A5049722343- Atmospheric chemistry and aerosols
- Air Quality and Health Impacts
- Air Quality Monitoring and Forecasting
- Atmospheric Ozone and Climate
- Atmospheric and Environmental Gas Dynamics
- Advanced Chemical Sensor Technologies
- Vehicle emissions and performance
- Toxic Organic Pollutants Impact
- Mass Spectrometry Techniques and Applications
- Plant responses to elevated CO2
- Wind and Air Flow Studies
- Metabolomics and Mass Spectrometry Studies
- Insect and Pesticide Research
- Forensic Toxicology and Drug Analysis
- Indoor Air Quality and Microbial Exposure
- Analytical Chemistry and Chromatography
- Odor and Emission Control Technologies
- Energy and Environment Impacts
- Plant Water Relations and Carbon Dynamics
- Alcohol Consumption and Health Effects
- Tree-ring climate responses
- Urban Green Space and Health
- Isotope Analysis in Ecology
- Urban Heat Island Mitigation
- Pharmacology and Nanomedicine Research
University of Birmingham
2020-2024
Lancaster University
2013-2023
Institute of Atmospheric Physics
2022
Chinese Academy of Sciences
2022
Max Planck Institute for Chemistry
2022
Guangzhou Institute of Geochemistry
2022
King Abdulaziz University
2022
Lancaster City Council
2020-2021
Ionicon Analytik (Austria)
2013-2015
Abstract. Measurements of OH, HO2, complex RO2 (alkene- and aromatic-related RO2) total radicals taken during the integrated Study AIR Pollution PROcesses in Beijing (AIRPRO) campaign central summer 2017, alongside observations OH reactivity, are presented. The concentrations were elevated, with reaching up to 2.8×107moleculecm-3, HO2 peaking at 1×109moleculecm-3 concentration 5.5×109moleculecm-3. reactivity (k(OH)) peaked 89 s−1 night, a minimum afternoon ≈22s-1 on average. An experimental...
Abstract. Wintertime in situ measurements of OH, HO2 and RO2 radicals OH reactivity were made central Beijing during November December 2016. Exceptionally elevated NO was observed on occasions, up to ∼250 ppbv. The daily maximum mixing ratios for radical species varied significantly day-to-day over the ranges 1–8×106 cm−3 (OH), 0.2–1.5×108 (HO2) 0.3–2.5×108 (RO2). Averaged full observation period, mean daytime peak 2.7×106, 0.39×108 0.88×108 total RO2, respectively. main source new via...
Abstract. The Atmospheric Pollution and Human Health in a Chinese Megacity (APHH-Beijing) programme is an international collaborative project focusing on understanding the sources, processes health effects of air pollution Beijing megacity. APHH-Beijing brings together leading China UK research groups, state-of-the-art infrastructure quality models to work four themes: (1) sources emissions pollutants; (2) atmospheric affecting urban pollution; (3) exposure impacts; (4) interventions...
Abstract. All eddy-covariance flux measurements are associated with random uncertainties which a combination of sampling error due to natural variability in turbulence and sensor noise. The former is the principal for systems where signal-to-noise ratio analyser high, as usually case when measuring fluxes heat, CO2 or H2O. Where signal limited, often other trace gases aerosols, instrument dominate. Here, we applying consistent approach based on auto- cross-covariance functions quantify total...
Abstract. In September 2017, we conducted a proton-transfer-reaction mass-spectrometry (PTR-MS) intercomparison campaign at the CESAR observatory, rural site in central Netherlands near village of Cabauw. Nine research groups deployed total 11 instruments covering wide range instrument types and performance. We applied new calibration method based on fast injection gas standard through sample loop. This approach allows calibrations timescales seconds, within few minutes an automated sequence...
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,...
Quantify the influence of aerosol light extinction on surface ozone photochemistry, highlight controlling VOC for improving air quality in Delhi.
Abstract. The impact of emissions volatile organic compounds (VOCs) to the atmosphere on production secondary pollutants, such as ozone and aerosol (SOA), is mediated by concentration nitric oxide (NO). Polluted urban atmospheres are typically considered be “high-NO” environments, while remote regions rainforests, with minimal anthropogenic influences, “low NO”. However, our observations from central Beijing show that this simplistic separation regimes flawed. Despite being in one largest...
Abstract. Twenty-nine different fuel types used in residential dwellings northern India were collected from across Delhi (76 samples total). Emission factors of a wide range non-methane volatile organic compounds (NMVOCs) (192 total) measured during controlled burning experiments using dual-channel gas chromatography with flame ionisation detection (DC-GC-FID), two-dimensional (GC × GC-FID), proton-transfer-reaction time-of-flight mass spectrometry (PTR-ToF-MS) and solid-phase extraction...
Abstract. Biomass burning emits significant quantities of intermediate-volatility and semi-volatile organic compounds (I/SVOCs) in a complex mixture, probably containing many thousands chemical species. These components are significantly more toxic have poorly understood chemistry compared to volatile routinely quantified ambient air; however, analysis I/SVOCs presents difficult analytical challenge. The gases particles emitted during the test combustion range domestic solid fuels collected...
Abstract. Direct measurements of NOx, CO and aromatic volatile organic compound (VOC) (benzene, toluene, C2-benzenes C3-benzenes) flux were made for a central area Beijing using the eddy-covariance technique. Measurements during two intensive field campaigns in as part Air Pollution Human Health (APHH) project, first November–December 2016 second May–June 2017, to contrast wintertime summertime emission rates. There was little difference magnitude NOx between seasons (mean 4.41 mg m−2 h−1...
Rapid economic growth and development have exacerbated air quality problems across India, driven by many poorly understood pollution sources understanding their relative importance remains critical to characterising the key drivers of pollution. A comprehensive suite measurements 90 non-methane hydrocarbons (NMHCs) (C2-C14), including 12 speciated monoterpenes higher molecular weight monoaromatics, were made at an urban site in Old Delhi during pre-monsoon (28-May 05-Jun 2018) post-monsoon...
Abstract. We present the first real-time composition of submicron particulate matter (PM1) in Old Delhi using high-resolution aerosol mass spectrometry (HR-AMS). is one most polluted locations world, and PM1 concentrations reached ∼ 750 µg m−3 during period, post-monsoon where increased by 188 % over pre-monsoon period. Sulfate contributes largest inorganic fraction (24 %) monsoon periods, with nitrate contributing period (8 %). The organics dominate (54 %–68 throughout three and, positive...
Abstract. Isoprene and monoterpene emissions to the atmosphere are generally dominated by biogenic sources. The oxidation of these compounds can lead production secondary organic aerosol; however impact this chemistry in polluted urban settings has been poorly studied. monoterpenes form aerosol (SOA) heterogeneously via anthropogenic–biogenic interactions, resulting formation organosulfate (OS) nitrooxy-organosulfate (NOS) species. Delhi, India, is one most cities world, but little known...
Abstract. Particle nucleation is one of the main sources atmospheric particulate matter by number, with new particles having great relevance for human health and climate. Highly oxidized multifunctional organic molecules (HOMs) have been recently identified as key constituents in growth and, sometimes, initial formation particles. While there many studies HOMs chambers, flow tubes, clean environments, analyses data from polluted environments are scarce. Here, measurements particle size...
Abstract. Mixing ratios of volatile organic compounds (VOCs) were recorded in two field campaigns central Beijing as part the Air Pollution and Human Health a Chinese Megacity (APHH) project. These data used to calculate, for first time Beijing, surface–atmosphere fluxes VOCs using eddy covariance, giving top-down estimation VOC emissions from area city. The results then evaluate accuracy Multi-resolution Emission Inventory China (MEIC). APHH winter summer took place November December 2016...
We study the anthropogenic and biogenic contributions to organic aerosol.
Abstract. Air pollution in urban environments has been shown to have a negative impact on air quality and human health, particularly megacities. Over recent decades, Delhi, India, suffered high atmospheric pollution, with significant particulate matter (PM) concentrations as result of anthropogenic activities. Organic aerosols (OAs) are composed thousands different chemical species one the main constituents submicron particles. However, quantitative knowledge OA composition, their sources...
Abstract. The impact of heterogeneous uptake HO2 on aerosol surfaces radical concentrations and the O3 production regime in Beijing summertime was investigated. coefficient onto surfaces, γHO2, calculated for AIRPRO campaign Beijing, summer 2017, as a function measured soluble copper concentration, [Cu2+]eff, liquid water content, [ALWC], particulate matter [PM]. An average γHO2 across entire 0.070±0.035 calculated, with values ranging from 0.002 to 0.15, found be significantly lower than...
The concentration and fate of ozone in the troposphere is dependent on ratio volatile organic compounds (VOCs) NOx gases emitted from both anthropogenic biogenic sources. biosphere emits over 1,000 Tg VOCs annually, half which come vegetation. ‘fingerprint’ chemical varies greatly between within vegetative species. This fingerprint influenced by environmental conditions an individual plant exposed to.  In a changing climate, rising atmospheric CO2 expected to...
Abstract. This paper reports the fluxes and mixing ratios of biogenically emitted volatile organic compounds (BVOCs) 4 m above a mixed oak hornbeam forest in northern Italy. Fluxes methanol, acetaldehyde, isoprene, methyl vinyl ketone + methacrolein, ethyl monoterpenes were obtained using both proton-transfer-reaction mass spectrometer (PTR-MS) time-of-flight (PTR-ToF-MS) together with methods virtual disjunct eddy covariance (using PTR-MS) PTR-ToF-MS). Isoprene was dominant compound mean...
The emissions of BVOCs from oilseed rape (Brassica napus), both when the plant is exposed to clean air and it fumigated with ozone at environmentally-relevant mixing ratios (ca. 135 ppbv), were measured under controlled laboratory conditions. Emissions recorded combined leaf root chambers using a recently developed Selective Reagent Ionisation-Time Flight-Mass Spectrometer (SRI-ToF-MS) enabling BVOC detection high time mass resolution, together ability identify certain molecular...
This study examines the volatility distribution of organic emissions from solid fuel combustion sources Delhi, India, and chemical drivers OH reactivity secondary aerosol production potential.
Delhi, India, suffers from periods of very poor air quality, but little is known about the chemical production secondary pollutants in this highly polluted environment. During postmonsoon period 2018, extremely high nighttime concentrations NOx (NO and NO2) volatile organic compounds (VOCs) were observed, with median mixing ratios ∼200 ppbV (maximum ∼700 ppbV). A detailed box model constrained to a comprehensive suite speciated VOC measurements revealed low oxidants, NO3, O3, OH, driven by...