Traffic-related air pollution reduction at UK schools during the Covid-19 lockdown.

Elevated urban Nitrogen Dioxide (NO2) is a consequence of road traffic and other fossil-fuel combustion sources, and the road transport sector provides a significant contribution to UK NO2 emissions. The inhalation of traffic-related air pollution, including NO2, can cause a range of problems to human health. Due to their developing organs, children are particularly susceptible to the negative effects of air pollution inhalation. Accordingly, schools and associated travel behaviours present an important area of study for the reduction of child exposure to these harmful pollutants. COVID-19 reached the UK in late January 2020. On the 23rd of March that year, the UK government announced a nationwide stay-at-home order, or lockdown, banning all non-essential travel and contact with people outside of their own homes. The lockdown was accompanied by the closure of schools, public facilities, amenities, businesses and places of worship. The current study aims to assess the significance of nationwide NO2 reductions at schools in England as a consequence of the lockdown in order to highlight the benefits of associated behavioural changes within the context of schools in England and potential child exposure. NO2 data were collected from all AURN (Automatic Urban and Rural Network) monitoring sites within 500 m of nurseries, primary schools, secondary schools and colleges in England. A significant reduction of mean NO2 concentrations was observed in the first month of the UK lockdown at background (-35.13%) and traffic (-40.82%) sites. Whilst lockdown restrictions are undoubtedly unsustainable, the study results demonstrate the possible reductions of NO2 at schools in England and potential reductions of child exposure that are achievable when public behaviours shift towards active travel, work from home policies and generally lower use of polluting vehicles.

Unprecedented reduction in air pollution and corresponding short-term premature mortality associated with COVID-19 lockdown in Delhi, India.

Countries around the world introduced strict restrictions on movement and activities known as 'lockdowns' to restrict the spread of the novel coronavirus disease (COVID-19) from the end of 2019. A sudden improvement in air quality was observed globally as a result of these lockdowns. To provide insight into the changes in air pollution levels in response to the COVID-19 restrictions we have compared surface air quality data in Delhi during four phases of lockdown and the first phase of the restriction easing period (25 March to 30 June 2020) with data from a baseline period (2018-2019). Simultaneously, short-term exposure of PM2.5 and O3 attributed premature mortality were calculated to understand the health benefit of the change in air quality. Ground-level observations in Delhi showed that concentrations of PM10, PM2.5 and NO2 dropped substantially in 2020 during the overall study period compared with the same period in previous years, with average reductions of ~49%, ~39%, and ~39%, respectively. An overall lower reduction in O3 of ~19% was observed for Delhi. A slight increase in O3 was found in Delhi's industrial and traffic regions. The highest peak of the diurnal variation decreased substantially for all the pollutants at every phase. The decrease in PM2.5 and O3 concentrations in 2020, prevented 904 total premature deaths, a 60% improvement when compared to the figures for 2018-2019. The restrictions on human activities during the lockdown have reduced anthropogenic emissions and subsequently improved air quality and human health in one of the most polluted cities in the world.Implications: I am submitting herewith the manuscript entitled "Unprecedented Reduction in Air Pollution and Corresponding Short-term Premature Mortality Associated with COVID-19 Forced Confinement in Delhi, India" for potential publishing in your journal.The novelty of this research lies in: (1) we utilized ground-level air quality data in Delhi during four phases of lockdown and the first phase of unlocking period (25th March to 30th June) for 2020 as well as data from the baseline period (2018-2019) to provide an early insight into the changes in air pollution levels in response to the COVID-19 pandemic, (2) Chatarize the change of diurnal variation of the pollutants and (3) we assess the health risk due to PM2.5 and O3. Results from ground-level observations in Delhi showed that concentrations of PM10, PM2.5 and NO2 substantially dropped in 2020 during the overall study period compared to the similar period in previous years, with an average reduction of ~49%, ~39%, and ~39%, respectively. In the case of O3, the overall reduction was observed as ~19% in Delhi, while a slight increase was found in industrial and traffic regions. And consequently, the highest peak of the diurnal variation decreased substantially for all the pollutants. The health impact assessment of the changes in air quality indicated that 904 short-term premature deaths (~60%) were prevented due to the decline in PM2.5 and O3 concentrations in the study period. The restrictions on human activities during the lockdown have reduced the anthropogenic emissions and subsequently improved air quality and human health in one of the most polluted cities in the world.

Risk of respiratory hospital admission associated with modelled concentrations of Aspergillus fumigatus from composting facilities in England.

Bioaerosols have been associated with adverse respiratory-related health effects and are emitted in elevated concentrations from composting facilities. We used modelled Aspergillus fumigatus concentrations, a good indicator for bioaerosol emissions, to assess associations with respiratory-related hospital admissions. Mean daily Aspergillus fumigatus concentrations were estimated for each composting site for first full year of permit issue from 2005 onwards to 2014 for Census Output Areas (COAs) within 4 km of 76 composting facilities in England, as previously described (Williams et al., 2019). We fitted a hierarchical generalized mixed model to examine the risk of hospital admission with a primary diagnosis of (i) any respiratory condition, (ii) respiratory infections, (iii) asthma, (iv) COPD, (v) diseases due to organic dust, and (vi) Cystic Fibrosis, in relation to quartiles of Aspergillus fumigatus concentrations. Models included a random intercept for each COA to account for over-dispersion, nested within composting facility, on which a random intercept was fitted to account for clustering of the data, with adjustments for age, sex, ethnicity, deprivation, tobacco sales (smoking proxy) and traffic load (as a proxy for traffic-related air pollution). We included 249,748 respiratory-related and 3163 Cystic Fibrosis hospital admissions in 9606 COAs with a population-weighted centroid within 4 km of the 76 included composting facilities. After adjustment for confounders, no statistically significant effect was observed for any respiratory-related (Relative Risk (RR) = 0.99; 95% Confidence Interval (CI) 0.96-1.01) or for Cystic Fibrosis (RR = 1.01; 95% CI 0.56-1.83) hospital admissions for COAs in the highest quartile of exposure. Similar results were observed across all respiratory disease sub-groups. This study does not provide evidence for increased risks of respiratory-related hospitalisations for those living near composting facilities. However, given the limitations in the dispersion modelling, risks cannot be completely ruled out. Hospital admissions represent severe respiratory episodes, so further study would be needed to investigate whether bioaerosols emitted from composting facilities have impacts on less severe episodes or respiratory symptoms.

Mapping ammonia risk on sensitive habitats in Ireland.

The aim of this study was to provide a simple, cost-effective, risk-based map of terrestrial areas in Ireland where environmental quality may be at risk from atmospheric ammonia. This risk-based approach identifies Natura 2000 sites in Ireland at risk from agricultural atmospheric ammonia, collating best available data using Geographical Information Systems (GIS). In mapping ammonia risk on sensitive habitats (MARSH), the method identifies sources of ammonia, classifying them on a scale of risk from 0 to 5. These sources are subsequently summed based on a weighting determined by their contribution to national emissions divided by their potentially impacted area. A Pearson's correlation coefficient of 0.72 allows for concentrations from United Kingdom's FRAME modelling to be applied to the MARSH model, which are corrected based on recent monitoring. Applying Designation Weighted Indicators (DWI), the MARSH model predicts that 80.7, 34.3 and 5.9% of Natura 2000 sites in Ireland may exceed ambient concentrations of 1, 2, and 3 µg/m3, respectively. A Nitroindex map of Ireland based on available lichen records was also developed and is presented as part of this study. This Nitroindex was used to identify areas where impacts have already been recorded, thus informing the classification of sites "at-risk". The combination of both the MARSH and Nitroindex models ascertains which Natura 2000 sites are most at risk, thereby providing valuable data to relevant authorities. The MARSH model acts as a first step towards screening and assessing Natura 2000 sites most at risk from atmospheric ammonia, providing a tool to demonstrate compliance with the National Emissions Ceilings Directive.

Scoping studies to establish the capability and utility of a real-time bioaerosol sensor to characterise emissions from environmental sources.

A novel dual excitation wavelength based bioaerosol sensor with multiple fluorescence bands called Spectral Intensity Bioaerosol Sensor (SIBS) has been assessed across five contrasting outdoor environments. The mean concentrations of total and fluorescent particles across the sites were highly variable being the highest at the agricultural farm (2.6 cm-3 and 0.48 cm-3, respectively) and the composting site (2.32 cm-3 and 0.46 cm-3, respectively) and the lowest at the dairy farm (1.03 cm-3 and 0.24 cm-3, respectively) and the sewage treatment works (1.03 cm-3 and 0.25 cm-3, respectively). In contrast, the number-weighted fluorescent fraction was lowest at the agricultural site (0.18) in comparison to the other sites indicating high variability in nature and magnitude of emissions from environmental sources. The fluorescence emissions data demonstrated that the spectra at different sites were multimodal with intensity differences largely at wavelengths located in secondary emission peaks for λex 280 and λex 370. This finding suggests differences in the molecular composition of emissions at these sites which can help to identify distinct fluorescence signature of different environmental sources. Overall this study demonstrated that SIBS provides additional spectral information compared to existing instruments and capability to resolve spectrally integrated signals from relevant biological fluorophores could improve selectivity and thus enhance discrimination and classification strategies for real-time characterisation of bioaerosols from environmental sources. However, detailed lab-based measurements in conjunction with real-world studies and improved numerical methods are required to optimise and validate these highly resolved spectral signatures with respect to the diverse atmospherically relevant biological fluorophores.

The rhetoric and realities of integrating air quality into the local transport planning process in English local authorities.

Regardless of its intent and purposes, the first decade of the Local Air Quality Management (LAQM) framework had little or no effect in reducing traffic-related air pollution in the UK. Apart from the impact of increased traffic volumes, the major factor attributed to this failure is that of policy disconnect between the process of diagnosing air pollution and its management, thereby limiting the capability of local authorities to control traffic-related sources of air pollution. Integrating air quality management into the Local Transport Plan (LTP) process therefore presents opportunities for enabling political will, funding and joined-up policy approach to reduce this limitation. However, despite the increased access to resources for air quality measures within the LTP process, there are local institutional, political and funding constraints which reduce the impact of these policy interventions on air quality management. This paper illustrate the policy implementation gaps between central government policy intentions and the local government process by providing evidence of the deprioritisation of air quality management compared to the other shared priorities in the LTP process. We draw conclusions on the policy and practice of integrating air quality management into transport planning. The evidence thereby indicate the need for a policy shift from a solely localised hotspot management approach, in which the LAQM framework operates, to a more holistic management of vehicular emissions within wider spatial administrative areas.

Evaluation of inflammatory effects of airborne endotoxin emitted from composting sources.

Because of the lack of effective methodology, the biological effects of environmental endotoxin have not been assessed. Here we have collected and measured airborne endotoxin at different locations around composting sites. Increased endotoxin concentrations were observed close to composting activities and also at nearby boundary areas. Analysis of proinflammatory effects of the environmental endotoxin on interleukin (IL)-8 and IL-6 release from human D562 pharyngeal epithelial and MM6 monocytic cell cultures showed an association between endotoxin level and cytokine induction. The cytokine-inducing effect of bioaerosol extracts was inhibited by polymyxin B, indicating that endotoxin was the cause of cytokine responses we found. The environmental endotoxin was also more active for stimulating cytokines in airway epithelial cells than commercially purified Escherichia coli endotoxin. Our results suggest that these in vitro inflammatory cell models may contribute to the assessment of health impacts of environmental endotoxin.

Endotoxin emissions from commercial composting activities.

This paper describes an exploratory study of endotoxin emissions and dispersal from a commercial composting facility. Replicated samples of air were taken by filtration at different locations around the facility on 10 occasions. Measurements were made of endotoxin and associated culturable microorganisms. The inflammatory response of cell cultures exposed to extracts from the filters was measured. Endotoxin was detected in elevated concentrations close to composting activities. A secondary peak, of lesser magnitude than the peak at source was detected at 100-150 m downwind of the site boundary. Unexpectedly high concentrations of endotoxin were measured at the most distant downwind sampling point. Extracted endotoxin was found to stimulate human monocytes and a human lung epithelial cell line to produce significant amounts of pro-inflammatory cytokines. On a weight basis, endotoxin extracted from the composting source has a greater inflammatory cytokine inducing effect than commercial E. coli endotoxin.

The influence of manure composition on emissions of odour and ammonia from finishing pigs fed different concentrations of dietary crude protein.

An investigation was conducted into the influence of manure composition on the odour emission rate (OER) and the emission rate of ammonia (NH(3)), when diets containing 130, 160, 190 and 210gkg(-1) crude protein (CP) were fed to finishing pigs. A group of four boars and four gilts, housed in environmentally sealed pens, were assigned to each diet for a 23-day experimental period which was replicated three times (n=3). Ventilation air from each pen was sampled for NH(3) and odour, by olfactometry, on four days during the trial period. Simultaneous collections of manure were taken from the surface and base of each pit. The pH and the concentrations of dry matter, total Kjeldahl nitrogen (TKN), total ammoniacal nitrogen (TAN) and volatile fatty acids in the manure were measured. Manure composition differed between samples from the surface and base of the pit (P<0.05). Reducing dietary CP concentration decreased the emission of NH(3) (linear, P<0.001). The acetic acid:propionic acid ratio in manure samples was correlated to OER (r=0.79, P<0.001). There was a quadratic relationship between dietary CP concentration and OER (P<0.05). OER decreased between 210gkg(-1) and 160gkg(-1) CP and increased between 160gkg(-1) and 130gkg(-1) CP. In conclusion, reducing dietary crude protein levels could be used effectively to reduce ammonia emissions and OER, although no significant advantage was to be gained in OER from reducing crude protein level below 160gkg(-1).