Thermally derived carbon fractions including organic (OC) and elemental (EC) have been reported for the U.S. Interagency Monitoring of PROtected Visual Environments (IMPROVE) network since 1987 found useful in source apportionment studies to evaluate quartz-fiber filter adsorption vapors. The IMPROVE_A temperature protocol defines plateaus thermally 140 degrees C OC1, 280 OC2, 480 OC3, 580 OC4 a helium (He) carrier gas EC1, 740 EC2, 840 EC3 98% He/2% oxygen (O2) gas. These temperatures...

Charring of organic carbon (OC) during thermal/optical analysis is monitored by the change in a laser signal either reflected from or transmitted through filter punch. Elemental (EC) suspended particulate matter collected on quartz-fiber filters defined as that evolves after detected optical attains value it had prior to commencement heating, with rest classified (OC). Heretofore, operational definitions EC were believed be caused different temperature protocols rather than method monitoring...

Abstract. We report the direct observation of laboratory production spherical, carbonaceous particles – "tar balls" from smoldering combustion two commonly occurring dry mid-latitude fuels. Real-time measurements spectrally varying absorption Ångström coefficients (AAC) indicate that a class light absorbing organic carbon (OC) with wavelength dependent imaginary part its refractive index optically defined as "brown carbon" is an important component tar balls. The spectrum parts their complex...

Presents a model for genetic regulatory networks with time delays, which is described by functional differential equations or delay (DDE), provide necessary and sufficient conditions simplifying the network model, further analyze nonlinear properties of in terms local stability bifurcation. The proposed transforms original interacting into several simple transcendental at an equilibrium, thereby significantly reducing computational complexity making analysis bifurcation tractable even...

This paper aims to develop a load forecasting method for short-term forecasting, based on an adaptive two-stage hybrid network with self-organized map (SOM) and support vector machine (SVM). In the first stage, SOM is applied cluster input data set into several subsets in unsupervised manner. Then, groups of 24 SVMs next day's profile are used fit training each subset second stage supervised way. The proposed structure robust different types can deal well nonstationarity series. particular,...

Many different thermal, optical, and thermal/optical carbon analysis methods for organic (OC), elemental (EC) or black (BC) have been applied throughout the world to evaluate visibility Earth's radiation balance. Dozens of intermethod interlaboratory comparison studies conducted. Several these are catalogued summarized here. BC EC concentrations found differ by up a factor 7 among methods; 2 differences common. Differences between not consistent studies, with some showing higher one set...

Abstract Receptor models are used to identify and quantify source contributions particulate matter volatile organic compounds based on measurements of many chemical components at receptor sites. These selected their consistent appearance in some types absence others. UNMIX, positive matrix factorization (PMF), effective variance different solutions the mass balance (CMB) model equations implemented available software. In more general form, CMB allow spatial, temporal, transport, particle...

Combustion of wildland fuels represents a major source particulate matter (PM) and light-absorbing elemental carbon (EC) on national global scale, but the emission factors profiles have not been well characterized with respect to different combustion phases. These uncertainties limit accuracy current inventories, smoke forecasts, apportionments. This study investigates evolution gaseous efficiency by burning in laboratory facility. Emission for dioxide (CO2), monoxide (CO), total hydrocarbon...

The 14‐month‐long (December 1999 to February 2001) Central California Regional PM 10 /PM 2.5 Air Quality Study (CRPAQS) consisted of acquiring speciated measurements at 38 sites representing urban, rural, and boundary environments in the San Joaquin Valley air basin. study's goal was understand development widespread pollution episodes by examining spatial variability , ammonium nitrate (NH 4 NO 3 ), carbonaceous material on annual, seasonal, episodic timescales. It found that NH...

Abstract Bulk aerosol samples were collected from 16 July 2008 to 26 2009 at Lulang, a high‐altitude (>3300m above sea level) site on the southeast Tibetan Plateau (TP); objectives determine chemical characteristics of and identify its major sources. We report (total suspended particulate, TSP) mass levels concentrations selected elements, carbonaceous species, water‐soluble inorganic ions. Significant buildup species (organic carbon, element nitrate, sulfate) occurred during premonsoon,...

Abstract. Field blanks (bQF) and backup filters (quartz-fiber behind quartz-fiber filter; QBQ) have been adopted by US long-term air quality monitoring networks to estimate PM2.5 organic carbon (OC) sampling artifacts. This study documents bQF QBQ levels for the: 1) Interagency Monitoring of Protected Visual Environments (IMPROVE); 2) Speciation Trends Network (STN; part the Chemical [CSN]); 3) Southeastern Aerosol Research Characterization (SEARCH) examines similarities/differences...

Abstract. Carbon (C) and nitrogen (N) released from biomass burning have multiple effects on the Earth's biogeochemical cycle, climate change, ecosystem. These depend relative abundances of C N species emitted, which vary with fuel type combustion conditions. This study systematically investigates emission characteristics under different moisture contents, through controlled experiments soil samples collected a typical alpine forest in North America. Fuel general lowers efficiency, shortens...

Abstract. A thermal/optical carbon analyzer equipped with seven-wavelength light source/detector (405–980 nm) for monitoring spectral reflectance (R) and transmittance (T) of filter samples allowed "thermal analysis (TSA)" wavelength (λ)-dependent organic-carbon (OC)–elemental-carbon (EC) measurements. Optical sensing was calibrated transfer standards traceable to absolute R T measurements, adjusted loading effects report absorption (as optical depth (τa, λ)), verified using diesel exhaust...

Abstract. The surface air warming over the Arctic has been almost twice as much global average in recent decades. In this region, unprecedented amounts of smoldering peat fires have identified a major emission source climate-warming agents. While is known about greenhouse gas emissions from these fires, there knowledge gap on nature particulate and their potential role atmospheric warming. Here, we show that aerosols emitted burning Alaskan Siberian peatlands are predominantly brown carbon...

Abstract Volatile organic compounds (VOCs) and semi-volatile (SVOCs) adsorb to quartz fiber filters during fine coarse particulate matter (PM2.5 PM10, respectively) sampling for thermal/optical carbon analysis that measures (OC) elemental (EC). Particulate SVOCs can evaporate after collection, with a small portion adsorbed within the filter. Adsorbed gases are measured as OC, so passive field blanks, backup filters, prefilter denuders, regression methods have been applied compensate positive...

Organic and elemental carbon (OC EC) are operationally-defined by the measurement process, so long-term trends may be interrupted with instrumentation changes. A modification to U.S. IMPROVE analysis protocol hardware is examined that replaces 633 nm laser light used for OC charring adjustments seven wavelengths ranging from 405 980 nm, including one at 635 nm. Reflectance (R) Transmittance (T) values each wavelength made traceable primary standards through transfer consisting of a range...

Since the World Health Organization has declared current outbreak of novel coronavirus (COVID-19) a global pandemic, some have been anticipating that mitigation could happen in summer like seasonal influenza, while medical solutions are still slow progress. Experimental studies revealed few evidences decayed quickly under exposure heat and humidity. This study aims to carry out an epidemiological investigation establish association between meteorological factors COVID-19 high risk areas...