Study on NO(2) absorption aimed at seeking a better NO(2) absorption chemical at pH 4.5 approximately 7.0 for application to existing wet flue gas desulfurization (FGD). The results from the double-stirred reactor indicated that ascorbic acid has very high absorption rate at this pH range. The rate constant of ascorbic acid reaction with NO(2) (0 approximately 1,000 x 10(-6) mol/mol) is about 3.54 x 10(6) mol/(Ls) at pH 5.4 approximately 6.5 at 55 degrees C.
Absorption ; Air Pollutants ; chemistry ; isolation & purification ; Ascorbic Acid ; chemistry ; Nitric Oxide ; chemistry ; isolation & purification

OBJECTIVETo study the characterization apportionment of main ion concentrations of PM10 under the influence of trajectory wind direction in London.

METHODSPM10 samples from 1 May 1995 to 30 October 1995 of Oxford Street of Central London were collected, the metals and anions of which were measured using atomic absorption spectrometry (AAS) and ion chromatography (IC). Composite trajectories representative of the air mass arriving in London at the same period were calculated based on basic routine back trajectories from the British Atmospheric Data Centre (BADC).

RESULTSConcentration apportionments of main ions were similar when the trajectory was plotted back at 6 h, 12 h, and 24 h, some were obviously different. Mg, Ba, Pb, and Cu had similar peak apportionments at the area 180 degrees-320 degrees, but Zn and Ni at the area of 90 degrees-270 degrees, NO3 and SO4(2-) at the area of 100 degrees-220 degrees. Cl- concentration peak apportionment was at the area of 220 degrees-300 degrees, which showed that Cl- mainly came from the North Sea.

CONCLUSIONTrajectory wind direction has important effect on ion concentration apportionment of PM10 in London. The ions have similar concentration peak apportionments or their correlation coefficients are statistically significant.

Air Pollutants ; analysis ; chemistry ; Anions ; analysis ; Cations ; analysis ; Environmental Monitoring ; London ; Particle Size ; Time Factors ; Wind

Air Pollutants ; analysis ; Humans ; Industry ; Lead ; analysis ; chemistry ; Spectrometry, Fluorescence ; methods ; Spectrophotometry, Atomic ; methods ; Workplace

Air Pollutants, Occupational ; chemistry ; Indium ; analysis ; Mass Spectrometry ; methods ; Occupational Exposure ; Spectrum Analysis ; methods ; Workplace

Mercury is emitted to the atmosphere from various natural and anthropogenic sources, and degrades with difficulty in the environment. Mercury exists as various species, mainly elemental (Hg0) and divalent (Hg2+) mercury depending on its oxidation states in air and water. Mercury emitted to the atmosphere can be deposited into aqueous environments by wet and dry depositions, and some can be re-emitted into the atmosphere. The deposited mercury species, mainly Hg2+, can react with various organic compounds in water and sediment by biotic reactions mediated by sulfur-reducing bacteria, and abiotic reactions mediated by sunlight photolysis, resulting in conversion into organic mercury such as methylmercury (MeHg). MeHg can be bioaccumulated through the food web in the ecosystem, finally exposing humans who consume fish. For a better understanding of how humans are exposed to mercury in the environment, this review paper summarizes the mechanisms of emission, fate and transport, speciation chemistry, bioaccumulation, levels of contamination in environmental media, and finally exposure assessment of humans.
Air Pollutants/chemistry/metabolism ; *Environmental Exposure ; Environmental Remediation ; Food Chain ; Humans ; Mercury/chemistry/*metabolism ; Methylmercury Compounds/chemistry/metabolism ; Photolysis ; Sulfur-Reducing Bacteria/metabolism ; Water Pollutants, Chemical/metabolism

Pulverized coal reburning, ammonia injection and advanced reburning in a pilot scale drop tube furnace were investigated. Premix of petroleum gas, air and NH3 were burned in a porous gas burner to generate the needed flue gas. Four kinds of pulverized coal were fed as reburning fuel at constant rate of 1g/min. The coal reburning process parameters including 15% approximately 25% reburn heat input, temperature range from 1100 degrees C to 1400 degrees C and also the carbon in fly ash, coal fineness, reburn zone stoichiometric ratio, etc. were investigated. On the condition of 25% reburn heat input, maximum of 47% NO reduction with Yanzhou coal was obtained by pure coal reburning. Optimal temperature for reburning is about 1300 degrees C and fuel-rich stoichiometric ratio is essential; coal fineness can slightly enhance the reburning ability. The temperature window for ammonia injection is about 700 degrees C approximately 1100 degrees C. CO can improve the NH3 ability at lower temperature. During advanced reburning, 72.9% NO reduction was measured. To achieve more than 70% NO reduction, Selective Non-catalytic NO(x) Reduction (SNCR) should need NH3/NO stoichiometric ratio larger than 5, while advanced reburning only uses common dose of ammonia as in conventional SNCR technology. Mechanism study shows the oxidization of CO can improve the decomposition of H2O, which will rich the radical pools igniting the whole reactions at lower temperatures.
Air Pollutants ; chemistry ; isolation & purification ; Carbon Monoxide ; chemistry ; Coal ; Computer Simulation ; Hot Temperature ; Models, Chemical ; Nitrogen Oxides ; chemistry ; isolation & purification ; Oxidation-Reduction ; Temperature

BACKGROUND: Wood is a valuable material for interiors, and the psychophysiological relaxation effects of volatile organic compounds (VOCs) from wood chips and essential oils have been reported. However, few studies have identified the odors in full-scale wooden environment, and also, differences in gender have not been clarified. In this study, we aimed to confirm the effects of VOCs emitted from interior wood walls in both human male and female participants. METHODS: We used Japanese cedar timber and analyzed VOCs in the experimental rooms with and without Japanese cedar timber by gas chromatography-mass spectrometry (GC-MS). The physiological effects were measured using neuroendocrinological and immunological parameters in saliva. A questionnaire was used to evaluate the subjective responses to each odor in the experimental rooms. RESULTS: The main compound emitted from Japanese cedar timber was δ-cadinene, and the total volume of VOCs in the wood condition (presence of VOCs emitted from Japanese cedar) was 282.4 (μg/m). Significant differences between genders in salivary parameters were shown that there were decreases of α-amylase in wood condition and increases of cortisol in the control (absence of VOCs) condition in female participants compared to male participants. The results demonstrated that VOCs in the experimental room with Japanese cedar timber tend to suppress the activation of the sympathetic nervous activity and non-VOCs of Japanese cedar in the control room increase cortisol in female participants. CONCLUSIONS These results suggest that an indoor environment with wood interior materials has the potential to be useful for health management, especially women's health.
Adult ; Air Pollutants ; analysis ; Air Pollution, Indoor ; adverse effects ; analysis ; Cryptomeria ; chemistry ; Female ; Gas Chromatography-Mass Spectrometry ; Humans ; Hydrocortisone ; metabolism ; Male ; Saliva ; chemistry ; Salivary alpha-Amylases ; metabolism ; Sesquiterpenes ; analysis ; Sex Factors ; Volatile Organic Compounds ; adverse effects ; Wood ; chemistry ; Young Adult

OBJECTIVES: We investigated the association between particulate matter less than 10 microm in aerodynamic diameter (PM10) exposure and non-accidental mortality in Asian populations by meta-analysis, using both time-series and case-crossover analysis. METHODS: Among the 819 published studies searched from PubMed and EMBASE using key words related to PM10 exposure and non-accidental mortality in Asian countries, 8 time-series and 4 case-crossover studies were selected for meta-analysis after exclusion by selection criteria. We obtained the relative risk (RR) and 95% confidence intervals (CI) of non-accidental mortality per 10 microg/m3 increase of daily PM10 from each study. We used Q statistics to test the heterogeneity of the results among the different studies and evaluated for publication bias using Begg funnel plot and Egger test. RESULTS: Testing for heterogeneity showed significance (p<0.001); thus, we applied a random-effects model. RR (95% CI) per 10 microg/m3 increase of daily PM10 for both the time-series and case-crossover studies combined, time-series studies relative risk only, and case-crossover studies only, were 1.0047 (1.0033 to 1.0062), 1.0057 (1.0029 to 1.0086), and 1.0027 (1.0010 to 1.0043), respectively. The non-significant Egger test suggested that this analysis was not likely to have a publication bias. CONCLUSIONS: We found a significant positive association between PM10 exposure and non-accidental mortality among Asian populations. Continued investigations are encouraged to contribute to the health impact assessment and public health management of air pollution in Asian countries.
Air Pollutants/*chemistry ; Asian Continental Ancestry Group ; Cross-Over Studies ; Databases, Factual ; *Environmental Exposure ; Humans ; Models, Theoretical ; *Mortality ; Particulate Matter/*chemistry ; Time Factors

Air Pollutants ; chemistry ; toxicity ; Cardiovascular Diseases ; epidemiology ; etiology ; Environmental Exposure ; Humans ; Particle Size ; Particulate Matter ; chemistry ; toxicity ; Respiratory Tract Diseases ; epidemiology ; etiology

OBJECTIVETo determine the metal contents of date palm (Pheonix dactylifera) samples in dry season from Denizli-Turkey for investigation of heavy metal-polluted traffic.

METHODThe levels of iron, copper, zinc, lead, cadmium, nickel, chromium, and manganese ions in the leaves of thirty five date palm (Pheonix dactylifera) samples collected from various levels of traffic in the streets of Denizli-Turkey were determined by graphite furnace or flame atomic absorption spectrometry. The wet, dry, and microwave digestion procedures for the date palm (Pheonix dactylifera) leaves were compared. The accuracy of the digestion procedures was checked using a standard reference material (IAEA-336 Lichen, SRM).

RESULTSMicrowave digestion procedure for the leaves was preferred because it was more proper with respect to both time and recovery than dry and wet digestion. The levels of the heavy metal ions investigated were the highest on the samples from high traffic level. Also correlations between metal levels and traffic volume for all the metals were investigated.

CONCLUSIONIn the light of our findings, the date palm (Phoenix dactylifera) leaves are suitable as a biomonitor for atmospheric heavy metal-polluted traffic. Significant correlations can be obtained between traffic levels and heavy metal concentrations.

Air Pollutants ; analysis ; Arecaceae ; chemistry ; Environmental Monitoring ; methods ; Metals, Heavy ; analysis ; Plant Leaves ; chemistry ; Seasons ; Spectrum Analysis ; Turkey ; Vehicle Emissions ; analysis