A5007509679- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Air Quality Monitoring and Forecasting
- Vehicle emissions and performance
- Toxic Organic Pollutants Impact
- Atmospheric Ozone and Climate
- Cardiac Imaging and Diagnostics
- Analytical Chemistry and Chromatography
- Mass Spectrometry Techniques and Applications
- Advanced Chemical Sensor Technologies
- Chemical Thermodynamics and Molecular Structure
- Water Quality Monitoring and Analysis
- Spectroscopy and Laser Applications
- Click Chemistry and Applications
- Extraction and Separation Processes
- Cardiovascular Function and Risk Factors
- Analytical chemistry methods development
- Wind and Air Flow Studies
- Climate Change and Health Impacts
- Adenosine and Purinergic Signaling
- COVID-19 impact on air quality
- Atmospheric aerosols and clouds
- Plant responses to elevated CO2
- Catalytic Processes in Materials Science
- Synthesis and biological activity
George Mason University
2025
University of Nottingham
2021-2024
University of Birmingham
2013-2023
University of Ottawa
2012-2017
Environmental Earth Sciences
2015-2017
The Edgbaston Hospital
2016
Center for Food Safety and Applied Nutrition
2011-2015
Jamia Hamdard
2007-2014
Université de Montréal
2013
McGill University
2013
Polycyclic aromatic hydrocarbons (PAH) are currently generating a great deal of interest because their recognised toxicity, including carcinogenicity. In this study, source apportionment (SA) has been carried out using Positive Matrix Factorisation (PMF) with dataset 29 individual PAH (sum vapour and particulate forms) collected by the UK National Network between 2002 2006. Analysis data from 14 urban sites revealed four major categories corresponding to unburned petroleum, diesel...
Polycyclic aromatic hydrocarbons (PAH) are often measured in studies of atmospheric chemistry or health effects air pollution, due to their known human carcinogenicity. In recent years, PAH quinone derivatives have also become a focus interest, primarily because they can contribute oxidative stress. This work reports concentrations 17 and 15 quinones samples collected at trafficked roadside. Data presented for four compounds not previously reported ambient air: 2-methyl-1,4-naphthoquinone,...
Abstract. Secondary Organic Aerosol (SOA) affects atmospheric composition, air quality and radiative transfer, however major difficulties are encountered in the development of reliable models for SOA formation. Constraints on processes involved formation can be obtained by interpreting speciation evolution organics gaseous condensed phase simultaneously. In this study we investigate from dark α-pinene ozonolysis with particular emphasis upon mass distribution particulate organic species. A...
The removal of SO<sub>2</sub>in the presence of<italic>cis</italic>-but-2-ene and ozone exhibits a strong dependence on water vapour concentration.
Abstract. There is considerable interest in using low-cost optical particle counters (OPCs) to supplement existing routine air quality networks that monitor mass concentrations. In order do this, OPC data need be comparable with reference instrumentation; however, there currently no widely agreed upon methodology accomplish this. Aerosol hygroscopicity known a key parameter consider when correcting concentrations derived from OPCs, particularly at high ambient relative humidity (RH)....
Abstract. The Indian megacity of Delhi suffers from some the poorest air quality in world. While ambient NO2 and particulate matter (PM) concentrations have received considerable attention city, high ground-level ozone (O3) are an often overlooked component pollution. O3 can lead to significant ecosystem damage agricultural crop losses, adversely affect human health. During October 2018, speciated non-methane hydrocarbon volatile organic compounds (C2–C13), oxygenated (o-VOCs), NO, NO2,...
The gas-phase reactions of ozone with alkenes can be significant sources free radicals (OH, HO(2) and RO(2)) in the Earth's atmosphere. In this study total radical production degradation products from ethene ozonolysis have been measured, under conditions relevant to troposphere, during a series detailed simulation chamber experiments. Experiments were carried out European photoreactor EUPHORE (Valencia, Spain), utilising various instrumentation including chemical-ionisation-reaction...
Abstract Adenosine is an endogenous metabolite produced during hypoxia or inflammation. Previously implicated as anti-inflammatory mediator in CD4+ T cell regulation, we report that adenosine acts via dendritic (DC) A2B receptor (A2BAR) to promote the development of Th17 cells. Mouse naive cells cocultured with DCs presence stable mimetic 5′-(N-ethylcarboximado) resulted differentiation IL-17– and IL-22–secreting elevation mRNA encode signature Th17-associated molecules, such IL-23R RORγt....
The sources of polycyclic aromatic hydrocarbon (PAH) in various environmental media have commonly been identified based on the ratios concentrations selected PAH congeners. These are applicable to and distinguish between originating from vehicular emissions, petroleum products, combustion, coal biomass burning. In this study an evaluation diagnostic is provided for vapour particulate phase samples collected simultaneously at well defined roadside suburban sites Birmingham, UK. It focuses 14...
Although GC×GC-ToF-MS allows the separation of thousands peaks, many these peaks are not positively identified owing to lack mass spectral library data and/or standard materials, leading a substantial amount information being inaccessible. The fragmentation patterns molecules in spectrometers using electron impact ionization at 70 eV can be useful for molecule identification, provided match is available published EI MS library, but indistinguishable isomeric organic compounds (for example,...
A number of major research questions remain concerning the sources and properties road traffic generated particulate matter. full understanding composition primary vehicle exhaust aerosol its contribution to secondary organic (SOA) formation still remains elusive, many uncertainties exist relating semi-volatile component particles. Semi-Volatile Organic Compounds (SVOCs) are compounds which partition directly between gas phases under ambient conditions. The SVOCs in engine typically...
Abstract. Airborne particles and vapours, like many other environmental samples including water, soils sediments, contain complex mixtures of hydrocarbons, often deriving from crude oil either before or after fractionation into fuels, lubricants feedstocks. Comprehensive 2D gas chromatography time-of-flight mass spectrometry (GC × GC-ToF-MS), offers a very powerful technique that separates identifies compounds in complicated hydrocarbon mixtures. However, quantification identification...
Abstract. Vapour and particle-associated concentrations of 15 polycyclic aromatic hydrocarbons (PAH) 11 PAH quinones have been measured in winter summer campaigns at the rural site, Weybourne eastern England. Concentrations individual are relatively smaller than average previously urban sites UK. The air masses originating from southern England mainland UK significantly larger those Eastern Europe North Atlantic, while quinone to parent ratios show an inverse behaviour, being highest more...
Polycyclic aromatic hydrocarbons (PAH) and their nitro oxy derivatives have been sampled every three hours over one week in winter at two sites Birmingham UK. One site is heavily influenced by road traffic close to residential dwellings, while the other a background urban location some distance from both sources of emission. The time series concentrations has examined along with ratio between sampling sites. A comparison averaged diurnal profiles shown different patterns behaviour which...
Organic aerosol is one of the dominant components PM2.5 in megacities. In order to understand sources and formation processes aliphatic carbonyl compounds, concentrations saturated unsaturated hydrocarbons compounds were determined from an urban area Beijing sampled November–December 2016 analysed using two dimensional gas chromatography coupled time-of-flight mass spectrometry (GC x GC-TOFMS). The data separated into non-haze haze days (PM2.5 ≥ 75 μg m−3). n-Alkanes (C10-C36) n-alkenes...
Secondary organic aerosol (SOA) is well-known to have adverse effects on air quality and human health. However, the dynamic mechanisms occurring during SOA formation evolution are poorly understood. The time-resolved composition formed photo-oxidation of three aromatic compounds, methyl chavicol, toluene 4-methyl catechol, were investigated at European Photoreactor. was collected using a particle into liquid sampler analyzed offline state-of-the-art mass spectrometry produce temporal...
A number of major studies have demonstrated that the SVOC (Semi-volatile organic compounds) within engine emissions derive predominantly from unburned fuel and lubricants, are a contributor to primary atmospheric aerosol containing thousands compounds. The GC × GC-ToF-MS (2 dimensional Gas Chromatography – Time Flight Mass Spectrometry) comprehensive analytical technique was utilized in this study, resolve complex mixtures characterize content eight different commercial including 5 W30...
Diesel engine emissions are by far the largest source of nanoparticles in many urban atmospheres, which they dominate particle number count, and may present a significant threat to public health. This paper reviews knowledge composition atmospheric properties diesel exhaust particles, exemplifies research this field through description FASTER project (Fundamental Studies Sources, Properties Environmental Behaviour Exhaust Nanoparticles from Road Vehicles) studied size distribution-and,...
Particulate and vapor phase emissions in the diluted exhaust of a light-duty diesel engine designed for Euro 5 application have been sampled. The was operated three modes, samples were collected from without aftertreatment but also with by an oxidation catalyst particle filter. analyzed two-dimensional gas chromatography time-of-flight mass spectral detection. results show overall removal efficiencies organic compound combination filter 50, 56, 74% high-speed/high-load, low-speed/low-load,...
Abstract. Particle number size distributions have been measured simultaneously by scanning mobility particle sizers (SMPSs) at five sites in central London for a 1 month campaign January–February 2017. These measurements were accompanied condensation counters (CPCs) to measure total count four of the and Aethalometers measuring black carbon (BC) sites. The spatial distribution inter-relationships SMPS counts with CPC analysed detail as well variations distributions. One site (Marylebone...