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Microbiological Quality of Bottled Water Available in Lahore City  [cached]
JPMS
Journal of Pakistan Medical Students , 2013,
Abstract: (CMH Lahore Medical College, Lahore, Pakistan)(Original Article; p110-112)
Tracer Elements analysis of Aerosols in the Atmosphere of Lahore using Radio analytical techniques  [cached]
Ata S.,Qadir M. A.,Rasool A.
E3S Web of Conferences , 2013, DOI: 10.1051/e3sconf/20130120005
Abstract: The perturbations of atmospheric processes by anthropogenic activities of man have been of great concern these days. The deposition of trace and major elements from the atmosphere to the ground is an important factor for animal and plant health, and it is of major consideration in studies on the cycling of elements that may function in the atmosphere as nutrients or potentially toxic pollutants. When assessing the input of materials in natural waters and land, the sources and composition of atmosphere need to be determined. Geological and anthropogenic contributions to air pollution were monitored by analyzing aerosol particulates present in the atmosphere of Lahore. Various sorts of experiments were performed for studying total suspended particulate matter (TSPs) using gravimetric techniques. The average value of TSPs was found 450 ug/m2 in working days and 240 ug/m2 in holidays. Their size distribution and trace elemental composition and their wet removal through precipitation in the atmosphere of Lahore was studied by using scanning electron microscopy (SEM) and instrumental neutron activation analysis (INAA) respectively. Eighteen elements were analyzed. Geological nature of the land was attributed the presence of Yb, Cs, Sc, Rb, Co, Eu, La, Ba, Zn and Hf s in the aerosol particulates. The presence of Cr, Fe, Ce, Pb and Cd could be linked to anthropogenic activities. Their amount was two times higher than the limits reccomended by the U.S. Environmental Protection Agency for the urban environment, mostly during working days and at various day and night time.
Particulate matter (PM2.5) concentration and source apportionment in lahore
Lodhi, Arifa;Ghauri, Badar;Khan, M. Rafiq;Rahman, S.;Shafique, Shoaib;
Journal of the Brazilian Chemical Society , 2009, DOI: 10.1590/S0103-50532009001000007
Abstract: the work reported in this paper was carried out to study the trends of pm2.5 (particles with an aerodynamic diameter of 2.5 μm or less) concentrations and source apportionment of pm2.5 monitored at an urban residential site in lahore, pakistan. pm2.5 aerosol samples were collected for 2 days in a week at 12 h interval in a day, both in dry and wet seasons, on zefluortm filter papers using thermo-electron corporation reference ambient air sampler (raas). total 310 samples were collected during the period under study, i.e., from november 2005 to december 2007. high pm2.5 loads were observed in winter, which were approximately 4 times greater than those observed in the summer, spring, fall and monsoon seasons in the yearlong measurements. source apportionment was performed on short duration analysis results of november 2005 to march 2006 using positive matrix factorization (pmf) model. the results derived from pmf model indicated that the major contributors to pm2.5 in lahore are: soil/road dust, industrial emissions, vehicular emissions and secondary aerosols. it is, therefore, concluded that in addition to local vehicular and industrial emissions, the city is also affected from trans-boundary air pollutants particularly due to secondary aerosols (especially so42-) during winter which increase pm2.5 concentrations manifold when relatively less mixing height exists. the sulfate particles also facilitate in haze/fog formation during calm highly humid conditions, thus reduce visibility and increase the incidents of respiratory diseases encountered in the city every year.
Measurement of ambient aerosols in northern Mexico City by single particle mass spectrometry
R. C. Moffet,B. de Foy,L. T. Molina,M. J. Molina
Atmospheric Chemistry and Physics Discussions , 2007,
Abstract: Continuous ambient measurements with aerosol time-of-flight mass spectrometry (ATOFMS) were carried out in an industrial/residential section in the northern part of Mexico City as part of the Mexico City Metropolitan Area – 2006 campaign (MCMA-2006) between 7–27 March, 2006. Biomass and organic carbon (OC) particle types were found to dominate the accumulation mode both day and night. The concentrations of both organic carbon and biomass particles were roughly equal early in the morning, but biomass became the largest contributor to the accumulation mode mass from the late morning until early evening. The diurnal pattern can be attributed to aging and/or a change in meteorology. Fresh elemental carbon (EC) particles were observed during rush hour. The majority of the EC particles were mixed with nitrate, sulfate, organic carbon and potassium. Submicron particles from industrial sources in the northeast were composed of an internal mixture of Pb, Zn, EC and Cl and peaked early in the morning. A unique nitrogen-containing organic (NOC) particle type was observed, and is hypothesized to be from industrial emissions based on the temporal profile and back trajectory analysis. This study provides unique insights into the real-time changes in single particle mixing state as a function of size and time for aerosols in Mexico City. These new findings indicate that biomass burning and industrial operations make significant contributions to particles in Mexico City. These sources have received relatively little attention in previous intensive field campaigns.
Thermodynamics and kinetics of the hydrolysis of atmospherically relevant organonitrates and organosulfates  [PDF]
K. S. Hu,A. I. Darer,M. J. Elrod
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2011, DOI: 10.5194/acp-11-8307-2011
Abstract: The presence of alcohol, organonitrate, and organosulfate species related to the gaseous precursor isoprene in ambient secondary organic aerosol (SOA) has stimulated investigations of the nature of SOA-phase chemical processing. Recent work has suggested that certain isoprene-derived organonitrates are able to efficiently convert to organosulfates and alcohols on ambient SOA. In order to better understand the structure activity relationships previously observed for the isoprene-derived organonitrates and organosulfates, the hydrolysis reactions of a number of monofunctional and difunctional organonitrates and organosulfates with varying carbon substitution properties were investigated. Nuclear magnetic resonance techniques were used to study the bulk phase aqueous reactions of these organonitrates and organosulfates in order to determine hydrolysis reaction rate and, in some cases, thermodynamics information. Electronic structure calculations were also carried out to determine the enthalpy of hydrolysis for these species, and for the previously studied isoprene-derived species. The results suggest that while organonitrates and organosulfates are thermodynamically unstable with respect to the corresponding alcohols at standard state, only the tertiary organonitrates (and perhaps some tertiary organosulfates) are able to efficiently hydrolyze on SOA timescales and acidities.
Evaluation of Risk Factors of HCV infection in Lahore, (Pakistan)  [cached]
Rao Muhammad Ijaz,Ahmad Saeed Akhter
Pakistan Journal of Statistics and Operation Research , 2007, DOI: 10.1234/pjsor.v3i1.77
Abstract: Hepatitis C Virus (HCV) infection is rapidly growing disease in world in general and in Pakistan in particular. In Pakistan more than 10 million persons have HCV +ve signs. Risk factors for this fatal disease included main, historic and demographic factors. Some researchers segregated few independent factors but other, include them in the category of depends. We have collected the data for Lahore (Pakistan) and analyzed this data by considering the aforesaid factors. Some results of this research do not match with the existing theories. We recommended that interaction effects of associated factors should also be considered in evaluation.
Photoacoustic optical properties at UV, VIS, and near IR wavelengths for laboratory generated and winter time ambient urban aerosols
M. Gyawali, W. P. Arnott, R. A. Zaveri, C. Song, H. Moosmüller, L. Liu, M. I. Mishchenko, L.-W. A. Chen, M. C. Green, J. G. Watson,J. C. Chow
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2012,
Abstract: We present the laboratory and ambient photoacoustic (PA) measurement of aerosol light absorption coefficients at ultraviolet wavelength (i.e., 355 nm) and compare with measurements at 405, 532, 870, and 1047 nm. Simultaneous measurements of aerosol light scattering coefficients were achieved by the integrating reciprocal nephelometer within the PA's acoustic resonator. Absorption and scattering measurements were carried out for various laboratory-generated aerosols, including salt, incense, and kerosene soot to evaluate the instrument calibration and gain insight on the spectral dependence of aerosol light absorption and scattering. Ambient measurements were obtained in Reno, Nevada, between 18 December 2009 and 18 January 2010. The measurement period included days with and without strong ground level temperature inversions, corresponding to highly polluted (freshly emitted aerosols) and relatively clean (aged aerosols) conditions. Particulate matter (PM) concentrations were measured and analyzed with other tracers of traffic emissions. The temperature inversion episodes caused very high concentration of PM2.5 and PM10 (particulate matter with aerodynamic diameters less than 2.5 μm and 10 μm, respectively) and gaseous pollutants: carbon monoxide (CO), nitric oxide (NO), and nitrogen dioxide (NO2). The diurnal change of absorption and scattering coefficients during the polluted (inversion) days increased approximately by a factor of two for all wavelengths compared to the clean days. The spectral variation in aerosol absorption coefficients indicated a significant amount of absorbing aerosol from traffic emissions and residential wood burning. The analysis of single scattering albedo (SSA), ngstr m exponent of absorption (AEA), and ngstr m exponent of scattering (AES) for clean and polluted days provides evidences that the aerosol aging and coating process is suppressed by strong temperature inversion under cloudy conditions. In general, measured UV absorption coefficients were found to be much larger for biomass burning aerosol than for typical ambient aerosols.
Quantitative assessment of organosulfates in size-segregated rural fine aerosol
H. Lukács, A. Gelencsér, A. Hoffer, G. Kiss, K. Horváth,Z. Hartyáni
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2009,
Abstract: Organosulfates have recently come into the focus of organic aerosol research as potentially important components of water-soluble secondary organic aerosol (SOA) which now dominate tropospheric fine aerosol. Their presence has been confirmed by the identification of sulfate esters of abundant biogenic carbonyl compounds in both smog chamber and continental aerosol. However, none of the studies have been able to determine the mass contribution of organosulfates to SOA. In this paper, as possibly the very first attempt to quantify organosulfates in ambient aerosol, we inferred the mass concentrations of organosulfates by concurrently determining mass concentrations of total sulfur, sulfate and methanesulfonate in rural fine aerosol using two highly sensitive analytical techniques. Although uncertainties were relatively large, we found that mass concentrations of organosulfates in water-soluble fine aerosol ranged from 0.02 μgS m 3 to 0.09 μgS m 3 yielding a mass contribution of 6–12% to bulk sulfur concentrations (or 6–14% to sulfate concentrations). The inferred size distribution of organosulfates suggested that they possibly form in heterogeneous reactions from semi-volatile carbonyl compounds with subsequent or concurrent condensation of gaseous sulfuric acid producing a refractory organic film on particle surfaces.
Quantitative assessment of organosulfates in size-segregated rural fine aerosol  [PDF]
H. Lukács,A. Gelencsér,A. Hoffer,G. Kiss
Atmospheric Chemistry and Physics Discussions , 2008,
Abstract: Organosulfates have recently come into the focus of organic aerosol research as potentially important components of water-soluble secondary organic aerosol (SOA) which now dominate tropospheric fine aerosol. Their presence has been confirmed by the identification of sulfate esters of abundant biogenic carbonyl compounds in both smog chamber and continental aerosol. However, none of the studies have been able to determine the mass contribution of organosulfates to SOA. In this paper, as possibly the very first attempt to quantify organosulfates in ambient aerosol, we inferred the mass concentrations of organosulfates by concurrently determining mass concentrations of total sulfur, sulfate and methanesulfonate in rural fine aerosol using two highly sensitive analytical techniques. Although uncertainties were relatively large, we found that mass concentrations of organosulfates in water-soluble fine aerosol ranged from 0.02 μgS m 3 to 0.09 μgS m 3 yielding a mass contribution of 6–12% to bulk sulfur concentrations (or 6–14% to sulfate concentrations). The inferred size distribution of organosulfates suggested that they possibly form in heterogeneous reactions from semi-volatile carbonyl compounds with subsequent or concurrent condensation of gaseous sulfuric acid producing a refractory organic film on particle surfaces.
Functional group composition of ambient and source organic aerosols determined by tandem mass spectrometry
J. Dron, I. El Haddad, B. Temime-Roussel, J.-L. Jaffrezo, H. Wortham,N. Marchand
Atmospheric Chemistry and Physics (ACP) & Discussions (ACPD) , 2010,
Abstract: The functional group composition of various organic aerosols (OA) is investigated using a recently developed analytical approach based on atmospheric pressure chemical ionisation-tandem mass spectrometry (APCI-MS/MS). The determinations of three functional groups contents are performed quantitatively by neutral loss (carboxylic and carbonyl groups, R-COOH and R-CO-R′ respectively) and precursor ion (nitro groups, R-NO2) scanning modes of a tandem mass spectrometer. Major organic aerosol sources are studied: vehicular emission and wood combustion for primary aerosol sources; and a secondary organic aerosol (SOA) produced through photooxidation of o-xylene. The results reveal significant differences in the functional group contents of these source aerosols. The laboratory generated SOA is dominated by carbonyls while carboxylics are preponderate in the wood combustion particles. On the other hand, vehicular emissions are characterised by a strong nitro content. The total amount of the three functional groups accounts for 1.7% (vehicular) to 13.5% (o-xylene photooxidation) of the organic carbon. Diagnostic functional group ratios are then used to tentatively discriminate sources of particles collected in an urban background environment located in an Alpine valley (Chamonix, France) during a strong winter pollution event. The three functional groups under study account for a total functionalisation rate of 2.2 to 3.8% of the organic carbon in this ambient aerosol, which is also dominated by carboxylic moieties. In this particular case study of a deep alpine valley during winter, we show that the nitro- and carbonyl-to-carboxylic diagnostic ratios can be a useful tool to discriminate sources. In these conditions, the total OA concentrations are highly dominated by wood combustion OA. This result is confirmed by an organic markers source apportionment approach which assess a wood burning organic carbon contribution of about 60%. Finally, examples of functional group mass spectra of all aerosols under study are presented, and additional perspectives offered by the mass spectra in terms of OA characterisation are discussed.
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