Form Of Fine Particulate Matter Research Articles

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.

COMBINED OPTOELECTRONIC METHODS USED IN THE MONITORING OF SO2 EMISSIONS AND IMISSIONS

This study focuses on the local scale behavior of SO2 emissions resulting from lignite-combustion thermal power plants. The investigations aimed at monitoring the SO2 emissions and imissions over a two week period in September 2010. One of the largest power plants from Eastern Europe was chosen for monitoring using different optoelectronic techniques. Rovinari power plant (44o54 45 N 23o09 44 E) is one of the largest electricity suppliers of Romania, having 4 groups of 330 MW each, with a total installed capacity of 1420 MW and is located in the Rovinari-Motru coal mining area This power plant along with similar facilities located in south-west of Romania is responsible for local and regional pollution problems concerning acid rain, formation of fine particulate matter, smog etc. Emissions from the stacks of Rovinari power plant were monitored with a UV camera that uses the strong absorption of SO2 molecules between 280 320 nm. Images with UV camera were collected from distances ranging between 1 and 2 km. Immisions measurements were made simultaneously with a HORIBA SO2 analyzer for continuous monitoring of atmospheric SO2 imissions using UV fluorescence method. Within the two weeks of measurements the SO2 immisions hourly limit of 350 g/m3 was exceeded two times, the highest measured concentration of 590 g/m3 occurring during stable meteorological conditions (very low wind speeds) inhibiting dispersion and favoring the accumulation of SO2 on a local scale. At the stacks, SO2 concentrations were constantly over 1000 ppm*m during the analyzed days.

Technical note: Contribution of ammonia emitted from livestock to atmospheric fine particulate matter (PM2.5) in the United States

Ammonia emitted from animal feeding operations is an air pollutant contributing to the formation of fine particulate matter (PM2.5), considered a major environmental risk to human health. In the United States, farm animals are the greatest contributor to gaseous ammonia emissions. Ammonia reacts with atmospheric nitric and sulfuric acids to form PM2.5 (nitrate and sulfate), but the proportion of PM2.5 attributable to ammonia emitted from animal farming operations has not been quantified. Thus, the objective of this analysis was to estimate the contribution of ammonia emitted from farm animals to PM2.5 in the United States. The following approach was used: (1) the amount of ammonium in sulfate and nitrate PM2.5 was calculated based on chemically speciated measurements published by the United States Environmental Protection Agency; and (2) the amount of ammonium in sulfate and nitrate PM2.5 originating from livestock was assumed equal to the fraction of the total ammonia emissions attributable to livestock. Across different regions of the United States and under different weather conditions, PM2.5 formed from ammonia emitted from livestock operations were estimated to contribute on average from 5 to 11% of the total PM2.5 concentrations. In certain areas (North Central, for example) and in cool weather, farm animal contribution to atmospheric PM2.5 concentration may be as much as 20%.

Investigating the potential role of ammonia in ion chemistry of fine particulate matter formation for an urban environment

To investigate the potential role of ammonia in ion chemistry of PM 2.5 aerosol, measurements of PM 2.5 (particulate matter having aerodynamic diameter < 2.5 µm) along with its ionic speciation and gaseous pollutants (sulfur dioxide (SO 2), nitrogen oxides (NO x ), ammonia (NH 3) and nitric acid (HNO 3)) were undertaken in two seasons (summer and winter) of 2007–2008 at four sampling sites in Kanpur, an urban-industrial city in the Ganga basin, India. Mean concentrations of water-soluble ions were observed in the following order (i) summer: SO 4 2− (26.3 µg m − 3 ) > NO 3 − (16.8) > NH 4 + (15.1) > Ca 2+ (4.1) > Na + (2.4) > K + (2.1 µg m − 3 ) and (ii) winter: SO 4 2− (28.9 µg m − 3 ) > NO 3 − (23.0) > NH 4 + (16.4) > Ca 2+(3.4) > K +(3.3) > Na + (3.2 µg m − 3 ). The mean molar ratio of NH 4 + to SO 4 2− was 2.8 ± 0.6 (mostly >2), indicated abundance of NH 3 to neutralize H 2SO 4. The excess of NH 4 + was inferred to be associated with NO 3 − and Cl −. Higher sulfur conversion ratio ( F s: 58%) than nitrogen conversion ratio ( F n: 39%) indicated that SO 4 2− was the preferred secondary species to NO 3 −. The charge balance for the ion chemistry of PM 2.5 revealed that compounds formed from ammonia as precursor are (NH 4) 2SO 4, NH 4NO 3 and NH 4Cl. This study conclusively established that while there are higher contributions of NH 4 +, SO 4 2− to PM 2.5 in summer but for nitrates (in particulate phase), it is the winter season, which is critical because of low temperatures that drives the reaction between ammonia and HNO 3 in forward direction for enhanced nitrate formation. In summary, inorganic secondary aerosol formation accounted for 30% mass of PM 2.5 and any particulate control strategy should include optimal control of primary precursor gases including ammonia.

Transport of Atmospheric Fine Particulate Matter: Part 1—Findings from Recent Field Programs on the Extent of Regional Transport within North America

Air quality field data, collected as part of the fine particulate matter Supersites program and other field measurements programs, have been used to assess the role of aerosol transport, over length scales of approximately 100–1000 km, on fine particulate matter concentrations. Assessment of data from New York, NY; Baltimore, MD; Pittsburgh, PA; Atlanta, GA; Houston, TX; St. Louis, MO; and Fresno, CA, indicates that in virtually all of the regions, transport of aerosol over distances of 100-1000 km has a significant impact on urban particulate matter concentrations and a dominant role in determining rural particulate matter concentrations, though the nature of the regional contributions differs from region to region. This assessment is generally consistent with previous conceptual models of fine particulate matter formation and accumulation in these regions. The nature of the transported aerosol is largely sulfate in Eastern and Midwestern cities and nitrate in the Central Valley of California. In addition to physical transport of aerosol over distances of 100–1000 km, regional transport of aerosol precursors may lead to conditions conducive to large-scale nucleation events. Regional nucleation events have been reported in the East, Midwest, and in California. The events occurred in the morning soon after surface layers coupled with layers aloft, and the events generate ultrafine particles. In some cases, these nucleation events have been correlated with availability of sulfur dioxide and, therefore, may be sulfate formation events.

Sensitivities of Ozone and Fine Particulate Matter Formation to Emissions under the Impact of Potential Future Climate Change

Impact of climate change alone and in combination with currently planned emission control strategies are investigated to quantify effectiveness in decreasing regional ozone and PM2.5 over the continental U.S. using MM5, SMOKE, and CMAQ with DDM-3D. Sensitivities of ozone and PM2.5 formation to precursor emissions are found to change only slightly in response to climate change. In many cases, mass per ton sensitivities to NO(x) and SO2 controls are predicted to be greater in the future due to both the lower emissions as well as climate, suggesting that current control strategies based on reducing such emissions will continue to be effective in decreasing ground-level ozone and PM2.5 concentrations. SO2 emission controls are predicted to be most beneficial for decreasing summertime PM2.5 levels, whereas controls of NO(x) emissions are effective in winter. Spatial distributions of sensitivities are also found to be only slightly affected assuming no changes in land-use. Contributions of biogenic VOC emissions to PM2.5 formation are simulated to be more important in the future because of higher temperatures, higher biogenic emissions, and lower anthropogenic NO(x) and SO2 emissions.

Modeling atmospheric transport and fate of ammonia in North Carolina—Part II: Effect of ammonia emissions on fine particulate matter formation

Accurate estimates of ammonia (NH 3) emissions are needed for reliable predictions of fine particulate matter (PM 2.5) by air quality models (AQMs), but the current estimates contain large uncertainties in the temporal and spatial distributions of NH 3 emissions. In this study, the US EPA Community Multiscale Air Quality (CMAQ) modeling system is applied to study the contributions of the agriculture–livestock NH 3 (AL-NH 3) emissions to the concentration of PM 2.5 and the uncertainties in the total amount and the temporal variations of NH 3 emissions and their impact on the formation of PM 2.5 for August and December 2002. The sensitivity simulation results show that AL-NH 3 emissions contribute significantly to the concentration of PM 2.5, NH 4 +, and NO 3 −; their contributions to the concentrations of SO 4 2− are relatively small. The impact of NH 3 emissions on PM 2.5 formation shows strong spatial and seasonal variations associated with the meteorological conditions and the ambient chemical conditions. Increases in NH 3 emissions in August 2002 resulted in >10% increases in the concentrations of NH 4 + and NO 3 −; reductions in NH 3 emissions in December 2002 resulted in >20% decreases in their concentrations. The large changes in species concentrations occur downwind of the high NH 3 emissions where the ambient environment is NH 3-poor or neutral. The adjustments in NH 3 emissions improve appreciably the model predictions of NH 4 + and NO 3 − both in August and December, but resulted in negligible improvements in PM 2.5 in August and a small improvement in December, indicating that other factors (e.g., inaccuracies in meteorological predictions, emissions of other primary species, aerosol treatments) might be responsible for model biases in PM 2.5.

Acid rain in Europe and the United States: an update

This paper discusses the evolution of science and policies to control acid rain in Europe and the United States over the past several decades. Acid rain gained prominence in the late 1960s because of its perceived effects on ecosystem integrity. Extensive research efforts in both Europe and the United States, however, have concluded that the effects of acid rain—at least those on terrestrial ecosystems—were less serious than originally believed. More recently, interest in controlling acid rain precursors stems primarily from health concerns, particularly their effects in the form of fine particulate matter. The paper discusses the emergence of acid rain as an environmental concern, scientific evidence about the effects of acidic deposition on natural ecosystems, US and European acid rain control policies, studies of the costs and benefits of reducing acid rain, and different policy contexts in Europe and the United States. © 2004 Elsevier Ltd. All rights reserved.