Abstract  This report consists of charts of toxic pollutants with the recommended water quality criteria listed for such things as freshwater, saltwater, human consumption, etc.

Abstract  A new ligand, pyridine-3,5-bis(benzimidazole-2-yl) (pbb), and four complexes containing pbb, namely [pbb(Hpbb)(2)]SO(4)center dot 7H(2)o (1), [Zn(pbb)(2)(H(2)O)(4)](NO(3))(2) center dot 2C(2)H(5)OH center dot 4H(2)O (2), [Cd(pbb)(2)(H(2)O)(4)](NO(3))(2)center dot 2C(2)H(5)OH center dot 4H(2)O (3) and [Zn(2)(pbb)(2)([L-OH)(mu-CAc)](OAc)(2)center dot 7H(2)O (4) (HOAc = acetic acid), have been designed, synthesized and characterized. Complexes 1-4 show 3D supramolecular architectures that are connected through hydrogen bonds and aromatic pi-pi interactions. A self-assembled (H(2)O)(12) cluster with a chair conformation (H(2)O)(6) ring core is observed in 1, which exhibits an unusual association mode of water molecules. Compounds 2 and 3 present 3D supramolecular structures involving I D open channels encapsulating NO(3)(-) ions, and crown-like rings are found in 4. In addition, the preliminary antibacterial activity of pbb and its complexes were investigated by two methods, which indicate a selective inhibition property for the tested strains. Strong emissions from the complexes were also changed by the coordination modes in the sold state. (C) 2008 Elsevier Ltd. All rights reserved.

Abstract  Using 1 year of aerosol optical thickness (AOT) retrievals from the MODerate resolution Imaging Spectro-radiometer (MODIS) on board NASA's Terra and Aqua satellite along with ground measurements of PM2.5 mass concentration, we assess particulate matter air quality over different locations across the global urban areas spread over 26 locations in Sydney, Delhi, Hong Kong, New York City and Switzerland. An empirical relationship between AOT and PM2.5 mass is obtained and results show that there is an excellent correlation between the bin-averaged daily mean satellite and ground-based values with a linear correlation coefficient of 0.96. Using meteorological and other ancillary datasets, we assess the effects of wind speed, cloud cover, and mixing height (MH) on particulate matter (PM) air quality and conclude that these data are necessary to further apply satellite data for air quality research. Our study clearly demonstrates that satellite-derived AOT is a good surrogate for monitoring PM air quality over the earth. However, our analysis shows that the PM2.5-AOT relationship strongly depends on aerosol concentrations, ambient relative humidity (RH), fractional cloud cover and height of the mixing layer. Highest correlation between MODIS AOT and PM2.5 mass is found under clear sky conditions with less than 40-50% RH and when atmospheric MH ranges from 100 to 200m. Future remote sensing sensors such as Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) that have the capability to provide vertical distribution of aerosols will further enhance our ability to monitor and forecast air pollution. This study is among the first to examine the relationship between satellite and ground measurements over several global locations.

Abstract  Thallus morphology and element concentrations (S, Al, Fe, Sr, Mn, Ni, Zn, Cu, Pb, As, F, and Cl) were comparedn samplesf the fruticose lichen genus Usnea at two heightsf the Abies sibirica canopyn the East Sayan Mountains (Krasnoyarsk District, Russia) sampled from three stations at 15, 25 and 35 km from Krasnoyark. Usnea species with an abnormal morphologyominatedn branchesn the upper canopy, 15-22 m above ground level, and normal thallin lower tree branches, 2-5 m above ground. Abnormal thalli at the tree-top level contained higher Al, Fe, Zn, F, Sr and Pb concentrations compared with normal thalli growing below, confirming austmpact. No such clear trend wasbserved between sampling stations. Crown canopy architecture, surface microtopography and the balance between the processesfeposition and the movement and lossf particles play a major rolen particlenterception andn pollutantelivery to Usnea.

Abstract  Background: Many chronic diseases are the product of an underlying pathologic condition and superimposed acute exacerbations. This model may apply to several conditions such as asthma, other obstructive lung diseases, or atherosclerosis. For exposures affecting both the development of chronic disease and its exacerbation, the usual methods to derive attributable risks (AR) are inappropriate. Methods: We expand traditional risk assessment methods to estimate the AR for exacerbations under a "chronic disease model." We use asthma in children as the chronic disease and air pollution as the exposure of interest. We estimate bronchitis symptom exacerbations attributable to air pollution, using data from the Children's Health Study to estimate asthma prevalence and symptom occurrence, and we examine the distribution of exposure and its acute and chronic effects. Results: In the combined AR model, 39.8% of exacerbations were attributable to air pollution, compared with 33.5% in the traditional model, which ignores a chronic effect of pollution on asthma development. Thus, there is a 1.19-fold higher estimated burden with the combined model. The difference is due to exacerbations caused by other factors (ie, not by air pollution) but nonetheless occurring among those assumed to have asthma that developed due to traffic-related pollution. The proposed model is applicable to other risk factors that play a role both in both the development of a chronic disease and its exacerbation. Conclusions: Traditional approaches to the calculation of attributable risk may underestimate the health impact of long-term environmental or other exposures that produce both chronic and acute disease.

Abstract  A multi-phase instrument comparison study was conducted on two different diesel engines on a dynamometer to compare commonly used particulate matter (PM) measurement techniques while sampling the same diesel exhaust aerosol and to evaluate inter- and intra-method variability. Included in this evaluation were a Tapered Element Oscillating Microbalance (TEOM), three Scanning Mobility Particle Sizers (SMPSs), a Condensation Particle Counter (CPC), a TSI DustTrak, a MET-One E-BAM, and two Electrical Low Pressure Impactors (ELPIs) as well as two types of time-integrated filter samplers. Of the five on-line analyzers evaluated for PM mass concentration, the TEOM was shown to have the best overall correlation to the gravimetric filter method. For measuring concentration by particle number, the two ELPIs and the Model 3936L25 SMPS provided generally comparable results during both test phases (data for the stand-alone CPC were invalidated). With respect to measuring particle size distribution (PSD) by gravimetric analysis, the ELPIs were not found to be useful for a variety of reasons whereas for differential number distribution, the SMPSs and ELPIs provided generally comparable results.

Abstract  Diesel exhaust (DE) has been shown to enhance allergic sensitization in animals following high-dose instillation or chronic inhalation exposure scenarios. The purpose of this study was to determine if short-term exposures to diluted DE enhance allergic immune responses to antigen, and identify possible mechanisms using microarray technology. BALB/c mice were exposed to filtered air or diluted DE to yield particle concentrations of 500 or 2000 µg/m3 4 h/day on days 0?4. Mice were immunized intranasally with ovalbumin (OVA) antigen or saline on days 0?2, challenged on day 18 with OVA or saline, and all mice were challenged with OVA on day 28. Mice were necropsied either 4 h after the last DE exposure on day 4, or 18, 48, and 96 h after the last challenge. Immunological endpoints included OVA-specific serum IgE, biochemical and cellular profiles of bronchoalveolar lavage (BAL), and cytokine production in the BAL. OVA-immunized mice exposed to both concentrations of DE had increased eosinophils, neutrophils, lymphocytes, and interleukin-6 (high dose only) post-challenge compared with OVA control, whereas DE/saline exposure yielded increases in neutrophils at the high dose only. Transcriptional microarray analysis 4 h after the last DE exposure demonstrated distinct gene expression profiles for the high-dose DE/OVA and DE/saline groups. DE/OVA induced oxidative stress and metabolism pathways, whereas DE in the absence of immunization modulated cell cycle control, growth and differentiation, G-proteins, and cell adhesion pathways. This study shows for the first time early changes in gene expression induced by the combination of DE inhalation and mucosal immunization, which resulted in stronger development of allergic eosinophilia.

Abstract  This review focuses on the role of oxidative processes in atherosclerosis and its resultant cardiovascular events. There is now a consensus that atherosclerosis represents a state of heightened oxidative stress characterized by lipid and protein oxidation in the vascular wall. The oxidative modification hypothesis of atherosclerosis predicts that low-density lipoprotein (LDL) oxidation is an early event in atherosclerosis and that oxidized LDL contributes to atherogenesis. In support of this hypothesis, oxidized LDL can support foam cell formation in vitro, the lipid in human lesions is substantially oxidized, there is evidence for the presence of oxidized LDL in vivo, oxidized LDL has a number of potentially proatherogenic activities, and several structurally unrelated antioxidants inhibit atherosclerosis in animals. An emerging consensus also underscores the importance in vascular disease of oxidative events in addition to LDL oxidation. These include the production of reactive oxygen and nitrogen species by vascular cells, as well as oxidative modifications contributing to important clinical manifestations of coronary artery disease such as endothelial dysfunction and plaque disruption. Despite these abundant data however, fundamental problems remain with implicating oxidative modification as a (requisite) pathophysiologically important cause for atherosclerosis. These include the poor performance of antioxidant strategies in limiting either atherosclerosis or cardiovascular events from atherosclerosis, and observations in animals that suggest dissociation between atherosclerosis and lipoprotein oxidation. Indeed, it remains to be established that oxidative events are a cause rather than an injurious response to atherogenesis. In this context, inflammation needs to be considered as a primary process of atherosclerosis, and oxidative stress as a secondary event. To address this issue, we have proposed an "oxidative response to inflammation" model as a means of reconciling the response-to-injury and oxidative modification hypotheses of atherosclerosis.

Abstract  Various methods have been developed recently to estimate personal exposures to ambient particulate matter less than 2.5 m in diameter (PM2.5) using fixed outdoor monitors as well as personal exposure monitors. One class of estimators involves extrapolating values using ambient-source components of PM2.5, such as sulfate and iron. A key step in extrapolating these values is to correct for differences in infiltration characteristics of the component used in extrapolation (such as sulfate within PM2.5) and PM2.5. When this is not done, resulting health effect estimates will be biased. Another class of approaches involves factor analysis methods such as positive matrix factorization (PMF). Using either an extrapolation or a factor analysis method in conjunction with regression calibration allows one to estimate the direct effects of ambient PM2.5 on health, eliminating bias caused by using fixed outdoor monitors and estimated personal ambient PM2.5 concentrations. Several forms of the extrapolation method are defined, including some new ones. Health effect estimates that result from the use of these methods are compared with those from an expanded PMF analysis using data collected from a health study of asthmatic children conducted in Denver, Colorado. Examining differences in health effect estimates among the various methods using a measure of lung function (forced expiratory volume in 1 s) as the health indicator demonstrated the importance of the correction factor(s) in the extrapolation methods and that PMF yielded results comparable with the extrapolation methods that incorporated correction factors.

Abstract  An instrument for on-line continuous measurement of the water-soluble organic carbon (WSOC) component of aerosol particles is described and results from an urban site in St. Louis are presented. A Particle-into-Liquid Sampler impacts ambient particles, grown to large water droplets, onto a plate and then washes them into a flow of purified water. The resulting liquid is filtered and the carbon content quantified by a Total Organic Carbon analyzer providing continuous six-minute integral measurements with a detection limit of 0.1 ?g C/m3. Summer and fall measurements of WSOC and organic carbon (OC) indicated WSOC/OC ratio typically ranged from 0.40 to 0.80. A diurnal variation in WSOC/OC that correlated with ozone was observed over extended periods in June; however, other periods in August had no correlation. The results suggested that WSOC was composed of a complex mixture of compounds that may contain a significant fraction from secondary organic aerosol formation.

Abstract  A thermodynamic model, the Gibbs Free-Energy Minimization model (GFEMN), was used to simulate the partitioning of PM2.5 nitrate aerosol and nitric acid using highly time-resolved inorganic measurements collected at the Pittsburgh Air Quality Study during July 2001 and January 2002. Model results were evaluated using independent, high time resolution measurements of aerosol nitrate. The mean observed concentration in July was 0.6 μg/m3 and 2.1 μg/m3 in January. Model predictions were in agreement with the observations within 0.5 μg/m3 on average, with measurement uncertainties often accounting for these discrepancies. The simulations were run assuming particles were liquid in July for all relative humidities (RHs) and solid below 60% RH in January. For both seasons the assumed physical state did not influence considerably the overall agreement with observations. The assumption of particle mixing state did appear to influence model error; however, assuming that particles were externally mixed during low RH periods in July improved agreement significantly. The exceptional sensitivity of predicted aerosol nitrate to ammonia in western Pennsylvania suggests that reductions in PM2.5 may be assisted by reductions in ammonia emissions.

Abstract  Exposure to ambient ultrafine particles induces airway inflammatory reactions and tissue remodeling. In this experiment, to determine whether ultrafine carbon black (ufCB) affects proliferation of airway epithelium and, if so, what the mechanism of action is, we studied human primary bronchial epithelial cell cultures. Incubation of cells in the serum-free medium with ufCB increased incorporations of [3H]thymidine and [3H]leucine into cells in a time- and dose-dependent manner. This effect was attenuated by Cu- and Zn-containing superoxide dismutase (Cu/Zn SOD) and apocynin, an inhibitor of NADPH oxidase, and completely inhibited by pretreatment with the epidermal growth factor receptor (EGF-R) tyrosine kinase inhibitors AG-1478 and BIBX-1382, and the mitogen-activated protein kinase kinase inhibitor PD-98059. Transfection of a dominant-negative mutant of H-Ras likewise abolished the effect ufCB. Stimulation with ufCB also induced processing of membrane-anchored proheparin-binding (HB)-EGF, release of soluble HB-EGF into the medium, association of phosphorylated EGF-R and Shc with glutathione-S-transferase-Grb2 fusion protein, and phosphorylation of extracellular signal-regulated kinase (ERK). Pretreatment with AG-1478, [Glu52]Diphtheria toxin, a specific inhibitor of HB-EGF, neutralizing HB-EGF antibody, Cu/Zn SOD, and apocynin each inhibited ufCB-induced ERK activation. These results suggest that ufCB causes oxidative stress-mediated proliferation of airway epithelium, involving processing of HB-EGF and the concomitant activation of EGF-R and ERK cascade.

Abstract  The extensive thermodynamic and optical properties recently reported [Tang and Munkelwitz, 1994a] for sulfate and nitrate solution droplets are incorporated into a visibility model for computing light scattering by hygroscopic aerosols. The following aerosol systems are considered: NH4HSO4, (NH4)2SO4, (NH4)3H(SO4), NaHSO4, Na2SO4, NH4NO3, and NaNO3. In addition, H2SO4 and NaCl are included to represent freshly formed sulfate and background sea-salt aerosols, respectively. Scattering coefficients, based on 1 ?g dry salt per cubic meter of air, are calculated as a function of relative humidity for aerosols of various chemical compositions and lognormal size distributions. For a given size distribution the light scattered by aerosol particles per unit dry-salt mass concentration is only weakly dependent on chemical constituents of the hygroscopic sulfate and nitrate aerosols. Sulfuric acid and sodium chloride aerosols, however, are exceptions and scatter light more efficiently than all other inorganic salt aerosols considered in this study. Both internal and external mixtures exhibit similar light-scattering properties. Thus for common sulfate and nitrate aerosols, since the chemical effect is outweighed by the size effect, it follows that observed light scattering by the ambient aerosol can be approximated, within practical measurement uncertainties, by assuming the aerosol being an external mixture. This has a definite advantage for either visibility degradation or climatic impact modeling calculations, because relevant data are now available for external mixtures but only very scarce for internal mixtures.

Abstract  A simple methodology was developed to collect measurements of duty cycle, the fraction of time the heating and air conditioning (HAC) system was operating, inside residences. The primary purpose of the measurements was to assess whether the HAC duty cycle was related to reductions in indoor particulate matter (PM) concentrations. A miniature temperature logger placed on an HAC outlet vent monitored changes in temperature as the system cooled or heated the residence. Temperature step changes signaling duty cycle periods were identified using spreadsheet macros. Parallel measurements of 24-h integrated air exchange rates (AERs) and indoor PM2.5 and PM10 concentrations were collected to determine relationships with the duty cycle. The mild temperatures (mean = 18.7°C) present during the Spring season of the RTP PM Panel Study and personal comfort preferences caused low and variable daily duty cycles (mean = 0.061, std, dev. = 0.054) in both heating and cooling mode. Warmer ambient temperatures during the Fall season of the Tampa Asthmatic Children's Study (TACS) resulted in cooling-only HAC operation, with a higher mean duty cycle of 0.21 (std. dev. = 0.11). Statistically significant linear relationships were observed between daily average duty cycle and the ambient temperature for both studies. Duty cycle exhibited a strong diurnal pattern commensurate with ambient temperature fluctuations. Duty cycles were positively associated with the residence AERs for heating-mode operations, but negatively associated when operating in cooling mode. Personal preferences contributed to the variability in the relationship between duty cycle and AER. The relationship between duty cycle and PM2.5 or PM10 indoor-outdoor ratios were not statistically significant. The association of duty cycle with indoor-outdoor ratio was confounded by the short time span (mean of 10.3 min for the TACS) of HAC system operation and the presence of strong indoor sources altering the indoor concentration levels.

Abstract  Biomass burning represents an important source of atmospheric aerosols and greenhouse gases, yet little is known about its interannual variability or the underlying mechanisms regulating this variability at continental to global scales. Here we investigated fire emissions during the 8 year period from 1997 to 2004 using satellite data and the CASA biogeochemical model. Burned area from 2001–2004 was derived using newly available active fire and 500 m. burned area datasets from MODIS following the approach described by Giglio et al. (2006). ATSR and VIRS satellite data were used to extend the burned area time series back in time through 1997. In our analysis we estimated fuel loads, including organic soil layer and peatland fuels, and the net flux from terrestrial ecosystems as the balance between net primary production (NPP), heterotrophic respiration (Rh), and biomass burning, using time varying inputs of precipitation (PPT), temperature, solar radiation, and satellite-derived fractional absorbed photosynthetically active radiation (fAPAR). For the 1997–2004 period, we found that on average approximately 58 Pg C year−1 was fixed by plants as NPP, and approximately 95% of this was returned back to the atmosphere via Rh. Another 4%, or 2.5 Pg C year−1 was emitted by biomass burning; the remainder consisted of losses from fuel wood collection and subsequent burning. At a global scale, burned area and total fire emissions were largely decoupled from year to year. Total carbon emissions tracked burning in forested areas (including deforestation fires in the tropics), whereas burned area was largely controlled by savanna fires that responded to different environmental and human factors. Biomass burning emissions showed large interannual variability with a range of more than 1 Pg C year−1, with a maximum in 1998 (3.2 Pg C year−1) and a minimum in 2000 (2.0 Pg C year−1).

Abstract  A thermal desorption GC/MS technique has been developed for the quantification of polycyclic aromatic hydrocarbons (PAHs) in airborne particulate matter using the NIST Standard Reference Material (SRM1649a) Urban Dust. The technique was developed using standard linearity tests in order to establish optimum sample weights and optimum desorption and chromatographic parameters. This direct analysis technique eliminates the use of solvents in the sample preparation (reducing volatile component losses) and also significantly reduces the sample preparation time (no extraction procedure). The technique has been shown to give linearity in terms of the overall TIC response as well as for a prominent series of n-alkanes (C-20-C-33) and 10 NIST priority PAHs, 8 of which have been quantified. The technique is reported to be uniquely sensitive (PAH concentrations 2-6 mg kg(-1)) and reproducible (MW = 178-228 SD less than or equal to 0.228 mg kg(-1), less than or equal to 7%; MW = 252 SD less than or equal to 0.922 mg kg(-1), less than or equal to 33%) over the range of sample weights (1-5 mg). Such sample weights illustrate that the technique can be equally applied to the analysis of airborne particulate samples collected over short time periods (24-48 h) using only commonly used low-volume collection devices.

Abstract  Long-term global radiation programs, such as AERONET and BSRN, have shown success in monitoring column averaged cloud and aerosol optical properties. Little attention has been focused on global measurements of vertically resolved optical properties. Lidar systems are the preferred instrument for such measurements. However, global usage of lidar systems has not been achieved because of limits imposed by older systems that were large, expensive, and logistically difficult to use in the field. Small, eye-safe, and autonomous lidar systems are now currently available and overcome problems associated with older systems. The first such lidar to be developed is the Micro-pulse lidar System (MPL). The MPL has proven to be useful in the field because it can be automated, runs continuously (day and night), is eye-safe, can easily be transported and set up, and has a small field-of-view which removes multiple scattering concerns. We have developed successful protocols to operate and calibrate MPL systems. We have also developed a data analysis algorithm that produces data products such as cloud and aerosol layer heights, optical depths, extinction profiles, and the extinction-backscatter ratio. The algorithm minimizes the use of a priori assumptions and also produces error bars for all data products. Here we present an overview of our MPL protocols and data analysis techniques. We also discuss the ongoing construction of a global MPL network in conjunction with the AERONET program. Finally, we present some early results from the MPL network.

Abstract  Aerosol time-of-flight mass spectrometry (ATOFMS) was used for characterizing the aerodynamic size and chemical composition of individual particles during the Atlanta Supersite Experiment in 1999. During certain time periods, increased numbers of particles scattered light but did not produce mass spectra. Upon comparison of the size-resolved unscaled particle counts from an aerosol time-of-flight mass spectrometer with those from a laser particle counter, the presence of a chemical bias became apparent in the single particle mass spectral measurements. Upon further analysis, it was determined that these events occurred during time periods of elevated ammonium and sulfate mass concentrations measured with semicontinuous particulate analysis instruments. The missed particle type occurred mostly in the smallest size range (0.35?0.54 ?m) and correlated well with optical scattering measurements. As described herein, a scaling procedure is developed that allows one to account for the ATOFMS chemical bias. This procedure is tested by comparing the scaled ATOFMS data with multiple measurements from other techniques made during the 1999 Atlanta Supersite study. This is the second paper in a two-part series focusing on ATOFMS data collected during the Atlanta Supersite experiment in 1999 [Prather et al., 2002].