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ABSTRACT Propionibacterium freudenreichii (PFR) DSM 20271T is a bacterium known for its ability to thrive in diverse environments and to produce vitamin B12. Despite its anaerobic preference, recent studies have elucidated its ability to prosper in the presence of oxygen, prompting a deeper exploration of its physiology under aerobic conditions. Here, we investigated the response of DSM 20271T to aerobic growth by employing comparative transcriptomic and surfaceome analyses alongside metabolite profiling. Cultivation under controlled partial pressure of oxygen (pO2) conditions revealed significant increases in biomass formation and altered metabolite production, notably of vitamin B12, pseudovitamin-B12, propionate, and acetate, under aerobic conditions. Transcriptomic analysis identified differential expression of genes involved in lactate metabolism, tricarboxylic acid cycle, and electron transport chain, suggesting metabolic adjustments to aerobic environments. Moreover, surfaceome analysis unveiled growth environment-dependent changes in surface protein abundance, with implications for adaptation to atmospheric conditions. Supplementation experiments with key compounds highlighted the potential for enhancing aerobic growth, emphasizing the importance of iron and α-ketoglutarate availability. Furthermore, in liquid culture, FeSO4 supplementation led to increased heme production and reduced vitamin B12 production, highlighting the impact of oxygen and iron availability on the metabolic pathways. These findings deepen our understanding of PFR’s physiological responses to oxygen availability and offer insights for optimizing its growth in industrial applications.IMPORTANCEThe study of the response of Propionibacterium freudenreichii to aerobic growth is crucial for understanding how this bacterium adapts to different environments and produces essential compounds like vitamin B12. By investigating its physiological changes under aerobic conditions, we can gain insights into its metabolic adjustments and potential for enhanced growth. These findings not only deepen our understanding of P. freudenreichii's responses to oxygen availability but also offer valuable information for optimizing its growth in industrial applications. This research sheds light on the adaptive mechanisms of this bacterium, providing a foundation for further exploration and potential applications in various fields.

Abstract Air quality negatively impacts agriculture, reducing the yield of staple food crops. While measured data on African ground-level ozone levels are scarce, experimental studies demonstrate the damaging impact of ozone on crops. Common beans (Phaseolus vulgaris), an ozone-sensitive crop, are widely grown in Uganda. Using modelled ozone flux, agricultural surveys, and a flux-effect relationship, this study estimates yield and production losses due to ozone for Ugandan beans in 2015. Analysis at this scale allows the use of localised data, and results can be presented at a sub-regional level. Soil nutrient stress, drought, flood risk, temperature and deprivation were also mapped to investigate where stresses may coincide. Average bean yield losses due to ozone were 17% and 14% (first and second growing season respectively), equating to 184 thousand tonnes production loss. However, for some sub-regions, losses were up to 27.5% and other crop stresses also coincided in these areas. This methodology could be applied widely, allowing estimates of ozone impact for countries lacking air quality and/or experimental data. As crop productivity is below its potential in many areas of the world, changing agricultural practices to mitigate against losses due to ozone could help to reduce the crop yield gap.

High-resolution modelling of surface ozone is an essential step in the quantification of the impacts on health and ecosystems from historic and future concentrations. It also provides a principled way in which to extend analysis beyond measurement locations. Often, such modelling uses relatively coarse-resolution chemistry transport models (CTMs), which exhibit biases when compared to measurements. EMEP4UK is a CTM that is used extensively to inform UK air quality policy, including the effects on ozone from mitigation of its precursors. Our evaluation of EMEP4UK for the years 2001–2018 finds a high bias in reproducing daily maximum 8 h average ozone (MDA8), due in part to the coarse spatial resolution. We present a machine learning downscaling methodology to downscale EMEP4UK ozone output from a 5×5 km to 1×1 km resolution using a gradient-boosted tree. By addressing the high bias present in EMEP4UK, the downscaled surface better represents the measured data, with a 128 % improvement in R2 and 37 % reduction in RMSE. Our analysis of the downscaled surface shows a decreasing trend in annual and March–August mean MDA8 ozone for all regions of the UK between 2001–2018, differing from increasing measurement trends in some regions. We find the proportion of the UK which fails the government objective to have at most 10 exceedances of 100 µg m−3 per annum is 27 % (2014–2018 average), compared to 99 % from the unadjusted EMEP4UK model. A statistically significant trend in this proportion of −2.19 % yr−1 is found from the downscaled surface only, highlighting the importance of bias correction in the assessment of policy metrics. Finally, we use the downscaling approach to examine the sensitivity of UK surface ozone to reductions in UK terrestrial NOx (i.e. NO + NO2) emissions on a 1×1 km surface. Moderate NOx emission reductions with respect to present day (20 % or 40 %) increase both average and high-level ozone concentrations in large portions of the UK, whereas larger NOx reductions (80 %) cause a similarly widespread decrease in high-level ozone. In all three scenarios, very urban areas (i.e. major cities) are the most affected by increasing concentrations of ozone, emphasizing the broader air quality challenges of NOx control.

Wood hemicelluloses have been used as a wall material for spray-dried microencapsulation of polyphenols. Nevertheless, their incomplete water solubility could negatively impact their encapsulation efficiency (EE) and the formation of a complete protective layer, which might be alleviated synergistically by combining them with carboxymethylcellulose (CMC). Here, we explored the effects of CMC addition (0.5–3.0 %, w/w of WM) on the capacity of galactoglucomannans (GGM) and glucuronoxylans (GX) to retain bioactive compounds of bilberry during spray drying; and its contribution to the formation of wall thickness. The results revealed that EE of GGM and GX increased by 4–8 % with the CMC addition at 0.5 %, but significantly declined at higher CMC concentrations. Adding CMC improved the microcapsules' antioxidant activities, surface smoothness, and solubility, but had no effect on their particle size, thermal properties, amorphous structure, or moisture content. The majority of the GGM and GX microcapsules had a hollow internal structure surrounded by continuous wall matrix with a thickness of about 2.3–2.6 μm, which increased to 3.1–3.5 μm with the addition of 0.5 % CMC. Therefore, using CMC at an optimized proportion as a co-encapsulant improved wood hemicelluloses' ability to protect bioactive compounds during spray drying and enhanced microcapsule wall formation.

The present work describes the implementation of the state of the art Cloud-J v7.3 photolysis rate calculation code in the EMEP MSC-W chemistry-transport model. Cloud-J calculates photolysis rates and accounts for cloud and aerosol optical properties at model run time, replacing the old system based on tabulated values. The performance of Cloud-J is evaluated against aerial photolysis rate observations made over the Pacific Ocean and against surface observations from three measurement sites in Europe. Numerical experiments are performed to investigate the sensitivity of the calculated photolysis rates to the spatial and temporal model resolution, input meteorology model, simulated ozone column, and cloud effect parameterization. These experiments indicate that the calculated photolysis rates are most sensitive to the choice of input meteorology model and cloud effect parameterization while also showing that surface ozone photolysis rates can vary by up to 20 % due to daily variations in total ozone column. Further analysis investigates the impact of Cloud-J on the oxidizing capacity of the troposphere, aerosol–photolysis interactions, and surface air quality predictions. Results find that the annual mean mass-weighted tropospheric hydroxyl concentration is increased by 26 %, while the photolytic impact of aerosols is mostly limited to large tropical biomass-burning regions. Overall, Cloud-J represents a major improvement over the tabulated system, leading to improved model performance for predicting carbon monoxide and daily maximum ozone surface concentrations.

The UK proposes additional bioenergy plantations and afforestation as part of measures to meet net-zero greenhouse gas emissions, but species and locations are not yet decided. Different tree species emit varying amounts of isoprene and monoterpene volatile organic compounds that are precursors to ozone and secondary organic aerosol (SOA) formation, the latter of which is a component of PM2.5. The forest canopy also acts as a depositional sink for air pollutants. All these processes are meteorologically influenced. We present here a first step in coupling information on tree species planting suitability and other planting constraints with data on UK-specific BVOC emission rates and tree canopy data to simulate, via the WRF-EMEP4UK high spatial-resolution atmospheric chemistry transport model, the impact on UK air quality of four potential scenarios. Our “maximum planting” scenarios are based on planting areas where yields are predicted to be ≥ 50 % of the maximum from the Ecological Site Classification decision support system (ESC DSS) for Eucalyptus gunnii, hybrid aspen (Populus tremula), Italian alder (Alnus cordata) and Sitka spruce (Picea sitchensis). The additional areas of forest in our scenarios are 2.0 to 2.7 times the current suggestions for new bioenergy and afforestation land cover in the UK. Our planting scenarios increase UK annual mean surface ozone concentrations by 1.0 ppb or 3 % relative to the baseline land cover for the highest BVOC-emitting species (e.g. E. gunnii). Increases in ozone reach 2 ppb in summer when BVOC emissions are greatest. In contrast, all the additional planting scenarios lead to reductions in UK annual mean PM2.5 – ranging from −0.2 µg m−3 (−3 %) for Sitka spruce to −0.5 µg m−3 (−7 %) for aspen – revealing that PM2.5 deposition to the additional forest canopy area more than offsets additional SOA formation. Relative decreases in annual mean PM2.5 are greater than the relative increases in annual mean ozone. Reductions in PM2.5 are least in summer, coinciding with the period of maximum monoterpene emissions. Although only a first step in evaluating the impact of increased forest plantation on UK air quality, our study demonstrates the need for locally relevant data on land cover suitability, emissions and meteorology in model simulations.

The reduction of fine particles (PM2.5) and reactive N (Nr) and S (Sr) species is a key objective for air pollution control policies because of their major adverse effects on human health, ecosystem diversity, and climate. The sensitivity of global and regional Nr, Sr, and PM2.5 to 20 % and 40 % individual and collective reductions in anthropogenic emissions of NH3, NOx, and SOx (with respect to a 2015 baseline) is investigated using the EMEP MSC-W (European Monitoring and Evaluation Programme Meteorological Synthesizing Centre – West) atmospheric chemistry transport model with WRF (Weather Research and Forecasting) meteorology. Regional comparisons reveal that the individual emissions reduction has multiple co-benefits and small disbenefits on different species, and those effects are highly geographically variable. A 40 % NH3 emission reduction decreases regional average NH3 concentrations by 47 %–49 % but only decreases NH4+ by 18 % in Euro_Medi, 15 % in East Asia, 12 % in North America, and 4 % in South Asia. This order follows the regional ammonia richness. A disbenefit is the increased SO2 concentrations in these regions (10 %–16 % for 40 % reductions) because reduced NH3 levels decrease SO2 deposition through altering atmospheric acidity. A 40 % NOx emission reduction reduces NOx concentrations in East Asia by 45 %, Euro_Medi and North America by ∼ 38 %, and South Asia by 22 %, whilst the regional order is reversed for fine NO3-, which is related to enhanced O3 levels in East Asia (and also, but by less, in Euro_Medi) and decreased O3 levels in South Asia (and also, but by less, in North America). Consequently, the oxidation of NOx to NO3- and of SO2 to SO42- is enhanced in East Asia but decreased in South Asia, which causes a less effective decrease in NO3- and even an increase in SO42- in East Asia but quite the opposite in South Asia. For regional policy making, it is thus vital to reduce three precursors together to minimize such adverse effects. A 40 % SOx emission reduction is slightly more effective in reducing SO2 (42 %–45 %) than SO42- (34 %–38 %), whilst the disbenefit is that it yields a ∼ 12 % increase in total NH3 deposition in the four regions, which further threatens ecosystem diversity. This work also highlights important messages for policy makers concerning the mitigation of PM2.5. More emissions controls focusing on NH3 and NOx are necessary for regions with better air quality, such as northern Europe and eastern North America. In East Asia, the three individual reductions are equally effective, whilst in South Asia only SOx reduction is currently effective. The geographically varying non-one-to-one proportionality of chemical responses of Nr, Sr, and PM2.5 to emissions reductions revealed by this work show the importance of both prioritizing emissions strategies in different regions and combining several precursor reductions together to maximize the policy effectiveness.

In the last six decades, the consumption of reactive nitrogen (Nr) in the form of fertilizer in India has been growing rapidly, whilst the nitrogen use efficiency (NUE) of cropping systems has been decreasing. These trends have led to increasing environmental losses of Nr, threatening the quality of air, soils, and fresh waters, and thereby endangering climate-stability, ecosystems, and human-health. Since it has been suggested that the fertilizer consumption of India may double by 2050, there is an urgent need for scientific research to support better nitrogen management in Indian agriculture. In order to share knowledge and to develop a joint vision, experts from the UK and India came together for a conference and workshop on “Challenges and Opportunities for Agricultural Nitrogen Science in India.” The meeting concluded with three core messages: (1) Soil stewardship is essential and legumes need to be planted in rotation with cereals to increase nitrogen fixation in areas of limited Nr availability. Synthetic symbioses and plastidic nitrogen fixation are possibly disruptive technologies, but their potential and implications must be considered. (2) Genetic diversity of crops and new technologies need to be shared and exploited to reduce N losses and support productive, sustainable agriculture livelihoods. (3) The use of leaf color sensing shows great potential to reduce nitrogen fertilizer use (by 10–15%). This, together with the usage of urease inhibitors in neem-coated urea, and better management of manure, urine, and crop residues, could result in a 20–25% improvement in NUE of India by 2030.

Faba bean is a promising source of ingredients for the production of meat analogs. However, sensory properties of faba bean, especially the bitter taste of the protein concentrate, restrict its use. Our aim was to assess the feasibility of two types of faba bean ingredients—flour (from germinated, gently heat-treated beans) and groat (from non-germinated, roasted beans)—in combination with pea protein isolate and oat fiber concentrate for producing meat analogs using high-moisture extrusion. We produced six samples using varying recipes, while maintaining constant process parameters. An untrained panel (55 participants) evaluated the samples for key sensory attributes (check-all-that-apply) and rated their pleasantness. The water absorption capacity and mechanical properties of the samples were assessed using instrumental measurements. The samples were frequently described as ‘beany’ and ‘tasteless’, but very rarely as ‘bitter’. The most frequently cited attributes for mouthfeel varied between the samples containing 30% (‘tough’, ‘gummy’) and 50% (‘crumbly’, ‘floury’) of faba bean flour/groat and were associated with corresponding mechanical properties. On average, the sample containing a blend of faba bean groat and pea protein isolate (50% each) appeared to be the most pleasant. Our results suggest that faba bean groat with pea protein isolate enables the production of fibrous meat analogs with acceptable taste and texture, without the bitter off-taste.

A wide range of pharmaceutical residues is known to occur in the environment. While they are released into surface waters mainly through centralized wastewater treatment plants (WWTPs), their primary emission sources are located upstream in the sewer network. Information on emissions from different types of primary emission sources is scarce. However, such information could help direct emission reduction measures more efficiently. In this study, we analysed the concentrations of selected active pharmaceutical ingredients (APIs) in wastewater samples taken from altogether ten sites, covering primary emission sources (hospitals and households), and conventional WWTPs. The concentrations in WWTP effluents were used to identify APIs causing risk in recipient waterbodies. Furthermore, the API loads from households and hospitals were compared to those reaching the WWTP in mixed influents. Our results confirm previously published observations of several pharmaceuticals exceeding their predicted no-effect concentrations in effluent wastewaters. Moreover, the concentrations of most of the analysed APIs are comparatively high in hospital wastewaters, resulting in elevated risk quotients. While the total API loads are relatively low from primary emission sources, owing to the low wastewater volume generated at those sites, per capita emissions were shown to be several times higher at hospital sites than at household sites for APIs such as metronidazole, trimethoprim, and ofloxacin. These findings indicate, that directing emission reduction measures to hospitals could be an effective way to decrease the loads of several risk-posing APIs into the environment, especially where hospital contribution to overall wastewater flow to WWTPs is high.

Exposure to ambient ozone (O3) O3 is associated with impacts on human health. O3 is a secondary pollutant whose concentrations are determined inter alia by emissions of precursors such as oxides of nitrogen (NOx) and volatile organic compounds (VOCs), and thus future health burdens depend on policies relating to climate and air quality. While emission controls are expected to reduce levels of PM2.5 and NO2 and their associated mortality burdens, for secondary pollutants like O3 the picture is less clear. Detailed assessments are necessary to provide quantitative estimates of future impacts to support decision-makers. We simulate future O3 across the UK using a high spatial resolution atmospheric chemistry model with current UK and European policy projections for 2030, 2040 and 2050, and use UK regional population-weighting and latest recommendations on health impact assessment to quantify respiratory emergency hospital admissions associated with short-term effects of O3. We estimate 60,488 admissions in 2018, increasing by 4.2%, 4.5% and 4.6% by 2030, 2040 and 2050 respectively (assuming a fixed population). Including future population growth, estimated emergency respiratory hospital admissions are 8.3%, 10.3% and 11.7% higher by 2030, 2040 and 2050 respectively. Increasing O3 concentrations in future are driven by reduced nitric oxide (NO) in urban areas due to reduced emissions, with increases in O3 mainly occurring in areas with lowest O3 concentrations currently. Meteorology influences episodes of O3 on a day-to-day basis, although a sensitivity study indicates that annual totals of hospital admissions are only slightly impacted by meteorological year. While reducing emissions results in overall benefits to population health (through reduced mortality due to long-term exposure to PM2.5 and NO2), due to the complex chemistry, as NO emissions reduce there are associated local increases in O3 close to population centres that may increase harms to health.

Legumes have been recognised as healthy and environmentally friendly protein sources. Knowledge about the vitamin B contents in legume ingredients and extrudates is scarce. In this study, we investigated thiamin, riboflavin, niacin, and folate in various faba bean, lupin, and pea ingredients. Further, the retention of B vitamins in high moisture extrusion was studied. Prior to liquid chromatographic determinations of thiamin, riboflavin, niacin, and folate, vitamins were extracted by acid hydrolysis (niacin), enzymatic treatment (folate), or their combination (thiamin and riboflavin). The contents (on a dry matter basis) varied greatly among different ingredients: the thiamin content was 0.2–14.2 µg/g; riboflavin, 0.3–5.9 µg/g; niacin, 8.8–35.5 µg/g, and folate, 45–1453 ng/g. Generally, the highest levels were in flours and protein concentrates, whereas low levels were observed in isolates. The retention of B vitamins was excellent in high moisture extrusion, except for folate in faba bean, where the folate contents were 42–67% lower in the extrudates than in the respective ingredient mixtures. In terms of both vitamin B contents and their retention, extrudates containing substantial amounts of flour or protein concentrate are promising plant-based sources of thiamin, riboflavin, niacin, and folate.

A large number of epidemiological studies have identified air pollution as a major risk to human health. Exposures to the pollutants PM _2.5 , NO _2 and O _3 cause cardiovascular and respiratory diseases, cancer and premature mortality. Whilst previous studies have reported demographic inequalities in exposure, with the most deprived and susceptible often being disproportionately exposed to the highest pollutant concentrations, the vast majority of these studies have quantified exposure based only on individuals’ place of residence. Here we use anonymised personal data from UK Census 2011, and hourly modelled air pollution concentrations at 0.8 km × 1.4 km spatial resolution in the Central Belt of Scotland, to investigate how inclusion of time spent at place of work or study affects demographic inequalities in exposure. We split the population by sex, ethnic group, age and socio-economic status. Exposure gradients are observed across all demographic characteristics. Air pollution exposures of males are more affected by workplace exposures than females. The White ethnic group has the lowest exposures to NO _2 and PM _2.5 , and highest to O _3 . Exposures to NO _2 and PM _2.5 tend to peak between the ages of 21 and 30, but those aged 31–50 tend to be most impacted by the inclusion of time spent at workplace in the exposure assessment. People in the two least deprived deciles consistently have the lowest residential-only and combined residential-workplace exposure to NO _2 and PM _2.5 , but experience the highest increase in exposure when including workplace. Overall, including workplace exposure results in relatively small change in median exposure but attenuates some of the exposure inequalities associated with ethnicity and socioeconomic status observed in exposure assessments based only on place of residence.

Air pollution is the greatest environmental risk to public health. Future air pollution concentrations are primarily determined by precursor emissions, which are driven by environmental policies relating to climate and air pollution. Detailed health impact assessments (HIA) are necessary to provide quantitative estimates of the impacts of future air pollution to support decision-makers developing environmental policy and targets. In this study we use high spatial resolution atmospheric chemistry modelling to simulate future air pollution concentrations across the UK for 2030, 2040 and 2050 based on current UK and European policy projections. We combine UK regional population-weighted concentrations with the latest epidemiological relationships to quantify mortality associated with changes in PM2.5 and NO2 air pollution. Our HIA suggests that by 2050, population-weighted exposure to PM2.5 will reduce by 28% to 36%, and for NO2 by 35% to 49%, depending on region. The HIA shows that for present day (2018), annual mortality attributable to the effects of long-term exposure to PM2.5 and NO2 is in the range 26,287 – 42,442, and that mortality burdens in future will be substantially reduced, being lower by 31%, 35%, and 37% in 2030, 2040 and 2050 respectively (relative to 2018) assuming no population changes. Including population projections (increases in all regions for 30+ years age group) slightly offsets these health benefits, resulting in reductions of 25%, 27%, and 26% in mortality burdens for 2030, 2040, 2050 respectively. Significant reductions in future mortality burdens are estimated and, importantly for public health, the majority of benefits are achieved early on in the future timeline simulated, though further efforts are likely needed to reduce impacts of air pollution to health.

We used the EMEP MSC-W (European Monitoring and Evaluation Programme Meteorological Synthesizing Centre – West) model version 4.34 coupled with WRF (Weather Research and Forecasting) model version 4.2.2 meteorology to undertake a present-day (2015) global and regional quantification of the concentrations, deposition, budgets, and lifetimes of atmospheric reactive N (Nr) and S (Sr) species. These are quantities that cannot be derived from measurements alone. In areas with high levels of reduced Nr (RDN = NH3+ NH4+), oxidized Nr (OXN = NOx+ HNO3+ HONO + N2O5 + NO3-+ “Other OXN” species), and oxidized Sr (OXS = SO2+ SO42-), RDN is predominantly in the form of NH3 (NH4+ typically <20 %), OXN has majority gaseous species composition, and OXS predominantly comprises SO42- except near major SO2 sources. Most continental regions are now “ammonia rich”, more so than previously, which indicates that, although reducing NH3 emissions will decrease the RDN concentration, decreasing these emissions will have little effect on mitigating secondary inorganic aerosol (SIA). South Asia is the most ammonia-rich region. Coastal areas around East Asia, northern Europe, and the north-eastern United States are “nitrate rich” where NH4NO3 formation is limited by NH3. These locations experience transport of OXN from the adjacent continent and/or direct shipping emissions of NOx, but NH3 concentrations are lower. The least populated continental areas and most marine areas are “sulfate rich”. Deposition of OXN (57.9 TgN yr−1, 51 %) and RDN (55.5 TgN yr−1, 49 %) contribute almost equally to total nitrogen deposition. OXS deposition is 50.5 TgS yr−1. Globally, wet and dry deposition contribute similarly to RDN deposition; for OXN and OXS, wet deposition contributes slightly more. Dry deposition of NH3 is the largest contributor to RDN deposition in most regions except for the Rest of Asia area and marine sectors where NH3 emissions are small and RDN deposition is mainly determined by the transport and rainout of NH4+ (rather than rainout of gaseous NH3). Thus, reductions in NH3 would efficiently reduce the deposition of RDN in most continental regions. The two largest contributors to OXN deposition in all regions are HNO3 and coarse NO3- (via both wet and dry deposition). The deposition of fine NO3- is only important over East Asia. The tropospheric burden of RDN is 0.75 TgN, of which NH3 and NH4+ comprise 32 % (0.24 TgN; lifetime of 1.6 d) and 68 % (0.51 TgN; lifetime of 8.9 d) respectively. The lifetime of RDN (4.9–5.2 d) is shorter than that of OXN (7.6–7.7 d), which is consistent with a total OXN burden (1.20 TgN) almost double that of RDN. The tropospheric burden of OXS is 0.78 TgS with a lifetime of 5.6–5.9 d. Total nitrate burden is 0.58 TgN with fine NO3- only constituting 10 % of this total, although fine NO3- dominates in eastern China, Europe, and eastern North America. It is important to account for contributions of coarse nitrate to global nitrate budgets. Lifetimes of RDN, OXN, and OXS species vary by a factor of 4 across different continental regions. In East Asia, lifetimes for RDN (2.9–3.0 d), OXN (3.9–4.5 d), and OXS (3.4–3.7 d) are short, whereas lifetimes in the Rest of Asia and Africa regions are about twice as long. South Asia is the largest net exporter of RDN (2.21 TgN yr−1, 29 % of its annual emission), followed by the Euro_Medi region. Despite having the largest RDN emissions and deposition, East Asia has only small net export and is therefore largely responsible for its own RDN pollution. Africa is the largest net exporter of OXN (1.92 TgN yr−1, 22 %), followed by Euro_Medi (1.61 TgN yr−1, 26 %). Considerable marine anthropogenic Nr and Sr pollution is revealed by the large net import of RDN, OXN, and OXS to these areas. Our work demonstrates the substantial regional variation in Nr and Sr budgets and the need for modelling to simulate the chemical and meteorological linkages underpinning atmospheric responses to precursor emissions.