The use of low-cost sensors for air quality measurements is expanding rapidly, with an associated rise in the number of citizens measuring air quality themselves. This has major implications for traditional air quality monitoring as performed by Environmental Protection Agencies. Here we reflect on the experiences of the Dutch Institute for Public Health and the Environment (RIVM) with the use of low-cost sensors, particularly NO₂ and PM₁₀/PM_2.5-sensors, and related citizen science, over the last few years. Specifically, we discuss the Dutch Innovation Program for Environmental Monitoring, which comprises the development of a knowledge portal and sensor data portal, new calibration approaches for sensors, and modelling and assimilation techniques for incorporating these uncertain sensor data into air pollution models. Finally, we highlight some of the challenges that come with the use of low-cost sensors for air quality monitoring, and give some specific use-case examples. Our results show that low-cost sensors can be a valuable addition to traditional air quality monitoring, but so far, their use in official monitoring has been limited. More research is needed to establish robust calibration methods while ongoing work is also aimed at a better understanding of the public’s needs for air quality information to optimize the use of low-cost sensors.

Background: The current food system has major consequences for the environment and for human health. Alignment of the food policy areas of mitigating climate change and public health will ensure coherent and effective policy interventions for sustaining human health and the environment. This paper explores literature on demand-side policies that aim to reduce consumption of animal-based foods, increase plant-based foods, and reduce overconsumption. Methods: We searched for publications, published between January 2000 and December 2019, considering the above policy domains. Articles were distinguished for type of policy instrument, for topic via keywords and examples were given. Results: The majority of demand-side policies focus on preventing overweight and obesity, using all types of policy instruments including more forceful market-based policies. Hardly any examples of public policies explicitly aiming to lower animal-based foods consumption were found. Policies combining health and sustainability objectives are few and mainly of the information type. Discussion: Moving towards environmentally sustainable and healthy diets is challenging as the implemented demand-side policies focus largely on human health, and not yet on environmental outcomes, or on win-wins. Policies targeting foods from the health perspective can contribute to lower environmental impacts, by indicating suitable animal-based food replacers, and aiming at avoiding overconsumption of energy dense-nutrient poor foods. Preferred policies include a variety of instruments, including strong measures. Conclusions: Working solutions are available to ensure coherent and effective demand side food policies aligning public health and environmental aims. Implementation of aligned and effective policy packages is urgent and needed.

Producing sufficient, healthy food for a growing world population amid a changing climate is a major challenge for the twenty-first century. Agricultural trade could help alleviate this challenge by using comparative productivity advantages between countries. However, agricultural trade has implications for national food security and could displace environmental impacts from developed to developing countries. This study illustrates the global effects resulting from the agricultural trade of a single country, by analysing the global cropland and greenhouse gas impacts of the UK's food and feed supply. The global cropland footprint associated with the UK food and feed supply increased by 2022 kha (+23%) from 1986 to 2009. Greenhouse gas emissions (GHGE) associated with fertilizer and manure application, and rice cultivation remained relatively constant at 7.9 Mt CO ₂ e between 1987 and 2008. Including GHGE from land-use change, however, leads to an increase from 19.1 in 1987 to 21.9 Mt CO ₂ e in 2008. The UK is currently importing over 50% of its food and feed, whereas 70% and 64% of the associated cropland and GHGE impacts, respectively, are located abroad. These results imply that the UK is increasingly reliant on external resources and that the environmental impact of its food supply is increasingly displaced overseas.

Air pollution, especially fine particulate matter (PM_2.5), is a major environmental risk factor for human health in Europe. Monitoring of air quality takes place using expensive reference stations. Low-cost sensors are a promising addition to this official monitoring network as they add spatial and temporal resolution at low cost. Moreover, low-cost sensors might allow for better characterization of personal exposure to PM_2.5. In this study, we use 500 dust (PM_2.5) sensors mounted on bicycles to estimate typical PM_2.5 levels to which cyclists are exposed in the province of Utrecht, the Netherlands, in the year 2020. We use co-located sensors at reference stations to calibrate and validate the mobile sensor data. We estimate that the average exposure to traffic related PM₂._5, on top of background concentrations, is approximately 2 μg/m³. Our results suggest that cyclists close to major roads have a small, but consistently higher exposure to PM_2.5 compared to routes with less traffic. The results allow for a detailed spatial representation of PM_2.5 concentrations and show that choosing a different cycle route might lead to a lower exposure to PM_2.5. Finally, we conclude that the use of mobile, low-cost sensors is a promising method to estimate exposure to air pollution.

Nutrition security describes the adequacy of the food supply to meet not only energy but also macronutrient and micronutrient requirements for the population. The aim of this study was to develop a method to assess trends in national nutrition security and the contribution of imports to nutrition security, using the UK as a case study. Food supply data from FAO food balance sheets and national food composition tables were used to estimate the nutrient content of domestically produced food, imported food and exported food. Nutrition security was defined as the total nutrient supply (domestic production, minus exports, plus imports) to meet population-level nutrient requirements. The results showed that the UK was nutrition secure over the period 1961–2011 for energy, macronutrients and key micronutrients, with the exception of total carbohydrates and fibre, which may be due to the loss of fibre incurred by processing cereals into refined products. The supply of protein exceeded population requirements and could be met with domestic production alone. Even excluding all meat there was sufficient protein for population requirements. The supply of total fat, saturated fat and sugar considerably exceeded the current dietary recommendation. As regards nutrition security in 2010, the UK was reliant on imported foods to meet energy, fibre, total carbohydrate, iron, zinc and vitamin A requirements. This analysis demonstrates the importance of including nutrients other than energy to determine the adequacy of the food supply. The methodology also provides an alternative perspective on food security and self-sufficiency by assessing the dependency on imports to meet population level nutritional requirements.