Ambient Particulate Air Research Articles

Measuring and modeling atmospheric particles and particle bound mercury Hg(p) at five characteristic-sampling sites

The main purpose of this study was to monitor ambient air particles and particulate-bound mercury Hg(p) in total suspended particulates (TSP) concentration, dry deposition at five characteristic-sampling sites. In addition, the calculated/measured dry deposition flux ratios of ambient air particles and particulate-bound mercury Hg(p) using three dry deposition models during the years of 2009–2010 were also studied. The results showed that the order of seasonal variations for mean particulate-bound mercury Hg(p) concentrations in TSP at Bei-shi (suburban/coastal), Chang-hua (downtown) and He-mei (residential) were all shown as spring > fall, winter > summer, respectively. However, the order of seasonal variations mean particulate-bound mercury Hg(p) concentrations in TSP that occurred at Gao-mei (wetland) were shown as spring > fall > winter > summer, respectively. Finally, the results of this study also indicated that using the Noll and Fang model exhibited batten prediction results for ambient air particles and particulate-bound mercury Hg(p) dry deposition when compared with the other depositions models at any of the characteristic-sampling sites for this study.

Determination of PM 10 deposition based on antimony flux to selected urban surfaces

Deposition of PM 10 particles to several types of urban surfaces was investigated within this study. Antimony was chosen as a tracer element to calculate dry deposition velocities for PM 10, since antimony proved to be present almost exclusively in PM 10 particles in ambient urban air. During 18 months, eight sampling sites in Berlin and Karlsruhe, two cities in Germany, were operated. PM 10 concentrations and dry deposition were routinely sampled as two week averages. Additionally, leaf-samples were collected at three sites with tall vegetation. The obtained deposition velocities ranged from 0.8 to 1.3 cm s −1 at roadside sites and from 0.4 to 0.5 cm s −1 at the other sites. With reference to the whole canopy, additional deposition velocities of about 0.5 cm s −1 were obtained for leaf surfaces. As a consequence, it can be concluded that vegetation-covered areas beside streets show the highest potential to capture particles in urban areas.

Application of Dry Deposition Models to Estimate Ambient Air Particulate and Particulate-Bound Mercury Hg(p) Dry Deposition

Ambient air samples were collected between September 3, 2009 and March 5, 2010 to determine total suspended particulate matter (TSP) and coarse and fine particulate and particle-bound mercury Hg(p) at the suburban/coastal sampling station of Sha-Lu at Taiwan. Results reveal that average concentrations of ambient air particles PM2.5, PM2.5–10, dry deposition, and TSP were 20.5 ± 6.3 (μg/m3), 11.2 ± 4.44 (μg/m3), 162 ± 92.7 (μg/[m2 min]), and 78.7 ± 34.4 (μg/m3), respectively. Average concentrations of PM2.5, PM2.5–10, dry deposition, and TSP of bound mercury Hg(p) were 0.007 ± 0.005 (ng/m3), 0.011 ± 0.006 (ng/m3), 0.156 ± 0.082 (ng/[m2 min]), and 0.07 ± 0.04 (ng/m3), respectively. Average calculated/measured dry deposition flux ratios with coarse (3.8 μm) and fine (0.68 μm) particle size for ambient air particle and particle-bound mercury Hg(p) by using Zhang's combined with William's were 2.49 and 3.44, respectively. Finally, results of this study also indicate that using Zhang's combined with William's model with the coarse (3.8 μm) and fine (0.68 μm) particle size exhibits better prediction results in ambient air particle and particle-bound mercury Hg(p) when compared with results of Zhang's model with average particle size (20 and 23 μm) in TSP for prediction of dry deposition.

Evaluation of the Filtration Performance of NIOSH-Approved N95 Filtering Facepiece Respirators by Photometric and Number-Based Test Methods

N95 particulate filtering facepiece respirators are certified by measuring penetration levels photometrically with a presumed severe case test method using charge neutralized NaCl aerosols at 85 L/min. However, penetration values obtained by photometric methods have not been compared with count-based methods using contemporary respirators composed of electrostatic filter media and challenged with both generated and ambient aerosols. To better understand the effects of key test parameters (e.g., particle charge, detection method), initial penetration levels for five N95 model filtering facepiece respirators were measured using NaCl aerosols with the aerosol challenge and test equipment employed in the NIOSH respirator certification method (photometric) and compared with an ultrafine condensation particle counter method (count based) for the same NaCl aerosols as well as for ambient room air particles. Penetrations using the NIOSH test method were several-fold less than the penetrations obtained by the ultrafine condensation particle counter for NaCl aerosols as well as for room particles indicating that penetration measurement based on particle counting offers a more difficult challenge than the photometric method, which lacks sensitivity for particles < 100 nm. All five N95 models showed the most penetrating particle size around 50 nm for room air particles with or without charge neutralization, and at 200 nm for singly charged NaCl monodisperse particles. Room air with fewer charged particles and an overwhelming number of neutral particles contributed to the most penetrating particle size in the 50 nm range, indicating that the charge state for the majority of test particles determines the MPPS. Data suggest that the NIOSH respirator certification protocol employing the photometric method may not be a more challenging aerosol test method. Filter penetrations can vary among workplaces with different particle size distributions, which suggests the need for the development of new or revised “more challenging” aerosol test methods for NIOSH certification of respirators.

Ambient PM exposure and DNA methylation in tumor suppressor genes: a cross-sectional study

Exposure to ambient air particles matter (PM) has been associated with increased risk of lung cancer. Aberrant tumor suppressor gene promoter methylation has emerged as a promising biomarker for cancers, including lung cancer. Whether exposure to PM is associated with peripheral blood leukocyte (PBL) DNA methylation in tumor suppressor genes has not been evaluated. In 63 male healthy steel workers with well-characterized exposure to metal-rich particles nearby Brescia, Italy, we evaluated whether exposure to PM and metal components was associated with PBL DNA methylation in 4 tumor suppressor genes (i.e., APC, p16, p53 and RASSF1A). Blood samples were obtained on the 1st (baseline) and 4th day (post-exposure) of the same work week and DNA methylation was measured using pyrosequencing. A linear mixed model was used to examine the correlations of the exposure with promoter methylation levels. Mean promoter DNA methylation levels of APC or p16 were significantly higher in post-exposure samples compared to that in baseline samples (p-values = 0.005 for APC, and p-value = 0.006 for p16). By contrast, the mean levels of p53 or RASSF1A promoter methylation was decreased in post-exposure samples compared to that in baseline samples (p-value = 0.015 for p53; and p-value < 0.001 for RASSF1A). In post-exposure samples, APC methylation was positively associated with PM10 (β = 0.27, 95% CI: 0.13-0.40), and PM1 (β = 0.23, 95% CI: 0.09-0.38). In summary, ambient PM exposure was associated with PBL DNA methylation levels of tumor suppressor genes of APC, p16, p53 and RASSF1A, suggesting that such methylation alterations may reflect processes related to PM-induced lung carcinogenesis.

Generation of metal nanoparticles by laser ablation

The process of nanoparticle generation during nanosecond and picosecond laser ablation of various metals (Ni, Al, W and stainless steel) in ambient air and argon gas was investigated. The number concentration of nanoparticles generated by laser ablation in argon gas was up to 100 times higher compared to the concentration in ambient air. Three stable separate size peaks of nucleation, Aitken and accumulation modes of nanoparticles were observed in case of argon gas, while in ambient air particles of a wide size spectrum (8–200 nm) were generated. The natural precursors in ambient air can have an effect on size spectrum of the particles composed of various chemical compounds with target material during the ablation process. The influence of laser process parameters and properties of investigated metals on the number concentration and size distribution of nanoparticles generated during ns- and ps-laser ablation was observed. Keywords: nanoparticles, nanosecond and picosecond laser ablation, metals, size distribution, number concentration, ambient air, argon gas

Seasonal Variations (Autumn, Winter, and Spring) of Atmospheric Particulate and Particulate-Bound Mercury Hg(p) at a Suburban/Coastal Area

From September 3, 2009, to March 5, 2010, the dry deposition, total suspended particulate (TSP) matter, coarse and fine particulates, and bound mercury (Hg[p]) in the atmosphere were investigated at Bei-Shi sampling site in central Taiwan. When using projection film as collection medium, the average ambient air particulates for day dry deposition fluxes and TSPs were 162.09 ± 97.69 (μg/(min/cm2)) and 78.71 ± 34.42 (μg/m3), respectively. The average fine particulate matter (PM2.5) and coarse particulate matter (PM2.5–10) were 20.5 ± 6.30 μgm−3 and 11.2 ± 4.44 μg m−3, respectively. Average atmospheric particulates Hg(p) in dry depositions, TSPs, PM2.5−10, and PM2.5were 0.156 ± 0.082 ng/m2*min, 0.07 ± 0.036 ng/m3, 0.011 ± 0.006 ng/m3,and 0.007 ± 0.005, respectively. The average compositions of atmospheric bound Hg Hg(p) in dry depositions, TSPs, PM2.5−10 and PM2.5 were 1.02, 36.8, 4.16 and 2.821, respectively. Also, the highest composition for particulate Hg(p) in TSP was observed in spring (50.74 ng/g), and the highest composition for particulate Hg(p) in PM2.5 occurred in autumn (3.11 ng/g). However, the highest composition for particulate Hg(p) in PM2.5−10 occurred in winter (4.67 ng/g). In what concerns particulate Hg(p) in TSP, the values were all less than those from previous studies (Wang et al., 2006). Related to Hg(p) in PM2.5, the values were also all less than those from previous studies (Tsai et al. 2003; Marsik et al. 2007). In what concerns Hg(p) in PM2.5−10, the values were all less than those of previous studies (Marsik et al. 2007). The data presented in this communication provides information that may be useful in forensic investigations of Hg environmental releases.

Monitoring of Ambient Air Particles and Inorganic Elements in China and Korea during an Asian Dust Storm

Concentrations of ambient air particles such as total suspended particulates (TSP), particulate matter <TEX>$(PM)_{10}$</TEX>, and <TEX>$PM_{2.5}$</TEX>, were monitored simultaneously from May to June, 2007, at four locations at Alashan and Beijing in China, and Seoul and Gosan in South Korea. These monitoring sites are in the pathway of Asian dust (AD) storms traveling from China to the Korean peninsula. An AD event was observed in the Korean peninsula on May 25-26. During the sampling period, the average concentrations of TSP and PM10 were each higher than <TEX>$150\;{\mu}g/m^3$</TEX> in Alashan and Beijing, but not in Seoul and Gosan. The concentration of TSP in Alashan (where the dust storm originated) on the day of the AD event reached <TEX>$1824.7\;{\mu}g/m^3$</TEX>, this being the highest concentration of air particles observed during the sampling period. The level was decreased to 15% of this (<TEX>$274.7\;{\mu}g/m^3$</TEX>) in Seoul and to 8.7% (<TEX>$159.0\;{\mu}g/m^3$</TEX>) in Gosan when the AD was observed two days later in Korea. Gosan, a representative background site in East Asia, displayed the lowest concentration of particles, with this maximal TSP concentration of <TEX>$159\;{\mu}g/m^3$</TEX>. Inorganic element contents in the air particles were also measured, and the concentrations in the four different regions compared. Concentrations of anthropogenically-enriched heavy metals in <TEX>$PM_{10}$</TEX> and <TEX>$PM_{2.5}$</TEX>, such as lead, arsenic, cadmium, and mercury, were higher in the metropolitan cities of Beijing and Seoul compared to non-industrialized regions of Alashan and Gosan. However, the concentrations of inorganic soil elements including iron, magnesium, aluminum sodium, and manganese, were higher in Alashan compared to those in other sampling sites.

Air pollution in the shore zone of a Large Alpine Lake – 1 – Road dust and urban aerosols at Lake Tahoe, California–Nevada

Abstract Concentrated human activity and limited atmospheric mixing create a high potential for airborne pollutant impacts to alpine lakes developed as mountain resorts. Lake Tahoe is a major alpine resort straddling the California–Nevada border, receiving more than two million visitors each year. The lake’s clarity has declined substantially since the inception of intense development in the Tahoe basin in the 1970s. The 2002–2004 Lake Tahoe Atmospheric Deposition Study (LTADS) was conducted as part of a multi-agency effort to develop a water quality management plan for the lake. Estimating aerosol deposition to the lake requires detailed knowledge of the spatial and temporal patterns of aerosol concentration, size distribution, and chemical composition over the entire basin – and developing a management plan requires also that the sources of the aerosols be known with considerable specificity. In lieu of the intensive measurement network implied by this level of detail, we hypothesized that a set of measurements to characterized the temporal, spatial, and size distribution patterns of particles in ambient air and in local emissions in the vicinity of Lake Tahoe could be used to extrapolate long time series of simple measurements to an annual aerosol deposition computation. Here we report the results of our detailed aerosol measurement campaign. Our results show that there are strong systematic and repeating gradients in aerosol loading that occur as functions of location, land use, traffic activity, and time of day, and that road dust is a major source of aerosols around the lake. In addition, we observed strong consistency of particle size distributions as a function of source type, largely independent of particle concentrations. Finally, we demonstrated the use of particle counters to directly observe downwind dispersion and deposition of particles. Together, these findings support the use of imputed location- and time-specific size distributions in annual aerosol deposition calculations, even though particle size distributions were not directly measured in the LTADS baseline monitoring program, and that program was conducted at only a limited set of sites in the Tahoe basin. Two companion articles in this journal issue describe the overall findings of the LTADS study (Dolislager et al., “Overview of the Lake Tahoe Atmospheric Deposition Study”) and the results of measurements taken on the lake itself (VanCuren et al., “Air Pollution in the Shore Zone of a Large Alpine Lake – 2 – Local and Regional Pollutant Distribution over Lake Tahoe California–Nevada”).

Measure and modeling the ambient air particles and particle bound mercury Hg(p) at a traffic sampling site

Ambient air samples were collected between Dec 9, 2008 and Jan 14, 2009 at a highway traffic site located in Sha-Lu, central Taiwan. Atmospheric particulates and particulate bound mercury Hg(p) dry deposition fluxes, concentrations and dry deposition velocities were also studied. The objective of this study was to: 1) measure the dry deposition concentrations of ambient air particles and particle bound mercury Hg(p) following one and two days of sampling events using the total suspended particulates (TSP) sampler, and dry deposition plate (DDP); 2) modeling the dry deposition fluxes of particles and particle bound mercury Hg(p) with calculated deposition velocities then to obtain a calculated dry deposition fluxes; and 3) compared the results of calculated dry deposition fluxes to measured dry deposition fluxes. All the results were presented with one and two days of sampling events with different deposition collection media (i.e., quartz filter and overhead projection film). The results indicated that the average calculated/measured dry deposition fluxes ratios for bound mercury (Hg(p)) for 24 sampling group were 2.27. The results also indicated that the one day calculated/measured dry deposition flux ratios for Hg(p) for overhead projection film and quartz filter were 2.62 and 1.92, respectively. In addition, the results indicated that the average calculated/measured dry deposition fluxes ratios for 24 sampling group were 4.03. The results also indicated that the two days of calculated/measured dry deposition flux ratios for Hg(p) for overhead projection film and quartz filter were 4.64 and 3.42, respectively. The results of particle bound mercury Hg(p) calculated dry deposition model are slightly higher than that of measured dry deposition flux in either one day or two days of sampling period for both of overhead projection and quartz filter collection medium. .Though there are no significant differences of mean values for both particulates and Hg(p) using overhead projection film or quartz filter as a collection media for the dry deposition-study (Fang et al., 2009), quartz filter exhibits better calculated/measured ratio in the prediction of particle bound mercury (Hg(p)) than that of overhead projection film for either one day of the two days of sampling periods.

Metal embryotoxicity from urban particles in Sao Paulo city: An experimental study in chicken embryos

Chicken eggs were inoculated with suspensions of ambient air particles (≤10μm, PM10) from Sao Paulo city in 3, 0.3 or 0.03μg doses on one of the four early days of embryo development. On the eleventh day of development alterations were observed on embryos inoculated with PM10 3μg on the third day. Particles analysis showed high content of metals. Hence, embryos were also inoculated with PM10 (3μg) combined with metal chelating EDTA. PM10 (3μg) embryos presented underdevelopment (stage 29.44±11.4) compared to vehicle and positive controls (stage 36.44±0.51 Saline and stage 31.20±9.7 Cyclophosphamide, p≤0.05); higher (47%) mortality rate (23% Saline and 42% Cyclophosphamide) and low (68%) viability (100% Saline and 70% Cyclophosphamide, p=0.04). Effects were attenuated when embryos received PM10+EDTA (stage 33.63±0.94, 18.9% mortality rate and 82% viability). PM10 from Sao Paulo city is embryotoxic and metal may be implicated in the toxic mechanism.

Environmental and occupational allergies

Airborne allergens are the major cause of allergic rhinitis and asthma. Daily exposure comes from indoor sources, chiefly at home but occasionally at schools or offices. Seasonal exposure to outdoor allergens, pollens, and molds is another important source. Exposure to unusual substances at work causes occupational asthma, accounting for about 5% of asthma in adults. Indoor and outdoor air pollutants trigger airway inflammation and increase the severity of asthma. Diesel exhaust particles increase the production of IgE antibodies. Identification and reduction of exposure to allergens is a very important part of the management of respiratory allergic diseases. The first section of this chapter discusses domestic allergens, arthropods (mites and cockroaches), molds, and mammals (pets and mice). Indoor humidity and water damage are important factors in the production of mite and mold allergens, and discarded human food items are important sources of proliferation of cockroaches and mice. Means of identifying and reducing exposure are presented. The second section discusses outdoor allergens: pollens and molds. The particular plants or molds and the amount of exposure to these allergens is determined by the local climate, and local pollen and mold counts are available to determine the time and amount of exposure. Climate change is already having an important effect on the distribution and amount of outdoor allergens. The third section discusses indoor and outdoor air pollution and methods that individuals can take to reduce indoor pollution in addition to eliminating cigarette smoking. The fourth section discusses the diagnosis and management of occupational asthma.

Seasonal trends of Benzo(a)pyrene in urban suspended particulate matter of Belgrade City, Serbia

Polycyclic aromatic hydrocarbons (PAHs) were identified to be one of the major toxic air pollutants in urban environment. PAHs are mostly formed during incomplete combustion or pyrolysis of organic material. According to Serbian National Legislation Benzo(a)pyrene (BaP) concentration in total suspended particles (TSP) in ambient air in Belgrade Metropolitan has been determined in the last ten years, as a part of local air pollution monitoring program performed by Public Health Institute of Belgrade and funded by Belgrade?s Municipality. Air samples for analysis of BaP in suspended particles have been collected (as 24h sample once per month) at selected monitoring sites within municipal air quality monitoring network. At the beginning, According to National Regulation, all samples were taken as total suspended particles (TSP). Since middle of 2008, the procedure of sampling methodology was harmonized with EU requirements and solid fraction PM10 has been collected and analyzed using GC/MS. In this study, we have analyzed results of TSP collected between 2005 and-2008. Looking through the results obtained during the period of whole year, it can be noticed that concentrations of BaP were much higher during winter season at almost all measuring sites.

Seasonal apportionment of the sources of ambient air particulates in the city of Trieste

A PCA/APCS model was applied to PM2.5 data, which were collected for the Svevo and Muggia districts of the City of Trieste. The sampling campaigns covered the winter and summer periods of 2006. The set of investigated species comprised major inorganic ions, organic and elemental carbon and several Polyaromatic Hydrocarbons (PAHs) that were considered as probable or possible carcinogens by internationally recognised health and environmental agencies. Identified pollution sources included vehicle engine combustion ('traffic'), 'secondary emission', 'domestic combustion processes' and 'sea spray'. 'Secondary emission and combustion' dominated, with a total contribution over 74%. The traffic contribution was quantified as 2?16%, while sea spray was 4?13%. In general, possible or probable carcinogenic PAHs were related to the 'traffic' source. The high correlation coefficient (R² > 0.90) between the measured and predicted values proves that the PCA/APCS modelling is an efficient tool for the estimation of pollution sources' contribution to PM2.5 composition.

Estimation of Atmospheric Particulates and Dry Deposition Particulate-bound Mercury Hg(p) in Sha-Lu, Taiwan

Ambient air samples were collected between March 17, 2009 and May 22, 2009 at a highway traffic site located in Sha-Lu, central Taiwan. Atmospheric particulates and particulate bound mercury Hg(p) dry deposition fluxes, concentrations (PM2.5, PM2.5–10 and TSP ) were studied. The results indicate that the average ambient air particles dry deposition, PM2.5, PM2.5–10 and TSP. concentrations were 145.03 μg/m2-min and 15.47, 9.50, 65.14 μg/m3, respectively. And the average dry deposition, PM2.5, PM2.5–10 and TSP bound mercury Hg(p) concentrations were 0.9519 ng/m2-min and 0.1140, 0.0106, 0.0763 ng/m3, respectively. In addition, the average ambient air particles bound mercury Hg(p) compositions for PM2.5, PM2.5–10 and TSP were 3.60, 3.45 and 44.99 ng/g, respectively. The results indicate that both of these two models (Baklanov and Sorensen, 2001; Zhang et al., 2001) are estimated as the measured dry deposition mass flux. The Baklanov model performs better results in the prediction of mass dry deposition flux. In addition, both of these two models slightly underestimate the measured dry deposition mass flux for particle bound Hg(p). Zhang’s model performs better results in the prediction of Hg(p) dry deposition flux.

Characterization of Ambient Air Particulates and Particulate Mercury at Sha-Lu, Central Taiwan

Ambient air samples were collected between December 9, 2008, and January 14, 2009, at a highway traffic site located in Sha-Lu, central Taiwan. Atmospheric particulates and particulate bound mercury Hg(p) dry deposition, concentrations and dry deposition velocities were also studied. The objective of this study was to: 1) estimate the dry deposition concentrations of ambient air particulates and Hg(p) following 1- and 2-day sampling events using the total suspended particulates (TSP) sampler, and dry deposition plate (DDP) data; and 2) compare Hg(p) concentrations and dry deposition using two different media (i.e., quartz filter and projection film). The results obtained using overhead projection film as collection medium indicated that the average ambient air particulates dry deposition fluxes for the 1- and 2-day periods were 65.99 and 87.88 μ g/min m2, respectively. The corresponding fluxes using quartz filter collection medium were 67.31 and 52.53 μ g/min m2, respectively. Previous Hg related depositional studies have commonly used quartz filter as a collection media; however, in the work reported here overhead projection film was chosen due to its low cost as one of the collection medium, and the results obtained have been compared with the those estimated using quartz. Using the overhead projection collection medium, the average ambient air particulates dry deposition velocities for 1- and 2-day periods were 2.02 and 2.70 cm/sec, respectively, and the corresponding velocities with quartz film collection medium were 1.85 and 1.41 cm/sec, respectively. The overhead projection film collection medium results indicated that the average ambient air particulates bound Hg(p) dry deposition fluxes for the 1- and 2-day periods were 0.16 and 0.09 ng/min m2, respectively, and the corresponding fluxes estimated using the quartz filter collection medium were 0.21 and 0.11 ng/min m2, respectively. The average Hg(p) concentrations ranged from 0.04 to 0.86 ng/m2. The average ambient air particulates bound Hg(p) dry deposition velocities using the overhead projection collection medium for the 1- and 2-day periods were 6.79 and 3.32 cm/sec, respectively, and the corresponding velocities using quartz film collection medium were 8.94 and 4.41 cm/sec, respectively. In addition, the Hg(p) values associated with plant obtained in this study help to establish Hg(p) background concentrations in the air of specific area and also help to establish additional sources of Hg(p) link to distinct pollution events in Taiwan.

MRT letter: Auto‐fluorescence by human alveolar macrophages after in vitro exposure to air pollution particles

Macrophages from smokers demonstrate an increased auto-fluorescence. Similarly, auto-fluorescence follows in vitro exposure of macrophages to cigarette smoke condensate (i.e., the particulate fraction of cigarette smoke). The composition of particles in cigarette smoke can be comparable to air pollution particles. We tested the postulate that macrophages exposed to air pollution particles could demonstrate auto-fluorescence. Healthy nonsmoking and healthy smoking volunteers (both 18-40 years of age) underwent fiberoptic bronchoscopy with bronchoalveolar lavage and alveolar macrophages isolated. Macrophages were incubated at 37 degrees C in 5% CO(2) with either PBS or 100 microg/mL particle for both 1 and 24 h. Particles included a residual oil fly ash, Mt. St. Helens volcanic ash, and ambient air particles collected from St. Louis, Missouri and Salt Lake City, Utah. At the end of incubation, 50 microL of the cell suspension was cytocentrifuged and examined at modes for viewing fluorescein isothiocyanate (FITC) and rhodamine fluorescence. Both emission source air pollution particles demonstrated FITC and rhodamine auto-fluorescence at 1 and 24 h, but the signal following incubation of the macrophages with oil fly ash appeared greater. Similarly, the ambient particles were associated with auto-fluorescence by the alveolar macrophages and this appeared to be dose-dependent. We conclude that exposure of macrophages to air pollution particles can be associated with auto-fluorescence in the FITC and rhodamine modes.

Effects of Exposure to Metal Rich Air Particles on Histone H3-K4 Dimethylation and H3-K9 Acetylation

ISEE-0222 Background and Objectives: Alteration in epigenetic regulation of gene expression is a frequent event in human cancer. The detrimental effects of inhalation of ambient and occupational air particles on respiratory and cardiovascular disease have been linked to systemic deregulation of gene expression. In vitro studies have shown that metal components of air particles, such as Cr and Ni, may determine histone acetylation or methylation, a main epigenetic mechanism for chromatin remodelling, and chronic exposure to these metal compounds could increase cancer incidence. Whether inhalation of metal particle components could modify histone modifications in humans is unresolved. We investigated whether metal components of air particles determine histone modifications in workers in an electric-furnace steel plant with well-characterized exposure to air particles and related metal components. Methods: We extracted total histones from blood collected from 63 workers on the last day of a workweek following three consecutive work days. Individual exposure to particulate matter with aerodynamic diameter <10μm (PM10) or <1μm (PM1), and metals (Cr, Pb, Cd, As, Ni, Mn) was estimated using work area measurements and time-activity records. We determined histone H3-K4 dimethylation and H3-K9 acetylation using PathScan Sandwich ELISA kits (Cell Signaling Technology). Results: H3-K4 dimethylation and H3-K9 acetylation were not associated with levels of PM mass (H3K4m2: β = 0.03, P = 0.34 for PM10, β = 0.02, P = 0.56 for PM1; H3K9ac: β = −0.07, P = 0.23 for PM10, β = −0.03, P = 0.70 for PM1). H3-K4 dimethylation increased in association with air levels of Cr (β = 0.18; P = 0.005), Pb (β = 0.18; P = 0.01), As (β = 0.16; P = 0.03) and Ni (β = 0.15; P = 0.04). H3-K9 acetylation showed a borderline negative association with airborne cadmium (β = −0.26; P = 0.06). Conclusions: Our results indicate histone modifications as a novel epigenetic mechanism induced by metal components of air particles in human subjects.

Particle size fractionation and human exposure of polybrominated diphenyl ethers in indoor dust from Chicago

The objective of this study was to investigate the concentration level, the mass distribution based on dust particle size, and the associated human exposure of polybrominated diphenyl ethers (PBDEs) in indoor dust. The total concentration of 13 PBDEs Σ13(BDEs) was found to be 500–6,944 ng/g in indoor dusts, 4,000 ng/g in car interior dust, 260–300 ng/g in outdoor ambient air particles, 30 ng/g in carpet fibers, and as high as 0.5% in carpet padding. Selected dust samples were fractionated based on particle size, and over 80% of the Σ13BDEs were associated with particles < 150 μm in diameter. Mass ratios of BDE206/BDE209 are higher in both indoor and outdoor samples than in commercial deca products; and mass ratio BDE47/BDEs(85+99+100) was much higher in outdoor than in indoor samples. Using EPA software ProUCL, the exposure of Americans to PBDEs via hand-to-mouth transfer of house dust was estimated under the central tendency exposure and reasonable maximum exposure scenarios. The results suggest that ingestion of PBDE-laden house dust via hand-to-mouth contact is likely a significant exposure pathway, especially for children.

Aerosol generation and circulation in the shore zone of a Large Alpine lake – 2 – Aerosol distributions over Lake Tahoe, CA

Abstract The temporal, spatial, and size-distribution patterns of particles in ambient air over the surface of Lake Tahoe (Nevada and California) were studied as part of the 2003–2004 Lake Tahoe atmospheric deposition study (LTADS). The concentration of population along the shoreline of Lake Tahoe makes accurate characterization of local aerosol generation and transport especially important in estimation of annual particle flux to the surface of the lake. Measurements taken while cruising on the lake show that aerosol concentrations in near shore areas are primarily controlled by a combination of diurnal cycling of land- and lake- breezes and particle emissions driven by cycles of human activity near the shore. These effects were observed to be highly localized. Highest concentrations were found just offshore from urbanized areas, especially shoreline centers of activity; lowest concentrations were found along undeveloped shoreline; low-to-intermediate concentrations were measured over the middle areas of the lake. The on-lake data reported here indicate that aerosols over the lake, and thus dry deposition to the lake, are dominated by the same processes that control onshore emissions, and that the impact is strongest in the near shore areas of the lake.