Showing papers in "Aerosol and Air Quality Research in 2015"

A Review: Microalgae and Their Applications in CO_2 Capture and Renewable Energy

Abstract: Fossil fuels, which are recognized as unsustainable sources of energy, are continuously consumed and decreased with increasing fuel demands. Microalgae have great potential as renewable fuel sources because they possess rapid growth rate and the ability to store high-quality lipids and carbohydrates inside their cells for biofuel production. Microalgae can be cultivated on opened or closed systems and require nutrients and CO_2 that may be supplied from wastewater and fossil fuel combustion. In addition, CO_2 capture via photosynthesis to directly fix carbon into microalgae has also attracted the attention of researchers. The conversion of CO_2 into chemical and fuel (energy) products without pollution via this approach is a promising way to not only reduce CO_2 emissions but also generate more economic value. The harvested microalgal biomass can be converted into biofuel products, such as biohydrogen, biodiesel, biomethanol, bioethanol, biobutanol and biohydrocarbons. Thus, microalgal cultivation can contribute to CO_2 fixation and can be a source of biofuels. This article reviews the literature on microalgae that were cultivated using captured CO_2, technologies related to the production of biofuels from microalgae and the possible commercialization of microalgae-based biofuels to demonstrate the potential of microalgae. In this respect, a number of relevant topics are addressed: the nature of microalgae (e.g., species and composition); CO_2 capture via microalgae; the techniques for microalgal cultivation, harvesting and pretreatment; and the techniques for lipid extraction and biofuel production. The strategies for biofuel commercialization are proposed as well.

An overview: Polycyclic aromatic hydrocarbon emissions from the stationary and mobile sources and in the ambient air

Abstract: Polycyclic aromatic hydrocarbons are a class of semi-volatile organic carbons that are emitted from both natural and anthropogenic sources therefore are ubiquitous in nature. Their main sources are both fossil and biomass fuels as well as other feedstocks used in chemical and combustion processes. Mostly the combustion processes are PAH depletion processes rather than PAH generating processes. PAHs are emitted from both stationary and mobile sources at varying levels depending on the operation conditions such as fuels, feedstock, and control devices in use as well as process parameters for example combustion temperatures. After emission from sources, the fates of PAHs in the atmosphere include partitioning between gas and particulate phases, particle size distribution, long range transport, dry and wet deposition on to water bodies, soil, vegetation and other receptor surfaces as well as resuspension from receptor surfaces back to the atmosphere. These processes are controlled by their physiochemical properties. Additionally, it is through these processes that human beings are exposed to PAHs via inhalation, ingestion and dermal contact. Dry deposition is the major process through which PAHs from the atmosphere are made available to receptor surfaces including the human respiratory system. From studies with cumulative fractions of dry deposition and size distribution for particulate PAHs, it is evident that the coarse particles are majorly responsible for the highest fraction of deposition fluxes. This is especially true for the high molecular weight PAHs, since the low molecular weight PAHs are majorly in the gas phase, which have lower dry deposition velocities. On the other hand, the highest risk for human being comes in the form of fine particles, whose mean aerodynamic diameter is below 2.5 µm. This is because the particle bound content results and particle size distributions of PAHs indicate that the fine particles have the most PAH content owing to their large surface areas and high organic carbon content. For the wet deposition of PAHs, more research is recommended for measurement of scavenging ratios of individual PAHs, since there is a scarcity of studies focusing on this issue. PAH mutagenic activity and exposure risk of humans can be estimated using the deposition rates, toxicity levels based on benzo(a)pyrene, or biomarkers such as urinary 1-hydroxypyrene. Other parameters that have been used to evaluate the risks of various exposure groups include inhalation exposure levels (IEL), incremental lifetime cancer risk (ILCR), and estimation of maximum consumption time (tmax). Highway toll workers, back carbon workers and food vendors in night markets are among susceptible groups identified using these biomarkers and exposure parameters. To reduce exposure to human beings, PAH emissions need to be controlled at the sources. Control and reduction of PAH emissions from various sources involves largely altering the fuel and feedstock characteristics, using air pollution control devices and/or adjusting the operating parameter’s such as temperatures and air-fuel ratios or turbulence in combustion processes. Unfortunately, albeit all the studies done on PAHs, they still remain a concern in our environment and more attention and research should be dedicated to this group of compounds.

Characterization and Source Identification of Heavy Metals in Ambient PM10 and PM2.5 in an Integrated Iron and Steel Industry Zone Compared with a Background Site

Abstract: The purpose of this study is to characterize heavy metals in ambient PM10 (particles with aerodynamic diameter below 10 µm) and PM2.5 (particles with aerodynamic diameter below 2.5 µm) particles in a typical integrated iron and steel industry zone (HG) and a background site (ZWY) during February 2011 to January 2012 in the Yangtze River Delta (YRD) region, China. Twelve elements were measured to study their levels, size distribution and sources. At the two sampling sites, Fe was found as the dominated metal in the total detected metals in both particle sizes, followed by Zn and Pb. They were regarded as the marker elements of iron and steel production emission along with Cr and Mn. The concentrations of all measured heavy metals in HG were 1–3.53 times higher than those measured in ZWY. When compared with previous studies, the concentrations of steel related elements (Fe, Zn, Mn) in this work were significantly high. The highest correlation coefficient was observed in HG for Fe and Zn. Additionally, Cd was found as the most enriched heavy metal by the enrichment factor analysis, followed by Zn, Pb, and Cu. The main sources contributing to heavy metals at HG site were identified by principle component analysis: steel dust (including coal combustion of coal-fired power plant, coke making and steel making emission), vehicle emission and road re-suspension dust and soil dust. Besides, steel dust was also found as the possible source of heavy metals at ZWY site. The result suggested the steel dust has influence on the whole study area.

Particulate Matter Distributions in China during a Winter Period with Frequent Pollution Episodes (January 2013)

Abstract: Particulate matter distributions in China during January 2013 were analyzed using hourly PM2.5 and PM10 concentrations from 74 cities. Five haze episodes occurred in this month. Both PM2.5 and PM10 concentrations increased rapidly at the beginning of January 2013 and remained at high levels throughout the month with monthly average values of 128.7 and 184.4 µg/m 3 , respectively. On January 12 th , the most polluted day in this month, 13 cites were severely polluted with daily average PM2.5 concentrations greater than 300 µg/m 3 , and 18 cities were heavily polluted with daily average PM2.5 concentrations between 200 and 300 µg/m 3 . These episodes often occurred in a large spatial domain with the North China Plain as the most polluted area, including Jing-Jin-Ji area (Beijing, Tianjin, and Heibei provinces). Both PM2.5 and PM10 had good correlations with ambient CO, NO2, and SO2 concentrations. High PM concentrations often occurred at low wind speeds and high relative humidity. In addition, PM levels in January 2013 were compared with those from other international cities.

An Innovative Approach to Integrated Carbon Mineralization and Waste Utilization: A Review

Abstract: Carbon dioxide (CO2) emission reduction in industry should be a portfolio option; for example, the carbon capture and utilization by mineralization (CCUM) process is a feasible and proven technology where both CO2 capture and alkaline waste treatment occur simultaneously through an integrated approach. In this study, the challengeable barriers and significant breakthroughs of CCUM via ex-situ carbonation were reviewed from both theoretical and practical perspectives. Recent progress on the performance of various carbonation processes for different types of alkaline solid wastes was also evaluated based on CO2 capture capacity and carbonation efficiency. Moreover, several process intensification concepts such as reactor integration and co-utilization with wastewater or brine solution were reviewed and summarized. In addition, the utilization of carbonated products from CCUM as green materials including cement, aggregate and precipitate calcium carbonate were investigated. Furthermore, the current status of worldwide CCUM demonstration projects within the iron- and steelmaking industries was illustrated. The energy consumption and cost analyses of CCUM were also evaluated.

Characterization of Black Carbon Aerosols over Darjeeling - A High Altitude Himalayan Station in Eastern India

Abstract: A continuous monitoring of black carbon (BC) aerosols was carried over a high altitude station Darjeeling (27°01'N, 88°15'E; 2200 m a.s.l.) at eastern part of Himalaya in India during January 2010-December 2011. In this article, we have presented the results of our analysis of the data collected during this interval. This study is focused on the investigation of the temporal variations, potential sources, long-range transport of BC aerosols along with the meteorological impact on these aerosols. BC is found to exhibit strong seasonal variation with the maximum concentration during premonsoon (5.0 ± 1.1 μg/m^3) followed by winter (3.9 ± 2.2 μg/m^3), postmonsoon (2.9 ± 1.0 μg/m^3) and minimum during monsoon (1.7 ± 0.7 μg/m^3). BC concentration varied between 0.2-12.8 μg/m^3 with an average of 3.4 ± 1.9 μg/m^3 over the entire period of study. The diurnal variation of BC aerosol shows sharp morning and evening peaks associated to the local anthropogenic activities as well as the impact of up-slope mountain wind. Amongst the long distant sources, BC concentration associated with the transport from Middle East countries and passing over South West countries like Pakistan, Afghanistan and Indo- Gangetic Plain is found to be comparatively higher. It is observed that the contributions of local emissions, long-range transport and mountain wind transport are approximately 56%, 27% and 17%, respectively, towards the total BC loading over Darjeeling during premonsoon. Fossil fuel emissions during premonsoon and biomass burning during winter are the major sources of BC with the overall dominance of fossil fuel burning throughout the entire study period. The BC concentration over Darjeeling is found to be much higher than any other high altitude stations in India and Nepal and even higher and comparable with some of the metro-cities in India.

Secondary Formation of Sulfate and Nitrate during a Haze Episode in Megacity Beijing, China

Abstract: A heavy haze episode that occurred in Beijing from 20 September to 27 September, 2011 was observed to explore the secondary processes of the haze episode. During the haze episode, the relatively stable synoptic conditions and regional transport from polluted areas in the south and southwest of Beijing favored the formation of haze. Significant increases of PM2.5/PM10 ratio was observed during haze period, which implied that the haze was caused by fine particles. Additionally, the presence of secondary inorganic pollutants (SO42–, NO3– and NH4+) sharply increased during the haze episode, which indicated that secondary processes significantly strengthened the haze episode. The sulfur oxidation ratio (SOR) sharply increased from a non-haze episode with a highest value of 0.11 to a haze episode with a highest value of 0.62. Low correlations between SOR and O3 and the temperature were found, whereas a high correlation between SOR and RH was found during the haze episode, which implied that sulfate was mainly produced by the aqueous-phase oxidation of SO2 rather than the gas-phase conversion of SO2 to sulfate in haze episode in Beijing. Furthermore, a fine linear relationship between SOR and the surface area (dS) of particles smaller than 1 µm confirmed the heterogeneous processes of sulfate formation in haze episode. The nitrogen oxidation ratio (NOR) also sharply increased from a non-haze episode with a highest value of 0.03 to a haze episode with a highest value of 0.26, which indicated more intense secondary formation of nitrate in haze episode. Nitrate was found to be mainly produced by a homogenous reaction under ammonium-rich conditions. Higher RH in haze episode reduced the thermodynamic equilibrium constant Ke’, and favored the thermodynamic equilibrium reaction of HNO3(g) + NH3(g) ↔ NH4NO3(s, aq) to formed nitrate, which might help explain the enhanced homogenous production of nitrate in haze episode. In addition, a good empirical fit (R2 = 0.70) between NOR and dS was found, which indicated that the particle surface area significantly contributed to the intense homogeneous production of nitrate in haze episode.

A Biomass Combustion Chamber: Design, Evaluation, and a Case Study of Wheat Straw Combustion Emission Tests

Abstract: Open biomass burning is a significant source of trace gases and particulate pollutants on a global scale and plays an important role in both atmospheric chemistry and climate change To study the emission characteristics of biomass burning, with a focus on crop residue combustion in Northwest China, a combustion chamber was established This paper describes the design, structure, and operating principles of the chamber A series of evaluation tests were conducted, demonstrating its applicability in emission studies The combustion chamber was equipped with a thermoanemometer and a dilution sampler as well as multiple sampling ports for interfacing with different monitors A case study of wheat straw combustion was performed to demonstrate reproducibility and comparability of the derived emission factors with prior studies The combustion chamber may be applied to develop emission factors to update emission inventories and source profiles for improving source apportionment

Emissions from Light-Duty Diesel and Gasoline in-use Vehicles Measured on Chassis Dynamometer Test Cycles

Abstract: The reduction in vehicle exhaust emissions achieved in the last two decades is offset by the growth in traffic, as well as by changes in the composition of emitted pollutants. The present investigation illustrates the emissions of eight in-use gasoline and diesel passenger cars using the official European driving cycle and the ARTEMIS real-world driving cycles. Measurements comprised gaseous regulated pollutants (CO, CO_2, NO_x and hydrocarbons), particulate matter and its carbonaceous content (organic and elemental carbon, OC and EC), as well as about 20 different volatile organic compounds (VOCs) in the C_6-C_11 range. It was observed that some of the vehicles do not comply with the corresponding regulations. Significant differences in emissions were registered between driving cycles. Not all regulated pollutants showed a tendency to decrease from Euro 3 to Euro 5. The particulate carbon emission factors were significantly lower under the ARTEMIS Road compared with the ARTEMIS Urban driving cycle with cold start. In general, cold start-up driving conditions produced the highest emission factors. A tendency to the decline of carbonaceous emissions from Euro 3 to Euro 5 diesel vehicles was observed, whilst this trend was not registered for petrol-powered cars. The fraction of total carbon composed of EC was much lower in particles emitted by petrol vehicles (＜ 10%) than by diesel engines (50-95%). However, the EC content in emissions from more modern vehicles equipped with diesel particulate filter (DPF) is almost negligible. Among VOCs, benzene, toluene and xylenes were generally the dominant species. A significant decrease in emissions from Euro 4 to Euro 5 petrol-powered vehicles was observed. The trend in VOC emissions is unclear when diesel engines are considered. During DPF regeneration cycles, pollutant emissions are several times larger than those during normal engine operation.

Characterization and Elemental Composition of Atmospheric Aerosol Loads during Springtime Dust Storm in Western Saudi Arabia

Abstract: Dust storm is a common phenomenonand, a severe environmental hazard in western Saudi Arabia. In this study, simultaneous measurement of PM_(10), PM_(2.5) and PM_(1.0) and elemental compositions analysis of PM_(2.5) in Jeddah city during springtime (March 2012) dust storm (DS) and non-dust storm (non-DS) periods were carried out to investigate the impact of DS on the levels, characterization and elemental compositions of atmospheric particles. Results indicate that PM fractions concentrations were higher in DS environment compared to non-DS. The diurnal variation of PM fractions concentrations was uni-modal in non-DS environment and bimodal in DS. PM_(1.0)/PM_(10), PM_(2.5)/PM_(10) and PM_(2.5)/PM_(2.5-10) ratios were relatively lower in DS, indicating that sand-dust events in spring carry much more coarse than fine particles to Jeddah. PM_(10), PM_(2.5) and PM_(1.0) in DS and PM_(10) and PM_(2.5) in non-DS might originate from similar sources. PM_(10), PM_(2.5), PM_(1.0) in DS and PM_(10) in non-DS were correlated negatively with relative humidity and positively with wind speed. PM_(2.5) and PM_(1.0) in non-DS were correlated positively with relative humidity and negatively with wind speed. The crustal elements accounted for 44.62 and 67.53% of the total concentrations of elements in non-DS and DS, respectively. The elements concentrations increased in DS, with highest DS/non-DS ratios for Ca, Si, Al and Fe. This indicates that the soil originating species contributed mainly in DS particles. The enrichment factors values and non-crustal fractions in both non-DS and DS indicate that the main sources of Na, Mg, Si, K, Ca, Ti, Cr, Mn, Fe, Rb and Sr are of a crustal type, whereas S, Cl, Co, Cu, Zn, Ga, As, Pb and Cd are anthropogenic. V and Ni in DS only are emitted from anthropogenic sources. The enrichment factors of these anthropogenic elements were lower in DS. They might originate mainly from local sources in Jeddah.

Emission Characteristics and Chemical Compositions of both Filterable and Condensable Fine Particulate from Steel Plants

Abstract: Steel production is an important source of particulate matter emission. In this study, both filterable and condensable fine particulate (PM2.5) emissions from an electric arc furnace (EAF) and four integrated iron and steel plants were measured. Chemical compositions including water soluble ions and metal elements of these two types of PM2.5 were analyzed. The results show that filterable PM2.5 concentrations emitted from sintering, coke making, blast furnace, basic oxygen furnace (BOF) and EAF are 1.01, 0.37, 0.16, 0.15 and 0.28 mg/Nm3, respectively. Sintering has the highest filterable PM2.5 emission concentrations. Condensable PM2.5 concentrations emitted from the above processes are 65.3, 89.7, 3.84, 1.32 and 2.02 mg/Nm3, respectively, which are much higher than filterable PM2.5. K, Fe, Pb and Zn concentrations are high in filterable PM2.5 for sintering process, which is attributed to the feedstocks of recycled materials. High sulfur content of the feedstocks results in high concentrations of SO42– for all the test plants. In addition to Fe, the emissions of Pb, Zn and Sn are high for EAF, which is due to the complexity of the recycled steel feedstock for EAF. SO42– is the highest emission ion for sinter process and coke making. For blast furnace, BOF and EAF, however, Na+, K+ and Cl– are the predominated ions. For metal elements, concentrations of Na and K are highest for all the plants, which might be caused by their high potential of vaporization.

Chemical Composition and Light Extinction Contribution of PM_(2.5) in Urban Beijing for a 1-Year Period

Abstract: Daily PM_(2.5) samples were collected in Beijing across four consecutive seasons from June 2012 to April 2013. Major water-soluble inorganic ions, carbonaceous species and elements were analyzed to investigate their temporal variations and evaluate their contributions to visibility impairment over different seasons and under different pollution levels. The mass concentrations of PM_(2.5) ranged from 4.3 to 592.4 μg m-3, with an annual average of 112.4±94.4 μg m^(-3). The predominant components of PM_(2.5) were secondary inorganic ions (NH_4^+, NO_3^- and SO_4^(2-)) and carbonaceous compounds, which accounted for 45.9% and 24.1% of the total PM_(2.5) mass, respectively. Distinct seasonal variation was observed in the mass concentrations and chemical components of PM_(2.5). The average mass concentrations of PM_(2.5) were the highest in winter, followed by spring, and lowest in autumn. Light extinction coefficients (b_(ext)) were discussed over four seasons. (NH_4)_2SO_4 was the largest contributor (28.8%) to b_(ext), followed by NH_4NO_3 (24.4%), organic matter (19.5%), elemental carbon (7.4%), and coarse mass (7.2%), while fine soil, sea salt, NO_2 and Rayleigh made minor contributions, together accounting for 12.7% of b_(ext). During the polluted periods, the contributions of (NH_4)_2SO_4 and NH_4NO_3 to b_(ext) increased dramatically. Therefore, in addition to control primary particulate emissions, the reduction of their precursors like SO_2, NO_x and NH_3 could effectively improve air quality and visibility in Beijing.

Measurement and Analysis of Fine Particulate Matter (PM_(2.5)) in Urban Areas of Pakistan

Abstract: In order to assess the extent of air quality within the major urban environments in Pakistan, PM_(2.5) pollutant has been analyzed during the period 2007-2011 in Islamabad; and 2007 to 2008 in Lahore, Peshawar and Quetta (high elevation, 1680 m MSL). Seasonal and diurnal variations of PM_(2.5) mass concentration formation and accumulation within these areas have been analyzed. Air quality monitoring data and meteorological data (both QA/QCed) were obtained from Federal and Provincial Pakistan Environmental Protection Agencies. In Islamabad, the annual average PM_(2.5) mass concentrations were 81.1 ± 48.4 μg/m^3, 93.0 ± 49.9 μg/m^3, 47.8 ± 33.2 μg/m^3, 79.0 ± 49.2 μg/m^3, and 66.1 ± 52.1 μg/m^3 during 2007 to 2011 respectively. Comparison of the four cities during summer 2007 to spring 2008 shows that all the four cities had PM_(2.5) concentration exceeding the Pakistan National Environmental Quality Standards (annual average concentration of 25 μg/m^3; and 24 hourly average concentration of 40 μg/m^3) for ambient air. During the same time period, the highest seasonal PM_(2.5) mass concentrations for Islamabad were observed as 98.5 μg/m^3 during spring 2008; 150.4 ± 87.9 μg/m^3; 104.1 ± 51.1 μg/m^3 and 72.7 ± 55.2 μg/m^3 for Lahore, Peshawar, and Quetta during fall 2007, respectively. Wind speed and temperature have a negative correlation with the mass concentration of PM_(2.5). Diurnal profile for all the cities suggests an association of PM_(2.5) with vehicular traffic. Back trajectory analysis conducted using the NOAA HYSPLIT model indicates that air trajectories, during high pollution episodes, influencing the urban regions commonly originate from either western India, especially in summer as part of the prevailing monsoon circulation; or are located in eastern Afghanistan. The source areas in Western India i.e., states of Gujarat, Rajasthan and Punjab have high concentration of industrial activities and crop residue burning, and are likely sources of enhanced PM_(2.5) concentrations, in addition to the local sources.

Chemical Characteristics of Fine Particles Emitted from Different Chinese Cooking Styles

Abstract: Cooking process was regarded as one of the most significant contributor to fine particles (PM_(2.5)) in ambient atmosphere and its chemical characteristics would be great different among various cooking styles. In this study, PM_(2.5) emitted from four different Chinese cooking styles, including Home cooking, Shandong cuisine, Hunan cuisine, and Barbecue, were collected using a dilution sampling system. Then, PM_(2.5) mass concentrations were weighted, and its chemical composition were analyzed. It was found that Barbecue emitted PM_(2.5) concentrations with the highest level, followed by Home cooking, Shandong cuisine and Hunan cuisine. PM_(2.5) emission amounts and emission factors were also estimated according to the measured data. Home cooking notably had the highest levels. The difference between Barbecue and other cuisines of PM_(2.5) chemical profiles were the largest by using the coefficient of divergence (CD) method. The predominant chemical composition was organic carbon (OC) in PM_(2.5). The main water-soluble ions were Na^+, SO_4^(2-), NO_3^-, Cl^-, and Ca^(2+), and Fe, S, and Ca had made up a big proportion of element. Little difference had been found between the mass fractions of n-alkanes and polycyclic aromatic hydrocarbons (PAHs) from different cooking cuisines. However, Barbecue displayed the highest mass fractions of organic acids in cooking fume.

Microalgae Oil: Algae Cultivation and Harvest, Algae Residue Torrefaction and Diesel Engine Emissions Tests

Abstract: Microalgae can be used as a biological photocatalyst to reduce the CO2 levels in the atmosphere, with the advantage of not competing with food crops for arable land, and thus offer a potential method for limiting climate change. Microalgae have also been proposed as a sustainable fuel source. This study investigated the microalgae harvest yields, the thermogravimetric behavior of both microalgae oil and microalgae residue, the torrefaction of microalgae residue, and diesel engine tests using diesel-microalgae biodiesel blends. The mean annual harvest rate of microalgae oil in open ponds was found to be 4355 kg per 10000 m 2 . Compared with conventional diesel, the fuel blends - B2 (2% microalgae biodiesel + 98% conventional diesel), B2-But20 (B2 + 20% Butanol) and B2-But20-W0.5 (B2-But20 + 0.5% water) showed a reduction of 22.0%, 57.2%, and 59.5% in PM emissions, and a decrease of 17.7%, 31.4% and 40.7% in BaPeq emissions, while B2-But20 and B2-But20-W0.5 had reduced NOx emissions, of approximately 25.0% and 28.2%, respectively, but B2 showed a 2.0% increase in NOx emissions. Conversely, the addition of water and butanol fractions in diesel increases HC and CO emissions, although these can be easily removed using tailpipe catalysts and absorbers. In addition, torrefaction of microalgae residue results in solid, liquid and gas products. This study is the first of its kind to report the liquid compositions from the torrefaction of microalgae residue. The condensate liquid products contained glucose molecules like 1,4:3,6-Dianhydro-α-d-glucopyranose, and furfural, limonene, pyridine, levoglucosan, and aziridine, among others. These compounds can be utilized as microalgae value added products, and applied in specialty industries as pharmaceutical, cosmetic, or solvent raw materials. Briefly, microalgae not only offer benefits in reducing CO2 from the atmosphere or providing raw materials for biodiesel production, but microalgae residue can also be treated via torrefaction to produce biochar. Based on the results of this study, more research is recommended on the economic potential of using both solid and liquid products from microalgae torrefaction.

Optical Calibration and Equivalence of a Multiwavelength Thermal/Optical Carbon Analyzer

Abstract: Organic and elemental carbon (OC and EC) are operationally-defined by the measurement process, so long-term trends may be interrupted with instrumentation changes. A modification to the U.S. IMPROVE carbon analysis protocol and hardware is examined that replaces the 633 nm laser light used for OC charring adjustments with seven wavelengths ranging from 405 to 980 nm, including one at 635 nm. Reflectance (R) and Transmittance (T) values for each wavelength are made traceable to primary standards through transfer standards consisting of a range of aerosol deposits on filter media similar to that of the analyzed samples. R and T values are assigned to these filters using a UV/VIS spectrometer calibrated with these standards. Using ambient and source (e.g., diesel exhaust, flaming biomass, and smoldering biomass) samples, it is demonstrated that R and T calibration is independent of the sample type. Total carbon (TC), OC, and EC comparisons with the earlier hardware design for urban- and non-urban samples demonstrate equivalence, within precisions derived from replicate analyses, for the 633 nm and 635 nm wavelengths. Several uses of the additional multiwavelength information are identified, including: 1) ground-truthing of multi-spectral remote sensors; 2) improving estimates of the Earth's radiation balance; 3) associating specific organic compounds with their light absorption properties; and 4) appropriating sources of black and brown carbon.

Primary Air Pollutant Emissions and Future Prediction of Iron and Steel Industry in China

Abstract: China is the largest iron and steel producing and consuming country in the world, which leads to enormous quantities of emitted air pollutants Direct emissions of air pollutants from the iron and steel industry in China were estimated by developing a process and technology-based methodology using information of the proportion of pig iron, crude steel, and rolled steel produced from different processes and technology Emissions of sulfur dioxide (SO2), nitrogen oxides (NOx), particulate matter (PM), volatile organic compound (VOCs), and dioxin (PCDD/Fs) were estimated for the year 2012, and future emissions of major pollutants (SO2, NOx, TSP) were projected up to 2030 based on technology developing trends and emission control policies According to the estimation, 2222 kt of SO2, 937 kt of NOx, 1886 kt of TSP, 555 kt of PM25, 254 kt of VOCs, 618 g I-TEQ of PCDD/Fs was produced in China in 2012 Sintering produced 724% of SO2, 494% of NOx, 225% of TSP, 240% of PM25, 696% of VOCs and 980% of PCDD/Fs, which is the main emission source Through faithful implementation of closing down outdated production and emission control policies, approximately 77%, 49%, 67% and 64% of SO2, NOx, TSP and PCDD/Fs emissions, respectively, could be further reduced in 2012 Emissions in 2020 and 2030 of iron and steel sectors were predicted applying scenario analysis The removal potential for SO2 and TSP is larger than NOx by improvement of removal facilities, and southwest, northwest, and north China has the largest SO2, NOx, TSP and PCDD/Fs removal potential respectively

Impact of Meteorological Parameters and Gaseous Pollutants on PM2.5 and PM10 Mass Concentrations during 2010 in Xi'an, China

Abstract: Mass concentrations of PM2.5 and PM10 from the six urban/rural sampling sites of Xi’an were obtained during two weeks of every month corresponding to January, April, July and October during 2010, together with the six meteorological parameters and the data of two precursors. The result showed that the average annual mass concentrations of PM2.5 and PM10 were 140.9 ± 108.9 µg m–3 and 257.8 ± 194.7 µg m–3, respectively. Basin terrain constrains the diffusion of PM2.5 and PM10 concentration spatially. High concentrations in wintertime and low concentrations in summertime are due to seasonal variations of meteorological parameters and cyclic changes of precursors (SO2 and NO2). Stepwise Multiple Linear Regression (MLR) analysis indicates that relative humidity is the main factor influencing on meteorological parameter. Entry MLR analysis suggests that SO2 from local coal-burning power plants is still the primary pollutant. Trajectory cluster results of PM2.5 at BRR indicate that the entrained urban pollutants carried by the westerly or winter monsoon forms the dominant regional pollution sources in winter and spring. Ultraviolet (UV) aerosol index verified the source and pathway of dust storm in spring.

Characterizations of PM2.5 Pollution Pathways and Sources Analysis in Four Large Cities in China

Abstract: Particulate matter with an aerodynamic diameter of 2.5 micrometers or less (PM2.5) is a primary pollutant in most cities in China. PM2.5 poses a significant human health risk, especially in the most densely populated urban areas. We used observations of PM2.5 and backward air mass trajectories modeled by HYSPLIT-4. We characterize how air movement patterns influence pollution levels in four large cities of China. Then we developed a method to evaluate regional and local sources and contributions of PM2.5. For Beijing and Shanghai, PM2.5 concentrations are sensitive to air moving direction, indicating significant influence of air movement on PM2.5 pollution. In Beijing, PM2.5 concentrations were higher when the air masses were from the south and the east. In Shanghai, pollution was greater with northerly air mass flows. Regional contributions of PM2.5 in Beijing during 2013 were 46, 62, 52, and 39% in spring, summer, autumn and winter, respectively. In Shanghai, regional contributions over four seasons were 36, 39, 45, and 35%. In Guangzhou and Chengdu, PM2.5 concentrations were more sensitive to speed rather than direction of air mass movements, indicating weaker pollution pathways. In Guangzhou, regional contributions were smaller over the four seasons: 15, 28, 16, and 22% while in Chengdu, they are 21, 52, 28, and 14%. These results are comparable to previous results obtained using complex atmospheric chemical transport models.

Particulate Matter and Its Source Apportionment in Peshawar, Northern Pakistan

Abstract: The present work is undertaken to investigate the aerosol volume and mass size distribution, concentration of Particulate Matter (PM) and its source apportionment by using GRIMM spectrometer data in the city of Peshawar, Northern Pakistan. In Peshawar, the concentration of Particulate matter (PM2.5 and PM10) was noticed to increase day by day due to rapid urbanization and industrialization. The use of several transportation activities, construction of buildings, roads and overhead bridges has badly affected the atmosphere of this region. Positive Matrix Factorization (PMF) Model has been used to find out different sources of PM in Peshawar. The data were collected for twenty days in April 2011 for both morning and afternoon periods. It has been observed that the values of aerosol volume size distribution were almost high during morning and afternoon rush hours. The mean concentrations of PM10 and PM2.5 were determined to be 480 µg/m 3 and 172 µg/m 3 , respectively. A reasonably significant correlation (R 2 = 0.65) was also found between observed and expected PM mass. The PMF result revealed five (05) sources in Peshawar, which were re-suspended road/soil dust, vehicular, industrial, brick kiln emission and household combustion emission.

Characterization of Ambient PM10 Bioaerosols in a California Agricultural Town

Abstract: Ambient bioaerosols in PM10 samples were measured at three sites in Corcoran, an agricultural town in the southern San Joaquin Valley (SJV) of California, during fall of 2000 corresponding to the cotton harvest season. Elevated bioaerosol concentrations were measured near grain elevators (GRA site) and a cotton handling facility (BAI site) as compared to levels in a residential community (COP site), ~2 km northeast of these sources. Average endotoxin levels (13 ± 17 EU/m3) at the grain elevator site were three to eight times higher than averages at the nearby cotton-handling and residential sites. The highest level (47.6 EU/m3) at the grain elevator site was about half of the exposure limit of 90 EU/m3 set by the Dutch Expert Committee on Occupational Safety. Particle counts of fungal spore (66,333 particles/m3) and pollen grain (2,600 particles/m3) concentrations were more than double those reported in the literature. Average fungal biomarker concentrations of 170 and 131 ng/m3 for arabitol and mannitol, respectively, were 1–2 orders of magnitude higher than those from non-agricultural areas. The low correlation (r < 0.11) of three fungal markers (i.e., (1→3)-β-D-glucan, arabitol, and mannitol) with fungi counts is consistent with findings by others and indicates that these are insufficient as surrogates to represent fungal exposure. Agricultural activities contributed measureable amounts to PM10 mass and organic carbon (OC), dominated by fungal spores (i.e., 5.4–5.8% PM10 mass and 11.5–14.7% OC). The sum of fungal spores, pollen grains, and plant detritus accounted for an average of 11–15% PM10 and 24–33% OC mass. Bioaerosols can be important contributors to PM10 mass in farming communities similar to Corcoran, especially during intense agricultural activities.

Characterization of PM2.5 Source Profiles for Traffic and Dust Sources in Raipur, India

Abstract: This paper describes results from a detailed source profile characterization study conducted in Raipur, India to prepare source profiles for traffic and dust-related sources. A companion paper has been published with results for a range of other combustion sources. PM_(2.5) samples were analyzed for mass, elements (Al, As, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Mo, Na, Ni, Pb, S, Sb, Se, V, Zn), ions (Na^+, K^+, Mg^(2+), Ca^(2+), NH_4 ^+, Cl^-, F^-, NO_3 ^-, SO_4 ^(2-)) and carbonaceous fractions (OC and EC). All dust profiles were dominated by crustal elements (Al, Ca, Fe and Mg), while carbonaceous species (OC and EC) were most abundant in vehicular emission profiles. Trace element fraction was found to be significantly higher in vehicular exhaust compared to the resuspended dust. Remarkably, sulphur abundance was observed to be several-fold higher in vehicular emission profiles than resuspended dust profiles. Al and Ca were identified as reliable markers for resuspended dust while V, Pb and EC were identified as markers for vehicular exhaust.

Temporal and Spatial Characteristics of Ambient Air Quality in Beijing, China

Abstract: The ambient air quality in Beijing was comprehensively assessed based on the real-time pollutant concentrations monitored at urban, suburban, roadside, and background sites in 2013. The results showed that the annual average concentration for CO, NO2, SO2, O3, PM2.5 and PM10 in 2013 was 2.0 mg/m3, 55.6 µg m–3, 28.5 µg m–3, 48.0 µg m–3, 92.2 µg m–3 and 118.6 µg m–3, respectively. The annual average concentration of CO, NO2, SO2, PM2.5 and PM10 was highest in roadside, while that of O3 was highest in background stations. The mean monthly statistics indicated the maximum concentration of CO, NO2, SO2, PM2.5 and PM10 occurred in January because of larger emissions in heating season, lower wind speed and higher relative humidity (RH), while the minimum was found in July or August due to larger precipitation or photochemical degradation. The peak concentrations of O3 occurred during May to August due to higher temperature and solar radiation which could promote the photochemistry activity. The monthly variation is also reflected in the corresponding season. Diurnally analysis showed the CO, NO2, SO2, PM2.5 and PM10 in urban and roadside area had two increase phases accompanying with the traffic peaks. Beside the temporal variation, we also found the spatial variation that higher concentrations of O3 and other pollutants occurred in northern and southern districts/counties, respectively. It could be attributed to the spatial distribution of various pollutant emissions in Beijing and the impact of pollutant transport from neighboring provinces. Moreover, we examined the visibility in Beijing and found its significant correlation with PM2.5 concentration and RH, respectively. Lastly, the air quality in Beijing was compared with that in other mega cities in the world. The higher pollutant concentrations and PM2.5/PM10 ratio indicated that the mitigation of the air pollution especially the PM2.5 pollution in Beijing still had a long way to go.

Vertical Distribution and Columnar Optical Properties of Springtime Biomass-Burning Aerosols over Northern Indochina during 2014 7-SEAS Campaign

Abstract: In this study, the aerosol optical properties and vertical distributions in major biomass-burning emission area of northern Indochina were investigated using ground-based remote sensing (i.e., four Sun-sky radiometers and one lidar) during the Seven South East Asian Studies/Biomass-burning Aerosols & Stratocumulus Environment: Lifecycles & Interactions Experiment conducted during spring 2014. Despite the high spatial variability of the aerosol optical depth (AOD; which at 500 nm ranged from 0.75 to 1.37 depending on the site), the temporal variation of the daily AOD demonstrated a consistent pattern among the observed sites, suggesting the presence of widespread smoke haze over the region. Smoke particles were characterized as small (Angstrom exponent at 440–870 nm of 1.72 and fine mode fraction of 0.96), strongly absorbing (single-scattering albedo at 440 nm of 0.88), mixture of black and brown carbon particles (absorption Angstrom exponent at 440–870 nm of 1.5) suspended within the planetary boundary layer (PBL). Smoke plumes driven by the PBL dynamics in the mountainous region reached as high as 5 km above sea level; these plumes subsequently spread out by westerly winds over northern Vietnam, southern China, and the neighboring South China Sea. Moreover, the analysis of diurnal variability of aerosol loading and optical properties as well as vertical profile in relation to PBL development, fire intensity, and aerosol mixing showed that various sites exhibited different variability based on meteorological conditions, fuel type, site elevation, and proximity to biomass-burning sources. These local factors influence the aerosol characteristics in the region and distinguish northern Indochina smoke from other biomass-burning regions in the world.

Atmospheric Aerosol Elements over the Inland Tibetan Plateau: Concentration, Seasonality, and Transport

Abstract: Between November 2005 and November 2007, weekly total suspended particle samples were collected at the Nam Co station in the inland Tibetan Plateau (TP). Through inductively coupled plasma mass spectrometry, twenty-nine elements were analyzed and their sources and fluxes were investigated. Mean elemental concentrations were lower than those at the edge of the TP. Some elements, such as Cr, Ni, Cd, and Pb, exhibited high enrichment factors (Cr: 22; Ni: 17; Cd: 23; and Pb: 9), indicating possible anthropogenic influence in this remote region, particularly during the pre-monsoon and monsoon seasons. In addition, an empirical orthogonal function analysis revealed the dominance of crustal-origin elements, rather than anthropogenic elements, in the aerosol. Furthermore, backward air mass trajectories demonstrated that the Nam Co region was mainly influenced by air masses from Central and South Asia. Accordingly, because of dust storms from Central Asia and within the TP, crustal element concentrations, such as of Al, were higher during winter and pre-monsoon seasons than during the monsoon season. By contrast, anthropogenic elements, such as Cr and Cd, were relatively higher during the pre-monsoon and monsoon seasons because of pollutants transported from South Asia, where atmospheric brown clouds are concentrated and biomass combustion is prevalent. Dry deposition of aerosols dominated in the Nam Co region, particularly during the non-monsoon period, which is useful to interpret the elemental records in the TP ice cores and lake sediments.

A Heavy Haze Episode in Shanghai in December of 2013: Characteristics, Origins and Implications

Abstract: As the largest Chinese city by population and the largest city proper by population in the world, Shanghai has frequently suffered the heavy haze in recent years. In this study, the observational data (PM_(2.5), PM_(10), O_3, NO_2, CO and SO_2) at the ten urban monitoring stations in Shanghai from November 25 to December 9, 2013, were used to analyze the haze pollution. The source contributions of PM_(2.5) in Shanghai were identified by trajectory clustering and hybrid receptor models (potential source contribution function (PSCF) and concentration weighted trajectory (CWT)). The results showed that for the whole study period, the ranges of pollutant concentrations are 2.0-635.0 μg m(-3) (PM_(2.5)), 2.0-726.0 μg m(-3) (PM_(10)), 1.0-139.0 μg m^(-3) (O_3), 11.0-197.0 μg m^(-3) (SO_2), 7.0-221.0 μg m^(-3) (NO_2), and 0.3-8.5 mg m^(-3) (CO). It was found that PM_(2.5) contributed more than 80% of PM_(10) for the whole period except the relatively clean period in which only 45% of PM_(10) is PM_(2.5). The model analyses show that clean air masses reaching at Shanghai were from the far away regions like Mongolia and Inner Mongolia with the high mean wind speed (fast air masses). On the other hand, the heavy haze air masses were mainly from the nearby industrialized and urbanized provinces with industrial cities. It was found that the formation of the extremely heavy haze from December 5 to 7 in Shanghai was mainly because of the air pollution transported from the nearby provinces (i.e., Anhui, Jiangsu, Zhejiang) and central part provinces (such as Shandong, Hebei) of eastern China. The correlation analyses among PM_(2.5) and other pollutants show that the PM_(2.5) formation in Shanghai is affected by the sources similar to those of CO such as combustion, industry, mobile and oxidation of hydrocarbons. Finally, the controlling strategies are discussed on the basis of this result.

Diurnal Variability in Secondary Organic Aerosol Formation over the Indo-Gangetic Plain during Winter Using Online Measurement of Water-Soluble Organic Carbon

Abstract: Understanding the secondary organic aerosol (SOA) formation is among most important topics in the field of aerosol research because its poor understanding leads to large uncertainty in the assessment of aerosol effects on air quality and climate. This study reports the diurnal and temporal variability in SOA formation over a site (Patiala: 30.2°N, 76.3°E, 249 m amsl) located in the Indo-Gangetic Plain (IGP) during winter using the first online measurements of water-soluble organic carbon (WSOC) over India. Online WSOC, measured with particle-into-liquid sampler (PILS) connected to total organic carbon (TOC) analyzer, ranged from 0.1 to 99 μg m^(-3) (avg: 15.6, sd: 9.4) with a considerable day-to-day and within the day variability, and attributed to meteorological conditions and regional sources. Diurnal trends of online WSOC suggest significant SOA formation during 7:00 to 22:00 hrs when sources of SOA precursors are active; and loss of SOA occurs during afternoon when ambient air temperature is at its peak. In parallel to online measurements, filterbased particulate matter smaller than 2.5 μm (PM_(2.5)) samples were also collected and analyzed for major cations, anions and carbonaceous aerosols. Filter-based PM2.5 composition suggests that the emissions from biomass burning contribute more to carbonaceous aerosols than those from fossil fuel burning. In spite of this, average primary WSOC was only ~20% whereas secondary WSOC (or SOA) dominated the total WSOC concentration with ~80% contribution. A strong linear relationship between PM1 and WSOC (R^2=0.83, slope=0.113, intercept=4.7), suggests that a significant fraction of fine particles are SOA.

Inhalation Risk Assessment of PAH Exposure Due to Combustion Aerosols Generated from Household Fuels

Abstract: The typical mixtures of polycyclic aromatic hydrocarbons are established as lung carcinogens, but their exposure and associated risk from different household fuels are less known. Five commonly used household fuels namely firewood, coal, dung cake, kerosene, and liquefied petroleum gas (LPG) were tested for their size-fractionated polycyclic aromatic hydrocarbon (PAHs) emission. A total of sixteen PAHs were analyzed in size fractionated combustion aerosols using HPLC-UV technique. Single box modeling approach is applied to estimate time average B[a]Peq concentration of PAHs in indoor air during cooking time. Incremental lifetime cancer risk (ILCR) of PAH exposure during cooking time was calculated, which was found to have a positively skewed distribution for all types of fuels combustion. The uncertainty and variability of the predicted exposure risk were evaluated using Monte Carlo simulation. The 50 th percentile of risk due to exposure of PAHs emissions during household use of fuels were found to be 6.25 × 10 –5 , 2.99 × 10 –5 , 9.11 × 10 –5 , 1.14 × 10 –5 , and 3.84 × 10 –6 for firewood, coal, dung cake, kerosene and LPG stove, respectively. The 50 th percentile value of risk indicates the hazard associated with solid biomass combustion is higher than non-solid fuels; the risk associated with LPG stove use is found to be one order of magnitude less compared to other fuels.

Emission Reductions of Nitrogen Oxides, Particulate Matter and Polycyclic Aromatic Hydrocarbons by Using Microalgae Biodiesel, Butanol and Water in Diesel Engine

Abstract: The transport sector is a major consumer of fossil fuels especially petroleum diesel, which is used to power diesel engines used on-road and off-road in trucks, tractors, passenger cars as well as marine vessels. This is because the diesel engine offers various benefits compared to the spark ignition engine. The advantages include superior fuel efficiency, higher thermal efficiency, greater power output, better fuel saving, lower carbon dioxide (CO2) emission, larger torque and greater durability. Conversely, the diesel engine is a major source of both criteria and non-criteria air pollutants, which contribute to the deteriorating air quality thereby putting the health of mankind at risk. The objective of this study was to investigate the performance of butanol- microalgae biodiesel-diesel blends in terms of energy performances and pollutants’ emission reductions by comparing the brake specific fuel consumption (BSFC), brake thermal efficiency (BTE) and exhaust gases temperatures as well as the nitrogen oxides (NOx), particulate matter (PM), polycyclic aromatic hydrocarbons (PAHs), carbon monoxide (CO) and hydrocarbons (HC) of various diesel blends and against the baseline performance of regular petroleum diesel. All diesel blends showed higher BSFCs and BTEs compared to regular petroleum diesel, whereby BT20W0.5 had the highest BSFC and BT15B2 had the best performance in terms of BTE. Among the diesel blends, only 2% microalgae added to diesel blends increased the NOx emissions by about 2%, while for the addition of 10–20% butanol fractions and 0.5% water fractions resulted in lower NOx emissions by about 12–28%, when compared to petroleum diesel. All the diesel blends considered in this study showed PM reductions ranging between 22.4% for B2 and 60.4% for BT15W0.5%, while reductions of PAH emissions were ranging from 6.5% for B2 to 22.76% for BT20W0.5. On the other hand, only the use of 2% microalgae biodiesel showed reductions in CO emissions of about 0.34% and 1.01% for B2 and BT20B2 blends, respectively, while other diesel blends showed increased CO emissions of about 1.72–2.94% in comparison to CO emissions of diesel fuel emissions. The addition of higher butanol fractions of 20% increased the HC emission factors by approximately 18% and 70%, while the HC emission factors for biodiesel, 10–15% butanol fractions and 0.5% water additions lead to reductions in emission by about 8–50%. According to the results of this study, more research is recommended on the economic potential of using of oxygenated additives in diesel engine especially water addition, higher alcohols and dieselhols blends to evaluate the possibility of synergetic properties of these kinds of fuels to achieve simultaneous reductions in the emissions of NOx, PM, CO, HC, PAHs and other persistent organic pollutants (POPs).

Characteristics of Concentrations and Metal Compositions for PM2.5 and PM2.5-10 in Yunlin County, Taiwan during Air Quality Deterioration

Abstract: Concentrations of twenty trace metals in ambient fine and coarse particles were characterized during the period of air quality deterioration of elevated particulate matters (PM episode) in winter in the suburban area, Yunlin County, Taiwan. The potential emission sources of fine- and coarse-size metals were identified using the enrichment factor (EF) analysis, principal component analysis (PCA) and backward trajectory model. The high concentrations of fine and coarse particles and their associated metals were observed during the PM episode in Yunlin County. Al, Fe, and Ca were predominant in fine and coarse particles for sampling periods, accounting for 75- 85% of all selected elements. When the PM episode occurred, mean concentrations of fine-size Pb and As were increased to 132% and 116%, respectively, while average concentrations of coarse-size Fe, Al, Mn, Ti, and Co were increased to 1.1- 2.2 times, in comparison with non-episode period. The mean value of fine-size As (6.67 ng m^(-3)) obtained from the episode period exceeds the proposed European Union standard (6 ng m^(-3)). EF values were decreased with increasing particle size for Sb, Se, As, Mo, Cr, Cu, V, Pb, Zn, Ni and Cd in both episode periods. Fine-size metals is likely to refer to coal combustion (36.5%), iron and steel industry (30.5%), vehicular emission and oil burning (16.3%), and Cu smelting source (13.1%), while coarse-size metals are associated with soil dust and crustal elements (61.6%), traffic-related re-suspended road dust (19.4%), industrial process (10.6%) and coal/oil combustion (6.3%) for the PM episode.