Inorganic PM2 Research Articles

Changes in PM2.5 sensitivity to NO x and NH3 emissions due to a large decrease in SO2 emissions from 2013 to 2018

The authors evaluated and compared the behavior of PM2.5 with respect to NOx and NH3 emission changes in high (the year 2013) and low (the year 2018) SO2 emission cases. Two groups of simulations were conducted based on anthropogenic emissions from China in 2013 and 2018, respectively. In each group of simulations, a respective 25% reduction in NOx and NH3 emissions were assumed. A sensitivity factor (β) was defined as the relative change in PM2.5 concentration due to 1% change in NOx or NH3 emissions. In the high SO2 emissions case, PM2.5 was more sensitive to NH3 (0.31) emissions change than NOx (0.21). Due to the significant decrease in SO2 emissions from the high to low SO2 emissions case, the sensitivity of PM2.5 to NOx increased to 0.33, while its sensitivity to NH3 decreased to 0.22. The result implies that now and in the future, PM2.5 is/will be less sensitive to NH3 emissions change, while NOx emissions control is more effective in reducing the surface PM2.5 concentration. Seasonally, in the low SO2 emissions case, the sensitivities of PM2.5 to NOx and NH3 in winter were higher than those in summer, indicating that to deal with severe winter haze more attention should be paid to the emissions control of inorganic PM2.5 precursors, especially NOx.

Spatial and temporal variations of PM2.5 mass closure and inorganic PM2.5 in the Southeastern U.S.

Fine particulate matter (i.e., PM2.5) has gained extensive attention owing to its adverse effects. The impacts of PM2.5 may vary in time and space due to the spatiotemporal variations of PM2.5 number size distribution and chemical compositions. This research analyzed the latest PM2.5 chemical compositions measurements with an aim to better understand the dynamic changes of PM2.5 in response to emission reductions due to the new regulations. The particulate measurements from the Southeastern Aerosol Research and Characterization (SEARCH) network between 2001 and 2016 were analyzed for the spatiotemporal variations of PM2.5 and inorganic PM2.5 (iPM2.5 = SO42- + NH4+ + NO3-) chemical compositions in the Southeastern United States (U.S.). It was discovered that PM2.5 and iPM2.5 mass concentrations exhibited significant downward trends in 2001-2016. Both PM2.5 and iPM2.5 mass concentrations were higher at urban and inland sites than rural/suburban and coastal sites. The higher iPM2.5 concentrations at agricultural sites were attributed to the influences of ammonia (NH3) emissions from animal feeding operations (AFOs). The iPM2.5 was the dominant contributor to PM2.5 in 2001-2016 at the coastal sites, whereas organic carbon matter (OCM) was the major contributor to PM2.5 after 2011 at the inland sites. Our data analysis suggests that significant decrease of PM2.5 concentrations is attributed to the reductions in nitrogen oxides (NOx) and sulfur dioxide (SO2) emissions in 2001-2016. Findings from this research provide insights into the development of effective PM2.5 control strategies and assessment of air pollutants exposure.

The sensitivity of PM<sub>2.5</sub> acidity to meteorological parameters and chemical composition changes: 10-year records from six Canadian monitoring sites

Abstract. Aerosol pH is difficult to measure directly but can be calculated if the chemical composition is known with sufficient accuracy and precision to calculate the aerosol water content and the H+ concentration through the equilibrium among acids and their conjugate bases. In practical terms, simultaneous measurements of at least one semi-volatile constituent, e.g. NH3 or HNO3, are required to provide a constraint on the calculation of pH. Long-term records of aerosol pH are scarce due to the limited monitoring of NH3 in conjunction with PM2.5. In this study, 10-year (2007–2016) records of pH of PM2.5 at six eastern Canadian sites were calculated using the E-AIM II model with the input of gaseous NH3, gaseous HNO3 and major water-soluble inorganic ions in PM2.5 provided by Canada's National Air Pollution Surveillance (NAPS) Program. Clear seasonal cycles of aerosol pH were found with lower pH (∼2) in summer and higher pH (∼3) in winter consistently across all six sites, while the day-to-day variations of aerosol pH were higher in winter compared to summer. Tests of the sensitivity of aerosol pH to meteorological parameters demonstrate that the changes in ambient temperature largely drive the seasonal cycle of aerosol pH. The sensitivity of pH to chemical composition shows that pH has different responses to the changes in chemical composition in different seasons. During summertime, aerosol pH was mainly determined by temperature with limited impact from changes in NHx or sulfate concentrations. However, in wintertime, both meteorological parameters and chemical composition contribute to the variations in aerosol pH, resulting in the larger variation during wintertime. This study reveals that the sensitivity of aerosol pH to chemical composition is distinctly different under different meteorological conditions and needs to be carefully examined for any particular region.

Differences in chemical composition of PM2.5 emissions from traditional versus advanced combustion (semi-gasifier) solid fuel stoves

A common strategy to improve indoor air quality in households burning coal and biomass is the introduction of advanced combustion solid fuel stoves, which can use existing fuels yet emit fewer pollutants. Chemical composition of PM is affected by numerous combustion parameters, but is often not considered in energy transitions, despite varying toxicity among chemical components. We analyzed PM2.5 emissions from combustion of solid fuels (coal, wood, and straw; whole and pelletized) in a variety of stoves (cookstoves and heating stoves; traditional and semi-gasifier, including forced versus natural draft and fixed versus reciprocating grate). To assess the effects of fuel and stove type on PM2.5 composition, we measured elemental carbon (EC), organic carbon (OC), water-soluble OC, water-soluble inorganic ions (e.g. SO42−, Cl−, K+), and organic molecular markers. PM2.5 emissions from traditional stoves were mostly carbonaceous: 76–90% organic matter (OM), 5–6% EC, and less than 2% inorganic ions. In contrast, semi-gasifier stoves emitted more inorganic PM2.5: on average, ions comprised 65%, 9% was OM, and 4% was EC. Within the semi-gasifier cookstoves, forced-draft cookstove emissions had lower OM (1–3%) and higher ion concentrations (84–88%) than the natural-draft cookstove (5–14% OM, 30–83% ions). Levoglucosan was detected in PM2.5 from combustion of wood in the traditional cookstove and biomass pellets in the natural-draft semi-gasifier cookstove, but not from wood pellets in the forced-draft semi-gasifier cookstove. Across a range of different fuels and stoves, stove type influenced emitted PM composition more than fuel type, underscoring the impact of combustion conditions on PM chemical composition.

Co-benefits of intercropping as a sustainable farming method for safeguarding both food security and air quality

Large-scale, industrialized farming has contributed significantly to the increased global food supply to feed the fast-growing world population over the past few decades, but it also comes with severe threats to the environment. In particular, the excessive application of chemical fertilizer has led to large emissions of reactive nitrogen compounds into the atmosphere, where they become significant components of fine particulate matter (PM2.5) air pollution. Intercropping has been considered as a sustainable agricultural practice that can reduce the environmental impacts of agriculture, but its potential benefits beyond the farm scale have rarely been examined. Here we develop a new parameterization scheme for belowground mutualistic interactions between intercropped crops in the DeNitificaiton-DeComposition biogeochemical model, which is then used to simulate and quantify the benefits of nationwide adoption of maize–soybean systems in China in terms of gains in crop production, decreases in fertilizer consumption, and reductions in ammonia (NH3) emission. We further examine how such a decline in NH3 emission could lessen the downwind formation of PM2.5 using the GEOS-Chem chemical transport model. We show that annual mean inorganic PM2.5 concentrations can be reduced by up to 1.5 μg m–3 with the nationwide adoption of maize–soybean intercropping, with a corresponding annual net economic benefit of US$67 billion, of which US$13 billion arises from saved health costs from reduced air pollution. This study demonstrates the economic and environmental values of intercropping systems in dually promoting food security and environmental health, which can serve as a basis for policy consideration as governments and stakeholders explore more sustainable farming options.

Isotopic evaluation on relative contributions of major NOx sources to nitrate of PM2.5 in Beijing

Nitrate (NO3−) is a key component of secondary inorganic aerosols and PM2.5. However, the contributions of nitrogen oxides (NOx) emission sources to NO3− in PM2.5 remain poorly constrained. This study measured nitrogen (N) isotopes of NO3− (hereafter as δ15N-NO3-) in PM2.5 collected at Beijing in 2014. We observed that δ15N-NO3- values in PM2.5 (−2.3‰ − 19.7‰; 7.3 ± 5.4‰ annually) were significantly higher in winter (11.9 ± 4.4‰) than in summer (2.2 ± 2.5‰). The δ15N differences between source NOx and NO3− in PM2.5 (hereafter as Δ values) were estimated by a computation module as 7.8 ± 2.2‰ − 10.4 ± 1.6‰ (8.8 ± 2.4‰). Using the Δ values and δ15N values of NOx from major fossil (coal combustion, vehicle exhausts) and non-fossil sources (biomass burning, microbial N cycle), contributions of major NOx sources to NO3− in PM2.5 were further estimated by the SIAR model. We found that seasonal variations of δ15N-NO3- values in PM2.5 of Beijing were mainly caused by those of NOx contributions from coal combustion (38 ± 10% in winter, 20 ± 9% in summer). Annually, NOx from coal combustion, vehicle exhausts, biomass burning, and microbial N cycle contributed 28 ± 12%, 29 ± 17%, 27 ± 15%, and 16 ± 7% to NO3− in PM2.5, respectively, showing actually comparable contributions between non-fossil NOx (43 ± 16%) and fossil NOx (57 ± 21%). These results are useful for planning the reduction of NOx emissions in city environments and for elucidating relationships between regional NOx emissions and atmospheric NO3− pollution or deposition.

Nonlinear relationships between air pollutant emissions and PM2.5-related health impacts in the Beijing-Tianjin-Hebei region

A direct and quantitative linkage of air pollution-related health effects to emissions from different sources is critically important for decision-making. While a number of studies have attributed the PM2.5-related health impacts to emission sources, they have seldom examined the complicated nonlinear relationships between them. Here we investigate the nonlinear relationships between PM2.5-related premature mortality in the Beijing-Tianjin-Hebei (BTH) region, one of the most polluted regions in the world, and emissions of different pollutants from multiple sectors and regions, through a combination of chemical transport model (CTM), extended response surface model (ERSM), and concentration-response functions (CRFs). The mortalities due to both long-term and short-term exposures to PM2.5 are most sensitive to the emission reductions of primary PM2.5, followed by NH3, nonmethane volatile organic compounds and intermediate volatility organic compounds (NMVOC+IVOC). The sensitivities of long-term mortality to emissions of primary organic aerosol (POA), NMVOC+IVOC and SO2 do not change much with reduction ratio, whereas the sensitivities to primary inorganic PM2.5 (defined as all chemical components of primary PM2.5 other than POA), NH3 and NOx increase significantly with the increase of reduction ratio. The emissions of primary PM2.5, especially those from the residential and commercial sectors, contribute a larger fraction of mortality in winter (57–70%) than in other seasons (28-42%). When emissions of multiple pollutants or those from both local and regional emissions are controlled simultaneously, the overall sensitivity of long-term mortality is much larger than the arithmetic sum of the sensitivities to emissions of individual pollutants or from individual regions. This implies that a multi-pollutant, multi-sector and regional joint control strategy should be implemented to maximize the marginal health benefits. For NOx emissions, we suggest a nationwide control strategy which significantly enhances the effectiveness for reducing mortality by avoiding possible side effects when only the emissions within the BTH region are reduced.

Responses of Secondary Inorganic PM2.5 to Precursor Gases in an Ammonia Abundant Area In North Carolina

ABSTRACT Secondary inorganic fine particulate matter (iPM2.5) constitutes a significant amount of the atmospheric PM2.5. The formation of secondary iPM2.5 is characterized by thermodynamic equilibrium gas-particle partitioning of gaseous ammonia (NH3) and aerosol ammonium (NH4+). To develop effective strategies for controlling atmospheric PM2.5, it is essential to understand the responses of secondary iPM2.5 to different precursor gases. In southeastern North Carolina, the amount of NH3 is in excess to fully neutralize acidic gases (i.e., NH3-rich conditions). NH3-rich conditions are mainly attributed to the significant NH3 emissions in the region, especially from the large amounts of animal feeding operation (AFO). To gain a better understanding of the impact of NH3 on the formation of secondary iPM2.5 in this area, the responses of iPM2.5 to precursor gases under different ambient conditions were investigated based upon three-year monitoring data of the chemical components in iPM2.5, gaseous pollutants, and meteorological conditions. The gas ratio (GR) was used to assess the degree of neutralization via NH3, and ISORROPIA II model simulation was used to examine the responses of iPM2.5 to changes in the total NH3, the total sulfuric acid (H2SO4), and the total nitric acid (HNO3). It was discovered that under different ambient temperature and humidity conditions, the responses of iPM2.5 to precursor gases vary. In general, iPM2.5 responds nonlinearly to the total NH3 but linearly to the total H2SO4 and the total HNO3. In NH3-rich regions, iPM2.5 is not sensitive to changes in the total NH3, but it is very sensitive to changes in the total H2SO4 and/or the total HNO3. Reducing the total H2SO4, as opposed to the total HNO3 or the total NH3, leads to a significant reduction in iPM2.5 and is thus a more effective strategy for decreasing the concentration of iPM2.5. This research provides insight into controlling and regulating PM2.5 in NH3-rich regions.

Spatial and Temporal Variations of PM2.5 in North Carolina

Studies have indicated that the adverse effects on human health and the decrease in visibility caused by fine particulate matter (PM2.5) exhibit spatial heterogeneity. Moreover, the environmental effects produced by different chemical compositions of PM2.5 vary on a regional scale. Therefore, understanding the spatiotemporal variations and chemical compositions of PM2.5 is necessary for assessing the regional impacts. Secondary inorganic PM2.5 (iPM2.5) is formed through chemical reactions between the base gas NH3 and acidic gas pollutants (e.g., NO2 or SO2). The major components of iPM2.5 include NH4+, SO42–, and NO3–. To fully comprehend the regional impacts of PM2.5, this research quantifies the spatiotemporal variations of iPM2.5 with the aim of evaluating the contributions from iPM2.5 to PM2.5 in North Carolina (NC). The concentrations (at 34 sites) and chemical components (at 7 sites) of PM2.5 from 2005 to 2014 were extracted from the EPA’s AirData, with the highest concentrations measured in the urban areas of central NC. Notably, PM2.5 concentrations have been significantly reduced over the past 10 years, with a concurrent decreasing trend in iPM2.5. Seasonal variation analysis indicates that PM2.5 concentrations were higher in summer and lower in winter; however, significant variation occurred only between 2005 and 2011. Although iPM2.5 formed the largest mass fraction of PM2.5 for 2005–2011, organic carbon matter (OCM) contributed the dominant share for 2012–2014. Significant seasonal variations in the iPM2.5 mass fractions were also observed, with NO3– and SO42– exhibiting inverse variations. This study links the ambient PM2.5 to various sources by revealing the spatiotemporal variations of PM2.5 and their associated chemical compositions in NC, thereby enabling the development of effective control and mitigation strategies.

Characterization and variability of inorganic aerosols and their gaseous precursors at a suburban site in northern France over one year (2015–2016)

Measurements of inorganic precursor gases (NO, NO2, HONO, NH3, SO2 and HCl) and PM2.5 inorganic water-soluble ions (NO3−, SO42−, NH4+, Cl−, Na+, Mg2+, Ca2+, K+) were performed at a suburban site in northern France for the first time using a MARGA 1S with an hourly time-resolution from August 2015 to July 2016. The observations were compared with other independent methods: HR-ToF-AMS, BAM-1020, SO2 and NH3 gas monitors over shorter time periods. The dominant particulate species were NO3−, SO42− and NH4+, with average annual mass contributions to PM2.5 of 28.0%, 13.1% and 9.9%, respectively. The highest concentrations of SIA were found in spring likely due to increased agricultural emissions of precursor gases. A strong formation of ammonium nitrate (NH4NO3) over nighttime was observed for every season and attributed to the condensation of its gaseous precursors NH3 and HNO3. The partitioning of NH4NO3 between the gas and particulate phases was compared with that obtained with the thermodynamic module ISORROPIA II and generally found to agree well except for HNO3. The local or distant origin of each species was determined by means of Non parametric Wind Regression (NWR) polar plots and Potential Source Contribution Function (PSCF) maps. SIA main origins were regional with significant contributions from Belgium, the Netherlands and western Germany. Additionally, several high PM2.5 episodes that lasted more than 2 days were analyzed, showing some common features.

A modeling study of the nonlinear response of fine particles to air pollutant emissions in the Beijing–Tianjin–Hebei region

Abstract. The Beijing–Tianjin–Hebei (BTH) region has been suffering from the most severe fine-particle (PM2. 5) pollution in China, which causes serious health damage and economic loss. Quantifying the source contributions to PM2. 5 concentrations has been a challenging task because of the complicated nonlinear relationships between PM2. 5 concentrations and emissions of multiple pollutants from multiple spatial regions and economic sectors. In this study, we use the extended response surface modeling (ERSM) technique to investigate the nonlinear response of PM2. 5 concentrations to emissions of multiple pollutants from different regions and sectors over the BTH region, based on over 1000 simulations by a chemical transport model (CTM). The ERSM-predicted PM2. 5 concentrations agree well with independent CTM simulations, with correlation coefficients larger than 0.99 and mean normalized errors less than 1 %. Using the ERSM technique, we find that, among all air pollutants, primary inorganic PM2. 5 makes the largest contribution (24–36 %) to PM2. 5 concentrations. The contribution of primary inorganic PM2. 5 emissions is especially high in heavily polluted winter and is dominated by the industry as well as residential and commercial sectors, which should be prioritized in PM2. 5 control strategies. The total contributions of all precursors (nitrogen oxides, NOx; sulfur dioxides, SO2; ammonia, NH3; non-methane volatile organic compounds, NMVOCs; intermediate-volatility organic compounds, IVOCs; primary organic aerosol, POA) to PM2. 5 concentrations range between 31 and 48 %. Among these precursors, PM2. 5 concentrations are primarily sensitive to the emissions of NH3, NMVOC + IVOC, and POA. The sensitivities increase substantially for NH3 and NOx and decrease slightly for POA and NMVOC + IVOC with the increase in the emission reduction ratio, which illustrates the nonlinear relationships between precursor emissions and PM2. 5 concentrations. The contributions of primary inorganic PM2. 5 emissions to PM2. 5 concentrations are dominated by local emission sources, which account for over 75 % of the total primary inorganic PM2. 5 contributions. For precursors, however, emissions from other regions could play similar roles to local emission sources in the summer and over the northern part of BTH. The source contribution features for various types of heavy-pollution episodes are distinctly different from each other and from the monthly mean results, illustrating that control strategies should be differentiated based on the major contributing sources during different types of episodes.

Ammonia Electrolysis in a Municipal Wastewater Treatment Plant

Background Ammonia emissions into air (ambient ammonia) and water represent an environmental challenge. Ambient NH3 not only contributes to inorganic PM2.5 (particulate matter with an aerodynamic diameter of less than 2.5 microns) directly but also plays an important role in secondary organic aerosol formation by interacting with gaseous phase organic acids and forming condensable salts.1 Various industries and other operations are considered ammonia emitters. These are fertilizer manufacture industry, livestock management, coke manufacture industry, fossil fuel combustion, and refrigeration methods.2 On the other hand, ammonia emissions in water are associated with environmental problems such as algae bloom.3 Methods for the removal of ammonia include biological and physicochemical methods. Currently, wastewater treatment solutions for ammonia (biological and chemical treatments) consume a significant amount of energy (4.5 to 50 kWh per kg of ammonia removed); have high operational costs ($4 per lb of ammonia removed); require significant capital investment ($658,000 per MGD –million gallons per day- for retrofit and $9,000,000 per MGD for grassroots plants –new constructions), are not easily adaptable to tighter emissions regulations; take a long time to start-up (in order for the micro-organisms to stabilize in the biological reactors), and are large in size.4 An alternative for efficient ammonia water treatment is the ammonia electrolysis technology. This technology has been under development at the Center for Electrochemical Research (CEER) at Ohio University for the treatment of wastewater.5-11 In this process, the direct oxidation of ammonia takes place at the anode of the electrochemical reactor in alkaline media producing nitrogen gas, while hydrogen is produced at the cathode of the cell. Ammonia can be removed from water while energy can be recovered from the hydrogen by-product produced. In this work, we developed a mobile system that was tested at the Athens Ohio Wastewater Treatment Facility to evaluate the performance of the process in a municipal wastewater treatment plant. Results A partnership between CEER and the City of Athens Ohio Wastewater Treatment Plant12 was established to evaluate and demonstrate the performance of a pilot scale ammonia electrolysis system. The components of the system were installed in a mobile trailer and connected to the water treatment plant as an electrical appliance (with minimum plumbing and direct connection to power). The water treatment system was tested and evaluated at different intervals totalizing over six months of operation. Successful removal of ammonia was demonstrated. Energy from the hydrogen was recovered using a fuel cell. Further results will be presented at the meeting. References K. Na, C. Song, C. Switzer, D. R. Cocker, D. R. Effect of ammonia on secondary organic aerosol formation from α-pinene ozonolysis in dry and humid conditions. Environ. Sci. Technol., 41 (17), 6096−6102 (2007).W. Meng, Q. Zhong, X. Yun, X. Zhu, T. Huang, H. Shen, Y. Chen, H. Chen, F. Zhou, J. Liu, X. Wang, E. Y. Zeng, S. Tao. Improvement of a global high-resolution ammonia emission inventory for combustion and industrial sources with new data from the residential and transportation sectors, Environ. Sci. Technol., 51, 2821-2829 (2017).R. Ferris, Why are there so many toxic algae blooms this year?, CNBC, http://www.cnbc.com/2016/07/26/why-are-there-so-many-toxic-algae-blooms-this-year.html (accessed April 2017).Montana Department of Environmental Quality, Wastewater Treatment Performance and Cost Data to Support an Affordability Analysis for Water Quality Standards, http://www.scribd.com/doc/217400634/Wastewater-Treatment-Performance-and-Cost-Data#scribd (accessed August 2015).G. G. Botte, Electro-catalysts for the Oxidation of Ammonia in Alkaline Media, U.S. Patent No. 7,803,264 (2010).G. G. Botte, M. Cooper, and F. Vitse, Electro-catalysts for the Oxidation of Ammonia in Alkaline Media, U.S. Patent No. 7,485,211 (2009).G. G. Botte, Electrochemical method for providing hydrogen using ammonia and ethanol, U.S. Patent No. 8,221,610 (2012).Gerardine G. Botte, Electrochemical Cell for Oxidation of Ammonia and Ethanol, U.S. Patent No. 8,216,437 (2012).G. G. Botte, Layered Electrocatalyst for Oxidation of Ammonia and Ethanol, U.S. Patent No. 8,216,956 (2012).L. Diaz, G. G. Botte, Electrochemical Deammonification of Swine Wastewater, Industrial & Engineering Chemistry Research, 51, 12167-12172 (2012).E. P. Bonnin, E. J. Biddinger, G. G. Botte, Effect of Catalyst on Electrolysis of Ammonia Effluents, Journal of Power Sources, 182, 284-290 (2008).City of Athens Ohio Wastewater Treatment Plant, http://www.ci.athens.oh.us/index.aspx?NID=225 (accessed April 2017).

Mitigating ammonia emission from agriculture reduces PM2.5 pollution in the Hai River Basin in China

The Hai River Basin (HRB), one of the most populated areas in China, is experiencing high NH3 emissions, mostly from agricultural sources, and suffering from strongly enhanced PM2.5 concentrations in all urban areas. Further population growth and urbanization projected until 2030 may exacerbate this situation. Here, the NUFER (NUtrient flows in Food chains, Environment and Resources use) and GAINS (Greenhouse gas – Air pollution Interactions and Synergies) models have been coupled for the first time to understand possible changes of agricultural NH3 emission between 2012 and 2030 and their impacts on ambient PM2.5 concentrations, and to explore options to improve this situation. Results show that agricultural ammonia emissions in the HRB were 1179kt NH3 in 2012, 45% of which was from the hotspots at or near conurbation areas, including Beijing-Tianjin, Tangshan-Qinhuangdao, Shijiazhuang-Baoding, Dezhou, Handan-Liaocheng, and Xinxiang. Without intervention, agricultural ammonia emissions will further increase by 33% by 2030. The impacts of several scenarios were tested with respect to air pollution. Compared to the business-as-usual scenario, a scenario of improved technology and management combined with human diet optimization could greatly reduce emission (by 60%), and lead to 22–43% and 9–24% decrease of the secondary inorganic aerosols and PM2.5 concentrations, respectively, in the hotspots of NH3 emissions. Our results further confirmed that ammonia control is needed for air pollution abatement strategies (SO2, NOx and primary PM reduction) to be effective in terms of PM2.5.

Effects of Typical Inorganics on the Emission Behavior of PM10 during Combustion of Ash-Removed Coals Loaded with Sodium and Quartz

To examine the real effects of typical inorganics on the emission behavior of PM10 during coal combustion and explore the interactions between the typical vaporized and refractory inorganics, Na-, Si-, and (Na+Si)-loaded coals prepared from the ash-removed PDS bituminous coal and ZD subbituminous coal were combusted in a high temperature drop-tube furnace (DTF) at 1500 °C in air. The produced inorganic PM10 and PM2.5 were collected and characterized. The experimentally measured PM emission results from the combustion of the (Na+Si)-loaded coals were compared with the calculated results that are the sum of PM emitted from the combustion of the Na- and Si-loaded coals. The calculated yields of PM0.3 of two studied coals are higher than the experimental ones, while the calculated yields of PM0.3-2.5 are lower. The experimental yield of PM0.3-2.5 is mainly enhanced by the sodium condensing heterogeneously on fine quartz particles, while the sodium would contribute to PM0.3 homogeneously, leading to the higher...

Public health costs accounting of inorganic PM2.5 pollution in metropolitan areas of the United States using a risk-based source-receptor model

In order to design effective strategies to reduce the public health burden of ambient fine particulate matter (PM2.5) imposed in an area, it is necessary to identify the emissions sources affecting that location and quantify their contributions. However, it is challenging because PM2.5 travels long distances and most constituents are the result of complex chemical processes. We developed a reduced-form source-receptor model for estimating locations and magnitudes of downwind health costs from a source or, conversely, the upwind sources that contribute to health costs at a receptor location. Built upon outputs from a state-of-the-art air quality model, our model produces comprehensive risk-based source apportionment results with trivial computational costs. Using the model, we analyzed all the sources contributing to the inorganic PM2.5 health burden in 14 metropolitan statistical areas (MSAs) in the United States. Our analysis for 12 source categories shows that 80–90% of the burden borne by these areas originates from emissions sources outside of the area and that emissions sources up to 800 km away need to be included to account for 80% of the burden. Conversely, 60–80% of the impacts of an MSA's emissions occurs outside of that MSA. The results demonstrate the importance of regionally coordinated measures to improve air quality in metropolitan areas.

Multi-year application of WRF-CAM5 over East Asia-Part I: Comprehensive evaluation and formation regimes of O3 and PM2.5

Accurate simulations of air quality and climate require robust model parameterizations on regional and global scales. The Weather Research and Forecasting model with Chemistry version 3.4.1 has been coupled with physics packages from the Community Atmosphere Model version 5 (CAM5) (WRF-CAM5) to assess the robustness of the CAM5 physics package for regional modeling at higher grid resolutions than typical grid resolutions used in global modeling. In this two-part study, Part I describes the application and evaluation of WRF-CAM5 over East Asia at a horizontal resolution of 36-km for six years: 2001, 2005, 2006, 2008, 2010, and 2011. The simulations are evaluated comprehensively with a variety of datasets from surface networks, satellites, and aircraft. The results show that meteorology is relatively well simulated by WRF-CAM5. However, cloud variables are largely or moderately underpredicted, indicating uncertainties in the model treatments of dynamics, thermodynamics, and microphysics of clouds/ices as well as aerosol-cloud interactions. For chemical predictions, the tropospheric column abundances of CO, NO2, and O3 are well simulated, but those of SO2 and HCHO are moderately overpredicted, and the column HCHO/NO2 indicator is underpredicted. Large biases exist in the surface concentrations of CO, NOx, and PM10 due to uncertainties in the emissions as well as vertical mixing. The underpredictions of NO lead to insufficient O3 titration, thus O3 overpredictions. The model can generally reproduce the observed O3 and PM indicators. These indicators suggest to control NOx emissions throughout the year, and VOCs emissions in summer in big cities and in winter over North China Plain, North/South Korea, and Japan to reduce surface O3, and to control SO2, NH3, and NOx throughout the year to reduce inorganic surface PM.

Wood burning pollution in southern Chile: PM2.5 source apportionment using CMB and molecular markers

Temuco is a mid-size city representative of severe wood smoke pollution in southern Chile; i.e., ambient 24-h PM2.5 concentrations have exceeded 150 μg/m3 in the winter season and the top concentration reached 372 μg/m3 in 2010. Annual mean concentrations have decreased but are still above 30 μg/m3. For the very first time, a molecular marker source apportionment of ambient organic carbon (OC) and PM2.5 was conducted in Temuco. Primary resolved sources for PM2.5 were wood smoke (37.5%), coal combustion (4.4%), diesel vehicles (3.3%), dust (2.2%) and vegetative detritus (0.7%). Secondary inorganic PM2.5 (sulfates, nitrates and ammonium) contributed 4.8% and unresolved organic aerosols (generated from volatile emissions from incomplete wood combustion), including secondary organic aerosols, contributed 47.1%. Adding the contributions of unresolved organic aerosols to those from primary wood smoke implies that wood burning is responsible for 84.6% of the ambient PM2.5 in Temuco. This predominance of wood smoke is ultimately due to widespread poverty and a lack of efficient household heating methods. The government has been implementing emission abatement policies but achieving compliance with ambient air quality standards for PM2.5 in southern Chile remains a challenge.

Public Health Costs of Primary PM2.5 and Inorganic PM2.5 Precursor Emissions in the United States.

Current methods of estimating the public health effects of emissions are computationally too expensive or do not fully address complex atmospheric processes, frequently limiting their applications to policy research. Using a reduced-form model derived from tagged chemical transport model (CTM) simulations, we present PM2.5 mortality costs per tonne of inorganic air pollutants with the 36 km × 36 km spatial resolution of source location in the United States, providing the most comprehensive set of such estimates comparable to CTM-based estimates. Our estimates vary by 2 orders of magnitude. Emission-weighted seasonal averages were estimated at $88,000-130,000/t PM2.5 (inert primary), $14,000-24,000/t SO2, $3,800-14,000/t NOx, and $23,000-66,000/t NH3. The aggregate social costs for year 2005 emissions were estimated at $1.0 trillion dollars. Compared to other studies, our estimates have similar magnitudes and spatial distributions for primary PM2.5 but substantially different spatial patterns for precursor species where secondary chemistry is important. For example, differences of more than a factor of 10 were found in many areas of Texas, New Mexico, and New England states for NOx and of California, Texas, and Maine for NH3. Our method allows for updates as emissions inventories and CTMs improve, enhancing the potential to link policy research to up-to-date atmospheric science.

Reduced-form modeling of public health impacts of inorganic PM2.5 and precursor emissions

It is challenging to estimate the public health costs of fine particulate matter (PM2.5) and its precursor emissions accurately and quickly for policy research because of their complex physical and chemical processes occurring over a large downwind area. We developed a method for building statistical regressions that estimate public health cost of emissions accurately like a state-of-the-art chemical transport model (CTM) but without its high computational cost. This method achieves detailed spatial resolution according to the location of the emission source, accounting for differences in the exposed population downwind. Using tagged CTM simulations, our method builds a large dataset of air quality public health costs from marginal emissions throughout the United States. Two methods were developed to describe exposed population, one that assumes a generic downwind plume concentration profile derived from CTM outputs and a simpler method that uses the size of population within certain distances as variables. Using the former method, we parameterized marginal public health cost [$/t] and intake fraction [ppm] as a function of exposed population and key atmospheric variables. We derived models for elemental carbon, sulfur dioxide, nitrogen oxides, and ammonia. Compared to estimates calculated directly using CTM outputs, our models generally show mean fractional errors of only 10%–30% and up to 50% for NOx in some seasons, which are generally similar to or less than CTM’s performance. Our results show that the public health costs of emissions can be efficiently parameterized for policy analyses based on state-of-the-art CTMs.

Concentrations and Emissions of Particulate Matter from Intensive Pig Production at a Large Farm in North China

ABSTRACTParticulate matter (PM) pollution from pig farms is of increasing environmental concern due to the rapid development of intensively managed pig farms worldwide. However, information on this topic is scarce in China to date. Therefore a two-year study to monitor the dynamics of total suspended particles (TSP) and particulate matter with diameter less than 10 µm (PM10) and their soluble ions was conducted at an industrial pig farm near Beijing. In total, two fattening pig houses were sampled during three fattening periods from 2010 to 2011. Daily mean indoor TSP and PM10 concentrations were 1.85 and 0.63 mg m–3 on average. The emissions of PM per livestock unit (LU unit =500 kg), and per unit area (m2) from the pig house averaged 467.5 mg h–1 LU–1 and 38.6 mg h–1 m–2 for TSP, while those for PM10 averaged 256.7 mg h–1 LU–1 and 16.8 mg h–1 m–2, respectively. Particulate NH4+ in both TSP and PM10 showed significant positive correlations with particulate NO3– and SO42– inside and outside the pig houses. Daily mean indoor concentrations of secondary inorganic aerosol (sum of NH4+, NO3– and SO42–) ranged from 10.8 to 368.8 µg m–3 (average 116 µg m–3) in TSP and from 5.1 to 220.1 µg m–3 (average 58.6 µg m–3) in PM10. Contributions of secondary inorganic PM to TSP and PM10 emissions varied from 0.3 to 50.8% and from 1.0 to 48.7%, respectively, with averages of 12.0 and 13.9%. Our results suggest elevated PM and secondary inorganic PM concentrations and substantial emissions of PM from the fattening pig houses in China.