Abstract  This Summary sets out the key policy-relevant findings of the Fourth Assessment of Working Group II of the Intergovernmental Panel on Climate Change (IPCC). The Assessment is of current scientific understanding of the impacts of climate change on natural, managed and human systems, the capacity of these systems to adapt and their vulnerability.1 It builds upon past IPCC assessments and incorporates new knowledge gained since the Third Assessment. Statements in this Summary are based on chapters in the Assessment and principal sources are given at the end of each paragraph.

Abstract  Background: Many studies have shown a consistent association between ambient air pollution and an increase in death due to cardiovascular causes. An increase in blood pressure is a common risk factor for a variety of cardiovascular diseases. However, the association between air pollution and blood pressure has not been evaluated extensively. Methods: In this cross-sectional study, we measured blood pressure in 10 459 subjects who had a health examination from 2001 to 2003, and calculated individual’s exposure to ambient levels of air pollutants. To evaluate the relationship between exposure to air pollutants and blood pressure with respect to season, we performed a multiple regression analysis, separately, according to season, controlling for individual characteristics and meteorological variables. Results: In the warm-weather season (July–September), particulate air pollutant of <10 μm (PM10) and nitrogen dioxide (NO2) concentrations were significantly associated with measures of blood pressure. During cold weather (October–December), blood pressure was significantly associated with sulphur dioxide (SO2) and ozone (O3) concentrations. The significant association between PM10 or NO2 and blood pressure disappeared during the cold-weather season. Conclusion: We found a seasonal variation for the association between ambient air-pollutant concentrations and blood pressure.

Abstract  U.S. Environmental Protection Agency. This paper presents the development of a small cut-off size slit-nozzle virtual impactor that operates at a small pressure drop. Operating with a preselective inlet that removes particles larger than 2.5 Ám in aerodynamic size, the impactor can sample ambient particles in the accumulation range (0.1

Abstract  This paper describes methods for the determination of low-molecular-weight (LMW) dicarboxylic acids in atmospheric aerosols as important chemical tracers for source apportionment of aerosol organics and for studying atmospheric processes leading to secondary organic aerosol formation. The two derivatization procedures most widely used in GC analysis of dicarboxylic acids were compared: esterification using BF(3)/alcohol reagent and silylation using N,O-bis(trimethylsilyl)-trifluoroacetamide (BSTFA). The advantages and drawbacks of the two methods are investigated and compared in terms of (1) precision and accuracy of the results and (2) sensitivity and detection limit of the procedure. The comparative investigation was performed on standard solutions containing target C(3)-C(9) dicarboxylic acids and on experimental particulate matter (PM) samples. Attention was focused on low-volume sampling devices that collect small amounts of sample for organic speciation. The results show that, overall, both the techniques appear suitable for the analysis of LMW dicarboxylic acids in atmospheric aerosols since they provide low detection limits (< or = 4 ng m(-3)) and satisfactory reproducibility (RSD% < or = 15%). Between them, BSTFA should be the reagent of choice under the most limiting conditions of PM filters collected by low-volume air samplers: It provides determination of all the target C(3)-C(9) dicarboxylic acids with lower detection limits (< or = 2 ng m(-3)) and higher reproducibility (RSD% < or = 10%).

Abstract  Simultaneous analysis of 24 carbonyl compounds (alkanals, unsaturated, dicarbonylic and aromatic aldehydes and ketones) derivatized with 2,4-dinitrophenylhydrazine and 16 polycyclic aromatic hydrocarbons (PAHs) using a photodiode-array (PDA) and a fluorescence (FL) detector in series is proposed. The separation is carried out with a reversed-phase column and gradient elution using four solvents (acetonitrile, water, tetrahydrofuran and methanol) in less than 35 min. Several critical pairs of carbonyl compounds with 3 and 4 carbon atoms and different functional groups, isomers of tolualdehyde, aromatic and aliphatic aldehydes were conditional on the gradient elution. Common pre-treatment for two groups of compounds consists in a step of extraction and derivatization in aqueous medium and a further clean-up using a polymeric phase SPE and concentration in a mixture of dichloromethane:methanol. A pre-concentration factor of 50 was achieved by this procedure. Acetone and formaldehyde blanks were minimized and remain controlled with a specific cleaning of glass material and washing the SPE cartridge. The limits of detection (LOD) ranged from 0.006 to 0.18 ng mL(-1) for PAHs and from 2.4 to 10.1 ng mL(-1) for carbonyl compounds and method precision was

Abstract  BACKGROUND: Air pollutants of iron- and steel-making operations have historically been an environmental and health hazard. These pollutants include gaseous substances such as sulfur oxide, nitrogen dioxide, and carbon monoxide. The Iran National Steel Industrial Group beam rolling mills factory has two production lines viz. line 630 and line 650, with different beam production capabilities and is capable of producing different types of beams. MATERIALS AND METHODS: A retrospective cross-sectional study on 400 workers in different exposure levels to environmental pollution was performed during 2005 to determine the mean value of respirable particulate matter (RPM) concentrations and its effects on the health status of workers. To elicit information regarding the health status of the worker, the National Institute for Occupational Safety and Health standard questionnaire was used. Fisher's exact test was performed to assess the relative risk (RR) of exposure to air pollution on cardiovascular diseases, chest tightness, cough, difficulty in retention, i.e. loss of memory, tension, occupational fatigue, and occupational stress in exposed workers. RESULTS: There was significant difference in RPM pollution level between two product lines. The RR of exposure to air pollution on cardiovascular diseases, chest tightness, cough, difficulty in retention, i.e. loss of memory, tension, occupational fatigue, and occupational stress in exposed workers were 2.78, 2.44, 2.15, 1.92, 1.57, 3.90, and 2.09, respectively.

Abstract  Background. Exposure to airborne particulate matter, which is a major component of air pollution, has been associated with increases in both exacerbations and hospitalizations for asthma. We have previously shown that exposure to ambient particulate matter collected in urban Baltimore (AUB) induces airway hyperresponsiveness (AHR), eosinophilic and neutrophilic inflammation, and the recruitment of T cells. However, the mechanism(s) by which it induces these features of asthma remain unknown. Objective. To determine whether T lymphocytes play a role in AUB-induced AHR. Methods. We compared the effects of AUB exposure on the allergic phenotype in wildtype Balb/c and recombinase-activating-gene-1 (Rag1) deficient mice lacking mature lymphocytes. Results. We found that exposure of wild-type mice to AUB induced AHR concomitant with increases in the numbers of bronchoalveolar lavage lymphocytes, eosinophils and neutrophils, and mucus containing cells in the lungs of wildtype mice. Interestingly, we show for the first time that these effects were associated with significant elevations in lung cell IL-17A and F and Th2 (IL-13, IL-5) cytokine levels and reductions in the levels of the suppressive cytokine, IL-10. Interestingly, Rag1-/- mice failed to develop AUB-induced AHR, however, AUB-induced BAL cellularity and mucus cell changes were only partially inhibited in Rag1-/- mice. Conclusions. Taken together our results suggest that AUB exposure increases the pathophysiological features of asthma via activation of lymphocyte-dependent pathways. These results provide a plausible biological mechanism for the strong association between PM exposure and the increased severity of asthma.

Abstract  Recently new European policies on ambient air quality— namely, the adoption of new standards for fine particulate matter (PM2.5), have generated a broad debate about choosing the air quality standards that can best protect public health. The Apheis network estimated the number of potential premature deaths from all causes that could be prevented by reducing PM2.5 annual levels to 25 mg/m3, 20 mg/m3, 15 mg/m3 and 10 mg/m3 in 26 European cities. The various PM2.5 concentrations were chosen as different reductions based on the limit values proposed by the new European Directive, the European Parliament, the US Environmental Protection Agency and the World Health Organization, respectively. The Apheis network provided the health and exposure data used in this study. The concentration-response function (CRF) was derived from the paper by Pope et al (2002). If no direct PM2.5 measurements were available, then the PM10 measurements were converted to PM2.5 using a local or an assumed European conversion factor. We performed a sensitivity analysis using assumptions for two key factors—namely, CRF and the conversion factor for PM2.5. Specifically, using the ‘‘at least’’ approach, in the 26 Apheis cities with more than 40 million inhabitants, reducing annual mean levels of PM2.5 to 15 mg/m3 could lead to a reduction in the total burden of mortality among people aged 30 years and over that would be four times greater than the reduction in mortality that could be achieved by reducing PM2.5 levels to 25 mg/m3 (1.6% vs 0.4% reduction) and two times greater than a reduction to 20 mg/m3. The percentage reduction could grow by more than seven times if PM2.5 levels were reduced to 10 mg/m3 (3.0% vs 0.4%). This study shows that more stringent standards need to be adopted in Europe to protect public health, as proposed by the scientific community and the World Health Organization.

Abstract  An intensive sampling campaign was performed in Fresno, CA during December 2003 measuring fine particulate matter including both the semi-volatile and nonvolatile fractions of the aerosol. Both the newly developed R&P FDMS Monitor and a PC-BOSS have been shown to measure total PM2.5 concentrations including semi-volatile nitrate and organic material. Good agreement was observed between the PC-BOSS and the R&P FDMS Monitor in this study with linear regression analysis resulting in a zerointercept slope of 1.00 ± 0.02 and an R2 = 0.93. Several real-time measuring systems including the R&P Differential TEOM, the Met One BAMS, and a GRIMM Monitor were also employed and comparisons of total PM2.5 mass were made with the R&P FDMS Monitor. Agreement among these various monitors was generally good. However, differences were sometimes seen. Reasons for observed differences in the real-time mass measurement systems are explained by the composition and complexity of the measured aerosol, most importantly the composition of semi-volatile material. A newly automated ion chromatographic system developed by Dionex was also field tested and compared to both R&P 8400N Nitrate and integrated PC-BOSS inorganic species measurements. Sulfate and nitrate determined by the Dionex and PC-BOSS systems agreed. However, nitrate measured by the 8400N was low during fog events compared to the other two systems.

Abstract   Owing to past and present discharge of industrial and chemical wastes in the New York Bight, sediments and biota of the NYB have been shown to contain elevated levels of enviro-toxic trace metals. These trace metals, produced by anthropogenic activities, persist at elevated levels and pose health risks to humans and the ecosystem. In this study, two sets of sediment samples collected over a period of 20 years have been studied to evaluate the health of the Bight system. The first series of samples were collected in summer of 1976 during the time of active dumping and the second series were collected in summer of 1997. The samples were analyzed by flame atomic absorption spectrophotometry (AAS) to determine sediment Pb, Cr, Cu, Zn, Cd and Ni concentrations. Estimated mineral composition of these samples was determined by powder X-ray diffractometry analysis (XRD). This study found greater Pb, Cr, Cu, Zn, Cd, and Ni concentrations in clay-silt fraction from sewage sludge, mud dumpsite and near shore mud-patches than their background values and greater than those of USEPA sediment quality guidelines. Zn had the highest concentration followed by Pb, Cr, Cu, Ni, and Cd. XRD analysis of the sediments showed that the dominant clay minerals were illite, chlorite, and kaolinite. The percentage of clays and trace metal levels showed the same trends, being highest within sewage sludge and mud dumpsites. These levels were slightly lower south and north of these dumpsites, and near shore environment. This indicates contaminants-laden clays on the floor of the NYB are being reworked by currents, transported, and scattered within the Bight. Statistical analysis showed weak correlation and nonnormal distribution of trace metals. This suggests that the geochemical behavior of these metals has been affected by pH, Eh, clay-metal cations selectivity, and hydrodynamics of the Bight. Therefore, result from this study may be useful in the development of management plans to clean up polluted sites and curtail sources of contamination.

Abstract  U.S. Environmental Protection Agency; National Institute of Environmental Health Sciences. A number of studies have underlined the importance of the acute and chronic effects of ambient particles on respiratory health. Because fine particles are capable of penetrating deeply into the respiratory system, most of the health studies have focused on the respirable portion of the particle size spectrum. Previous studies to examine exposure/ response relationships between particle exposure and adverse respiratory effects have been based on artificial preparations, or collected and resuspended ambient particles, rather than the natural material found in ambient air. Artificial particles may not be representative, and collected particles may be difficult to redisperse. In addition, the chemical and physical characteristics of ambient particles may change upon resuspension. We have developed a new technique that enables us to increase the concentration of ambient particles to levels about 10 times higher for more, if desirable) than their ambient values and supply them to an exposure chamber. Ambient aerosol containing particles in the size range 0.1-2.5 Ám can be concentrated using a series of two slit-nozzle virtual impactors. The intake flow rates are 1m3/min and 200 L/min in the first and second virtual impactors, respectively. The virtual impactors were characterized in terms of their cutpoints and interstage losses using artificial monodisperse fluorescent aerosols as well as indoor ambient aerosols. Since the concentrated particles are maintained airborne, they can be supplied to a human or animal exposure chamber for conduction of exposure studies. The supply flow rate in the prototype concentrator is 40 L/min. Higher flow rates can be achieved by using more than one such system in parallel.

Abstract  This paper presents the development and evaluation of ambient fine particle concentrators for conducting animal and human exposure studies. These systems utilize the technology of virtual impactors to concentrate particles in the range 0.15-2.5 Ám. Ambient particles are first drawn at 5000 l m-1 through a preselective inlet that removes particles above 2.5 Ám. Subsequently, the remaining aerosol is drawn through a series of virtual impactors, which increase particle concentration by a factor of about 10 and 30, for human and animal exposures, respectively. Results from the experimental characterization of the concentrators showed that the concentration enrichment process occurs without any distortion in the size distribution and chemical composition of the sampled ambient aerosols. Furthermore, labile constituents of fine particles, such as volatile ammonium nitrate are preserved during this process.

Abstract  National Institute of Environmental Health Sciences. INTRODUCTION: Efficient elimination of inhaled soluble and insoluble particulate compounds deposited in the respiratory tract is necessary to keep its mucosal surfaces clean and functionally intact. In addition, the characteristic clearance processes and kinetics prevailing in different regions of the respiratory tract determine the retained dose of an inhaled substance in structures of the respiratory system. Thus, whether deposition and subsequent retention of inhaled particles is considered in clinical situations involving diagnostic or therapeutic aerosols or in toxicology with occupational or environmental pollutant aerosols, knowledge of the clearance of these substances is crucial in understanding their respiratory tract dosimetry. Clearance mechanisms are not only different for different regions of the respiratory tract, but also depend on physico-chemical characteristics of the deposited particulate material. Several recent review articles provide detailed descriptions and discussions of different processes governing the removal of inhaled solid and solute particles after deposition in the respiratory tract (Lauweryns and Baert, 1977; Morrow, 1977; Camner, 1980; Jones et al., 1982; Effros and Mason, 1983; Jones, 1984; Pavia, 1984; Morrow and Yu, 1985; Schlesinger, 1985; Brain, 1985, 1986; Cuddihy and Yeh, 1988). Because of the multitude and complexity of the diverse respiratory tract clearance processes, the present article will selectively review aspects of soluble and insoluble particle removal from tracheobronchial and deep lung regions. In addition, the article emphasizes clinical and toxicological implications of these removal processes and considers some unresolved issues related to lung clearance.

Abstract  Mucociliary clearance of deposited particles in the conducting airways of the human lung was investigated using various symmetric and stochastically generated asymmetric models of the conducting tree. Mucous velocities in all airways of the conducting airways were calculated from the principle of mass balance for the mucus. These velocities were used to calculate particle residence time in all the airways of the conducting tree. Equations for the transport of particles by the mucous escalator were developed and solved numerically. The retained mass in the tracheobronchial region was calculated for a scenario of 1 h exposure followed by 2 days of post exposure. Initial deposition pattern of particles in the conducting airways was found to be crucial for the analysis of retention curves. Particles deposited in peripheral bronchiolar airways of asymmetric stochastic lungs cleared more slowly than those in more central airways. Consequently, the retention curves of the stochastic lungs with a greater number of bronchial generations exhibited longer tails than those of symmetric lungs. The results indicated that the asymmetric stochastic lung models may predict significant lung burdens even after 24 h. The extent of the difference in inter-subject variability in retained particle mass may partially explain the observation of investigators regarding greater than expected retained mass in the TB region after 24 h, without invoking any additional slow bronchial clearance mechanisms.

Abstract  U.S. Environmental Protection Agency; Electric Power Research Institute; New York State Energy Research & Development Authority; Duke University; Georgia Tech. #In this study, the concept of scale analysis is applied to evaluate two state-of-science meteorological models, namely MM5 and RAMS3b, currently being used to drive regional-scale air quality models. To this end, seasonal time series of observations and predictions for temperature, water vapor, and wind speed were spectrally decomposed into fluctuations operating on the intra-day, diurnal, synoptic and longer-term time scales. Traditional model evaluation statistics are also presented to illustrate how the method of spectral decomposition can help provide additional insight into the models' performance. The results indicate that both meteorological models under-represent the variance of fluctuations on the intra-day time scale. Correlations between model predictions and observations for temperature and wind speed are insignificant on the intra-day time scale, high for the diurnal component because of the inherent diurnal cycle but low for the amplitude of the diurnal component, and highest for the synoptic and longer-term components. This better model performance on longer time scales suggests that current regional-scale models are most skillful for characterizing average patterns over extended periods. The implications of these results to using meteorological models to drive photochemical models are discussed.

Abstract  Airborne particulate matter (PM) is hypothesized to play a role in increases in asthma prevalence, although a causal relationship has yet to be established. To investigate the effects of real-world PM exposure on airway reactivity (AHR) and bronchoalveolar lavage (BAL) cellularity, we exposed naive mice to a single dose (0.5 mg/ mouse) of ambient PM, coal fly ash, or diesel PM. We found that ambient PM exposure induced increases in AHR and BAL cellularity, whereas diesel PM induced significant increases in BAL cellularity, but not AHR. On the other hand, coal fly ash exposure did not elicit significant changes in either of these parameters. We further examined ambient PM-induced temporal changes in AHR, BAL cells, and lung cytokine levels over a 2-wk period. Ambient PM-induced AHR was sustained over 7 d. The increase in AHR was preceded by dramatic increases in BAL eosinophils, whereas a decline in AHR was associated with increases in macrophages. A Th2 cytokine pattern (IL-5, IL-13, eotaxin) was observed early on with a shift toward a Th1 pattern (IFN-"gamma"). In additional studies, we found that the active component(s) of ambient PM are not water-soluble and that ambient PM-induced AHR and inflammation are dose-dependent. We conclude that ambient PM can induce asthmalike parameters in naive mice, suggesting that PM exposure may be an important factor in increases in asthma prevalence.

Abstract  Particle deposition to indoor surfaces is frequently modeled by assuming that indoor airflow is homogeneously and isotropically turbulent. Existing formulations of such models, based on the seminal work of Corner and Pendlebury (1951, Proc. Ph vs. Soc. Lond. B 64, 645), lack a thorough physical foundation. We apply the results of recent studies of near-surface turbulence to produce an analogous model for particle deposition Onto indoor surfaces that remains practical to use yet hasa stronger physical basis. The model accounts for the effects of Brownian and turbulent diffusion and gravitational settling. It predicts deposition to smooth surfaces as a function of particle size and density. The only required input parameters are enclosure geometry and friction velocity. Model equations are presented for enclosures with vertical and horizontal surfaces, and for sphericalcavities. The model helps account for a previously unexplained experimental observation regarding the functional dependence of deposition velocity on particle size. Model predictions agree well with recently published experimental data for a spherical cavity (Cheng, Y. S., Aerosol Sci. Technol. 27,131-146, (1997)).

Abstract  This is a study of the ventilatory functions of 1,805 normal Mexican-American. white, and black students of six public schools in Houston, Texas, with ages ranging from 7 to 20. A roll-seal piston type spirometer was used. The best performed forced vital capacity curve of each student was selected by the computer program from which the following measurements were extracted: FVC, FEV1, FEV1 / FVC ratio, PEFR, and MMEF. Each student also had the peak expiratory flow rate measured by the Wright peak ftowmeter to establish normal values with this instrument. Significant differences of lung volume and flow rate exist among the three races, and between male and female subjects. Prediction equations and prediction curves for each race and sex are presented. The results of the present study are compared with those of previously published works.

Abstract  Residence in urban areas with much traffic has been associated with various negative health effects. However, the contribution of traffic emissions to these adverse health effects has not been fully determined. Therefore, the objective of this in vivo study is to compare the pulmonary and systemic responses of rats exposed to particulate matter (PM) obtained from various locations with contrasting traffic profiles. Samples of coarse (2.5 microm-10 microm) and fine (0.1 microm-2.5 microm) PM were simultaneously collected at nine sites across Europe with a high-volume cascade impactor. Six PM samples from various locations were selected on the basis of contrast in in vitro analysis, chemical composition, and traffic profiles. We exposed spontaneously hypertensive (SH) rats to a single dose (3 mg PM/kg body weight or 10 mg PM/kg body weight) of either coarse or fine PM by intratracheal instillation. We assessed changes in biochemical markers, cell differentials, and histopathological changes in the lungs and blood 24 h postexposure. The dose-related adverse effects that both coarse and fine PM induced in the lungs and vascular system were mainly related to cytotoxicity, inflammation, and blood viscosity. We observed clear differences in the extent of these responses to PM from the various locations at equivalent dose levels. There was a trend that suggests that samples from high-traffic sites were the most toxic. It is likely that the toxicological responses of SH rats were associated with specific PM components derived from brake wear (copper and barium), tire wear (zinc), and wood smoke (potassium).

Abstract  Size-fractionated particulate matter (PM) samples were collected from six U.S. cities and chemically analyzed as part of the Multiple Air Pollutant Study. Particles were administered to cultured lung cells and the production of three different proinflammatory markers was measured to explore the association between the health effect markers and PM. Ultrafine, fine, and coarse PM samples were collected between December 2003 and May 2004 over a 4-wk period in each city. Filters were pooled for each city and the PM samples were extracted then analyzed for trace metals, ions, and elemental carbon. Particle extracts were applied to cultured human primary airway epithelial cells, and the secreted levels of interleukin-8 (IL-8), heme oxygenase-1, and cyclooxygenase-2 were measured 1 and 24 h following exposure. Fine PM sources were quantified by the chemical mass balance (CMB) model. The relationship between toxicological measures, PM sources, and individual species were evaluated using linear regression. Ultrafine and fine PM mass were associated with increases in IL-8 (r2 = .80 for ultrafine and r2 =.52 for fine). Sources of fine PM and their relative contributions varied across the sampling sites and a strong linear association was observed between IL-8 and secondary sulfate from coal combustion (r2 =.79). Ultrafine vanadium, lead, copper, and sulfate were also associated with increases in IL-8. Increases in inflammatory markers were not observed for coarse PM mass and source markers. These findings suggest that certain PM size fractions and sources are associated with markers of lung injury or inflammation.

Abstract  BACKGROUND: Interest in the health effects of particulate matter (PM) has focused on identifying sources of PM, including biomass burning, power plants, and gasoline and diesel emissions that may be associated with adverse health risks. Few epidemiologic studies, however, have included source-apportionment estimates in their examinations of PM health effects. We analyzed a time-series of chemically speciated PM measurements in Atlanta, Georgia, and conducted an epidemiologic analysis using data from three distinct source-apportionment methods. OBJECTIVE: The key objective of this analysis was to compare epidemiologic findings generated using both factor analysis and mass balance source-apportionment methods. METHODS: We analyzed data collected between November 1998 and December 2002 using positive-matrix factorization (PMF), modified chemical mass balance (CMB-LGO), and a tracer approach. Emergency department (ED) visits for a combined cardiovascular (CVD) and respiratory disease (RD) group were assessed as end points. We estimated the risk ratio (RR) associated with same day PM concentrations using Poisson generalized linear models. RESULTS: There were significant, positive associations between same-day PM(2.5) (PM with aero-dynamic diameter