Form Of Fine Particulate Matter Research Articles

Comparative life cycle assessment of conventional, electric and hybrid passenger vehicles in Spain

Electric and hybrid vehicles are being promoted in European countries to significantly improve air quality in urban areas and reduce Greenhouse Gases emissions . This study evaluates and compares the potential environmental effects of electric, hybrid, petrol, and diesel cars in Spain using a cradle-to-grave Life Cycle Assessment approach. It aims to accomplish a precise analysis of a wide range of environmental impact categories. To this end, we provide a transparent inventory of components and vehicle manufacture, their distribution, use phase, and end-of-life, together with a detailed description of the Spanish 2014–2018 electricity generation mix. Furthermore, based on European projections, the work evaluates future energy scenarios, 2030 and 2050, to assess the impact of increasing renewable electricity in electric cars. In the current Spanish scenario and assuming a lifetime of 150,000 km, BEV life cycle CO 2 -eq emissions are 48% lower than petrol ICEV. Future scenarios of the Spanish electricity grid confirm that a massive introduction of renewable energies would lead to a 19.26% and 27.41% decrease of CO 2 -eq emissions in 2030 and 2050, respectively. Nevertheless, current and future energy scenario predictions show that electric vehicles will produce an increase in fine particulate matter formation (26%), human carcinogenic (20%) and non-carcinogenic toxicity (61%), terrestrial ecotoxicity (31%), freshwater ecotoxicity (39%), and marine ecotoxicity (41%) relative to petrol vehicles. Transfer of environmental burdens from the use phase to the raw materials extraction and manufacturing phases entails a delocalisation of the impacts, which constitutes a new challenge at environmental, social, and legal levels. This study is the first comparative analysis of the environmental impacts of passenger vehicles in Spain from a cradle-to-grave perspective, considering different impact categories and time scopes. • Future scenarios for Spain enhance electric vehicle carbon footprint reduction. • Electric vehicles show the highest toxicity on ecosystems and human health. • Electric and hybrid vehicles transfer most of their impacts to the manufacture. • Future scenarios rise the geographical delocalisation of environmental impacts. • Data inventories are proposed for the current and future Spanish electricity mixes.

Laboratory-Scale Life-Cycle Assessment: A Comparison of Existing and Emerging Methods of Poly(ε-caprolactone) Synthesis

Poly(e-caprolactone) (PCL) is a widely employed biodegradable polymer synthesized commercially using stannous octoate-mediated ring-opening polymerization (ROP) of e-caprolactone (e-CL). It needs to be revisited in alignment with green chemistry principles, such as less hazardous chemical syntheses. We identified and optimized two emerging methods—Route A: acid-catalyzed ROP of e-CL using hydrogen chloride (HCl) in diethyl ether; and Route B: free-radical ROP using cyclic ketene acetal (CKA) monomer, 2-methylene-1,3-dioxepane (MDO), which are essentially solvent-free, metal-free, and organic-catalyst-free. They were then compared with the laboratory-scale reproduction of Route C: stannous octoate-mediated ROP of e-CL. Laboratory-scale life-cycle assessment (LCA) is employed to analyze the potential environmental profiles of these three routes by employing a cradle-to-gate system boundary, starting from extraction of raw materials and ending with production of 1 g of PCL homopolymer. The overall findings showed that Route A, the low-temperature acid-catalyzed approach, was more power-efficient and less hazardous compared to Routes B and C, with consideration of sensitivity and uncertainty analysis results. Route A was demonstrated to be the most environmentally sustainable route with environmental impact reductions of 79.46% (climate change), 54.53% (fossil fuel depletion), 45.10% (terrestrial acidification), and 66.36% (water depletion) per 1 g of PCL, in contrast to Route B. In comparison to Route C, Route A achieved 43.54% (fine particulate matter formation) and 98.41% (human toxicity) impact reductions per 1 g of PCL. Route B contributes largely to climate change, whereas Route C has the most significant influence on human toxicity.

Effect of Reducing Ammonia Volatilization from the Arable Soil with Iron Sulfate

Ammonia (NH3) reacts with nitric acid or sulfuric acid in the atmosphere and contributes to the formation of fine particulate matter. It is mainly produced by application of nitrogen fertilizer and livestock manure to the arable soil. Volatilization of NH3 could decrease with application of acidic amendments such as iron sulfate (FeSO4) through decreasing soil pH. This study was conducted to determine an optimum application rate of FeSO4 to reduce NH3 volatilization and maintain crop productivity in arable soil. Iron sulfate was applied at the rates of 0, 50, 100, and 200 kg Fe ha-1. Cabbage (Brassica rapa L.) was planted on April 8th 2020 and harvested on June 10th 2020. The NH3 gas was collected using static chamber (300 mm in length and 120 mm diameter) method. Cumulative NH3-N volatilization decreased significantly with increasing application rate of FeSO4. It decreased by ca. 21% at 200 kg Fe ha-1 of FeSO4. Soil pH decreased significantly with increasing application rate of FeSO4. A decrease in cumulative NH3-N volatilization with FeSO4 was mainly attributed to decrease in soil pH. Cabbage yield did not decreased with increasing application rate of FeSO4. The maximum cabbage yield was 7.10 Mg ha-1 and cumulative NH3-N volatilization decreased by 10.2% from 28.4 kg ha-1 63 days-1 to 25.8 kg ha-1 63 days-1 with 110 kg Fe ha-1 of FeSO4 application. Cumulative NH3-N volatilization from soils amended with different rates of FeSO4

Effects of particle size and additives on the formation of fine particulate matter during sludge incineration

ABSTRACT With the development of urbanization and industrialization, vast plenty of sewage sludge was produced. Incineration has been becoming the mainstream disposal method due to its many advantages. However, the problem of fine particulate matter produced from the incineration process made a restriction on the development of this method. In this study, the effects of temperature, particle size, and calcium-based additives (CaO) on the generation characteristics and micrographs of fine particulate matter were investigated via a lab-scale fluidized bed. The results revealed that the fine particulate matter showed a bimodal distribution and the two peaks was located at around 0.5 μm and 5 μm, respectively. With the increasing of temperature from 750°C to 950°C, the mass concentration of PM0.5 increased by 12.88 mg/g, while PM5 increased by 57.79 mg/g, which indicated as the temperature increases, the crushing degree of minerals and coke particles is more intense, which further leads to an increase in the amount of fine particles. The number of fine particles increased when the feed size getting smaller, which showed an intense link to the feed size. That was because the smaller the particle size, the more severe the degree of crushing, and the greater the number of fine particles formed after crushing. Furthermore, the results also found that CaO can be used as a good binder between particles to promote the growth and agglomeration of fine particles and inhibit the generation of fine particles. When the additive ratio was 3%, 6%, and 9%, the mass concentration of PM0.3 decreased by 53.7%, 63.5%, and 86.1%, while the mass concentration of PM3 decreased by 43.9%, 74.7%, and 91.7%. Therefore, CaO can be used to reduce the production of fine particles in practical engineering applications.

Inequality amplifies the negative association between life expectancy and air pollution: A cross-national longitudinal study

Ambient air pollution, in the form of fine particulate matter (PM2.5), poses serious population health risks. We estimate cross-national longitudinal models to test whether the negative relationship between life expectancy and PM2.5 concentration is larger in nations with higher levels of income inequality. The dependent variable is average life expectancy at birth, and the focal predictor variables include PM2.5 concentration, income inequality, and the two-way interaction between them. We also estimate the average marginal effects of PM2.5 concentration from low to high values of income inequality, and the predicted values of life expectancy from low to high values of PM2.5 concentration and income inequality. Results indicate that the negative relationship between life expectancy and PM2.5 concentration is larger in nations with higher levels of income inequality, and the reductions in predicted life expectancy are substantial when both PM2.5 concentration and income inequality are high. We suggest that the theoretical principles of Power, Proximity, and Physiology help explain our findings. This study underscores the importance in considering the multiplicative impacts of environmental conditions and socioeconomic factors in the modeling of population health.

Evaluating the potential health and economic effects of nitrogen fertilizer application in grain production systems of China

In past decades, large amounts of N fertilizers have been applied in agricultural production of China. N fertilizer has not only underpinned food production but also led to great concerns about negative environmental impacts. We used a life cycle assessment (LCA) approach to assess nitrogen fertilizer induced potential human health risk (HHR) and human capital loss (HCL) of rice, wheat and maize production systems. We found that the HHR of rice, wheat and maize was 633004, 264105 and 418644 DALY/yr, respectively. The rice production system caused the highest potential risk while the wheat production system the lowest. Fine particulate matter formation (FPMF) was the most serious health risk index, and accounted for nearly 87% of HHR. Sown area and crop type both play an important role in HHR. The potential loss of human capital caused by rice, wheat and maize production are 37.5, 15.6 and 24.8 billion RMB/yr, respectively. The total HCL accounted for about 5.9% of the Chinese grain yield value in 2017. We constructed 3 scenarios to evaluate the potential for reduction of human health risk. In scenario A, reducing N fertilizer rates to an appropriate level, the HHR decreased by about 23%, while in scenario B, enhancing nitrogen use efficiency and production technology, decreased HHR by about 22%. Furthermore, when we combined both scenario A and B, the HHR was reduced by as much as 37%. Improving fertilizer management practices in grain production in China has a great potential to reduce adverse impacts on human health, and more attention should also be paid to the impacts of air pollutant emissions from agricultural production on human health.

The environmental cost of recovering energy from municipal solid waste

Municipal solid waste (MSW) incinerators require effective flue gas treatment (FGT) to meet stringent environmental regulations. However, this in turn generates additional environmental costs through the impacts of materials and energy used in the treatment – these impacts are currently scarcely known. Therefore, this study uses life cycle assessment to estimate the impacts of different FGT systems typically found in modern MSW incinerators. A total of 12 scenarios are modelled to consider different combinations of the following eight technologies: electrostatic precipitators and fabric filters for removal of particulate matter; dry, semi-dry and wet scrubbers for acid gases; selective non-catalytic and catalytic reduction of nitrogen oxides (NOx); and activated carbon for removal of dioxins and heavy metals. The data are sourced from 90 full-scale incinerators operating in France. The results reveal that a dry system using sodium bicarbonate and selective non-catalytic reduction (SNCR) is the best option for seven out of 18 impacts, including climate change (37.1 kg CO2 eq./t MSW). By contrast, a dry system with calcium hydroxide and selective catalytic reduction (SCR) has the highest impacts in six categories, including climate change (102 kg CO2 eq./t MSW). The wet systems have higher impacts than the dry alternatives, with the semi-dry options being in between. Compared to SNCR, the use of SCR decreases the NOx-related impacts (fine particulate matter formation, terrestrial acidification and photochemical ozone formation) but increases other impacts. For example, the SCR systems have 49–284% greater climate change and 43–150% higher depletion of fossil resources than their SNCR counterparts. Overall, all FGT systems reduce significantly fine particulate matter formation (by 81–88%), photochemical ozone formation (76–90%) and terrestrial acidification (83–90%). However, they also cause 14 other impacts which would not be generated if the flue gas was left untreated, thus creating additional environmental costs. These include climate change, resource depletion and human and ecotoxicities. Therefore, these trade-offs should be considered carefully to minimise the unintended environmental consequences of flue gas treatment from incineration of MSW.

Performance evaluation methods and effect analysis of VOCs-related enterprises in key industries

VOCs pollution has a significant impact on the atmospheric environment. Volatile organic compounds (VOCs) are important precursors for the formation of fine particulate matter (PM2.5) and ozone (O3), and have become one of the main pollutants of atmospheric pollution. In order to further improve the ambient air quality, it is urgent to comprehensively strengthen the comprehensive management of VOCs in key industries. Based on the characteristics of pollution production in VOCs-related industries, focusing on source control, unorganized collection, and end-of-line governance, develop a multi-factor and multi-indicator performance evaluation system, and use field surveys-field monitoring-site scoring-suggestions-corporate rectification Performance evaluation of key emission enterprises. On-site assessment was conducted on 380 companies in key industries related to VOCs, such as pharmaceuticals, pesticides, and chemicals, and 2,396 suggestions on environmental protection related rectification were put forward to guide enterprises to upgrade and achieve precise and scientific pollution control. After the improvement of deep governance, the calculation of emission reduction performance of VOCs-related companies shows that the annual emission reduction of VOCs in the pharmaceutical industry is 722.113 t·a−1, the annual emission reduction of pesticide industry is 842.555 t·a−1, and the emission reduction of chemical industry is 1498.835 t·a−1. The annual emission reduction is 3227.63 t·a−1, and the source control emission reduction is 6929.862 t·a−1. The total reduction of VOCs in 2019 is 13220.994 t·a−1.

Where Is the Clean Air? A Bayesian Decision Framework for Personalised Cyclist Route Selection Using R-INLA

Exposure to air pollution in the form of fine particulate matter (PM2.5) is known to cause diseases and cancers. Consequently, the public are increasingly seeking health warnings associated with levels of PM2.5 using mobile phone applications and websites. Often, these existing platforms provide one-size-fits-all guidance, not incorporating user specific personal preferences. This study demonstrates an innovative approach using Bayesian methods to support personalised decision making for air quality. We present a novel hierarchical spatio-temporal model for city air quality that includes buildings as barriers and captures covariate information. Detailed high resolution PM2.5 data from a single mobile air quality sensor is used to train the model, which is fit using R-INLA to facilitate computation at operational timescales. A method for eliciting multi-attribute utility for individual journeys within a city is then given, providing the user with Bayes-optimal journey decision support. As a proof-of-concept, the methodology is demonstrated using a set of journeys and air quality data collected in Brisbane city centre, Australia.

Filterable PM2.5, Metallic Elements, and Organic Carbon Emissions from the Exhausts of Diesel Vehicles

ABSTRACT Urban air pollution in the form of fine particulate matter (PM2.5) constitutes substantial health risks to human via inhalation. To determine the inhalation risks of PM2.5 containing metallic elements, we characterized and quantified PM2.5 emissions from the exhaust of 15 diesel vehicles having accrued mileages ranging from 28,306 to 883,374 km (average of 525,854 km). These vehicles originated from several manufacturers and covered model years from 1988 to 2005. The concentrations of metallic elements (Fe, Zn, Mg, K, Ca, Al, and Cr) were studied with the help of Inductively Coupled Plasma Optical Emission Spectroscopy (ICP-OES). The results demonstrate that the metallic element composition in exhaust PM2.5 was in descending order as follows: Ca, Zn, Al, K, Fe, and Cr. The exhaust components containing PM2.5 and other chemical compositions were obtained based on carbonaceous materials (total carbon -TC, organic carbon - OC and elemental carbon - EC). Our results demonstrate that elemental carbon (EC) and organic carbon (OC) were the key concentrations of carbonaceous components: EC accounted for 2051 µg m-3 of PM2.5, while the OC fraction accounted for 1410 μg m-3, and TC accounted for 3461 µg m-3, respectively. The results have revealed Ca had the highest EFs among all the investigated atmospheric metallic elements, which ranged between 45.3 and 259 μg/L-fuel (with an average of 132 μg/L-fuel). Zn and Cr had the lowest EFs, accounting for a mean average of 13.1 μg/L-fuel and 1.91 μg/L-fuel, respectively. The concentrations and EFs of metallic elements in PM2.5 exhaust also were studied in relationship to atmospheric PM2.5 composition. These results will help further an understanding of how PM2.5 emissions from diesel vehicles contribute to metallic element concentrations in the natural environment and their potential negative effects.

China targets health-harming ozone

China is expanding its air-quality improvement effort to address volatile organic compounds (VOCs). VOCs are responsible for the formation of fine particulate matter and ground-level ozone, each of which causes health problems. China already shuttered thousands of steel, chemical, and power plants in the northern part of the country. According to an annual report on the country’s environmental status issued in May by the Ministry of Ecology and Environment (MEE), average concentrations of airborne particulates dropped around 20% and sulfur dioxide plunged 44% from 2015 to 2018 in 338 Chinese cities. Ground-level ozone, however, remains a significant problem. It increased roughly 13% across the 338 cities from 2015 to 2018. Thus comes the new focus on VOCs, which are released from burning fuel such as gasoline, wood, coal, or natural gas. VOCs also come from many consumer products and industrial production processes, including many that use chemical solvents. The varied

Primary emissions versus secondary formation of fine particulate matter in the most polluted city (Shijiazhuang) in North China

Abstract. Particulate matter (PM) pollution is a severe environmental problem in the Beijing–Tianjin–Hebei (BTH) region in North China. PM studies have been conducted extensively in Beijing, but the chemical composition, sources, and atmospheric processes of PM are still relatively less known in nearby Tianjin and Hebei. In this study, fine PM in urban Shijiazhuang (the capital of Hebei Province) was characterized using an Aerodyne quadrupole aerosol chemical speciation monitor (Q-ACSM) from 11 January to 18 February in 2014. The average mass concentration of non-refractory submicron PM (diameter <1 µm, NR-PM1) was 178±101 µg m−3, and it was composed of 50 % organic aerosol (OA), 21 % sulfate, 12 % nitrate, 11 % ammonium, and 6 % chloride. Using the multilinear engine (ME-2) receptor model, five OA sources were identified and quantified, including hydrocarbon-like OA from vehicle emissions (HOA, 13 %), cooking OA (COA, 16 %), biomass burning OA (BBOA, 17 %), coal combustion OA (CCOA, 27 %), and oxygenated OA (OOA, 27 %). We found that secondary formation contributed substantially to PM in episodic events, whereas primary emissions were dominant (most significant) on average. The episodic events with the highest NR-PM1 mass range of 300–360 µg m−3 were comprised of 55 % of secondary species. On the contrary, a campaign-average low OOA fraction (27 %) in OA indicated the importance of primary emissions, and a low sulfur oxidation degree (FSO4) of 0.18 even at RH >90 % hinted at insufficient oxidation. These results suggested that in Shijiazhuang in wintertime fine PM was mostly from primary emissions without sufficient atmospheric aging, indicating opportunities for air quality improvement by mitigating direct emissions. In addition, secondary inorganic and organic (OOA) species dominated in pollution events with high-RH conditions, most likely due to enhanced aqueous-phase chemistry, whereas primary organic aerosol (POA) dominated in pollution events with low-RH and stagnant conditions. These results also highlighted the importance of meteorological conditions for PM pollution in this highly polluted city in North China.

Terahertz-dependent PM2.5 monitoring and grading in the atmosphere

Rapid industrialization and economic development have led to serious pollution in the form of fine particulate matter (PM2.5, particulate matter with a diameter of less than 2.5 μm). In China, PM2.5 has been one of the most debated topics in councils of government and issues of public concern. Terahertz (THz) radiation was employed to measure the PM2.5 in the atmosphere from September 2014 to April 2015 in Beijing. Comparison of the PM2.5 level from the website with THz absorbance revealed a significant phenomenon: THz radiation can be used to monitor PM2.5 in the atmosphere. During Asia-Pacific Economic Cooperation (APEC) 2014, “APEC Blue” was also recorded in a THz system. The relationship between absorbance and PM2.5 demonstrates that THz radiation is an effective selection for air pollution grading. Based on the absorbance spectra, the elemental compositions were studied by two-dimensional correlation spectroscopy (2DCOS) in conjunction with X-ray fluorescence. Several single absorption peaks were revealed and caused by sulphate from coal combustion, vehicle exhaust emissions and secondary reactions. Furthermore, mathematical algorithms, such as the BPANN and SVM, can process the THz absorbance data and greatly improve the precision of the estimation of PM2.5 mass. Our results suggest that THz spectroscopy can not only reveal the component information for pollution source determination, but quantitatively monitor the PM2.5 content for pollution level evaluation. Therefore, the use of THz radiation is a new method for future air pollution monitoring and grading systems.

Characteristics of fine particulate matter formation during combustion of lignite riched in AAEM (alkali and alkaline earth metals) and sulfur

The high contents of AAEM (alkali and alkaline earth metals) and sulfur in zhundong coal result in more fine particulate matter during coal combustion. In this paper, the emission of fine particulates from zhundong coal riched in AAEM-sulfur and zhunnan coal riched in aluminum-silicon was investigated in a drop tube furnace. Co-combustion of zhundong coal and zhunnan coal was further investigated to study the effect of interaction among different elements in coal on the PM formation. The size distribution, concentration and composition of the particulates were analyzed by low pressure impactor (DLPI) and scanning electron microscopy (SEM). The distribution of sodium, magnesium, calcium, iron and sulfur in fine particulates and their effects on the generation of fine particulates were obtained. The results show that the fine particulates from AAEM-sulfur rich coal combustion mainly consist of sulfates and oxides of AAEM. The amount of fine particulates from burning aluminum-silicon rich coal decreased significantly. The composition of PM0.4 and PM0.4+ are significantly different. Co-firing of AAEM-sulfur rich coal with aluminum-silicon rich coal has an obviously synergetic effect of reducing the fine particulates emission. The capture of AAEM and iron by aluminum-silicon compounds plays an important role in PM10 reduction during blended coal combustion. The change of sulfur content in PM0.4 is consistent with the change of AAEM content.

Promotional role of Mn doping on catalytic oxidation of VOCs over mesoporous TiO2 under vacuum ultraviolet (VUV) irradiation

Volatile organic compounds (VOCs) are the crucial precursors to the formation of fine particulate matter and photochemical smog. Photocatalytic oxidation (PCO) under vacuum ultraviolet (VUV) irradiation has attracted increasing interest for VOCs degradation owing to its strong oxidation capability and excellent stability. However, the generation of O3 from VUV irradiation causes secondary pollution and needs to be addressed. In this study, the Mn doped mesoporous TiO2 (Mn/meso-TiO2) was developed and first combined with VUV irradiation to remove O3 as well as enhance benzene degradation via O3-assited catalytic oxidation. Results indicate that the Mn doped TiO2 exhibited a much higher benzene removal efficiency (82%) than undoped one (70%) and commercial TiO2 P25 (48%). The O3 by-product can be completely eliminated by Mn/meso-TiO2 and contributed to benzene removal efficiency of about 34%. The excellent performance was attributed to the formation of highly reactive oxidizing species such as O(1D), O(3P), hydroxyl radicals (OH) via catalytic decomposition of O3 over oxygen vacancy sites of Mn oxides. Mn/meso-TiO2 cooperated well with VUV and such a VUV-PCO process is very promising for VOCs degradation.

Spatiotemporal patterns of remotely sensed PM 2.5 concentration in China from 1999 to 2011

Air pollution in the form of fine particulate matter, or PM2.5, can decrease human life expectancy and increase the overall mortality rate. Based on a time series of remotely sensed PM2.5 concentrations, this study analyzed the spatiotemporal patterns of this crucial pollutant in China from 1999 to 2011 using trend analysis and standard deviation ellipse analysis, and carried out a health risk assessment of human exposure to PM2.5. The results showed that PM2.5 concentrations increased significantly from 1999 to 2011 in China, especially in the central and eastern parts of the country. The proportion of areas with PM2.5 concentrations higher than 35 μg/m3 increased year by year, and the areas with PM2.5 concentrations lower than the annual primary standard of 15 μg/m3 decreased continuously. The areas most polluted by PM2.5 were south of Hebei, north of Henan and west of Shandong provinces, with changes in the overall spatial distribution of the pollutant occurring faster along a south–north axis than along an east–west axis, and also faster along an east–south axis than along a west–north axis. Based on the PM2.5 concentrations in China from 1999 to 2011, a two-tier standard (level-I and level-II) was proposed for delineated areas to assist in nationwide air pollution control. It was also found that the proportion of the population exposed to PM2.5 concentrations greater than 35 μg/m3 increased year by year, and increased faster than the proportion of population exposed to PM2.5 concentrations in the range 15–35 μg/m3. The health risk in the central and eastern areas of the country was the highest. Based on these results, PM2.5 pollution poses an increasingly serious risk to human health across China and there is an immediate need to implement its regional control. In addition, more attention should be paid at the national scale in terms of pollution risk, rather than focusing narrowly on a city scale.

Petroleum coke in the urban environment: a review of potential health effects.

Petroleum coke, or petcoke, is a granular coal-like industrial by-product that is separated during the refinement of heavy crude oil. Recently, the processing of material from Canadian oil sands in U.S. refineries has led to the appearance of large petcoke piles adjacent to urban communities in Detroit and Chicago. The purpose of this literature review is to assess what is known about the effects of petcoke exposure on human health. Toxicological studies in animals indicate that dermal or inhalation petcoke exposure does not lead to a significant risk for cancer development or reproductive and developmental effects. However, pulmonary inflammation was observed in long-term inhalation exposure studies. Epidemiological studies in coke oven workers have shown increased risk for cancer and chronic obstructive pulmonary diseases, but these studies are confounded by multiple industrial exposures, most notably to polycyclic aromatic hydrocarbons that are generated during petcoke production. The main threat to urban populations in the vicinity of petcoke piles is most likely fugitive dust emissions in the form of fine particulate matter. More research is required to determine whether petcoke fine particulate matter causes or exacerbates disease, either alone or in conjunction with other environmental contaminants.

Composition and secondary formation of fine particulate matter in the Salt Lake Valley: Winter 2009

Under the National Ambient Air Quality Standards (NAAQS), put in place as a result of the Clean Air Amendments of 1990, three regions in the state of Utah are in violation of the NAAQS for PM10 and PM2.5 (Salt Lake County, Ogden City, and Utah County). These regions are susceptible to strong inversions that can persist for days to weeks. This meteorology, coupled with the metropolitan nature of these regions, contributes to its violation of the NAAQS for PM during the winter. During January–February 2009, 1-hr averaged concentrations of PM10-2.5, PM2.5, NOx, NO2, NO, O3, CO, and NH3 were measured. Particulate-phase nitrate, nitrite, and sulfate and gas-phase HONO, HNO3, and SO2 were also measured on a 1-hr average basis. The results indicate that ammonium nitrate averages 40% of the total PM2.5 mass in the absence of inversions and up to 69% during strong inversions. Also, the formation of ammonium nitrate is nitric acid limited. Overall, the lower boundary layer in the Salt Lake Valley appears to be oxidant and volatile organic carbon (VOC) limited with respect to ozone formation. The most effective way to reduce ammonium nitrate secondary particle formation during the inversions period is to reduce NOx emissions. However, a decrease in NOx will increase ozone concentrations. A better definition of the complete ozone isopleths would better inform this decision.Implications: Monitoring of air pollution constituents in Salt Lake City, UT, during periods in which PM2.5 concentrations exceeded the NAAQS, reveals that secondary aerosol formation for this region is NOx limited. Therefore, NOx emissions should be targeted in order to reduce secondary particle formation and PM2.5. Data also indicate that the highest concentrations of sulfur dioxide are associated with winds from the north-northwest, the location of several small refineries.

Addressing the Burden of Disease Attributable to Air Pollution in India: The Need to Integrate across Household and Ambient Air Pollution Exposures

Addressing the Burden of Disease Attributable to Air Pollution in India: The Need to Integrate across Household and Ambient Air Pollution Exposures

Formation of Fine Particulate Matter in a Domestic Pellet-Fired Boiler

This study concentrates on the formation of fine particulate matter (PM) in a domestic pellet-fired boiler and includes a detailed characterization of the combustion process inside the combustion chamber of the boiler. Measurements of local mean gas temperatures, major gas species concentrations, and PM concentrations and size distributions are reported for a representative boiler operating condition. In addition, a number of selected PM samples were also morphologically and chemically characterized. The results revealed that (i) most particles present aerodynamic diameters below 1 μm, regardless of the measurement location, and the mass size distributions peak in the size range of 50–130 nm; (ii) early in the flame, the PM size distributions present a bimodal size distribution, but this attribute vanishes as the final stages of the combustion process are approached; (iii) soot particles are rapidly formed early in the combustion process, but these carbon-rich particles also oxidize rapidly in the near burner region; (iv) the aerodynamic diameter corresponding to the maximum amount of particles increases slightly from the fuel bed until ≈4/5 of the combustion chamber height; (v) for a given measurement location and particle sizes below 1 μm, the PM chemical composition varies marginally among size ranges, indicating that the existing chemical compounds tend to form different size aggregates of similar composition; (vi) the element mass concentration varies according to the measurement location; early in the combustion process, the PM is dominated by carbon, with smaller amounts of O and Si, while in the final stages of the combustion process, the PM composition is dominated by inorganic material; and (vii) large fractions of the alkali metals are present as chlorides in the fine PM, and small fractions of the alkalis are present as sulfates.