Source apportionment of anthropogenic and biogenic organic aerosol over the Tokyo metropolitan area from forward and receptor models.

Organic aerosol (OA) is a dominant component of PM, and accurate knowledge of its sources is critical for identification of cost-effective measures to reduce PM. For accurate source apportionment of OA, we conducted field measurements of organic tracers at three sites (one urban, one suburban, and one forest) in the Tokyo Metropolitan Area and numerical simulations of forward and receptor models. We estimated the source contributions of OA by calculating three receptor models (positive matrix factorization, chemical mass balance, and secondary organic aerosol (SOA)-tracer method) using the ambient concentrations, source profiles, and production yields of OA tracers.

Application of inert gas-mediated ionization for qualitative screening of chlorinated aromatics in house dust by comprehensive two-dimensional gas chromatography-high-resolution time-of-flight mass spectrometry.

The development of highly selective and sensitive analytical methods for the nontarget screening of persistent organic pollutants such as halogenated compounds in environmental samples is a challenging task. Soft ionization mass spectrometry has emerged as a powerful technique for obtaining essential molecular information, and it is expected to reveal compounds that remain hidden with conventional fragmentation techniques such as electron ionization (EI). In this study, a soft ionization method based on electron capture negative ionization using an inert gas was developed for the nontarget screening of chlorinated aromatics in environmental samples and was applied to comprehensive two-dimensional gas chromatography-high-resolution time-of-flight mass spectrometry (GC × GC-HRToFMS).

Volatility Distribution of Organic Compounds in Sewage Incineration Emissions.

Intermediate volatility and semivolatile organic compounds (IVOC/SVOC) are important precursors of secondary organic aerosol (SOA) while SVOC is an important contributor to primary organic aerosol (POA). However, combustion emissions data for volatility classes are limited. This study reports the gas and particle emissions that were sampled with various dilution factors from a sewage sludge incinerator burning fuel oil.

Contributions of Condensable Particulate Matter to Atmospheric Organic Aerosol over Japan.

Because emission rates of particulate matter (PM) from stationary combustion sources have been measured without dilution or cooling in Japan, condensable PM has not been included in Japanese emission inventories. In this study, we modified an emission inventory to include condensable PM from stationary combustion sources based on the recent emission surveys using a dilution method. As a result, emission rates of organic aerosol (OA) increased by a factor of 7 over Japan.

Sensitivities of Simulated Source Contributions and Health Impacts of PM to Aerosol Models.

Chemical transport models are useful tools for evaluating source contributions and health impacts of PM in the atmosphere. We recently found that concentrations of PM compounds over Japan were much better reproduced by a volatility basis set model with an enhanced dry deposition velocity of HNO and NH compared with a two-product yield model. In this study, we evaluated the sensitivities to organic aerosol models of the simulated source contributions to PM concentrations and of PM-related mortality.

Nontarget approach for environmental monitoring by GC × GC-HRTOFMS in the Tokyo Bay basin.

In this study, we developed an approach for sequential nontarget and target screening for the rapid and efficient analysis of multiple samples as an environmental monitoring using a comprehensive two-dimensional gas chromatograph coupled to a high resolution time-of-flight mass spectrometer (GC × GC-HRTOFMS). A key feature of the approach was the construction of an accurate mass spectral database learned from the sample via nontarget screening. To enhance the detection power in the nontarget screening, a global spectral deconvolution procedure based on non-negative matrix factorization was applied.

Selective and comprehensive analysis of organohalogen compounds by GC × GC-HRTofMS and MS/MS.

Thousands of organohalogen compounds, including hazardous chemicals such as polychlorinated biphenyls (PCBs) and other persistent organic pollutants (POPs), were selectively and simultaneously detected and identified with simple, or no, purification from environmental sample extracts by using several advanced methods. The methods used were software extraction from two-dimensional gas chromatography-high-resolution time-of-flight mass spectrometry (GC × GC-HRTofMS) data, measurement by negative chemical ionization with HRTofMS, and neutral loss scanning (NLS) with GC × GC-MS/MS. Global and selective detection of organochlorines and bromines in environmental samples such as sediments and fly ash was achieved by NLS using GC × GC-MS/MS (QQQ), with the expected losses of Cl and Br.

Global spectral deconvolution based on non-negative matrix factorization in GC × GC-HRTOFMS.

A global spectral deconvolution, based on non-negative matrix factorization (NMF) in comprehensive two-dimensional gas chromatography high-resolution time-of-flight mass spectrometry, was developed. We evaluated the ability of various instrumental parameters and NMF settings to derive high-performance detection in nontarget screening using a sediment sample. To evaluate the performance of the process, a NIST library search was used to identify the deconvoluted spectra.

Retrospective analysis by data processing tools for comprehensive two-dimensional gas chromatography coupled to high resolution time-of-flight mass spectrometry: a challenge for matrix-rich sediment core sample from Tokyo Bay.

Data processing tools for non-target analysis using comprehensive two-dimensional gas chromatography coupled with high-resolution time-of-flight mass spectrometry (GC×GC-HRTOFMS) were developed and applied to a sediment core in Tokyo Bay, focusing on chlorinated compounds in this study. The processing tools were classified in two different methods: (1) the consecutive use of mass defect filter followed by artificial neutral loss scan (MDF/artificial NLS) as a qualitative non-target screening method and (2) Entire Domain Combined Spectra Extraction and Integration Program (ComSpec) and two-dimensional peak sentinel (T-SEN) as a semi-quantitative target screening method. MDF/artificial NLS as a non-target screening approach revealed that PCBs, followed by octachlorodibenzo dioxin (OCDD), were the main chlorinated compounds present in all sediment layers.

Rapid automatic identification and quantification of compounds in complex matrices using comprehensive two-dimensional gas chromatography coupled to high resolution time-of-flight mass spectrometry with a peak sentinel tool.

Comprehensive two-dimensional gas chromatography coupled to mass spectrometry (GC×GC-MS) is a powerful tool for comprehensive analysis of organic pollutants. In this study, we developed a powerful analytical method using GC×GC for rapid and accurate identification and quantification of compounds in environmental samples with complex matrices. Specifically, we have developed an automatic peak sentinel tool, T-SEN, with free programming software, R.

Selective extraction of halogenated compounds from data measured by comprehensive multidimensional gas chromatography/high resolution time-of-flight mass spectrometry for non-target analysis of environmental and biological samples.

We developed a method that selectively extracts a subset from comprehensive 2D gas chromatography (GC×GC) and high-resolution time-of-flight mass spectrometry (HRTOFMS) data to detect and identify trace levels of organohalogens. The data were obtained by measuring several environmental and biological samples, namely fly ash, soil, sediment, the atmosphere, and human urine. For global analysis, some samples were measured without purification.

Seasonal differences of the atmospheric particle size distribution in a metropolitan area in Japan.

We compared the effect of ambient temperature observed in two different seasons on the size distribution and particle number concentration (PNC) as a function of distance (up to ~250 m) from a major traffic road (25% of the vehicles are heavy-duty diesel vehicles). The modal particle diameter was found between 10 and 30 nm at the roadside in the winter. However, there was no peak for this size range in the summer, even at the roadside.

Thermal desorption - comprehensive two-dimensional gas chromatography coupled with tandem mass spectrometry for determination of trace polycyclic aromatic hydrocarbons and their derivatives.

We developed a highly sensitive method for determination of polycyclic aromatic hydrocarbons (PAHs) and their derivatives (oxygenated, nitrated, and methylated PAHs) in trace particulate samples by using thermal desorption followed by comprehensive two-dimensional gas chromatography coupled with tandem mass spectrometry (TD-GC×GC-MS/MS) with a selected reaction monitoring mode. The sensitivity of TD-GC×GC-MS/MS was greater than that of TD-GC-HRMS and TD-GC×GC-QMS by one or two orders of magnitude. The instrumental detection limits were 0.

Stir bar sorptive extraction and comprehensive two-dimensional gas chromatography coupled to high-resolution time-of-flight mass spectrometry for ultra-trace analysis of organochlorine pesticides in river water.

A method for the determination of ultra-trace amounts of organochlorine pesticides (OCPs) in river water was developed by using stir bar sorptive extraction (SBSE) followed by thermal desorption and comprehensive two-dimensional gas chromatography coupled to high-resolution time-of-flight mass spectrometry (SBSE-TD-GC×GC-HRTOF-MS). SBSE conditions such as extraction time profiles, phase ratio (β: sample volume/polydimethylsiloxane (PDMS) volume), and modifier addition, were examined. Fifty milli-liter sample including 10% acetone was extracted for 3 h using stir bars with a length of 20 mm and coated with a 0.

Radiocarbon (14C) diurnal variations in fine particles at sites downwind from Tokyo, Japan in summer.

The radiocarbon ((14)C) of total carbon (TC) in atmospheric fine particles was measured at 6 h or 12 h intervals at two sites, 50 and 100 km downwind from Tokyo, Japan (Kisai and Maebashi) in summer 2007. The percent modern carbon (pMC) showed clear diurnal variations with minimums in the daytime. The mean pMC values at Maebashi were 28 ± 7 in the daytime and 45 ± 16 at night (37 ± 15 for the overall period).

Global and selective detection of organohalogens in environmental samples by comprehensive two-dimensional gas chromatography-tandem mass spectrometry and high-resolution time-of-flight mass spectrometry.

We successfully detected halogenated compounds from several kinds of environmental samples by using a comprehensive two-dimensional gas chromatograph coupled with a tandem mass spectrometer (GC×GC-MS/MS). For the global detection of organohalogens, fly ash sample extracts were directly measured without any cleanup process. The global and selective detection of halogenated compounds was achieved by neutral loss scans of chlorine, bromine and/or fluorine using an MS/MS.

An association between long-term exposure to ambient air pollution and mortality from lung cancer and respiratory diseases in Japan.

Background: Evidence for a link between long-term exposure to air pollution and lung cancer is limited to Western populations. In this prospective cohort study, we examined this association in a Japanese population.

Methods: The study comprised 63 520 participants living in 6 areas in 3 Japanese prefectures who were enrolled between 1983 and 1985.

Contrasting diurnal variations in fossil and nonfossil secondary organic aerosol in urban outflow, Japan.

Diurnal variations of fossil secondary organic carbon (SOC) and nonfossil SOC were determined for the first time using a combination of several carbonaceous aerosol measurement techniques, including radiocarbon (¹⁴C) determinations by accelerator mass spectrometry, and a receptor model (chemical mass balance, CMB) at a site downwind of Tokyo during the summer of 2007. Fossil SOC showed distinct diurnal variation with a maximum during daytime, whereas diurnal variation of nonfossil SOC was relatively small. This behavior was reproduced by a chemical transport model (CTM).

Characterization of dilution conditions for diesel nanoparticle inhalation studies.

Diesel exhaust nanoparticles easily coagulate during transportation from the engine to the inhalation chamber, depending on concentrations and residence times. Although dilution is effective in suppressing coagulation growth of nanoparticles, volatile organic carbon (OC) evaporates as a result of dilution. Thus, the design of an inhalation facility to investigate the health effects of nanoparticle-rich exhaust is important.

Quantification of polychlorinated dibenzo-p-dioxins and dibenzofurans by direct injection of sample extract into the comprehensive multidimensional gas chromatograph/high-resolution time-of-flight mass spectrometer.

Polychlorinated dibenzo-p-dioxins and dibenzofurans in crude extracts of fly ash and flue gas from municipal waste incinerators were quantified using a comprehensive multidimensional gas chromatograph (GC x GC) coupled to a high-resolution time-of-flight mass spectrometer (HR-TOFMS). For identification and quantification, we developed our own program to prepare 3D chromatograms of selected mass numbers from the data of the GC x GC/HR-TOFMS. Isolation of all congeners with a TCDD toxic equivalency factor from the other isomers by only one injection was confirmed.

Comparison of carbonaceous aerosols in Tokyo before and after implementation of diesel exhaust restrictions.

We compared the status of carbonaceous aerosols in Tokyo before and after the implementation of a diesel vehicle regulation intended to reduce the quantity of particulate carbon from diesel engines in one of the largest scale ever attempts at vehicle exhaust control. Radiocarbon (14C) in elemental carbon (EC) and total carbon (TC) were analyzed to identify fossil fuel carbonaceous particles emitted from diesel-powered vehicles. One-sided paired-month t-tests showed no distinct difference in the absolute concentrations of particles in terms of total mass (19.

Investigation of characterization method for nanoparticles in roadside atmosphere by thermal desorption-gas chromatography/mass spectrometry using a pyrolyzer.

Atmospheric nanoparticles (<0.050 microm) have caused great concern recently due to their potential to affect human health. However, little is known about the chemical composition, sources, and atmospheric behavior of atmospheric nanoparticles.

Comprehensive two-dimensional gas chromatography coupled to high-resolution time-of-flight mass spectrometry and simultaneous nitrogen phosphorous and mass spectrometric detection for characterization of nanoparticles in roadside atmosphere.

A method is described for characterization of size-resolved particles including the nanoparticles fraction with a diameter of 29-58 nm in roadside atmosphere. The method is based on thermal desorption (TD) of a sample followed by comprehensive two-dimensional gas chromatography (GC x GC) with novel detection capabilities, including high resolution time-of-flight mass spectrometry (HRTOF-MS) and simultaneous detection with a nitrogen phosphorous detector (NPD) and a quadrupole mass spectrometer (qMS). Increased selectivity with the GC x GC-HRTOF-MS allows a group type separation of a selected chemical class, e.

Nonsteroidal progesterone receptor ligands (I): synthesis and SAR of new tetrahydronaphthofuranone derivatives.

We have synthesized a series of nonsteroidal progesterone receptor (PR) ligands, tetrahydronaphthofuranones, structurally based on the fungal metabolite PF1092C. Structure-activity relationship studies revealed that substituents at the 6- and 7-positions were critical for PR binding affinity and for agonist or antagonist activity. Compounds in this series, exemplified by 19i, exhibited high affinity and high specificity for PR over other steroid hormone receptors and acted as selective PR antagonists.

Nonsteroidal progesterone receptor ligands (II); synthesis and SAR of new tetrahydrobenzindolone derivatives.

The human progesterone receptor (PR) binding affinity and the PR agonistic or antagonistic potency of tetrahydronaphthofuranone derivatives were shown previously to be markedly influenced by substituents at the 6- and 7-positions. Here, we synthesized tetrahydrobenzindolones possessing a lactam ring, which enabled us to modify the 6- and 7-positions more freely, since tetrahydrobenzindolones are chemically more stable than tetrahydronaphthofuranones. The tetrahydrobenzindolone derivatives generally showed higher PR binding affinity than the corresponding tetrahydronaphthofuranones.