Total Particulate Matter Concentrations Research Articles

Differences in the Spatial Distribution and Chemical Composition of PM10 Between the UK and Poland

The Fine Resolution Atmospheric Multi-pollutant Exchange Model was used to calculate the spatial distribution and chemical composition of PM10 concentrations for two geographically remote countries in Europe – the United Kingdom (UK) and Poland – for the year 2007. These countries are diverse in terms of pollutant emissions as well as climate conditions. Information on the contribution of natural and anthropogenic as well as national and imported particles in total PM10 concentrations in both countries is presented. The paper shows that the modelled national annual average PM10 concentrations, calculated for the entire country area, is similar for the UK and Poland and close to 12 μg m-3. Secondary inorganic aerosols dominate the total PM10 concentrations in Poland. Primary particulate matter has the greatest contribution to total PM10 in the UK, with large contribution of base cations. Anthropogenic sources predominate (81%) in total PM10 concentrations in Poland, whereas natural prevail in the UK – hence, the future reduction of PM10 air concentrations by emissions reduction could be more difficult in the UK than in Poland.

The effect of source type and source strength on inhaled mass of particulate matter during episodic indoor activities

A two-week campaign was performed in a naturally ventilated apartment to quantify indoor sources and to estimate the total inhaled mass of particulate matter (PM). DustTrak photometers were used to record PM2.5 concentrations continuously. Indoor activities were recorded in a detailed time–activity diary. The results showed that short episodic indoor sources influenced the indoor PM concentration for several hours and significantly affected daily average PM2.5 concentrations, indoor/outdoor ratios and indoor/outdoor correlation coefficients. Activities leading to increased PM concentrations occurred in 9% of the total time monitored, and accounted for 68% of the total PM concentration. Among the many indoor activities recorded, smoking and hair spraying were the strongest sources of fine aerosol. The outcomes of cooking episodes were the most variable in terms of duration and aerosol levels. The calculated inhaled mass corresponded to the source strength but not to the duration of the source activity. The total mass of aerosol potentially inhaled by an adult individual during the time outside the episodes was 1367 µg and during the episodes 2895 µg. During one hour, one person potentially inhaled approximately 36 µg and 294 µg of aerosol for the non-episode and the episode periods, respectively.

Indoor particulate matter in urban residences of Alexandria, Egypt

Indoor particulate matter samples were collected in 17 homes in an urban area in Alexandria during the summer season. During air measurement in all selected homes, parallel outdoor air samples were taken in the balconies of the domestic residences. It was found that the mean indoor PM2.5 and PM10 (particulate matter with an aerodynamic diameter ≤2.5 and ≤10 μm, respectively) concentrations were 53.5 ± 15.2 and 77.2 ± 15.1 µg/m3, respectively. The corresponding mean outdoor levels were 66.2 ± 16.5 and 123.8 ± 32.1 µg/m3, respectively. PM2.5 concentrations accounted, on average, for 68.8 ± 12.8% of the total PM10 concentrations indoors, whereas PM2.5 contributed to 53.7 ± 4.9% of the total outdoor PM10 concentrations. The median indoor/outdoor mass concentration (I/O) ratios were 0.81 (range: 0.43–1.45) and 0.65 (range: 0.4–1.07) for PM2.5 and PM10, respectively. Only four homes were found with I/O ratios above 1, indicating significant contribution from indoor sources. Poor correlation was seen between the indoor PM10 and PM2.5 levels and the corresponding outdoor concentrations. PM10 levels were significantly correlated with PM2.5 loadings indoors and outdoors and this might be related to PM10 and PM2.5 originating from similar particulate matter emission sources. Smoking, cooking using gas stoves, and cleaning were the major indoor sources contributed to elevated indoor levels of PM10 and PM2.5. Implications: The current study presents results of the first PM2.5 and PM10 study in homes located in the city of Alexandria, Egypt. Scarce data are available on indoor air quality in Egypt. Poor correlation was seen between the indoor and outdoor particulate matter concentrations. Indoor sources such as smoking, cooking, and cleaning were found to be the major contributors to elevated indoor levels of PM10 and PM2.5.

Evaluation of AERMOD and CALPUFF for predicting ambient concentrations of total suspended particulate matter (TSP) emissions from a quarry in complex terrain

Concentrations of particulate emissions from a quarry located in hilly terrain were calculated by two common atmospheric dispersion models, AERMOD and CALPUFF. Evaluation of these models for emissions from quarries/open pit mines that are located in complex topography is missing from the literature. Due to severe uncertainties in the input parameters, numerous scenarios were simulated and model sensitivity was studied. Model results were compared among themselves, and to measured total suspended particulate (TSP). For a wide range of meteorological and topographical conditions studied, AERMOD predictions were in a better agreement with the measurements than those obtained by CALPUFF. The use of AERMOD's “Open pit” tool seems unnecessary when accurate digital topographic data are available. Onsite meteorological data are shown to be crucial for reliable dispersion calculations in complex terrain.

Particulate matter investigation in indoor environment

Particulate matter is one of the most important indoor air pollutants involved in a number of adverse health effects, such as premature deaths and increased mortality of infants and other parts of sensitive population. This paper focuses on investigation of metal substances of suspended as well as settled particulate matter in indoor environment. The monitoring of particulate matter concentration was carried out in three rooms of a selected flat building in the city of Košice, Slovakia. The sampling of settled particulate matter was carried out by passive methods during the period of 28 days. The investigation of suspended particulate matter investigation focused on total suspended particles (TSP) and thoracic fraction called PM10. The presence of selected metals in the samples was detected by atomic absorption spectrometry. The surface concentrations of settled particulate matter were detected in the range from 276.43 μg cm-2 to 570.70 μg cm-2, mass concentrations of total suspended particulate matter from 59.028 to 114.583 μg m-3. PM10 concentration values reached about half of the TSP concentration values (PM10/TSP ratio was from 0.48 to 0.6). Higher percentage of metals was detected in suspended particulate matter in comparison to the settled particles. Higher values were detected for all metals (except iron and zinc) in each measured room.

Urban air-quality assessment and source apportionment studies for Bhubaneshwar, Odisha

Acid- and water-soluble component of suspended particulate matter was studied from January 2009 to December 2009 at Bhubaneshwar, an urban coastal location of eastern India, by high-volume sampler, environmental dust monitor using GRIMM®, and scanning electron microscope and energy dispersive X-ray spectrometer. The water-soluble components accounted for 30–45 % of the total suspended particulate matter, and the major elements were observed to be ammonium and nitrate as the cationic and anionic species, respectively. The acid-soluble component like copper, nickel, cobalt, iron, and lead accounted for 5–15 % of the total particulate matter concentration. The composition of particulate matter shows a clear seasonal variation in relation to wind speed, wind direction, and trajectories of the air mass movement. The GRIMM spectrometer analysis shows higher concentration of fine particulate matter. Source apportionment and enrichment factor analysis indicated that except sodium and chloride, all other elements have emerged from different sources such as crustal as well as anthropogenic.

The Influence of Cigarette Smoke on the Selected Bronchoalveolar Cells in Experiment

The occurence of lung diseases (obstructive, malignant) resulting from smoking has an increasing tendency. The lung is the primary organ at risk from the effects of inhaled cigarette smoke and smoking has been implicated as a contributing factor to the causation of various respiratory diseases. The aim of presented work was to find out the subchronic effect of the 6-month exposure to cigarette smoke on the selected inflammatory and cytotoxic parameters of bronchoalveolar lavage in W rats and thus to contribute to understanding of the mechanism of action of tobacco smoke and/or path mechanism of lung injury developed after cigarette smoking. In special chamber, the animals smoked 8 standard research 1R1 type of cigarettes per day, except Saturdays and Sundays, during 6 months. The daily concentration of total particulate matter (TPM)/m3 air for two hours per exposure requiring to burn eight cigarettes was 85 mg. Animals were sacrificed after the 6-month exposure and bronchoalveolar lavage (BAL) was performed and selected inflammatory and cytotoxic BAL parameters were examined and compared with the control group. Following BAL parameters were investigated: the total cell and alveolar macrophages (AM) count in BAL, the differential cell count (% of AM, % of polymorphonuclears--PMN, % of lymphocytes--Ly), proportion of immature AM, proportion of bi-nucleated cells--BNC, viability, the phagocytic activity of AM, cytokines TNF-alpha (tumor necrosis factor alpha) and IL-1beta (interleukin-1beta). A) The 6-month smoking of eight cigarettes daily significantly changed prevailing number of examined BAL parameters; B) The presence of inflammatory and cytotoxic responses in lung tissue can probably signalize beginning or developing of disease process.

Improving Indoor Air Quality by Using the New Generation of Corrugated Cardboard-Based Filters

Indoor Air Quality (IAQ) is strictly affected by the concentration of total suspended particulate matter (TSP). Air filtration is by far the most feasible suggestion to improve IAQ. Unfortunately, highly effective HEPA filters also have a few major weaknesses that have hindered their widespread use. There is therefore a renewed interest in developing novel, cost-effective filtration systems. We have recently reported the development of cardboard-based filters for bacterial removal that were further implemented and tested herein. A parallelepiped filter manufactured by aligning strips of corrugated cardboard and surrounded by a cardboard frame was specifically designed with an internal pocket holding a partially cut antistatic pleated fabric (HP). This filter, together with its parent version (CTRL) and a commercially sourced specimen (CAF), were assessed comparatively in a long-time test to assess their effectiveness on TSP removal. We found that the TSP abatement efficiency (E%) of the HP filter was relatively high and invariable over the 93 days of test and the pressure drop (PD%) decrease because of filter clogging was moderate. Most important, the HP filter was the most effective if assessed in terms of overall yield (Y%) and its performance was quite constant over the entire period considered. This work disclosed this novel class of corrugated cardboard-based filters as promising tools to ameliorate IAQ in light of their good TSP removal properties that endure over time. Moreover, cardboard is a lightweight, inexpensive, and eco-friendly material and corrugated cardboard-based air filters are very easy to shape and mount on and/or replace in existing ventilation systems.

The toxic effects of cigarette additives. Philip Morris' project mix reconsidered: an analysis of documents released through litigation.

In 2009, the promulgation of US Food and Drug Administration (FDA) tobacco regulation focused attention on cigarette flavor additives. The tobacco industry had prepared for this eventuality by initiating a research program focusing on additive toxicity. The objective of this study was to analyze Philip Morris' Project MIX as a case study of tobacco industry scientific research being positioned strategically to prevent anticipated tobacco control regulations. We analyzed previously secret tobacco industry documents to identify internal strategies for research on cigarette additives and reanalyzed tobacco industry peer-reviewed published results of this research. We focused on the key group of studies conducted by Phillip Morris in a coordinated effort known as "Project MIX." Documents showed that Project MIX subsumed the study of various combinations of 333 cigarette additives. In addition to multiple internal reports, this work also led to four peer-reviewed publications (published in 2001). These papers concluded that there was no evidence of substantial toxicity attributable to the cigarette additives studied. Internal documents revealed post hoc changes in analytical protocols after initial statistical findings indicated an additive-associated increase in cigarette toxicity as well as increased total particulate matter (TPM) concentrations in additive-modified cigarette smoke. By expressing the data adjusted by TPM concentration, the published papers obscured this underlying toxicity and particulate increase. The animal toxicology results were based on a small number of rats in each experiment, raising the possibility that the failure to detect statistically significant changes in the end points was due to underpowering the experiments rather than lack of a real effect. The case study of Project MIX shows tobacco industry scientific research on the use of cigarette additives cannot be taken at face value. The results demonstrate that toxins in cigarette smoke increase substantially when additives are put in cigarettes, including the level of TPM. In particular, regulatory authorities, including the FDA and similar agencies elsewhere, could use the Project MIX data to eliminate the use of these 333 additives (including menthol) from cigarettes.

Density effects on the clearance rate of the zebra mussel Dreissena polymorpha: flume study results

Zebra mussel filtration rates and regulating factors have been addressed earlier in a number of studies. Still, only a few of them have taken into consideration the refiltration phenomenon, and therefore the direct extrapolation of experimental results may only give the potential filtering capacity, and hence, over- or underestimate the actual amount of seston being removed by zebra mussels in an ecosystem. The current experimental study aimed to gain insight into the refiltration effect on the clearance rate of the zebra mussels at relatively high seston concentrations, and its potential role in controlling the filtration efficiency of the zebra mussel population. The experiment was conducted in a laboratory flume following the Latin squares design with one fixed (mussel density) and three random factors (initial total particulate matter (TPM) concentration, flume “wall effect” and distance from the flume inflow area) considered. The results showed the significant effects of mussel density and the TPM concentration on the effective clearance rate (ECR) of zebra mussels. The higher ECR values were obtained at denser mussel clumps and lower TPM concentrations. The flume “wall effect” had no significant effect on the ECR, whereas the distance from the flume inflow area appeared to have a significant impact. A positive relationship between ECR and the zebra mussel density was most evident in the proximity of the TPM source. Based on the results, we assume that at high TPM concentration, refiltration may assert itself by the elevated net clearance rate of mussels within dense clumps compared to that of mussels at relatively low individual densities. This should be taken into consideration while modelling and assessing the role of the zebra mussel in energy flow and redistribution of organic matter in an ecosystem.

Size distribution and seasonal variation of airborne particulate matter in five areas in Istanbul, Turkey

Many studies have focused on measuring fine and course particulate matter (PM) in urban and rural sites around the world. The aim of this research is to gain information on the size distribution of particles. The physical characteristics of PM in the urban air of Istanbul were determined. PM sampling was carried out at five stations (Avcılar, Beşiktaş, Kilyos, Rasathane, and Göztepe) over a period of 2 years. PM filter samples were collected for eight different size ranges (<0.43, 0.43-1, 1-1.7, 1.7-2.6, 2.6-3.5, 3.5-5.2, 5.2-6.5, 6.5-8, and >8 μm) using a Cascade Impactor. The size distributions of the PM samples were determined. The mean total PM concentrations were 48.6 ± 34.0, 34.8 ± 11.6, 28.6 ± 13.6, 21.5 ± 9.1, and 16.8 ± 5.1 μg/m(3) for the Göztepe, Beşiktaş, Avcılar, Rasathane, and Kilyos stations, respectively. The total PM concentrations were found to be 1.2-1.5 times higher in the fall and winter than in the spring and summer, except for at the station in Avcılar. The PM concentrations in Avcılar did not exhibit seasonal variations. This is thought to result from the intense industrial activity in the area. PM(2.6) (below 2.6 μm particles) comprised up to 62% of the total amount of PM in samples collected at the Göztepe, Beşiktaş, and Rasathane stations during the fall and winter. PM(1) was determined to be approximately 45% of the total, corresponding to 57% of the amount of PM(2.5). A multi-modal PM size distribution was observed. The lowest Mass Median Aerodynamic Diameter (MMAD) values observed in Avcılar, Beşiktaş, Rasathane, and Göztepe were 4.2, 3.9, 2.9, and 3.5 μm, respectively, and were observed during the season of active household heating. No difference was measured in the MMAD values (5.2 μm) between the seasons of heating and non-heating in Kilyos.

Impact of Diwali celebrations on urban air and noise quality in Delhi City, India

A study was conducted in the residential areas of Delhi, India, to assess the variation in ambient air quality and ambient noise levels during pre-Diwali month (DM), Diwali day (DD) and post-Diwali month during the period 2006 to 2008. The use of fireworks during DD showed 1.3 to 4.0 times increase in concentration of respirable particulate matter (PM(10)) and 1.6 to 2.5 times increase in concentration of total suspended particulate matter (TSP) than the concentration during DM. There was a significant increase in sulfur dioxide (SO(2)) concentration but the concentration of nitrogen dioxide (NO(2)) did not show any considerable variation. Ambient noise level were 1.2 to 1.3 times higher than normal day. The study also showed a strong correlation between PM(10) and TSP (R (2) ≥ 0.9) and SO(2) and NO(2) (R (2) ≥ 0.9) on DD. The correlation between noise level and gaseous pollutant were moderate (R (2) ≥ 0.5). The average concentration of the pollutants during DD was found higher in 2007 which could be due to adverse meteorological conditions. The statistical interpretation of data indicated that the celebration of Diwali festival affects the ambient air and noise quality. The study would provide public awareness about the health risks associated with the celebrations of Diwali festival so as to take proper precautions.

Assessment of Air Quality During Mastoidectomy

The Occupational Health and Safety Administration (OSHA) outlines specific requirements governing the use of respiratory protection for workers dealing with dust or other aerosolized compounds. Health care workers may be exposed to bone dust produced during otologic procedures, creating an occupational hazard. The purpose of this research was to quantify the total suspended particulate matter (TSPM) and respirable particulate matter (PM(5)) created during cortical mastoidectomy and investigate whether the concentration of aerosolized dust during mastoidectomy would require the use of a particulate respirator. Cadaveric study to assess air quality during cortical mastoidectomy. Temporal bone laboratory. A simple mastoidectomy was performed on 3 cadaveric temporal bones. Suspended particulate concentration was measured using gravimetric filter methodology for TSPM and PM(5). Concentration of particulate exposure was compared between mannequins positioned near the surgical field with a standard surgical mask, surgical respirator, or controls. The average total particulate matter concentration during cortical mastoidectomy was 1.89 mg/m(3). The average quantity of respirable particles was below detection levels. The calculated particulate exposure concentrations for TSPM and PM(5) did not exceed OSHA's requirement for respirator use. The particulate respirator prevented exposure to bone particulates compared with controls (P = .028). The concentration of bone dust produced during cortical mastoidectomy is below regulatory guidelines for use of particulate respirators. However, experimental studies show the use of a surgical respirator may decrease particulate exposure.

Development and application of a model (ExDoM) for calculating the respiratory tract dose and retention of particles under variable exposure conditions

The ExDoM is a model for calculating the human exposure and the deposition, dose, clearance, and finally retention of aerosol particles in the respiratory tract at specific times during and after exposure, under variable exposure conditions. Specifically, the model incorporates an exposure module which allows the user to set variable or static exposure conditions (exposure concentration, physical exertion levels, and different environments) or in the case of the physical exertion levels and exposure environment to choose from a list of typical exposure scenarios (activity pattern, exposure environment, and physical exertion level). The exposure concentration can refer to total particulate matter (PM) concentration or chemically resolved particles of variant size distributions. The aerosol size parameters can be introduced to the model either directly as median aerodynamic diameter and geometric standard deviation or are estimated by the model from measurement data. The model treats monodisperse or polydisperse aerosol size distributions. The human respiratory tract (RT) model of the International Commission on Radiological protection (ICRP Publication 66) is utilized for the respiratory tract deposition calculations. The above together with the dose and clearance/retention modules can be used to study together exposure and dose of chemically resolved particles of variant size distributions. The ExDoM model implementation in order to study the exposure and dose of particles in the human RT is demonstrated at two locations. In particular, the dose and retention of particles to RT and the mass transferred to the gastrointestinal tract and blood capillaries are estimated for an adult Caucasian male exposed to PM10 at a coastal remote site in the eastern Mediterranean. In addition, the regional lung doses of specific chemical components of PM10 (inorganic ions and carbonaceous compounds) during realistic exposure conditions outdoors at a residential background area in Oslo, Norway, were assessed. The results from the two studies showed that the dose was enhanced for the carbonaceous fine fraction of particles in the alveolar region of the lung whereas the dose of crustal material dominated in the extrathoracic region.

Theoretical versus Observed Gas-Particle Partitioning of Carbonyl Emissions from Motor Vehicles

A state-of-the-science thermodynamic model describing gas-particle absorption processes was used to predict the gas-particle partitioning of mixtures of approximately 60 carbonyl compounds emitted from low-emission gasoline-powered vehicles, three-way catalyst gasoline-powered vehicles, heavy-duty diesel vehicles under the idle-creep condition (HDDV idle), and heavy-duty diesel vehicles under the five-mode test (HDDV 5-mode). Exhaust was diluted by a factor of 120–580 with a residence time of approximately 43 sec. The predicted equilibrium absorption partitioning coefficients differed from the measured partitioning coefficients by several orders of magnitude. Time scales to reach equilibrium in the dilution sampling system were close to the actual residence time during the HDDV 5-mode test and much longer than the actual residence time during the other vehicle tests. It appears that insufficient residence time in the sampling system cannot uniformly explain the failure of the absorption mechanism to explain the measured partitioning. Other gas-particle partitioning mechanisms (e.g., heterogeneous reactions, capillary adsorption) beyond the simple absorption theory are needed to explain the discrepancy between calculated carbonyl partitioning coefficients and observed partitioning. Both of these alternative partitioning mechanisms imply great challenges for the measurement and modeling of semi-volatile primary organic aerosol (POA) species from motor vehicles. Furthermore, as emitted particle concentrations from newer vehicles approach atmospheric background levels, dilution sampling systems must fundamentally change their approach so that they use realistic particle concentrations in the dilution air to approximately represent real-world conditions. Samples collected with particle-free dilution air yielding total particulate matter concentrations below typical ambient concentrations will not provide a realistic picture of partitioning for semi-volatile compounds.

Hexavalent Chromium Exposure and Control in Welding Tasks

Studies of exposure to the lung carcinogen hexavalent chromium (CrVI) from welding tasks are limited, especially within the construction industry where overexposure may be common. In addition, despite the OSHA requirement that the use of engineering controls such as local exhaust ventilation (LEV) first be considered before relying on other strategies to reduce worker exposure to CrVI, data on the effectiveness of LEV to reduce CrVI exposures from welding are lacking. The goal of the present study was to characterize breathing zone air concentrations of CrVI during welding tasks and primary contributing factors in four datasets: (1) OSHA compliance data; (2) a publicly available database from The Welding Institute (TWI); (3) field survey data of construction welders collected by the Center for Construction Research and Training (CPWR); and (4) controlled welding trials conducted by CPWR to assess the effectiveness of a portable LEV unit to reduce CrVI exposure. In the OSHA (n = 181) and TWI (n = 124) datasets, which included very few samples from the construction industry, the OSHA permissible exposure level (PEL) for CrVI (5 μg/m3) was exceeded in 9% and 13% of samples, respectively. CrVI concentrations measured in the CPWR field surveys (n = 43) were considerably higher, and 25% of samples exceeded the PEL. In the TWI and CPWR datasets, base metal, welding process, and LEV use were important predictors of CrVI concentrations. Only weak-to-moderate correlations were found between total particulate matter and CrVI, suggesting that total particulate matter concentrations are not a good surrogate for CrVI exposure in retrospective studies. Finally, in the controlled welding trials, LEV reduced median CrVI concentrations by 68% (p = 0.02). In conclusion, overexposure to CrVI in stainless steel welding is likely widespread, especially in certain operations such as shielded metal arc welding, which is commonly used in construction. However, exposure could be substantially reduced with proper use of LEV.

Elemental and organic carbon in aerosols over urbanized coastal region (southern Baltic Sea, Gdynia)

Studies on PM 10, total particulate matter (TSP), elemental carbon (EC) and organic carbon (OC) concentrations were carried out in the Polish coastal zone of the Baltic Sea, in urbanized Gdynia. The interaction between the land, the air and the sea was clearly observed. The highest concentrations of PM 10, TSP and both carbon fractions were noted in the air masses moving from southern and western Poland and Europe. The EC was generally of primary origin and its contribution to TSP and PM 10 mass was on average 2.3% and 3.7% respectively. Under low wind speed conditions local sources (traffic and industry) influenced increases in elemental carbon and PM 10 concentrations in Gdynia. Elemental carbon demonstrated a pronounced weekly cycle, yielding minimum values at the weekend and maximum values on Thursdays. The role of harbors and ship yards in creating high EC concentrations was clearly observed. Concentration of organic carbon was ten times higher than that of elemental carbon, and the average OC contribution to PM 10 mass was very high (31.6%). An inverse situation was observed when air masses were transported from over the Atlantic Ocean, the North Sea and the Baltic Sea. These clean air masses were characterized by the lowest concentrations of all analysed compounds. Obtained results for organic and elemental carbon fluxes showed that atmospheric aerosols can be treated, along with water run-off, as a carbon source for the coastal waters of the Baltic Sea. The enrichment of surface water was more effective in the case of organic carbon (0.27 ± 0.19 mmol m − 2 d − 1). Elemental carbon fluxes were one order of magnitude smaller, on average 0.03 ± 0.04 mmol m − 2 d − 1. We suggest that in some situations atmospheric carbon input can explain up to 18% of total carbon fluxes into the Baltic coastal waters.

Mechanism of cigarette smoke-induced kinin B 1 receptor expression in rat airways

Pulmonary inflammation is an important pathological feature of tobacco smoke related lung diseases such as chronic obstructive pulmonary disease (COPD). Kinin type 1 and type 2 receptors (B 1R, B 2R) are known to be associated with inflammatory responses of the lungs and other organs. In this study, we investigated whether cigarette smoke-induced airway inflammation could up-regulate B 1R and B 2R in correlation with IL-1β and TNF-α. Rat lung slices treated with 5 μg/ml total particulate matter (TPM) of cigarette smoke for 24 h showed an enhanced expression of B 1R and IL-1β by 5-fold and 30-fold, respectively, in comparison to vehicle treatment (dimethyl sulfoxide). However, higher concentrations of TPM failed to induce B 1R. No significant increase of B 2R or TNF-α gene induction was observed. IL-1 receptor antagonist (IL-1Ra, 2 ng/ml) significantly blocked B 1R gene induction by TPM, while 500 μM pentoxifylline, TNF-α inhibitor, reduced it partially. Western blot analysis showed a 2-fold enhanced expression of B 1R in rat lung slices treated with 5 μg/ml TPM for 24 h and such protein expression was totally blocked by a co-treatment with IL-1Ra but not with pentoxifylline. In addition to the lower airways, rat trachea subchronically exposed to cigarette whole smoke exhibited 11-fold B 1R gene induction in comparison with those exposed only to air. Our results demonstrate the involvement of B 1R in cigarette smoke-induced airway inflammation through a mechanism which is mediated by the pro-inflammatory cytokine IL-1β.

Hot-Recycling of Tar-Containing Asphalt Pavements

ABSTRACT Hot recycling in pavement construction leads to the emission of hazardous compounds when tar-containing recycled asphalt pavement (RAP) is used. This is due to the relatively high content of substances such as phenols and polycyclic aromatic hydrocarbons (PAH) in tar. The latter are of special interest, because some PAHs have carcinogenic and/or mutagenic properties. High tar content in combination with high pavement temperatures during construction increases the potential health risk for workmen. Switzerland does not currently consider a complete ban of RAP in hot recycling for economical and ecological reasons. Since RAP might always contain some tar, there is a need to fix a scientifically sound limit for the maximum tar content. However, scientific data on the emissions of PAH, as well as the resulting occupational health risk are rare, which motivated the present research. In the laboratory, several parameters, such as temperature, PAH content and viscosity, were varied in an experimental setup to quantify their effect on the resulting emissions. It was shown that temperature is the major factor determining the emissions in the 140 to 240°C range. A PAH content of up to 20000 ppm EPA-PAH in RAP had no significant effect on total particulate matter (TPM) emissions. However, emissions of PAH in the fumes increased proportionally with the PAH concentration in the RAP. Three field tests were carried out with RAP containing up to 5600 ppm EPA-PAH. Occupational health data for the workmen were collected with personal samplers. TPM concentrations were between 2–4 mg/m3, close to the occupational health limit value for bitumen fumes (10 mg/m3). Concentrations of Benzo(a)pyrene (BaP), which is often used as a lead compound, were in all cases below the occupational health limit value of 2 μg/m3 by at least a factor of three. This study indicates that the current Swiss recommended maximum value of 5000 ppm for EPA-PAH in the binder of RAP may be considered as adequate. However, conditions in the field trials did not include a worst-case scenario and the margin to occupational health limit values is small.

Development of a tagged species source apportionment algorithm to characterize three‐dimensional transport and transformation of precursors and secondary pollutants

We developed a new tagged species source apportionment (TSSA) algorithm for tracking the direct mass contributions of selected emissions sources to the formation of particulates such as aerosol sulfate, nitrate, ammonium, elemental carbon, and secondary organic aerosols in the U.S. EPA Community Multiscale Air Quality Model (CMAQ). The focus of this paper is on sulfate, nitrate, and elemental carbon. The objective of the TSSA algorithm is to provide useful results in modeling studies for identifying important emissions categories and identifying possible emissions reduction strategies to attain particulate matter (PM) air quality goals. TSSA differs from model sensitivity approaches because it tracks direct mass contributions from specific emissions sources to the total PM concentration at selected receptor sites, while results from sensitivity approaches are affected by nonlinear chemistry that can change the concentration of sulfate, nitrate, and organic carbon secondary particulates. We evaluated the algorithm by comparing CMAQ/TSSA results with results from zero‐out CMAQ sensitivity simulations. As expected, TSSA results were almost identical to the CMAQ sensitivity results for chemical species that do not undergo nonlinear chemical reactions. For chemical species with nonlinear chemical reaction, the TSSA results are expected to differ from model sensitivity results, but for small emissions changes the results are similar in the two approaches. We also compared CMAQ/TSSA to CAMx/PSAT. Because there are significant differences in the CMAQ and CAMx model predicted concentrations, the source attribution results differed for TSSA and PSAT; however, the rank order of emissions sources were similar for the two approaches at most receptor sites.