrospray ionization-mass spectrometry/mass spectrometry (LC-ESI-MS/MS) after solid-phase extraction. Aerosol exposure in the workplace was measured by particle size spectrometers, a scanning mobility particle sizer (SMPS) and an aerodynamic particle sizer (APS), and by aerosol concentration monitors, P-TRAK and DustTRAK DRX. Total aerosol concentrations in workplace locations varied greatly in both time and space. The median mass concentration was 0.083 mg m(-3) (IQR 0.063-0.133 mg m(-3)) and the median particle concentration was 66 800 particles cm(-3) (IQR 16,900-86,900 particles cm(-3)). In addition, more than 80% of particles were smaller than 100 nm in diameter. Markers of oxidative stress, malondialdehyde (MDA), 4-hydroxy-trans-hexenale (HHE), 4-hydroxy-trans-nonenale (HNE), 8-isoProstaglandin F2α (8-isoprostane) and aldehydes C6-C12, in addition to markers of nucleic acid oxidation, including 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), 5-hydroxymethyl uracil (5-OHMeU), and of proteins, such as o-tyrosine (o-Tyr), 3-chlorotyrosine (3-ClTyr), and 3-nitrotyrosine (3-NOTyr) were analysed in EBC and urine by LC-ESI-MS/MS. Almost all markers of lipid, nucleic acid and protein oxidation were elevated in the EBC of workers comparing with control subjects. Elevated markers were MDA, HNE, HHE, C6-C10, 8-isoprostane, 8-OHdG, 8-OHG, 5-OHMeU, 3-ClTyr, 3-NOTyr, o-Tyr (all p < 0.001), and C11 (p < 0.05). Only aldehyde C12 and the pH of samples did not differ between groups. Markers in urine were not elevated. These findings suggest the adverse effects of nano iron oxide aerosol exposure and support the utility of oxidative stress biomarkers in EBC. The analysis of urine oxidative stress biomarkers does not support the presence of systemic oxidative stress in iron oxide pigment production workers.

Markers of nucleic acids and proteins oxidation among office workers exposed to air pollutants including (nano)TiO2 particles.

OBJECTIVES: Experimental studies using nanoscale TiO2 have documented lung injury, inflammation, oxidative stress, and genotoxicity. Human health data are extremely scarce. METHODS: In exhaled breath condensate (EBC) and urine of 22 office employees occupationally exposed to TiO2 during their visit in the production workshops for average 14±9 min/day a panel of biomarkers of nucleic acids and proteins oxidation was studied, specifically 8-hydroxy-2-deoxyguanosine (8-OHdG), 8-hydroxyguanosine (8-OHG), 5-hydroxymethyl uracil (5-OHMeU), o-tyrosine (o-Tyr), 3-chlorotyrosine (3-ClTyr), and 3-nitrotyrosine (3-NOTyr). Examination was performed also in 14 comparable controls. RESULTS: The median respirable TiO2 mass concentration in the workshops was 0.40 mg/m3, median number concentration was 2.32×104 particles/cm3 with 80% of the particles being <100 nm in diameter. All 6 markers of oxidation were elevated in EBC in factory office employees relative to controls (p<0.01). Significant association was found between their job in TiO2 production plant and 5 markers of oxidation (except 3-NOTyr) in the EBC in multivariate analysis. No elevation of markers was detected in the urine. CONCLUSION: This pilot study suggests that even short nanoTiO2 exposure may lead to pulmonary oxidative stress; however this effect may be short-term and reversible. The clinical significance of these findings is unclear and more studies are needed.

Raman microspectroscopy of exhaled breath condensate and urine in workers exposed to fine and nano TiO2 particles: a cross-sectional study.

The health effects of engineered nanoparticles in humans are not well-understood; however experimental data support the theory of oxidative stress promoting fibrogenesis and carcinogenicity. The aim of this study was to detect TiO2 particles in exhaled breath condensate (EBC) and urine samples to ascertain their presence and potential persistence and excretion in urine.EBC and urine samples were collected from 20 workers exposed to TiO2 aerosol; among them, 16 had a higher risk level of exposure (production workers) and four had medium risk level (research workers); in addition to 20 controls. Titanium levels in EBC and urine were analysed using the inductively coupled plasma mass spectrometry (ICP-MS) method. A Raman microspectroscopic analysis was performed in EBC and urine to identify the phase composition of TiO2 particles observed. Aerosol exposure in the workplaces was measured using SMPS and APS spectrometers and P-TRAK and DustTRAK DRX monitors.The median concentration of TiO2 aerosol was 1.98 × 10(4) particles cm(-3), the interquartile range (IQR) was 1.50 × 10(4) - 3.01 × 10(4) particles cm(-3) and the median mass concentration was 0.65 mg m(-3) (IQR 0.46-.0.83 mg m(-3)); 70-82% of the particles were smaller than 100 nm in diameter. In any part of the plant, the median TiO2 air concentration did not exceed the national airborne exposure limit of 10 mg m(-3) for inert dust. Particles of rutile and/or anatase were found in the EBC of exposed workers in 8/20 (40%) of the pre-shift and 14/20 (70%) of the post-shift samples. In the urine of workers, TiO2 particles were detected in 2/20 post-shift urine samples only. The mean concentration of titanium in the EBC in production workers was 24.1 ± 1.8 µg/l. In the research workers the values were below the limit of quantitation; LOQ = 4.0 ± 0.2 µg/l), as well as in the controls. In the urine samples of all of the subjects, titanium was under the limit of detection (LOD = 1.2 µg/l). Raman microanalysis of EBC in the workers confirmed the presence of TiO2 anatase and/or rutile crystal phases in the pre-shift samples and their persistence from previous shifts in the workers.