SAMHE Outputs

This page hosts summaries of all reports and research papers about the SAMHE project that have been published by the SAMHE team to date, with links to the full versions for those interested in reading about our work in more detail. We have also produced an evidence synthesis with recommendations for policy and practice, titled 'Improving air quality in UK schools'.

Some of these publications have related activities in the Web App to help pupils understand the findings from the project.

As further papers and reports using the SAMHE data are published in coming months, they will be added here.

  • Three school children in a classroom looking at digital tablets

    The SAMHE (Schools' Air quality Monitoring for Health and Education) project is the first stage of the SAMHE initiative. It introduces a new way to generate and analyse large datasets about air quality and school classrooms via a collaborative citizen science method. This method was chosen because it allows us to collect information about air quality whilst raising awareness about the topic amongst pupils, teachers and other staff.

    SAMHE is important because children in the UK spend a large proportion of their days inside school classrooms, and the project will help us understand the quality of the air in those classrooms. The paper talks about why good indoor air quality is important, and what is known so far. The paper describes how we plan to give 2000 low-cost air quality monitors to classrooms and provide a Web App to pupils and staff through which they can submit contextual data (school buildings characteristics and operation, behavioural patterns etc), interact with the data gathered in their school and use it in specially created learning activities.

    SAMHE has proved popular with schools, showing that this new method could be valuable more widely for gathering indoor air quality datasets while simultaneously enabling schools to better manage their indoor environment and empowering students and teachers to reduce their environmental health risks.

    Read the paper: Schools' air quality monitoring for health and education: Methods and protocols of the SAMHE initiative and project

    Watch a short video designed for pupils in which Sarah West introduces this paper and our co-design paper and explains why we wrote them and what we learned through the process of co-design.

  • Primary school children in a classroom holding up pieces of paper with green ticks or red crosses

    Central to the SAMHE project is the Web App, where teachers and pupils can see air quality data from their classroom, learn about its significance, enter important contextual information to support data analysis by researchers, and do experiments.

    School use of the Web App is essential to the project's aims to

    1. improve understanding of air quality in schools;
    2. empower teachers and pupils to make informed decisions about managing their classroom environment, including ventilation; and
    3. support the next generation to think differently about IAQ.

    Therefore, it was critical that the Web App was co-designed with schools, to maximise its acceptability and ensure that teachers and pupils engage with it.

    Pupils participated in co-design workshops with a teacher, either as a class group or as a lunchtime or after-school extra-curricular group such as a science club, school council or eco-group. Arkwright Scholars, aged 16+, participated without teachers. Teachers also participated, without students, in small group discussions and could input via Padlet boards at times that suited them. Schools seemed to enjoy the interactions with researchers, including chats about our careers, and their input has created a co-designed Web App which they enjoy using and gives researchers important contextual data.

    Read the paper: 'Co-Designing an Air Quality Web App with School Pupils and Staff: The SAMHE Web App'

    Watch a short video designed for pupils in which Sarah West introduces this paper and our methods paper and explains why we wrote them and what we learned through the process of co-design.

  • Three maps of the UK showing AURN site PM2.5 readings as coloured dots. In the first image, the PMs are highest around London and the north of England. On the second, the high PMs are more evenly distributed throughout the country. In the third, much lower PM levels can be seen all around the country.

    In September 2023, dust from the Sahara desert, in Africa, was carried by a storm to the UK. We looked at air quality data in classrooms, measured using SAMHE monitors, to see if this affected the amount of particulate matter (PM) in classrooms. To support our investigation, we also looked at air quality measurements made outdoors (by the Automatic Urban and Rural Network, AURN).

    During the period that Sahara dust was reported to be over the UK (based on satellite and weather data) the PM levels recorded were significantly higher both indoors and outdoors. Also, the regional variation in outdoor PM measurements increased during this period, suggesting that some regions of the UK were more strongly affected than others.

    Interestingly, although almost all schools with SAMHE monitors showed increased PM levels during this dust event, they differed widely in how much this increase reflected the change in the outdoor PM measurements. If we can discover what factors caused some schools to be more affected by the increased outdoor PMs than others, this could help develop practices to improve air quality indoors in general, perhaps even in environments where the outdoor air quality is poor.

    Read the tech report: Evidence of a Saharan dust event from air quality measurements in UK schools within the SAMHE project

  • School classroom with some windows open.

    How can we measure the amount of fresh air entering a room? We need to know this 'ventilation rate' to understand how air pollution gets in or out. However, it's hard to measure because air can enter and leave a room by a variety of routes: not just through open windows and doors but also through tiny gaps in the material of the walls, floor and ceiling.

    We looked at school classrooms and explored how we can use simple measurements of carbon dioxide (CO2) to predict the ventilation rate. These two things are connected because people in a room add CO2 to the air by breathing and it is removed by ventilation.

    There are two complicating factors: classrooms can vary significantly between schools, or even within the same school (e.g. by classroom size and pupil numbers and ages), and the ventilation rate can change throughout the day (e.g. as a result of changing winds or windows being opened or closed).

    Despite this variability, we show that it is possible to work out daily average ventilation rates (per person) from the CO2 levels measured in classrooms to an accuracy of ±24%. We suggest ways to improve the accuracy (to around ±12%) including by using multiple CO2 sensors in one classroom. We hope these findings will improve scientists' understanding of factors that affect indoor air quality in schools, leading to better management in the future.

    Read the paper: 'Inferring ventilation rates with quantified uncertainty in operational rooms using point measurements of carbon dioxide: Classrooms as a case study'

  • red and yellow fireworks exploding against a black sky.

    In the UK, during autumn, fireworks are used in the celebration of Fireworks Night (or Guy Fawkes Night) and Diwali. Setting off fireworks releases pollutants, including particulate matter (PM). We investigated whether these fireworks events could be detected by SAMHE monitors in UK schools. We compared the indoor concentration of PM2.5 (particulate matter smaller than 2.5 microns), as recorded by SAMHE monitors, to the outdoor concentration of PM2.5, as recorded by Defra's AURN (Department for Environment, Food & Rural Affairs Automatic Urban and Rural Network) weather stations, during autumn 2023.

    As the concentration of PM2.5 increased outdoors after people set off fireworks, the concentration measured by SAMHE monitors also increased. Most of the fireworks events occurred over the weekends and during the evenings, when we expect most schools to be closed and have lower ventilation levels than during school hours. Even so, the concentration of PM2.5 indoors increased, showing that PM2.5 can get into schools even when they are closed.

    Levels of PM2.5 were not significantly increased during school hours in the weeks after each fireworks event. Reassuringly, we can conclude that, whilst the PM from fireworks did enter schools, it did not have a large effect on air quality during school hours.

    Read the tech report: The impact of fireworks events on classroom air quality

  • View through a frosty window from inside.

    We used data from about 300 SAMHE monitors (all those which were submitting data at the time) to investigate air quality in UK schools over the 2023 Autumn term. The UK experienced changeable weather in Autumn 2023 with unseasonably warm weather at the start of term and a period of far colder weather later on in the term, each followed by periods of intermediate temperature.

    Classroom temperatures were slightly higher during the really warm period but during all other times they remained more or less the same, independent of the weather outside. In the cold period, classroom carbon dioxide (CO2) levels were substantially higher than during the warm period, indicating ventilation was likely to have been reduced; in fact, during the cold period, many monitors recorded daily mean CO2 values above the maximum government guideline of 1500 ppm. We all breathe out air which is of high humidity and high CO2 concentration, but the humidity measured by SAMHE monitors did not show the same trend as CO2. During the cold period, when CO2 was high, the classroom humidities measured were low. We know that outdoor humidity varies significantly with the weather. Typically humidity becomes lower (i.e. the air is drier) during colder weather, so our data suggests that classroom humidity is directly influenced by the weather, whereas CO2 is influenced differently.

    Particulate matter (PM2.5) levels varied widely over the course of the term in ways that were not dependent on outdoor temperature, suggesting that classroom PM2.5 concentration depends on a range of indoor and outdoor factors. Reassuringly, PM2.5 levels in SAMHE classrooms generally remained below the maximum daily mean value of 15 μ/m3 recommended by the World Health Organisation.

    Read the tech report: Findings from Autumn term 2023 for SAMHE Champions and other interested schools/parties

  • Thermometer hanging outside

    We used data from about 350 SAMHE monitors (all those which were submitting data at the time) to investigate air quality in UK schools over the 2024 Spring term.

    Classroom temperatures remained relatively constant throughout the Spring term, independent of the weather outside. During the brief cold period at the start of term, classroom carbon dioxide (CO2) levels were slightly elevated compared to the warmer period that followed, indicating ventilation was likely to have been reduced. In fact, during the cold period, many monitors recorded daily mean CO2 values above the maximum government guideline of 1500 ppm.

    During the cold period, when CO2 levels were elevated, the measured classroom humidity levels were low. We know that outdoor humidity varies significantly with the weather. Typically, humidity levels are lower (i.e. the air is drier) during colder weather, so our data suggests that classroom humidity is directly influenced by the weather, whereas CO2 is influenced differently.

    Particulate matter (PM2.5) levels fluctuated over the course of the term but generally remained below the maximum daily mean value of 15 μg/m3 recommended by the World Health Organisation. There is no correlation of PM2.5 concentrations to outdoor temperatures; however, the spikes in PM2.5 recorded from classroom data do correlate with outdoor PM measurements across the country. This suggests that the classroom environments are not only affected by conditions local to the school but are also influenced by weather and long-range events.

    Read the tech report: Findings from Spring term 2024 for SAMHE Champions and other interested schools/parties

  • Map showing distribution of schools with SAMHE monitors as blue marks on a map of the UK. The monitors can be seen to give good coverage of the southern and middle part of England and the Scottish central belt, with lower density in northern England, Wales, Northern Ireland and SW and the east coast of Scotland, and particularly low densities in mid Wales and the rest of Scotland.

    We used data from SAMHE monitors to investigate air quality in UK schools over the 2023/2024 academic year.

    Classroom temperatures remained relatively constant throughout the year, independent of the weather outside. During the cold periods at the end of the Autumn term 2023 and at the start of the Spring term 2024, classroom carbon dioxide (CO2) levels were slightly elevated compared to the warmer periods seen at the beginning and end of the academic year. This indicates that classroom ventilation was likely to have been reduced. In fact, during the cold periods, some monitors recorded daily mean CO2 values above the maximum government guideline of 1500 ppm.

    During the cold periods, when CO2 levels were elevated, the measured classroom humidity levels were low. We know that outdoor humidity varies significantly with the weather. Typically, humidity levels are lower (i.e. the air is drier) during colder weather, so our data suggests that classroom humidity is directly influenced by the weather, whereas CO2 is influenced indirectly, via behavioural changes.

    Particulate matter (PM2.5) levels fluctuated over the course of the academic year but generally remained below the maximum daily mean value of 15 μg/m3 recommended by the World Health Organisation. There is no correlation of PM2.5 concentrations to outdoor temperatures; however, the rise and fall in PM2.5 recorded from classroom data does correlate with outdoor PM measurements across the country. This suggests that classroom environments are not only affected by conditions local to the school but are also influenced by weather and long-range events.

    Read the tech report: Findings from the academic year 2023/2024 for SAMHE Schools, SAMHE Champions and other interested parties

  • We analysed air quality data from 190 SAMHE air quality monitors over the Autumn term 2023 to assess ventilation rates in classrooms. UK government guidance states that the daily average concentration of CO2 in occupied classrooms should be kept under 1500 ppm. We found that whether classroom CO2 levels stayed below this threshold or not depended strongly on outdoor temperature. When it's colder outside, windows tend to be kept closed more of the time, reducing ventilation. Overall, most schools adhered to the guideline level but a number of individual schools regularly exceeded it, often by a substantial amount.

    We also used a novel method to assess the ventilation rate per person in occupied classrooms. Generally this was low. Schools in poorer areas were usually more poorly ventilated than those in richer areas, and state schools were usually more poorly ventilated than fee-paying schools. Schools with more pupils than their target number were generally more poorly ventilated too. Primary schools and secondary schools showed similar ventilation rates, but secondary schools generally had higher CO2 levels, as older children, being bigger, breathe out more CO2

    Read the paper: Assessing classroom ventilation rates using CO2 data from a nationwide study of UK schools and identifying school-wide correlation factors