Evaluation of Oxidative Potential of Pyrenequinone Isomers by the Dithiothreitol (DTT) Assay

Atmospheric quinoid polycyclic aromatic hydrocarbons (PAHQs) have adverse health effects as redox-active species in particulate matter (PM). Several PAHQs are known to be very reactive in the dithiothreitol (DTT) assay; however, it is unclear if pyrenequinones, their parent pyrene is one of the most abundant polycyclic aromatic hydrocarbons (PAHs) in the atmosphere, contribute to the loss of DTT in PM extracts. Herein, by employing the DTT assay, we evaluated oxidative potentials of three pyrenequinone isomers (4, 5-pyrenequinone [4, 5-PyQ] and a mixture of 1, 6-/1, 8-pyrenequinones [1, 6-/1, 8-PyQ]), along with 9, 10-phenanthrenequinone (PQN), 1, 2-naphthoquinone (1, 2-NQ), and 1, 4-naphthoquinone (1, 4-NQ), of which DTT loss rates were examined previously. Our results demonstrate that the DTT consumption by ortho-type PAHQs is fast, particularly by 4, 5-PyQ. The order of DTT loss rate by the PAHQs tested in this study was as follows: 4, 5-PyQ ∼ PQN > 1, 2-NQ > 1, 4-NQ ∼ 1, 6-/1, 8-PyQ. 4, 5-PyQ was confirmed to be active in the DTT assay for the first time in this study. The DTT consumption rate by 4, 5-PyQ is 14.6 ± 0.8 mol/min/PAHQ-mol, which is comparable to that of PQN (14.4 ± 0.1 mol/min/PAHQ-mol) known as the most active PAHQs by the DTT assay so far

Comparison of PM10 Pattern and PM2.5 Carbonaceous Fraction from Episodic and Non Episodic Period of Peat Land Wildfire

The peatland wildfire in Indonesia was periodically occurs even in nun ENSO period thus may pose health risk do the inhabitants each year. During non episodic peatland wildfire, we measured PM2.5 using 2 sets of PM2.5 samplers combined with secondary data from fixed monitoring station for ambient PM10. We compare the data with previous Study on episodic wildfire in this peatland area. EC and OC concentrations in PM2.5 were determined using a thermal/optical carbon analyzer with IMPROVE-A protocol. The pattern of PM10 during episodic peatland wildfire can reach more Ethan ten times of PM10 standard (24 h). This is may pose health risk since this high concentration may persist during one month or more. While during non episodic wildfire the ambient PM10 showed moderate fluctuation. During episodic burning period, the ambient atmosphere are enriched by OC1 and OC2 fraction, while in non episodic burning, fraction of OC2, OC3 as well as OC4 shows higher level than OC1. Based on EC ratio analysis the char-EC in biomass burning shows higher than soot-EC leading to dominant fraction of low temperatur elemental carbon originated from biomass burnin

Chemical speciation of water-soluble ionic components in PM2.5 derived from peatland fires in Sumatra Island

We conducted a field study to characterize water-soluble ionic species in PM2.5 from peatland fires using ground-based samplings at fire sources and receptor sites in the Riau Province, Sumatra, Indonesia. We determined the concentrations of PM2.5 mass, water-soluble ions, and some chemical elements. Through PM2.5 field samplings at three peatland fire sources, we have shown that the mass fractions of typical peatland fire water-soluble ionic components tend to differ between peatland fire sources. Thus, our results indicate that PM2.5 source profiles of water-soluble ionic components for peatland fire must be selected with extreme caution if applied to a receptor model. From the viewpoint of ionic composition of each peatland fire sample, Cl− and NH4+ were consistently dominant anions and cations, respectively, for all peatland fire samples, i.e., NH4Cl was a consistently dominant component. Through field samplings of the ambient PM2.5 in Pekanbaru during peatland fire-induced haze and non-haze periods, we found differences in PM2.5 mass and total water-soluble ionic component concentrations between haze and non-haze samples. Four components, C2O42−, NO3−, SO42−, and NH4+, showed highly elevated levels during haze periods. Since these four ions are recognized as the major secondarily formed aerosol components, the increased total concentrations of water-soluble ionic components during haze periods can mainly be derived from the gas-to-aerosol conversion process. The ionic compositions of haze samples at receptor sites are obviously different from those at peatland fire source samples. In particular, NH4Cl, which is characteristic of peatland fire PM2.5 sources, is low at sites during haze periods

Chemical speciation of water-soluble ionic components in PM2.5 derived from peatland fires in Sumatra Island

We conducted a field study to characterize water-soluble ionic species in PM2.5 from peatland fires using groundbased samplings at fire sources and receptor sites in the Riau Province, Sumatra, Indonesia. We determined the concentrations of PM2.5 mass, water-soluble ions, and some chemical elements. Through PM2.5 field samplings at three peatland fire sources, we have shown that the mass fractions of typical peatland fire water-soluble ionic components tend to differ between peatland fire sources. Thus, our results indicate that PM2.5 source profiles of water-soluble ionic components for peatland fire must be selected with extreme caution if applied to a receptor model. From the viewpoint of ionic composition of each peatland fire sample, Cl− and NH4+ were consistently dominant anions and cations, respectively, for all peatland fire samples, i.e., NH4Cl was a consistently dominant component. Through field samplings of the ambient PM2.5 in Pekanbaru during peatland fire-induced haze and non-haze periods, we found differences in PM2.5 mass and total water-soluble ionic component concentrations between haze and non-haze samples. Four components, C2O42−, NO3−, SO42−, and NH4+, showed highly elevated levels during haze periods. Since these four ions are recognized as the major secondarily formed aerosol components, the increased total concentrations of water-soluble ionic components during haze periods can mainly be derived from the gas-to-aerosol conversion process. The ionic compositions of haze samples at receptor sites are obviously different from those at peatland fire source samples. In particular, NH4Cl, which is characteristic of peatland fire PM2.5 sources, is low at sites during haze period

Indoor particle counts during Asian dust events under everyday conditions at an apartment in Japan.

[Objective]Asian dust storms originating from arid regions of Mongolia and China are a well-known springtime phenomenon throughout East Asia. Evidence is increasing for the adverse health effects caused by airborne desert dust inhalation. Given that people spend approximately 90 % of their time indoors, indoor air quality is a significant concern. The present study aimed to examine the influence of outdoor particulate matter (PM) levels on indoor PM levels during Asian dust events under everyday conditions. [Methods]We simultaneously monitored counts of particles larger than 0.3, 0.5, 1, 2, and 5 μm using two direct-reading instruments (KC-01D1 airborne particle counter; Rion), one placed in an apartment room and another on the veranda, under everyday conditions before and during an Asian dust event. We also examined how indoor particle counts were affected by opening a window, crawling, and air purifier use. [Results]An Asian dust event on 24 April 2012 caused 50- and 20-fold increases in PM counts in outdoor and indoor air, respectively. A window open for 10 min resulted in a rapid increase of indoor PM counts up to 70 % of outside levels that did not return to baseline levels after 3 h. An air purifier rapidly reduced PM counts for all particle sizes measured. [Conclusions]It is important to account for occupant behavior, such as window-opening and air purifier use, when estimating residential exposure to particulate matter

Consumption in the G20 nations causes particulate air pollution resulting in two million premature deaths annually

G20の消費がPM2.5の排出を通じて年200万人の早期死亡者を生むことを推計. 京都大学プレスリリース. 2021-11-05.Worldwide exposure to ambient PM₂.₅ causes over 4 million premature deaths annually. As most of these deaths are in developing countries, without internationally coordinated efforts this polarized situation will continue. As yet, however, no studies have quantified nation-to-nation consumer responsibility for global mortality due to both primary and secondary PM2.5 particles. Here we quantify the global footprint of PM₂.₅-driven premature deaths for the 19 G20 nations in a position to lead such efforts. G20 consumption in 2010 was responsible for 1.983 [95% Confidence Interval: 1.685–2.285] million premature deaths, at an average age of 67, including 78.6 [71.5–84.8] thousand infant deaths, implying that the G20 lifetime consumption of about 28 [24–33] people claims one life. Our results indicate that G20 nations should take responsibility for their footprint rather than focusing solely on transboundary air pollution, as this would expand opportunities for reducing PM2.5-driven premature mortality. Given the infant mortality footprint identified, it would moreover contribute to ensuring infant lives are not unfairly left behind in countries like South Africa, which have a weak relationship with G20 nations

Synthesis and characterization of TiO2 powders by the double-nozzle electrospray pyrolysis method. Part 2. Material evaluation

Here we report the synthesis and characterization of anatase TiO2 powders by the double-nozzle electrospray pyrolysis method. Titanium(IV) bis(ammonium lactato) dihydroxide (TALH) aqueous solution (2.0 wt%) and pure H2O were separately injected into capillaries by using two syringe pumps, and were electrosprayed by using positive (+4 kV) and negative (−4 kV) DC voltage, respectively. Under a stream of dry clean air, the droplets were carried to the stainless steel tube heated with a tubular furnace at 350–450 °C. Thanks to the neutralization of droplets by the double-nozzle electrospray, the final TiO2 powder yield after pyrolysis was much improved from 6% (by single nozzle) to 55.4% (in this study), although the particle size distribution became wider due to the electrical neutralization and coalescence of the droplets. Photocatalytic activity for H2 evolution was studied

Characteristics of Carbonaceous Aerosols Emitted from Peatland Fire in Riau, Sumatra, Indonesia

Biomass burning is a significant source of fine particulate matter (PM 2.5). Forest, bush, and peat fires in Kalimantan and Sumatra, Indonesia are major sources of transboundary haze pollution in Southeast Asia. However, limited data exist regarding the chemical characteristics of aerosols at sources. We conducted intensive field studies in Riau Province, Sumatra, Indonesia, during the peatland fire and non-burning seasons Ni 2012. We characterized PM carbonaceous aerosols emitted from peatland fire based on ground-based source-dominated sampling. PM 2.5 aerosols were collected with two mini-volume samplers using Teflon and quartz fiber filters. Background aerosols were also sampled during the transition period between the non-burning and fire seasons. We analyzed the carbonaceous content (organis carbon (OC) and elemental carbon (EC)) by a thermal optical reflectance utilizing the IMPROVE_A protokol and the major organic components of the aerosols by a gas chromatography/mass spectrometry. PM 2.5 aerosols emitted from peatland fire were observed in high concentrations of 7120 _ 3620 mgm and were primarily composed of OC (71.0 _ 5.11% of PM mass). Levoglucosan exhibited the highest total ion current and was present at concentrations of 464 _ 183 µg m-3. The OC/EC ratios (36.4 _ 9.08), abundances of eight thermally-derived carbon fractions, OC/Levoglucosan ratios (10.6 _ 1.96), and Levoglucosan/Mannosan ratios (10.6 _ 2.03) represent a signature profile that is inherent in peatland fire. These data will be useful in identifying contributions from single bor multiple species in atmospheric aerosol samples collected from peatland fires

Ambient fine and coarse particles in Japan affect nasal and bronchial epithelial cells differently and elicit varying immune response

Ambient particulate matter (PM) epidemiologically exacerbates respiratory and immune health, including allergic rhinitis (AR) and bronchial asthma (BA). Although fine and coarse particles can affect respiratory tract, the differences in their effects on the upper and lower respiratory tract and immune system, their underlying mechanism, and the components responsible for the adverse health effects have not been yet completely elucidated. In this study, ambient fine and coarse particles were collected at three different locations in Japan by cyclone technique. Both particles collected at all locations decreased the viability of nasal epithelial cells and antigen presenting cells (APCs), increased the production of IL-6, IL-8, and IL-1β from bronchial epithelial cells and APCs, and induced expression of dendritic and epithelial cell (DEC) 205 on APCs. Differences in inflammatory responses, but not in cytotoxicity, were shown between both particles, and among three locations. Some components such as Ti, Co, Zn, Pb, As, OC (organic carbon) and EC (elemental carbon) showed significant correlations to inflammatory responses or cytotoxicity. These results suggest that ambient fine and coarse particles differently affect nasal and bronchial epithelial cells and immune response, which may depend on particles size diameter, chemical composition and source related particles types