Variations in Particle Composition and Size Distributions in and Around a Deep Pit Swine Operation

Agricultural facilities are the source of many types of particles and gases that can exhibit an influence on air quality. Emissions potentially impacting air quality from agricultural sources have become a concern for regulatory agencies such as the United States Department of Agriculture (USDA) and the Environmental Protection Agency (EPA). Particle mass concentration influences from agricultural sources can include both primary particles (direct emissions such as dust) and secondary particles (formed from gaseous precursors such as ammonia)

Patient adherence to prescribed artemisinin-based combination therapy in Garissa County, Kenya, after three years of health care in a conflict setting.

BACKGROUND: Current day malaria cases and deaths are indicative of a lack of access to both methods of prevention, diagnosis, and treatment; an important determinant of treatment efficacy is adherence. This study is a follow up to the baseline study of adherence to artemether-lumefantrine (AL) carried out in Garissa District in 2010. The study presented evaluates any changes in adherence levels which may have occurred in the area during this period and after nearly three years of sustained use of ACT across the public health sector. METHODS: The study was carried out in Garissa County in the North Eastern Province of Kenya and included patients fitting the suspected malaria case definition and having been prescribed AL, regardless of confirmatory diagnosis. A questionnaire assessed the intake of AL via both self-reporting by the participant and observation of blister packs by the interviewer. On separate occasions exit interviews with patients and observations of prescribers were also carried out. RESULTS: Of the 218 participants enrolled, 195 were successfully followed up. 60% of participants were found to be adherent to the three-day AL regimen, this is 4.7% lower than the proportion of participants adherent in 2010; the result of a two-sided z-test was not significant (p = 0.23). The odds of the patient being adherent to AL increased by 65% with each additional correct statement regarding how to take AL that a patient could recall (between zero and four statements), this was the only variable significantly associated with patient adherence (p = 0.01). CONCLUSION: Sustaining the ACT adherence rates at the 2010 levels, through 2.5 years of insecurity in the study area is an achievement and suggests that if security can be improved barriers to improving health service quality and patient adherence to AL would be removed. This study, by looking specifically at anti-malarial adherence over a prolonged period and in a setting of severe conflict, provides a valuable and rare insight in to the challenges and barriers to ACT adherence in such settings

Perceptions of malaria and acceptance of rapid diagnostic tests and related treatment practises among community members and health care providers in Greater Garissa, North Eastern Province, Kenya.

BACKGROUND: Conventional diagnosis of malaria has relied upon either clinical diagnosis or microscopic examination of peripheral blood smears. These methods, if not carried out exactly, easily result in the over- or under-diagnosis of malaria. The reliability and accuracy of malaria RDTs, even in extremely challenging health care settings, have made them a staple in malaria control programmes. Using the setting of a pilot introduction of malaria RDTs in Greater Garissa, North Eastern Province, Kenya, this study aims to identify and understand perceptions regarding malaria diagnosis, with a particular focus on RDTs, and treatment among community members and health care workers (HCWs). METHODS: The study was conducted in five districts of Garissa County. Focus group discussions (FGD) were performed with community members that were recruited from health facilities (HFs) supported by the MENTOR Initiative. In-depth interviews (IDIs) and FGDs with HCWs were also carried out. Interview transcripts were then coded and analysed for major themes. Two researchers reviewed all codes, first separately and then together, discussed the specific categories, and finally characterized, described, and agreed upon major important themes. RESULTS: Thirty-four FGDs were carried out with a range of two to eight participants (median of four). Of 157 community members, 103 (65.6%) were women. The majority of participants were illiterate and the highest level of education was secondary school. Some 76% of participants were of Somali ethnicity. Whilst community members and HCWs demonstrated knowledge of aspects of malaria transmission, prevention, diagnosis, and treatment, gaps and misconceptions were identified. Poor adherence to negative RDT results, unfamiliarity and distrust of RDTs, and an inconsistent RDT supply were the main challenges to become apparent in FGDs and IDIs. CONCLUSION: Gaps in knowledge or incorrect beliefs exist in Greater Garissa and have the potential to act as barriers to complete and correct malaria case management. Addressing these knowledge gaps requires comprehensive education campaigns and a reliable and constant RDT supply. The results of this study highlight education and supply chain as key factors to be addressed in order to make large scale roll out of RDTs as successful and effective as possible

A long-term study of new particle formation in a coastal environment: Meteorology, gas phase and solar radiation implications

New particle formation (NPF) was investigated at a coastal background site in Southwest Spain over a four-year period using a Scanning Particle Mobility Sizer (SMPS). The goals of the study were to characterise the NPF and to investigate their relationship to meteorology, gas phase (O3, SO2, CO and NO2) and solar radiation (UVA, UVB and global). A methodology for identifying and classifying the NPF was implemented using the wind direction and modal concentrations as inputs. NPF events showed a frequency of 24% of the total days analyzed. The mean duration was 9.2±4.2 hours. Contrary to previous studies conducted in other locations, the NPF frequency reached its maximum during cold seasons for approximately 30% of the days. The lowest frequency took place in July with 10%, and the seasonal wind pattern was found to be the most important parameter influencing the NPF frequency. The mean formation rate was 2.2±1.7 cm-3 s-1, with a maximum in the spring and early autumn and a minimum during the summer and winter. The mean growth rate was 3.8±2.4 nm h-1 with higher values occurring from spring to autumn. The mean and seasonal formation and growth rates are in agreement with previous observations from continental sites in the Northern Hemisphere. NPF classification of different classes was conducted to explore the effect of synoptic and regional-scale patterns on NPF and growth. The results show that under a breeze regime, the temperature indirectly affects NPF events. Higher temperatures increase the strength of the breeze recirculation, favouring gas accumulation and subsequent NPF appearance. Additionally, the role of high relative humidity in inhibiting the NPF was evinced during synoptic scenarios. The remaining meteorological variables (RH), trace gases (CO and NO), solar radiation, PM10 and condensation sink, showed a moderate or high connection with both formation and growth rates.This work was partially supported by the Andalusian Regional Government through projects P10-RNM-6299 and P12-RNM-2409, the Spanish Ministry of Science and Technology (MINECO) through projects CGL2010-18782, CGL2011-24891/CLI, CGL2013-45410-R and the Complementary Action CGL2011-15008-E.European Union through the ACTRIS project (EU INFRA-2010-1.1.16-262254)

Molecular understanding of sulphuric acid-amine particle nucleation in the atmosphere

4 pages 359-363 in the print version, additional 7 pages online.Peer reviewe

Sources and Source Processes of Organic Nitrogen Aerosols in the Atmosphere

The research in this dissertation explored the sources and chemistry of organic nitrogen aerosols in the atmosphere. Two approaches were employed: field measurements and laboratory experiments. In order to characterize atmospheric aerosol, two ambient studies were conducted in Cache Valley in Northern Utah during strong winter inversions of 2004 and 2005. The economy of this region is heavily dependent on agriculture. There is also a fast growing urban population. Urban and agricultural emissions, aided by the valley geography and meteorology, led to high concentrations of fine particles that often exceeded the national ambient air quality standards. Aerosol composition was dominated by ammonium nitrate and organic species. Mass spectra from an aerosol mass spectrometer revealed that the organic ion peaks were consistent with reduced organic nitrogen compounds, typically associated with animal husbandry practices. Although no direct source characterization studies have been undertaken in Cache Valley with an aerosol mass spectrometer, spectra from a study at a swine facility in Ames, Iowa, did not show any evidence of reduced organic nitrogen species. This, combined with temporal and diurnal characteristics of organic aerosol peaks, was a pointer that the organic nitrogen species in Cache Valley likely formed from secondary chemistry. Application of multivariate statistical analyses to the organic aerosol spectra further supported this hypothesis. To quantify organic nitrogen signals observed in ambient studies as well as understand formation chemistry, three categories of laboratory experiments were performed. These were calibration experiments, smog chamber studies, and an analytical method development. Laboratory calibration experiments using standard calibrants indicated that quantifying the signals from organic nitrogen species was dependent on whether they formed through acid-base chemistry or via secondary organic aerosol pathway. Results from smog chamber reactions of amines with ozone, nitrogen oxides, nitrate radical, and nitric acid showed that the secondary organic aerosol pathway was more plausible than acid-base chemistry, thus making the contribution of the organic nitrogen species to the total aerosol mass in Cache Valley significant. Gas phase and aerosol products formed from the smog chamber reactions were identified and used to devise reaction mechanisms. Finally, an ion chromatographic method for detecting and quantifying some key organic nitrogen species in aerosol was developed and tested

The effect of trimethylamine on atmospheric nucleation involving H₂SO₄

Field observations and quantum chemical calculations have shown that organic amine compounds may be important for new particle formation involving H₂SO₄. Here, we report laboratory observations that investigate the effect of trimethylamine (TMA) on H₂SO₄-H₂O nucleation made under aerosol precursor concentrations typically found in the lower troposphere ([H₂SO₄] of 10⁶&minus;10⁷ cm⁻³; [TMA] of 180–1350 pptv). The threshold [H₂SO₄] needed to produce the unity <i>J</i> was from 10⁶&minus;10⁷ cm⁻³ and the slopes of Log <i>J</i> vs. Log [H₂SO₄] and Log <i>J</i> vs. Log [TMA] were 4–6 and 1, respectively, strikingly similar to the case of ammonia (NH₃ ternary nucleation (Benson et al., 2011). At lower RH, however, enhancement in <i>J</i> due to TMA was up to an order of magnitude greater than that due to NH₃. These findings imply that both amines and NH₃ are important nucleation species, but under dry atmospheric conditions, amines may have stronger effects on H₂SO₄ nucleation than NH₃. Aerosol models should therefore take into account inorganic and organic base compounds together to fully understand the widespread new particle formation events in the lower troposphere

Particle Composition and Size Distributions in and around a Deep Pit Swine Operation

The contribution of emissions from agricultural facilities is rapidly becoming a major concern for local and regional air quality. Characterization of particle properties such as physical size distribution and chemical composition can be valuable in understanding the processes contributing to emissions and ultimate fate of particulate matter from agricultural facilities. A measurement campaign was conducted at an Iowa, deep-pit, three-barn swine finishing facility to characterize near-source ambient particulate matter. Size-specific mass concentrations were determined using minivol samplers, with additional size distribution information obtain using optical particle counters. Particulate composition was determined via ion chromatographic analysis of the collected filters. A thermal-CO2 elemental/organic carbon analyzer measured particulate carbon. The chemical composition and size distribution of sub-micron particles were determined via real-time aerosol mass spectrometry. Primary particulate was not found to be a major emission from the examined facility, with filter-based impactor samples showing average near-source increases (~15–50 m) in ambient PM10 of 5.8 ± 2.9 μg m−3 above background levels. PM2.5 also showed contribution attributable to the facility (1.7 ± 1.1 μg m−3). Optical particle counter analysis of the numerical size distributions showed bimodal distributions for both the upwind and downwind conditions, with maximums around 2.5 μm and below the minimum quantified diameter of 0.3 μm. The distributions showed increased numbers of coarse particles (PM10) during periods when wind transport came from the barns, but the differences were not statistically significant at the 95% confidence level. The PM10 aerosols showed statistically increased concentrations of sulfate, nitrate, ammonium, calcium, organic carbon, and elemental carbon when the samplers were downwind from the pig barns. Organic carbon was the major constituent of the barn-impacted particulate matter in both sub-micron (54%) and coarse size (20%) ranges. The AMS PM1 chemical speciation showed similar species increases, with the exception of NO−3NO3− and Ca+2, the latter not quantified by the AMS