A5027149652- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Air Quality and Health Impacts
- Atmospheric Ozone and Climate
- Air Quality Monitoring and Forecasting
- Plant responses to elevated CO2
- Vehicle emissions and performance
- Atmospheric aerosols and clouds
- Spectroscopy and Laser Applications
- Advanced Chemical Sensor Technologies
- Marine and coastal ecosystems
- Satellite Communication Systems
- Odor and Emission Control Technologies
- Oil Palm Production and Sustainability
- Indoor Air Quality and Microbial Exposure
- Telecommunications and Broadcasting Technologies
- Radio Wave Propagation Studies
- Wind and Air Flow Studies
- Polar Research and Ecology
- Radio Astronomy Observations and Technology
- GNSS positioning and interference
- Groundwater and Isotope Geochemistry
- Mass Spectrometry Techniques and Applications
- Metabolomics and Mass Spectrometry Studies
- Ocean Acidification Effects and Responses
University of Leicester
2002-2023
University of Chester
2016-2023
Cosine (Netherlands)
2023
GEDI Gruppo Editoriale (Italy)
2022
Max Planck Institute for Chemistry
2009-2018
Max Planck Society
2011-2016
UK Centre for Ecology & Hydrology
2009-2012
Natural Environment Research Council
2011
University of Leeds
2010-2011
National Centre for Atmospheric Science
2010
Abstract. Organic matter frequently represents the single largest fraction of fine particulates in urban environments and yet exact contributions from different sources processes remain uncertain, owing part to its substantial chemical complexity. Positive Matrix Factorisation (PMF) has recently proved be a powerful tool for purposes source attribution profiling when applied ambient organic aerosol data Aerodyne Aerosol Mass Spectrometer (AMS). Here we present PMF analysis AMS UK cities...
The fading of a radio wave once reflected from an irregular ionosphere is discussed in terms the variable diffraction pattern produced at ground. It pointed out that may arise either by drift past receiver, or variations pattern, both mechanisms together shown how, observations three receiving points, it possible to deduce rate which changing and velocity with drifts over ground This interest as be related wind ionospheric heights atmosphere, but relation produces not detail
We present the first measurements of nitryl chloride (ClNO 2 ) over continental Europe. Significant quantities ClNO , up to 800 pptv, were measured at a mountaintop field site in Hessen, southwest Germany. was detected during majority nights between 15th August and 16th September 2011, its largest mixing ratios being associated with air masses influenced by sea salt anthropogenic NO x emissions. persisted measurable until early afternoons on days low photolysis frequencies. As consequence,...
More than half the world's rainforest has been lost to agriculture since Industrial Revolution. Among most widespread tropical crops is oil palm (Elaeis guineensis): global production now exceeds 35 million tonnes per year. In Malaysia, for example, 13% of land area plantation, compared with 1% in 1974. There are enormous pressures increase food, domestic products, and, especially, biofuels. Greater use biofuel predicated on assumption that an "environmentally friendly" fuel feedstock. Here...
Abstract. In April–July 2008, intensive measurements were made of atmospheric composition and chemistry in Sabah, Malaysia, as part the "Oxidant particle photochemical processes above a South-East Asian tropical rainforest" (OP3) project. Fluxes concentrations trace gases particles from rainforest canopy at Bukit Atur Global Atmosphere Watch station nearby Sabahmas oil palm plantation, using both ground-based airborne measurements. Here, measurement modelling strategies used, characteristics...
Abstract. The REgents PARk and Tower Environmental Experiment (REPARTEE) comprised two campaigns in London October 2006 October/November 2007. experiment design involved measurements at a heavily trafficked roadside site, urban background sites an elevated site 160–190 m above ground on the BT Tower, supplemented second campaign by Doppler lidar of atmospheric vertical structure. A wide range airborne particle physical metrics chemical composition were made as well considerable gas phase...
Abstract. Ambient total OH reactivity was measured at the Finnish boreal forest station SMEAR II in Hyytiälä (Latitude 61°51' N; Longitude 24°17' E) July and August 2010 using Comparative Reactivity Method (CRM). The CRM – method is a direct, in-situ determination of loss rate hydroxyl radicals (OH) caused by all reactive species air. During intensive field campaign HUMPPA-COPEC (Hyytiälä United Measurements Photochemistry Particles Air Comprehensive Organic Precursor Emission Concentration...
Abstract. Eddy-covariance measurements of carbon dioxide fluxes were taken continuously between October 2006 and May 2008 at 190 m height in central London (UK) to quantify emissions study their controls. Inner London, with a population 8.2 million (~5000 inhabitants per km2) is heavily built up 8% vegetation cover within the boroughs. CO2 found be mainly controlled by fossil fuel combustion (e.g. traffic, commercial domestic heating). The measurement period allowed investigation both...
Abstract. Biogenic influences on the composition and characteristics of aerosol were investigated Bird Island (54°00' S, 38°03' W) in South Atlantic during November December 2010. This remote marine environment is characterised by large seabird seal colonies. The chemical submicron particles, measured an mass spectrometer (AMS), was 21% non-sea-salt sulfate, 2% nitrate, 8% ammonium, 22% organics 47% sea salt including sulfate. A new method to isolate spray signature from high-resolution AMS...
Abstract. We analysed the extensive dataset from HUMPPA-COPEC 2010 and HOPE 2012 field campaigns in boreal forest rural environments of Finland Germany, respectively, estimated abundance stabilised Criegee intermediates (SCIs) lower troposphere. Based on laboratory tests, we propose that background OH signal observed our IPI-LIF-FAGE instrument during aforementioned is caused at least partially by SCIs. This hypothesis based correlations with temperature concentrations unsaturated volatile...
In certain observations of a downcoming radio wave, made for the purpose measuring horizontal drifts ionospheric irregularities, time shifts between fading curves obtained at three spaced receiving points are used to calculate velocity and direction drift amplitude pattern over ground. Two simplifying assumptions about frequently made, namely (i) detail remains constant as it moves, (ii) is statistically isometric, i.e. separation two which amplitudes have given fixed correlation independent...
Abstract. We present an estimation of the uptake coefficient (γ) and yield nitryl chloride (ClNO2) (f) for heterogeneous processing dinitrogen pentoxide (N2O5) using simultaneous measurements particle trace gas composition at a semi-rural, non-coastal, mountain site in summer 2011. The ClNO2 varied between (0.035 ± 0.027) (1.38 0.60) with campaign average (0.49 0.35). large variability f reflects highly variable content particles site. Uptake coefficients were also minimum, maximum γ values...
Abstract. Concentrations and fluxes of eight volatile organic compounds (VOCs) were measured during October 2006 from a high telecom tower above central London, as part the CityFlux contribution to REPARTEE I campaign. A continuous flow disjunct eddy covariance technique with analysis by proton transfer reaction mass spectrometry was used. Daily averaged VOC mixing ratios within range 1–19 ppb for oxygenated (methanol, acetaldehyde acetone) 0.2–1.3 aromatics (benzene, toluene C2-benzenes)....
Abstract. This paper reports the first direct eddy covariance fluxes of reactive biogenic volatile organic compounds (BVOCs) from oil palms to atmosphere using proton-transfer-reaction mass spectrometry (PTR-MS), measured at a plantation in Malaysian Borneo. At midday, net isoprene flux constituted largest fraction (84 %) all emitted BVOCs measured, up 30 mg m−2 h−1 over 12 days. By contrast, sum its oxidation products methyl vinyl ketone (MVK) and methacrolein (MACR) exhibited clear...
Abstract. We describe measurements of peroxyacetyl nitrate (CH3C(O)O2NO2, PAN) and peroxyacetic acid (CH3C(O)OOH, PAA) in the Boreal forest using iodide chemical ionization mass spectrometry (ICIMS). The were made during Hyytiälä United Measurement Photochemistry Particles – Comprehensive Organic Particle Environmental Chemistry (HUMPPA-COPEC-2010) measurement intensive. Mixing ratios PAN PAA determined by measuring acetate ion signal (CH3C(O)O−, m/z = 59) resulting from reaction CH3C(O)O2...
Abstract. We describe a thermal dissociation cavity ring-down spectrometer (TD-CRDS) for measurement of ambient NO2, total peroxy nitrates (ΣPNs) and alkyl (ΣANs). The has two separate cavities operating at ∼ 405.2 408.5 nm. One (reference) samples NO2 continuously from an inlet temperature, the other sequentially 473 K in which PNs are converted to or 723 both ANs difference signals being used derive mixing ratios ΣPNs ΣANs. extensive set laboratory experiments numerical simulations...
Abstract. The Mediterranean is a climatically sensitive region located at the crossroads of air masses from three continents: Europe, Africa, and Asia. chemical processing over this has implications not only for quality but also long-range transport pollution. To obtain comprehensive understanding oxidation processes Mediterranean, atmospheric concentrations hydroxyl radical (OH) hydroperoxyl (HO2) were measured during an intensive field campaign (CYprus PHotochemistry EXperiment,...
Here, we present a new automated instrument for semicontinuous gradient measurements of water-soluble reactive trace gas species (NH3, HNO3, HONO, HCl, and SO2) their related aerosol compounds (NH4+, NO3−, Cl−, SO42−). Gas samples are collected simultaneously at two heights using rotating wet-annular denuders steam-jet collectors, respectively. Online (real-time) analysis ion chromatography (IC) anions flow injection (FIA) NH4+ NH3 provide half-hourly averaged gradients within each hour....
This paper reports measurements of land-atmosphere fluxes sensible and latent heat, momentum, CO(2), volatile organic compounds (VOCs), NO, NO(2), N(2)O O(3) over a 30 m high rainforest canopy 12 oil palm plantation in the same region Sabah Borneo between April July 2008. The daytime maximum CO(2) flux to two canopies differs by approximately factor 2, 1200 mg C m(-2) h(-1) for 700 rainforest, with showing substantially greater quantum efficiency. Total VOC emissions are also larger than 3....
Abstract. During two field campaigns (OP3 and ACES), which ran in Borneo 2008, we measured large emissions of estragole (methyl chavicol; IUPAC systematic name 1-allyl-4-methoxybenzene; CAS number 140-67-0) ambient air above oil palm canopies (0.81 mg m−2 h−1 3.2 ppbv for mean midday fluxes mixing ratios respectively) subsequently from flower enclosures. However, did not detect this compound at a nearby rainforest. Estragole is known attractant the African weevil (Elaeidobius kamerunicus),...
Abstract. We present a chemical ionization quadrupole mass spectrometer (CI-QMS) with radio-frequency (RF) discharge ion source through N2∕CH3I as of primary ions. In addition to the expected detection PAN, peracetic acid (PAA) and ClNO2 well-established ion–molecule reactions I− its water cluster, instrument is also sensitive SO2, HCl acetic (CH3C(O)OH) additional chemistry unique our source. schemes for along illustrative datasets from three different field campaigns underlining potential...
The theory of diffraction by a random screen developed Booker, Ratcliffe and Shinn is presented in convenient form for practical application ionospheric experiments. It shown that measurements the correlation fading reflected wave observed at spaced receiving points can be used to find extent angular spreading downcoming wave.
Abstract. Although laboratory studies show that biogenic volatile organic compounds (VOCs) yield substantial secondary aerosol (SOA), production of SOA as indicated by upward fluxes has not been conclusively observed over forests. Further, while aerosols are known to deposit surfaces, few techniques exist provide chemically-resolved particle deposition fluxes. To better constrain sources and sinks, we have developed a new technique directly measure submicron using the high-resolution...