Imperial College London

DrSeanBeevers

Faculty of MedicineSchool of Public Health

Reader in Atmospheric modelling
 
 
 
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Contact

 

s.beevers

 
 
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Location

 

Norfolk PlaceSt Mary's Campus

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Summary

 

Publications

Publication Type
Year
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129 results found

Desouza C, Marsh D, Beevers S, Molden N, Green Det al., 2024, Emissions from the construction sector in the United Kingdom, Emission Control Science and Technology, Vol: 10, Pages: 70-80, ISSN: 2199-3637

The UK national atmospheric emissions inventory estimates of construction industry emissions use a top-down approach, based on fuel consumption and employment. It estimates that the sector is the 2nd largest emitter of PM2.5 (14%) and 4th largest emitter of NOX (7%). In this study, we have adopted a bottom-up approach to assess emissions of NOX from the sector and show that emissions are 39% higher than the existing estimates. By developing a novel fleet turnover model to predict the population and emission standard of construction machinery up to 2025, we demonstrate a significant shift in the quantity and types of machines used. The overall uncertainty of the model was calculated to be 55%. Applying the estimated uncertainties to the model, in 2018, the non-road mobile machinery fleet in the UK emitted 36.6 ± 10.0 kilo-tonnes of NOX, whilst the NAEI estimated 33.2 kilo-tonnes for the same sector. For the subsequent years 2019 and 2020, the NAEI estimate was within the model’s uncertainty prediction—28.0 kilo-tonnes compared with 32.7 ± 8.9 kilo-tonnes for 2019 and 23.2 kilo-tonnes compared with 29.5 ± 8.1 kilo-tonnes for 2020. Overall, the size of the non-road mobile machinery fleet in the UK is predicted to reduce by 4% in 2025 compared to 2018. Furthermore, the introduction of Stages IV and V emission regulations for new machines will lead to a 58% reduction in fleet NOX emissions over the same period. These emission regulations are targeted at the larger, more polluting machines, with smaller machines not required to meet tighter emissions standards under Stage V. As a result, mini-excavators are the most common machines and consequently become the dominant source of NOX emissions from the fleet, contributing 55% in 2025. Therefore, tighter emissions regulations, or the uptake of battery power in the form of electrification, for these small machines would yield significant emissions redu

Journal article

Han W, Zhang J, Xu Z, Yang T, Huang J, Beevers S, Kelly F, Li Get al., 2024, Could the association between ozone and arterial stiffness be modified by fish oil supplementation?, Environmental Research, Vol: 249, ISSN: 0013-9351

BACKGROUND: Arterial stiffness (AS) is an important predicting factor for cardiovascular disease. However, no epidemiological studies have ever explored the mediating role of biomarkers in the association between ozone and AS, nor weather fish oil modified such association. METHODS: Study participants were drawn from the UK biobank, and a total of 95,699 middle-aged and older adults were included in this study. Ozone was obtained from Community Multiscale Air Quality (CMAQ) model matched to residential addresses, fish oil from self-reported intake, and arterial stiffness was based on device measurements. First, we applied a double robust approach to explore the association between ozone or fish oil intake and arterial stiffness, adjusting for potential confounders at the individual and regional levels. Then, how triglycerides, apolipoprotein B (Apo B)/apolipoprotein A (ApoA) and non-high-density lipoprotein cholesterol (Non-HDL-C) mediate the relationship between ozone and AS. Last, the modifying role of fish oil was further explored by stratified analysis. RESULTS: The mean age of participants was 55 years; annual average ozone exposure was associated with ASI (beta:0.189 [95%CI: 0.146 to 0.233], P < 0.001), and compared to participants who did not consume fish oil, fish oil users had a lower ASI (beta: 0.061 [95%CI: -0.111 to -0.010], P = 0.016). The relationship between ozone exposure and AS was mediated by triglycerides, ApoB/ApoA, and Non-HDL-C with mediation proportions ranging from 10.90% to 18.30%. Stratified analysis showed lower estimates on the ozone-AS relationship in fish oil users (P = 0.011). CONCLUSION: Ozone exposure was associated with higher levels of arterial stiffness, in contrast to fish oil consumption, which showed a protective association. The association between ozone exposure and arterial stiffness was partially mediated by some biomarkers. In the general population, fish oil consumption might provide prote

Journal article

Wu Y-T, Kitwiroon N, Beevers S, Barratt B, Brayne C, Cerin E, Franklin R, Houlden V, Woods B, Zied Abozied E, Prina M, Matthews Fet al., 2024, The longitudinal associations between ambient air pollution exposure and dementia in the UK: results from the cognitive function and ageing study II and Wales., BMC Public Health, Vol: 24

BACKGROUND: Air pollution has been recognised as a potential risk factor for dementia. Yet recent epidemiological research shows mixed evidence. The aim of this study is to investigate the longitudinal associations between ambient air pollution exposure and dementia in older people across five urban and rural areas in the UK. METHODS: This study was based on two population-based cohort studies of 11329 people aged ≥ 65 in the Cognitive Function and Ageing Study II (2008-2011) and Wales (2011-2013). An algorithmic diagnosis method was used to identify dementia cases. Annual concentrations of four air pollutants (NO2, O3, PM10, PM2.5) were modelled for the year 2012 and linked via the participants' postcodes. Multistate modelling was used to examine the effects of exposure to air pollutants on incident dementia incorporating death and adjusting for sociodemographic factors and area deprivation. A random-effect meta-analysis was carried out to summarise results from the current and nine existing cohort studies. RESULTS: Higher exposure levels of NO2 (HR: 1.04; 95% CI: 0.94, 1.14), O3 (HR: 0.90; 95% CI: 0.70, 1.15), PM10 (HR: 1.17; 95% CI: 0.86, 1.58), PM2.5 (HR: 1.41; 95% CI: 0.71, 2.79) were not strongly associated with dementia in the two UK-based cohorts. Inconsistent directions and strengths of the associations were observed across the two cohorts, five areas, and nine existing studies. CONCLUSIONS: In contrast to the literature, this study did not find clear associations between air pollution and dementia. Future research needs to investigate how methodological and contextual factors can affect evidence in this field and clarity the influence of air pollution exposure on cognitive health over the lifecourse.

Journal article

Wang W, Gulliver J, Beevers S, Freni Sterrantino A, Davies B, Atkinson RW, Fecht Det al., 2024, Short-term nitrogen dioxide exposure and emergency hospital admissions for asthma in children: a case-crossover analysis in England, Journal of Asthma and Allergy, Vol: 17, Pages: 349-359, ISSN: 1178-6965

Background:There is an increasing body of evidence associating short-term ambient nitrogen dioxide (NO2) exposure with asthma-related hospital admissions in children. However, most studies have relied on temporally resolved exposure information, potentially ignoring the spatial variability of NO2. We aimed to investigate how daily NO2 estimates from a highly resolved spatio-temporal model are associated with the risk of emergency hospital admission for asthma in children in England.Methods:We conducted a time-stratified case-crossover study including 111,766 emergency hospital admissions for asthma in children (aged 0–14 years) between 1st January 2011 and 31st December 2015 in England. Daily NO2 levels were predicted at the patients’ place of residence using spatio-temporal models by combining land use data and chemical transport model estimates. Conditional logistic regression models were used to obtain the odds ratios (OR) and confidence intervals (CI) after adjusting for temperature, relative humidity, bank holidays, and influenza rates. The effect modifications by age, sex, season, area-level income deprivation, and region were explored in stratified analyses.Results:For each 10 µg/m³ increase in NO2 exposure, we observed an 8% increase in asthma-related emergency admissions using a five-day moving NO2 average (mean lag 0–4) (OR 1.08, 95% CI 1.06–1.10). In the stratified analysis, we found larger effect sizes for male (OR 1.10, 95% CI 1.07–1.12) and during the cold season (OR 1.10, 95% CI 1.08–1.12). The effect estimates varied slightly by age group, area-level income deprivation, and region.Significance:Short-term exposure to NO2 was significantly associated with an increased risk of asthma emergency admissions among children in England. Future guidance and policies need to consider reflecting certain proven modifications, such as using season-specific countermeasures for air pollution control, to protect the at-r

Journal article

Wood D, Evangelopoulos D, Beevers S, Kitwiroon N, Demakakos P, Katsouyanni Ket al., 2024, Exposure to ambient air pollution and cognitive function: an analysis of the English Longitudinal Study of Ageing cohort, Environmental Health, Vol: 23, ISSN: 1476-069X

BackgroundAn increasing number of studies suggest adverse effects of exposure to ambient air pollution on cognitive function, but the evidence is still limited. We investigated the associations between long-term exposure to air pollutants and cognitive function in the English Longitudinal Study of Ageing (ELSA) cohort of older adults.MethodsOur sample included 8,883 individuals from ELSA, based on a nationally representative study of people aged ≥ 50 years, followed-up from 2002 until 2017. Exposure to air pollutants was modelled by the CMAQ-urban dispersion model and assigned to the participants’ residential postcodes. Cognitive test scores of memory and executive function were collected biennially. The associations between these cognitive measures and exposure to ambient concentrations of NO2, PM10, PM2.5 and ozone were investigated using mixed-effects models adjusted for time-varying age, physical activity and smoking status, as well as baseline gender and level of education.ResultsIncreasing long-term exposure per interquartile range (IQR) of NO2 (IQR: 13.05 μg/m3), PM10 (IQR: 3.35 μg/m3) and PM2.5 (IQR: 2.7 μg/m3) were associated with decreases in test scores of composite memory by -0.10 (95% confidence interval [CI]: -0.14, -0.07), -0.02 [-0.04, -0.01] and -0.08 [-0.11, -0.05], respectively. The same increases in NO2, PM10 and PM2.5 were associated with decreases in executive function score of -0.31 [-0.38, -0.23], -0.05 [-0.08, -0.02] and -0.16 [-0.22, -0.10], respectively. The association with ozone was inverse across both tests. Similar results were reported for the London-dwelling sub-sample of participants.ConclusionsThe present study was based on a long follow-up with several repeated measurements per cohort participant and long-term air pollution exposure assessment at a fine spatial scale. Increasing long-term exposure to NO2, PM10 and PM2.5 was associated with a decrease in cognitive function in older adults in England.

Journal article

Jin J, Xu Z, Beevers SD, Huang J, Kelly F, Li Get al., 2024, Long-term ambient ozone, omega-3 fatty acid, genetic susceptibility, and risk of mental disorders among middle-aged and older adults in UK biobank, Environmental Research, Vol: 243, ISSN: 0013-9351

BACKGROUND: Evidence linking ozone to depression and anxiety disorders remains sparse and results are heterogeneous. It remains unknown whether omega-3 fatty acid, or genetic susceptibility of mental disorders modify the impacts of ozone. The aim is to assess the associations of ambient ozone with depression and anxiety, and further explore the potential modification effects of omega-3 fatty acid and genetic susceptibility. METHODS: In total of 257,534 participants were enrolled from 2006 to 2010 and followed up to 2016. Depression and anxiety were assessed using mental health questionnaires, primary care records and hospital admission records. The annual average concentrations of ozone were calculated and linked to individuals by home address. Dietary intake and plasma concentration were selected to reflect levels of omega-3 fatty acid. Polygenetic risk scores were selected to reflect genetic susceptibility. We examined the associations of ozone and incident mental disorders, and potential modification of omega-3 fatty acid and genetic susceptibility. RESULTS: Incidences of depression (N = 6957) and anxiety (N = 6944) was associated with increase of ozone. Higher levels of omega-3 fatty acid might attenuate the ozone related depression risk. However, the modification effects of genetic susceptibility were not found. CONCLUSIONS: Long-term exposure to ambient ozone increase the risk of mental disorders among the middle aged and older adults, and omega-3 fatty acid could reduce the adverse effects of ozone on mental health. Higher intake of omega-3 fatty acid is a potential strategy to prevent the risks caused by ozone on public mental health.

Journal article

Sheehan A, Beddows A, Green DC, Beevers Set al., 2023, City scale traffic monitoring using WorldView satellite imagery and deep learning: a case study of Barcelona, Remote Sensing, Vol: 15, ISSN: 2072-4292

Accurate traffic data is crucial for a range of different applications such as quantifying vehicle emissions, and transportation planning and management. However, the availability of traffic data is geographically fragmented and is rarely held in an accessible form. Therefore, there is an urgent need for a common approach to developing large urban traffic data sets. Utilising satellite data to estimate traffic data offers a cost-effective and standardized alternative to ground-based traffic monitoring. This study used high-resolution satellite imagery (WorldView-2 and 3) and Deep Learning (DL) to identify vehicles, road by road, in Barcelona (2017–2019). The You Only Look Once (YOLOv3) object detection model was trained and model accuracy was investigated via parameters such as training data set specific anchor boxes, network resolution, image colour band composition and input image size. The best performing vehicle detection model configuration had a precision (proportion of positive detections that were correct) of 0.69 and a recall (proportion of objects in the image correctly identified) of 0.79. We demonstrated that high-resolution satellite imagery and object detection models can be utilised to identify vehicles at a city scale. However, the approach highlights challenges relating to identifying vehicles on narrow roads, in shadow, under vegetation, and obstructed by buildings. This is the first time that DL has been used to identify vehicles at a city scale and demonstrates the possibility of applying these methods to cities globally where data are often unavailable.

Journal article

Tsocheva I, Scales J, Dove R, Chavda J, Kalsi H, Wood HE, Colligan G, Cross L, Newby C, Hall A, Keating M, Sartori L, Moon J, Thomson A, Tomini F, Murray A, Hamad W, Tijm S, Hirst A, Vincent BP, Kotala P, Balkwill F, Mihaylova B, Grigg J, Quint JK, Fletcher M, Mon-Williams M, Wright J, van Sluijs E, Beevers S, Randhawa G, Eldridge S, Sheikh A, Gauderman W, Kelly F, Mudway IS, Griffiths CJet al., 2023, Investigating the impact of London's ultra low emission zone on children's health: children's health in London and Luton (CHILL) protocol for a prospective parallel cohort study, BMC Pediatrics, Vol: 23, ISSN: 1471-2431

BACKGROUND: Air pollution harms health across the life course. Children are at particular risk of adverse effects during development, which may impact on health in later life. Interventions that improve air quality are urgently needed both to improve public health now, and prevent longer-term increased vulnerability to chronic disease. Low Emission Zones are a public health policy intervention aimed at reducing traffic-derived contributions to urban air pollution, but evidence that they deliver health benefits is lacking. We describe a natural experiment study (CHILL: Children's Health in London and Luton) to evaluate the impacts of the introduction of London's Ultra Low Emission Zone (ULEZ) on children's health. METHODS: CHILL is a prospective two-arm parallel longitudinal cohort study recruiting children at age 6-9 years from primary schools in Central London (the focus of the first phase of the ULEZ) and Luton (a comparator site), with the primary outcome being the impact of changes in annual air pollutant exposures (nitrogen oxides [NOx], nitrogen dioxide [NO2], particulate matter with a diameter of less than 2.5micrograms [PM2.5], and less than 10 micrograms [PM10]) across the two sites on lung function growth, measured as post-bronchodilator forced expiratory volume in one second (FEV1) over five years. Secondary outcomes include physical activity, cognitive development, mental health, quality of life, health inequalities, and a range of respiratory and health economic data. DISCUSSION: CHILL's prospective parallel cohort design will enable robust conclusions to be drawn on the effectiveness of the ULEZ at improving air quality and delivering improvements in children's respiratory health. With increasing proportions of the world's population now living in large urban areas exceeding World Health Organisation air pollution limit guidelines, our study findings will have important implications for the design and implementation of Low Emission and Clean Air Zones

Journal article

Hicks W, Green DC, Beevers S, 2023, Quantifying the change of brake wear particulate matter emissions through powertrain electrification in passenger vehicles, ENVIRONMENTAL POLLUTION, Vol: 336, ISSN: 0269-7491

Journal article

Dajnak D, Assareh N, Kitwiroon N, Beddows AV, Stewart GB, Hicks W, Beevers SDet al., 2023, Can the UK meet the World Health Organization PM2.5 interim target of 10 μg m-3 by 2030?, Environ Int, Vol: 181

The recent United Kingdom (UK) Environment Act consultation had the intention of setting two targets for PM2.5 (particles with an aerodynamic diameter less than 2.5 μm), one related to meeting an annual average concentration and the second to reducing population exposure. As part of the consultation, predictions of PM2.5 concentrations in 2030 were made by combining European Union (EU) and UK government's emissions forecasts, with the Climate Change Committee's (CCC) Net Zero vehicle forecasts, and in London with the addition of local policies based on the London Environment Strategy (LES). Predictions in 2018 showed 6.4% of the UK's area and 82.6% of London's area had PM2.5 concentrations above the World Health Organization (WHO) interim target of 10 μg m-3, but by 2030, over 99% of the UK's area was predicted to be below it. However, kerbside concentrations in London and other major cities were still at risk of exceeding 10 μg m-3. With local action on PM2.5 in London, population weighted concentrations showed full compliance with the WHO interim target of 10 μg m-3 in 2030. However, predicting future PM2.5 concentrations and interpreting the results will always be difficult and uncertain for many reasons, such as imperfect models and the difficulty in estimating future emissions. To help understand the sensitivity of the model's PM2.5 predictions in 2030, current uncertainty was quantified using PM2.5 measurements and showed large areas in the UK that were still at risk of exceeding the WHO interim target despite the model predictions being below 10 μg m-3. Our results do however point to the benefits that policy at EU, UK and city level can have on achieving the WHO interim target of 10 μg m-3. These results were submitted to the UK Environment Act consultation. Nevertheless, the issues addressed here could be applicable to other European cities.

Journal article

Scales J, Chavda J, Ikeda E, Tsocheva I, Dove RE, Wood HE, Kalsi H, Colligan G, Griff L, Day B, Crichlow C, Keighley A, Fletcher M, Newby C, Tomini F, Balkwill F, Mihaylova B, Grigg J, Beevers S, Eldridge S, Sheikh A, Gauderman J, Kelly F, Randhawa G, Mudway IS, van Sluijs E, Griffiths CJet al., 2023, Device-measured change in physical activity in primary school children during the UK COVID-19 pandemic lockdown: a longitudinal study, Journal of Physical Activity and Health, Vol: 20, Pages: 639-647, ISSN: 1543-3080

Background: Lockdown measures, including school closures, due to the COVID-19 pandemic have caused widespread disruption to children’s lives. The aim of this study was to explore the impact of a national lockdown on children’s physical activity using seasonally matched accelerometry data. Methods: Using a pre/post observational design, 179 children aged 8 to 11 years provided physical activity data measured using hip-worn triaxial accelerometers worn for 5 consecutive days prepandemic and during the January to March 2021 lockdown. Multilevel regression analyses adjusted for covariates were used to assess the impact of lockdown on time spent in sedentary and moderate to vigorous physical activity. Results: A 10.8-minute reduction in daily time spent in moderate to vigorous physical activity (standard error: 2.3 min/d, P < .001) and a 33.2-minute increase in daily sedentary activity (standard error: 5.5 min/d, P < .001) were observed during lockdown. This reflected a reduction in daily moderate to vigorous physical activity for those unable to attend school (−13.1 [2.3] min/d, P < .001) during lockdown, with no significant change for those who continued to attend school (0.4 [4.0] min/d, P < .925). Conclusion: These findings suggest that the loss of in-person schooling was the single largest impact on physical activity in this cohort of primary school children in London, Luton, and Dunstable, United Kingdom.

Journal article

Ronaldson A, Stewart R, Mueller C, Das-Munshi J, Newbury JB, Mudway IS, Broadbent M, Fisher HL, Beevers S, Dajnak D, Hotopf M, Hatch SL, Bakolis Iet al., 2023, Associations between air pollution and mental health service use in dementia: a retrospective cohort study, BMJ MENTAL HEALTH, Vol: 26

Journal article

Bos B, Barratt B, Batalle D, Gale-Grant O, Hughes EJ, Beevers S, Cordero-Grande L, Price AN, Hutter J, V Hajnal J, Kelly FJ, Edwards D, Counsell SJet al., 2023, Prenatal exposure to air pollution is associated with structural changes in the neonatal brain, Environment International, Vol: 174, ISSN: 0160-4120

BackgroundPrenatal exposure to air pollution is associated with adverse neurologic consequences in childhood. However, the relationship between in utero exposure to air pollution and neonatal brain development is unclear.MethodsWe modelled maternal exposure to nitrogen dioxide (NO2) and particulate matter (PM2.5 and PM10) at postcode level between date of conception to date of birth and studied the effect of prenatal air pollution exposure on neonatal brain morphology in 469 (207 male) healthy neonates, with gestational age of ≥36 weeks. Infants underwent MR neuroimaging at 3 Tesla at 41.29 (36.71–45.14) weeks post-menstrual age (PMA) as part of the developing human connectome project (dHCP). Single pollutant linear regression and canonical correlation analysis (CCA) were performed to assess the relationship between air pollution and brain morphology, adjusting for confounders and correcting for false discovery rate.ResultsHigher exposure to PM10 and lower exposure to NO2 was strongly canonically correlated to a larger relative ventricular volume, and moderately associated with larger relative size of the cerebellum. Modest associations were detected with higher exposure to PM10 and lower exposure to NO2 and smaller relative cortical grey matter and amygdala and hippocampus, and larger relaive brainstem and extracerebral CSF volume. No associations were found with white matter or deep grey nuclei volume.ConclusionsOur findings show that prenatal exposure to air pollution is associated with altered brain morphometry in the neonatal period, albeit with opposing results for NO2 and PM10. This finding provides further evidence that reducing levels of maternal exposure to particulate matter during pregnancy should be a public health priority and highlights the importance of understanding the impacts of air pollution on this critical development window.

Journal article

Karamanos A, Lu Y, Mudway IS, Ayis S, Kelly FJ, Beevers SD, Dajnak D, Fecht D, Elia C, Tandon S, Webb AJ, Grande AJ, Molaodi OR, Maynard MJ, Cruickshank JK, Harding Set al., 2023, Associations between air pollutants and blood pressure in an ethnically diverse cohort of adolescents in London, England, PLoS One, Vol: 18, Pages: 1-18, ISSN: 1932-6203

Longitudinal evidence on the association between air pollution and blood pressure (BP) in adolescence is scarce. We explored this association in an ethnically diverse cohort of schoolchildren. Sex-stratified, linear random-effects modelling was used to examine how modelled residential exposure to annual average nitrogen dioxide (NO2), particulate matter (PM2.5, PM10) and ozone (O3), measures in μg/m3, associated with blood pressure. Estimates were based on 3,284 adolescents; 80% from ethnic minority groups, recruited from 51 schools, and followed up from 11–13 to 14–16 years old. Ethnic minorities were exposed to higher modelled annual average concentrations of pollution at residential postcode level than their White UK peers. A two-pollutant model (NO2 & PM2.5), adjusted for ethnicity, age, anthropometry, and pubertal status, highlighted associations with systolic, but not diastolic BP. A μg/m3 increase in NO2 was associated with a 0.30 mmHg (95% CI 0.18 to 0.40) decrease in systolic BP for girls and 0.19 mmHg (95% CI 0.07 to 0.31) decrease in systolic BP for boys. In contrast, a 1 μg/m3 increase in PM2.5 was associated with 1.34 mmHg (95% CI 0.85 to 1.82) increase in systolic BP for girls and 0.57 mmHg (95% CI 0.04 to 1.03) increase in systolic BP for boys. Associations did not vary by ethnicity, body size or socio-economic advantage. Associations were robust to adjustments for noise levels and lung function at 11–13 years. In summary, higher ambient levels of NO2 were associated with lower and PM2.5 with higher systolic BP across adolescence, with stronger associations for girls.

Journal article

Wood D, Evangelopoulos D, Beevers S, Kitwiroon N, Katsouyanni Ket al., 2022, Exposure to Ambient Air Pollution and the Incidence of Dementia in the Elderly of England: The ELSA Cohort, INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH, Vol: 19

Journal article

Vu TV, Stewart GB, Kitwiroon N, Lim S, Barratt B, Kelly FJ, Thompson R, Smith RB, Toledano MB, Beevers SDet al., 2022, Assessing the contributions of outdoor and indoor sources to air quality in London homes of the SCAMP cohort, Building and Environment, Vol: 222, Pages: 1-8, ISSN: 0360-1323

Given that many people typically spend the majority of their time at home, accurate measurement and modelling of the home environment is critical in estimating their exposure to air pollution. This study investigates the fate and impact on human exposure of outdoor and indoor pollutants in London homes, using a combination of sensor measurements, outdoor air pollution estimated from the CMAQ-urban model and indoor mass balance models. Averaged indoor concentrations of PM2.5, PM10 and NO2 were 14.6, 24.7 and 14.2 μg m−3 while the outdoor concentrations were 14.4, 22.6 and 21.4 μg m−3, respectively. Mean infiltration factors of particles (0.6–0.7) were higher than those of NO2 (0.4). In contrast, higher loss rates were found for NO2 (0.5–0.8 h−1) compared to those for particles (0.1–0.3 h−1). The average concentrations of PM2.5, PM10 and NO2 in kitchen environments were 22.0, 33.7 and 20.8 μg m−3, with highest hourly concentrations (437, 644 and 136 μg m−3, respectively) during cooking times (6–7 pm). Indoor sources increased the indoor concentrations of particles and NO2 by an average of 26–37% in comparison to the indoor background level without indoor sources. Outdoor and indoor air exchange plays an important role in reducing air pollution indoors by 65–86% for particles and 42–65% for NO2.

Journal article

Wang W, Fecht D, Beevers S, Gulliver Jet al., 2022, Predicting daily concentrations of nitrogen dioxide, particulate matter and ozone at fine spatial scale in Great Britain, Atmospheric Pollution Research, Vol: 13, Pages: 101506-101506, ISSN: 1309-1042

Short-term exposure studies have often relied on time-series of air pollution measurements from monitoring sites. However, this approach does not capture short-term changes in spatial contrasts in air pollution. To address this, models representing both the spatial and temporal variability in air pollution have emerged in recent years. Here, we modelled daily average concentrations of nitrogen dioxide (NO2), particulate matter (PM2.5 and PM10) and ozone (O3) on a 25 m grid for Great Britain from 2011 to 2015 using a generalised additive mixed model, with penalised spline smooth functions for covariates. The models included local-scale predictors derived using a Geographic Information System (GIS), daily estimates from a chemical transport model, and daily meteorological characteristics. The models performed well in explaining the variability in daily averaged measured concentrations at 48–85 sites: 63% for NO2, 77% for PM2.5, 80% for PM10 and 85% for O3. Outputs of the study include daily air pollution maps that can be applied in epidemiological studies across Great Britain. Daily concentration values can also be predicted for specific locations, such as residential addresses or schools, and aggregated to other exposure time periods (including weeks, months, or pregnancy trimesters) to facilitate the needs of different health analyses.

Journal article

Drysdale WS, Vaughan AR, Squires FA, Cliff SJ, Metzger S, Durden D, Pingintha-Durden N, Helfter C, Nemitz E, Grimmond CSB, Barlow J, Beevers S, Stewart G, Dajnak D, Purvis RM, Lee JDet al., 2022, Eddy covariance measurements highlight sources of nitrogen oxide emissions missing from inventories for central London, Atmospheric Chemistry and Physics, Vol: 22, Pages: 9413-9433, ISSN: 1680-7316

During March–June 2017 emissions of nitrogen oxides were measured via eddy covariance at the British Telecom Tower in central London, UK. Through the use of a footprint model the expected emissions were simulated from the spatially resolved National Atmospheric Emissions Inventory for 2017 and compared with the measured emissions. These simulated emissions were shown to underestimate measured emissions during the daytime by a factor of 1.48, but they agreed well overnight. Furthermore, underestimations were spatially mapped, and the areas around the measurement site responsible for differences in measured and simulated emissions were inferred. It was observed that areas of higher traffic, such as major roads near national rail stations, showed the greatest underestimation by the simulated emissions. These discrepancies are partially attributed to a combination of the inventory not fully capturing traffic conditions in central London and both the spatial and temporal resolution of the inventory not fully describing the high heterogeneity of the urban centre. Understanding of this underestimation may be further improved with longer measurement time series to better understand temporal variation and improved temporal scaling factors to better simulate sub-annual emissions.

Journal article

Shoari N, Beevers S, Brauer M, Blangiardo Met al., 2022, Towards healthy school neighbourhoods: a baseline analysis in Greater London, Environment International, Vol: 165, ISSN: 0160-4120

Creating healthy environments around schools is important to promote healthy childhood development and is a critical component of public health. In this paper we present a tool to characterize exposure to multiple urban environment features within 400 m (5-10 minutes walking distance) of schools in Greater London. We modelled joint exposure to air pollution (NO2 and PM2.5), access to public greenspace, food environment, and road safety for 2,929 schools, employing a Bayesian non-parametric approach based on the Dirichlet Process Mixture modelling. We identified 12 latent clusters of schools with similar exposure profiles and observed some spatial clustering patterns. Socioeconomic and ethnicity disparities were manifested with respect to exposure profiles. Specifically, three clusters (containing 645 schools) showed the highest joint exposure to air pollution, poor food environment, and unsafe roads and were characterized with high deprivation. The most deprived cluster of schools had a median of 2.5 ha greenspace, 29.0 µg/m3 of NO2, 19.3 µg/m3 of PM2.5, 20 fast food retailers, and five child pedestrian crashes over a three-year period. The least deprived cluster of schools had a median of 21.8 ha greenspace, 15.6 µg/m3 of NO2, 15.1 µg/m3 of PM2.5, 2 fast food retailers, and one child pedestrian crash over a three-year period. To have a school-level understanding of exposure levels, we then benchmarked schools based on the probability of exceeding the median exposure to various features of interest. Our study accounts for multiple exposures, enabling us to highlight spatial distribution of exposure profile clusters, and to identify predominant exposure to urban environment features for each cluster of schools. Our findings can help relevant stakeholders, such as schools and public health authorities, to compare schools based on their exposure levels, prioritize interventions, and design local policies that target the schools most in need.

Journal article

Dimakopoulou K, Samoli E, Analitis A, Schwartz J, Beevers S, Kitwiroon N, Beddows A, Barratt B, Rodopoulou S, Zafeiratou S, Gulliver J, Katsouyanni Ket al., 2022, Development and Evaluation of Spatio-Temporal Air Pollution Exposure Models and Their Combinations in the Greater London Area, UK, INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH, Vol: 19

Journal article

Wang J, Alli AS, Clark S, Hughes A, Ezzati M, Beddows A, Vallarino J, Nimo J, Bedford-Moses J, Baah S, Owusu G, Agyemang E, Kelly F, Barratt B, Beevers S, Agyei-Mensah S, Baumgartner J, Brauer M, Arku REet al., 2022, Nitrogen oxides (NO and NO2) pollution in the Accra metropolis: spatiotemporal patterns and the role of meteorology, Science of the Total Environment, Vol: 803, ISSN: 0048-9697

Economic and urban development in sub-Saharan Africa (SSA) may be shifting the dominant air pollution sources in cities from biomass to road traffic. Considered as a marker for traffic-related air pollution in cities, we conducted a city-wide measurement of NOx levels in the Accra Metropolis and examined their spatiotemporal patterns in relation to land use and meteorological factors. Between April 2019 to June 2020, we collected weekly integrated NOx (n = 428) and NO2 (n = 472) samples at 10 fixed (year-long) and 124 rotating (week-long) sites. Data from the same time of year were compared to a previous study (2006) to assess changes in NO2 concentrations. NO and NO2 concentrations were highest in commercial/business/industrial (66 and 76 μg/m3, respectively) and high-density residential areas (47 and 59 μg/m3, respectively), compared with peri-urban locations. We observed annual means of 68 and 70 μg/m3 for NO and NO2, and a clear seasonal variation, with the mean NO2 of 63 μg/m3 (non-Harmattan) increased by 25–56% to 87 μg/m3 (Harmattan) across different site types. The NO2/NOx ratio was also elevated by 19–28%. Both NO and NO2 levels were associated with indicators of road traffic emissions (e.g. distance to major roads), but not with community biomass use (e.g. wood and charcoal). We found strong correlations between both NO2 and NO2/NOx and mixing layer depth, incident solar radiation and water vapor mixing ratio. These findings represent an increase of 25–180% when compared to a small study conducted in two high-density residential neighborhoods in Accra in 2006. Road traffic may be replacing community biomass use (major source of fine particulate matter) as the prominent source of air pollution in Accra, with policy implication for growing cities in SSA.

Journal article

Carruthers D, Stocker J, Stidworthy A, Hood C, Jackson R, McCosh G, Smith S, Connolly D, Tong S, Davies A, Beevers S, Kitwiroon N, Assareh N, Bright V, Neal L, Agnew P, Stedman J, Conlan B, Vieno M, Nemitz E, Reis Set al., 2022, DEFRA 2021 AIR QUALITY MODEL INTER-COMPARISON EXERCISE

The UK takes a combined measurement and modelling approach to reporting associated with the Air Quality Standards Regulations (AQSR, previously the EU Air Quality Directive) pollutant metrics, with modelling currently being performed on behalf of the UK Department for Environment, Food & Rural Affairs (Defra) by Ricardo using the Pollution Climate Mapping (PCM) system. The primary purpose of the Defra 2021 Air Quality Model Inter-Comparison Exercise was to assess the capabilities of four air quality modelling systems in terms of their suitability for AQSR reporting, specifically: PCM; the CMAQ-Urban model driven by WRF meteorology (Environmental Research Group at Imperial College, London); the Air Quality model within the UK Met Office's Unified Model (AQUM-SPPO); and a WRF-EMEP application for the UK (UK Centre for Ecology and Hydrology). This paper provides a project overview and presents key conclusions. All models were configured to calculate pollutant concentrations for 2018 at over 400 monitor locations, gridded concentrations at the models' highest resolution over all of the UK, and, for three of the four models, near-road concentrations associated with the major road network. A wide range of metrics were calculated to assess model performance using NOx, NO2, O3, PM2.5 and PM10 measurement datasets. In addition to visual comparison of air quality maps, derived statistics such as areas in exceedance were calculated separately for 28 agglomeration and 15 non-agglomeration zones. A documented assessment of the models' formulations, configurations and inputs led to an informed model inter-comparison. Meteorological model performance has been evaluated at seven sites over the UK (wind speed, direction and temperature), and the relationship between modelled wind and pollutant concentrations has been investigated. Technical diagnostics have been used to assess how well the models account for NOx chemistry, in addition to the models' ability to represent coarse a

Conference paper

Newbury JB, Stewart R, Fisher HL, Beevers S, Dajnak D, Broadbent M, Pritchard M, Shiode N, Heslin M, Hammoud R, Hotopf M, Hatch SL, Mudway IS, Bakolis Iet al., 2021, Association between air pollution exposure and mental health service use among individuals with first presentations of psychotic and mood disorders: retrospective cohort study, The British Journal of Psychiatry, Vol: 219, Pages: 678-685, ISSN: 0007-1250

Background:Growing evidence suggests that air pollution exposure may adversely affect the brain and increase risk for psychiatric disorders such as schizophrenia and depression. However, little is known about the potential role of air pollution in severity and relapse following illness onset.Aims:To examine the longitudinal association between residential air pollution exposure and mental health service use (an indicator of illness severity and relapse) among individuals with first presentations of psychotic and mood disorders.Method:We identified individuals aged ≥15 years who had first contact with the South London and Maudsley NHS Foundation Trust for psychotic and mood disorders in 2008–2012 (n = 13 887). High-resolution (20 × 20 m) estimates of nitrogen dioxide (NO2), nitrogen oxides (NOx) and particulate matter (PM2.5 and PM10) levels in ambient air were linked to residential addresses. In-patient days and community mental health service (CMHS) events were recorded over 1-year and 7-year follow-up periods.Results:Following covariate adjustment, interquartile range increases in NO2, NOx and PM2.5 were associated with 18% (95% CI 5–34%), 18% (95% CI 5–34%) and 11% (95% CI 3–19%) increased risk for in-patient days after 1 year. Similarly, interquartile range increases in NO2, NOx, PM2.5 and PM10 were associated with 32% (95% CI 25–38%), 31% (95% CI 24–37%), 7% (95% CI 4–11%) and 9% (95% CI 5–14%) increased risk for CMHS events after 1 year. Associations persisted after 7 years.Conclusions:Residential air pollution exposure is associated with increased mental health service use among people recently diagnosed with psychotic and mood disorders. Assuming causality, interventions to reduce air pollution exposure could improve mental health prognoses and reduce healthcare costs.

Journal article

Desouza CD, Marsh DJ, Beevers SD, Molden N, Green DCet al., 2021, A spatial and fleet disaggregated approach to calculating the NOX emissions inventory for non-road mobile machinery in London, Atmospheric Environment: X, Vol: 12, Pages: 1-8, ISSN: 2590-1621

The latest London atmospheric emissions inventory (2016), which is calculated using fuel consumption and construction employment, estimates that, the construction sector contributes 34% of the total PM10 emissions (the largest source), and 7% of the total NOX emissions (5th largest source). These contribute significantly to NO2 and PM2.5 pollution problems in London, which is a major concern for public health. Real-world emission factors from tail-pipe measurements were coupled to a register for construction machinery, to develop a novel ‘spatial and fleet disaggregated’ emissions inventory for the construction sector in London. This method estimated 1294 tonnes of NOX in 2018 and 1578 tonnes of NOX in 2019 from non-road mobile machinery in the construction sector, approximately 55% and 45% lower for 2018 and 2019 respectively, than the current (2016) London atmospheric emissions inventory (2850 tonnes). However, compared to the current London atmospheric emissions inventory, the new NOX emissions are higher in central London, under-estimating the importance of this source in central London. The fleet-disaggregated emissions inventory enables potential policy to be developed by focusing on high-emitters registered on the London database. As a demonstration, two emission abatement scenarios were modelled – first: by retrofitting older generators with a SCR-DPF system, a potential 53% reduction in overall NOX emissions was predicted from all NRMM; and second: by accelerating the excavator fleet-turnover – a more modest 2-tonne reduction in overall NOX emissions was predicted from all NRMM in London.

Journal article

Karamanos A, Mudway I, Webb A, Lu Y, Kelly F, Dajnak D, Beevers SD, Elia C, Maynard M, Harding S, Cruickshank JKet al., 2021, Air pollution and Blood Pressure change over time in 3323 adolescents in London: differences by gender and ethnicity, 2021 Annual Scientific Meeting of the British and Irish Hypertension Society (BIHS), Publisher: Springer Nature [academic journals on nature.com], Pages: 2-2, ISSN: 0950-9240

Conference paper

Latham RM, Kieling C, Arseneault L, Rocha TB-M, Beddows A, Beevers SD, Danese A, De Oliveira K, Kohrt BA, Moffitt TE, Mondelli V, Newbury JB, Reuben A, Fisher HLet al., 2021, Childhood exposure to ambient air pollution and predicting individual risk of depression onset in UK adolescents, JOURNAL OF PSYCHIATRIC RESEARCH, Vol: 138, Pages: 60-67, ISSN: 0022-3956

Journal article

Ashworth M, Analitis A, Whitney D, Samoli E, Zafeiratou S, Atkinson R, Dimakopoulou K, Beavers S, Schwartz J, Katsouyanni Ket al., 2021, Spatio-temporal associations of air pollutant concentrations, GP respiratory consultations and respiratory inhaler prescriptions: a 5-year study of primary care in the borough of Lambeth, South London, ENVIRONMENTAL HEALTH, Vol: 20

Journal article

Karamanos A, Mudway I, Kelly F, Beevers SD, Dajnak D, Elia C, Cruickshank JK, Lu Y, Tandon S, Enayat E, Dazzan P, Maynard M, Harding Set al., 2021, Air pollution and trajectories of adolescent conduct problems: the roles of ethnicity and racism; evidence from the DASH longitudinal study, Social Psychiatry and Psychiatric Epidemiology: the international journal for research in social and genetic epidemiology and mental health services, Vol: 56, Pages: 2029-2039, ISSN: 0933-7954

PurposeNo known UK empirical research has investigated prospective associations between ambient air pollutants and conduct problems in adolescence. Ethnic minority children are disproportionately exposed to structural factors that could moderate any observed relationships. This prospective study examined whether exposure to PM2.5 and NO2 concentrations is associated with conduct problems in adolescence, and whether racism or ethnicity moderate such associations.MethodsLongitudinal associations between annual mean estimated PM2.5 and NO2 concentrations at the residential address and trajectories of conduct problems, and the potential influence of racism and ethnicity were examined school-based sample of 4775 participants (2002–2003 to 2005–2006) in London, using growth curve models.ResultsOverall, in the fully adjusted model, exposure to lower concentrations of PM2.5 and NO2 was associated with a decrease in conduct problems during adolescence, while exposure to higher concentrations was associated with a flattened trajectory of conduct symptoms. Racism amplified the effect of PM2.5 (β = 0.05 (95% CI 0.01 to 0.10, p < 0.01)) on adolescent trajectories of conduct problems over time. At higher concentrations of PM2.5, there was a divergence of trajectories of adolescent conduct problems between ethnic minority groups, with White British and Black Caribbean adolescents experiencing an increase in conduct problems over time.ConclusionThese findings suggest that the intersections between air pollution, ethnicity, and racism are important influences on the development of conduct problems in adolescence.

Journal article

Reuben A, Arseneault L, Beddows A, Beevers SD, Moffitt TE, Ambler A, Latham RM, Newbury JB, Odgers CL, Schaefer JD, Fisher HLet al., 2021, Association of Air Pollution Exposure in Childhood and Adolescence With Psychopathology at the Transition to Adulthood, JAMA NETWORK OPEN, Vol: 4, ISSN: 2574-3805

Journal article

Hicks W, Beevers S, Tremper A, Stewart G, Priestman M, Kelly F, Lanoisellé M, Lowry D, Green Det al., 2021, Quantification of non-exhaust particulate matter traffic emissions and the impact of COVID-19 lockdown at London Marylebone Road, Atmosphere, Vol: 12, Pages: 1-19, ISSN: 2073-4433

This research quantifies current sources of non-exhaust particulate matter traffic emissions in London using simultaneous, highly time-resolved, atmospheric particulate matter mass and chemical composition measurements. The measurement campaign ran at Marylebone Road (roadside) and Honor Oak Park (background) urban monitoring sites over a 12-month period between 1 September 2019 and 31 August 2020. The measurement data has been used to determine the traffic increment (roadside – background) and covers a range of meteorological conditions, seasons and driving styles, as well as the influence of the COVID-19 ‘lockdown’ on non-exhaust concentrations. Non-exhaust PM10 concentrations are calculated using chemical tracer scaling factors for brake wear (barium), tyre wear (zinc) and resuspension (silicon) and as average vehicle fleet non-exhaust emission factors, using a CO2 ‘dilution approach’. The effect of lockdown, which saw a 32% reduction in traffic volume and a 15% increase in average speed on Marylebone Road, resulted in lower PM10 and PM2.5 traffic increments and brake wear concentrations, but similar tyre and resuspension concentrations, confirming that factors that determine non-exhaust emissions are complex. Brake wear was found to be the highest average non-exhaust emission source. In addition, results indicated that non-exhaust emission factors are dependent upon speed and road surface wetness conditions. Further statistical analysis incorporating a wider variability in vehicle mix, speeds and meteorological conditions, as well as advanced source apportionment of the PM measurement data, will be undertaken to enhance our understanding of these important vehicle sources.

Journal article

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