Reducing Interference Effects in the Chemiluminescent Measurement of Nitric Oxides from Combustion Systems

Experiments were carried out to determine the relative chemiluminescence quenching efficiencies as a function of third body concentration for each of the common combustion products, H₂O, CO₂, CO, H₂, O₂ and Ar. These results are compared with those of other investigators. The effect of reaction chamber pressure on analyzer response and the development of an analyzer design which incorporates an adjustable sample capillary inlet capable of maintaining a constant molar flow rate of sample gas to the reaction chamber are discussed. The effect of carbon monoxide interference on chemiluminescent NO_x measurement has been isolated and found to be significant. A means of correcting NO, measurements for these CO interference effects is described. Quantification of NO and NO₂ absorption in liquid water in NO_x sampling systems has been made. Recommendations for sample system designs to handle the presence of water in the sample gas are made.     

CO2 from waste to resource by developing novel mixed matrix membranes

Environmental Science and Pollution Research - Mixed matrix membranes (MMMs) were fabricated by the hydrothermal synthesis of ordered mesoporous KIT-6 type silica and incorporating in polyimide...     

Comparative analysis using EIA for developed and developing countries: case studies of hydroelectric power plants in Pakistan,Norway and Sweden

Environmental impact assessment (EIA) is an important legislative and scientific tool that may assist and improve the quality assistance for the decision-making process in sustainable development. Here, a comparison of EIAs from three cases of hydropower projects in Pakistan, Norway and Sweden is reported. A huge difference concerning the incorporation of environmental considerations into the decisionmaking process between developed and developing countries is observed. The EIA system of Pakistan appears to be less efficient in the application and review process. In addition, the appraisal of issues, the decision-making process and evaluation through post-monitoring is not as well performed in Pakistan as in cases of hydroelectric power plants in Sweden and Norway. The key reason for this shortcoming is misconceptions about the EIA process, which initially receives intense attention but becomes weakened by the time of implementation. This implies that there is a need to adopt simplified and flexible EIA techniques suitable for the infrastructure and resources of a specific country, taking into account institutional, technical and financial constraints. Improvements are required in public participation, awareness, as well as in environmental control and data system sectors in Pakistan, besides simply enacting legislation to achieve the goals of the EIA system.     

Association of human cohorts exposed to blood and urinary biomarkers of PAHs with adult asthma in a South Asian metropolitan city

Semi-volatile organic compounds (SVOCs) are a major global problem that causes the greatest impact on urban settings and have been linked to bronchial asthma in both children and adults in Pakistan. The association between exposure of polycyclic aromatic hydrocarbons (PAHs) and asthma in the adult population is less clear. The current study aimed to assess the clinico-chemical parameters and blood levels of naphthalene phenanthrene, pyrene, and 1,2-benzanthracene and urinary levels of 1-OH pyrene and 1-OH phenanthrene as well as asthma-related biomarkers immunoglobulin E (IgE), resistin, and superoxide dismutase (SOD) of oxidative stress and other hematologic parameters in adults and their relationship with bronchial asthma. The GC/MS analysis showed higher mean concentrations of blood PAHs in asthma respondents (4.48 ± 1.34, 3.46 ± 1.04, 0.10 ± 0.03, and 0.29 ± 0.09) (ng/mL) as compared to controls (3.07 ± 0.92, 1.71 ± 0.51, 0.06 ± 0.02, and 0.11 ± 0.03) (ng/mL), with p = .006, p = .001, p = .050, and p = .001. Similarly, urinary levels of 1-OHpyr and 1-OHphe were significantly increased in adults with bronchial asthma (0.54 ± 0.16; 0.13 ± 0.04) (μmol/mol-Cr) than in controls (0.30 ± 0.09; 0.05 ± 0.02) (μmol/mol-Cr), with p = .002 and p = .0001, respectively, with a significant positive correlation to asthma severity. The asthma-related biomarkers IgE, resistin, and SOD were significantly higher (p 0.0001, 0.0001, and 0.0001) in people with asthma than in control persons. The findings showed that higher blood and urine PAHs levels were linked to higher asthma risk in adults and significant interaction with participants who smoked, had allergies, had a family history of asthma, and were exposed to dust. The current study’s findings will be useful to local regulatory agencies in Lahore in terms of managing exposure and advocating efforts to minimize PAH pollution and manage health.

     

Modeling the impacts of temperature and precipitation changes on soil CO2 fluxes from a Switchgrass stand recently converted from cropland

Switchgrass(Panicum virgatum L.) is a perennial C_4 grass native to North America and successfully adapted to diverse environmental conditions. It offers the potential to reduce soil surface carbon dioxide(CO_2) fluxes and mitigate climate change. However, information on how these CO_2 fluxes respond to changing climate is still lacking. In this study, CO_2 fluxes were monitored continuously from 2011 through 2014 using high frequency measurements from Switchgrass land seeded in 2008 on an experimental site that has been previously used for soybean(Glycine max L.) in South Dakota, USA. DAYCENT, a process-based model, was used to simulate CO_2 fluxes. An improved methodology CPTE[Combining Parameter estimation(PEST) with "Trial and Error" method] was used to calibrate DAYCENT. The calibrated DAYCENT model was used for simulating future CO_2 emissions based on different climate change scenarios. This study showed that:(i) the measured soil CO_2 fluxes from Switchgrass land were higher for 2012 which was a drought year, and these fluxes when simulated using DAYCENT for long-term(2015–2070) provided a pattern of polynomial curve;(ii) the simulated CO_2 fluxes provided different patterns with temperature and precipitation changes in a long-term,(iii) the future CO_2 fluxes from Switchgrass land under different changing climate scenarios were not significantly different, therefore, it can be concluded that Switchgrass grown for longer durations could reduce changes in CO_2 fluxes from soil as a result of temperature and precipitation changes to some extent.     

Organochlorine pesticides in the surrounding soils of POPs destruction facility: source fingerprinting,human health,and ecological risks assessment

Environmental Science and Pollution Research - The elimination of persistent organic pollutants (POPs) obsolete pesticides stockpiles, particularly the organochlorine pesticides (OCPs), is one of...     

Role of ambient air pollution in asthma spread among various population groups of Lahore City: a case study

Environmental Science and Pollution Research - Air pollution levels rise as a result of industrial and vehicular emissions, epidemiological issues such as asthma become more prevalent in Lahore,...