Cheaper cars pollute more than expensive cars, leading to emissions inequality
Lower-income individuals are more likely to own cheaper, higher-emitting vehicles and, therefore, contribute disproportionately to their local urban air pollution
University of Birmingham
More expensive cars emit lower levels of pollution - meaning that motorists owning cheaper, higher-emitting vehicles contribute disproportionately to their local urban air quality problems, a new study reveals.
Research by University of Birmingham scientists highlights a previously overlooked inequality - that lower-income individuals are more likely to own cheaper, higher-emitting vehicles and, therefore, contribute disproportionately to their local urban air pollution.
Publishing their findings today (14 Nov) in Journal of Cleaner Production, the researchers’ analysis suggests that spending an additional £10,000 on a diesel vehicle is associated with a more than 40% reduction in nitrogen oxide (NOx), emissions per litre of diesel.
Their discovery reverses the usual pattern, where wealthy households typically cause more greenhouse gas emissions through higher consumption.
Scientists analysed over 50,000 vehicles using advanced remote sensing technology measuring in real-time emissions from vehicles on the city’s streets.
They combined machine learning-based price estimation with real-world emission data to connect pricier vehicles and lower pollutant emissions — particularly NO₂, NOx, carbon monoxide (CO), and particulate matter (PM).
The research was supported by the Natural Environment Research Council (NERC) via the WM-Air project. The researchers report that:
- Higher-priced vehicles emit significantly fewer pollutants, even within the same Euro emission class. Average NOx emissions are approximately 8.8 g/litre of diesel for £5,000 cars, compared with 5.6 g/litre for £15,000 cars.
- Diesel vehicles show greater emission reductions per £1,000 increase in price than petrol vehicles - for every additional £1,000 spent on a diesel car, nitrogen dioxide (NO₂) emissions decrease by around 0.4 g/litre of fuel.
- Older diesel models (Euro 5) exhibit emission reductions 1.5 times steeper with price than newer Euro 6 models, suggesting that price is a stronger proxy for emissions in older vehicles.
Report co-author Professor Francis Pope from the University of Birmingham said: "Our study provides the first clear evidence to support vehicle price being a reliable indicator of emission performance - powerfully illustrating how citizens’ economic capacity can directly influence environmental outcomes and urban air quality.
“Individuals from lower-income households may be more likely to own older, cheaper, and higher-emitting vehicles — contributing disproportionately to local air pollution.”
The study calls for policy makers to take several actions to help reduce emissions while promoting social equity. These include:
- Progressive tax structures based on vehicle emissions and price to incentivise cleaner vehicle adoption.
- Rebate schemes or scrappage incentives for lower-income households to accelerate the transition to cleaner transport.
- Enhanced inspection and maintenance programmes for older vehicles may offer a cost-effective way to reduce emissions in the short term.
Report co-author Dr Omid Ghaffarpasand from the University of Birmingham said: “Our findings underscore the need for targeted policy interventions to address environmental injustice. Lower-income communities bear the brunt of local air pollution due to limited access to cleaner vehicles - exacerbating health risks and pollution exposure in disadvantaged urban areas.”
The researchers also advocate for further investigation into how vehicle affordability, emissions, and urban planning interact with each other to contribute to urban air pollution; stressing the importance of integrating socioeconomic data into transport and environmental policy frameworks to ensure equitable outcomes.
WM-Air has been working with partners to bring research organisations together with businesses, policy bodies and other actors contributing to economic development specific to their location, to deliver significant regional impact from NERC environmental science. Previous studies from WM-Air have highlighted major contributions of domestic woodburning to PM2.5 emissions, and that air pollution in the West Midlands has caused up to 2,300 premature deaths each year.
ENDS
For media enquiries please contact University of Birmingham press office - pressoffice@contacts.bham.ac.uk or +44 (0)121 414 2772.
Notes to editor:
- The University of Birmingham is ranked amongst the world’s top 100 institutions. Its work brings people from across the world to Birmingham, including researchers, educators and more than 8,000 international students from over 150 countries.
- ‘Air Pollution Emissions from Vehicles as a Function of Their Current Real World Market Price’ - Omid Ghaffarpasand and Francis D. Pope is published in Journal of Cleaner Production.
Journal
Journal of Cleaner Production
Method of Research
Data/statistical analysis
Subject of Research
Not applicable
Article Title
Air Pollution Emissions from Vehicles as a Function of Their Current Real World Market Price
Article Publication Date
14-Nov-2025
Pollution and cardiac arrest: a study by the Politecnico di Milano reveals a direct link between peak air pollution and cardiac risk
Politecnico di Milano
image:
Graphical abstract: Pollution and cardiac arrest: a study by the Politecnico di Milano reveals a direct link between peak air pollution and cardiac risk
view moreCredit: Politecnico di Milano
In Lombardy, the risk of suffering cardiac arrest may increase on days recording high levels of air pollution. This emerges from a study conducted by the Politecnico di Milano and published in the international journal Global Challenges.
Researchers analysed 37,613 cases of out-of-hospital cardiac arrest in Lombardy between 2016 and 2019 by assessing, for each episode, the daily concentrations of various pollutants (PM₂.₅, PM₁₀, NO₂, O₃ and CO) obtained from satellite data of the European Copernicus programme (ESA). The study used advanced spatio-temporal statistical models to identify the relationship between pollution peaks and increased risk of cardiac events.
“We observed a strong association with nitrogen dioxide (NO₂). Indeed, for every 10 micrograms per cubic metre increase, the risk of cardiac arrest rises by 7% over the next 96 hours,” says Amruta Umakant Mahakalkar, researcher at the Department of Electronics, Information and Bioengineering, Politecnico di Milano, and first author of the study.
“Even particulate matter PM₂.₅ and PM₁₀ present a 3% and 2.5% increase in the risk rate, respectively, on the same day of exposure.”
The effect is more pronounced in urban areas but significant associations are also observed in rural towns. The risk particularly marks an upswing in the warm months, suggesting a possible interaction between heat and pollutants. The association was also observed at levels below legal limits, suggesting that there is no safe exposure threshold.
“The link between air quality and out-of-hospital cardiac arrest is a wake-up call for local health systems,” adds Enrico Caiani, professor at the Politecnico di Milano and co-author of the study. “Emergency services should expect a potential surge in calls for action during high pollution periods.”
The study highlights how air pollution is a significant risk factor for cardiovascular health, even in the short term, and calls for this evidence to be considered in prevention policies and in the management of health emergencies.
According to the World Health Organisation, air pollution is the second environmental risk factor for non-communicable diseases. It accounts for millions of deaths worldwide each year. Lombardy, one of the most industrialised and densely populated regions in Europe, is particularly exposed to episodes of smog in winter, when system boilers are turned on and worsen air quality, along with poor atmospheric dispersion.
The results of the study provide a useful tool for institutions and emergency services. Integrating environmental data into health forecasting systems could anticipate the increase in emergency calls in the future, and thus improve resource planning.
The new CLIMA-CARE project, funded by the European Space Agency (ESA), officially kicks off today. It follows this trend of research. The project will use satellite data to analyse the impact of environmental conditions on public health and, in particular, on emergency medical services in Lombardy, both today and in the future, by creating climate projections.
Project partners include the German Aerospace Centre (DLR) - the initiative's lead partner - and the Group on Earth Observation (GEO), coordinated by the World Meteorological Organisation (WMO).
“The project will give us the opportunity to address the impact of climate change on a population-wide scale,” comments Lorenzo Gianquintieri, Researcher, Department of Electronics, Information and Bioengineering, Politecnico di Milano. “Consistently with the One-Health vision, which combines human, environmental and animal health, we promote a preventive adaptation approach based on scientific evidence.”
THE STUDY: A.U. Mahakalkar, E. G. Caiani, G. Stirparo, E. Picozzi, L. Gianquintieri,
Short-term effect of air pollution on OHCA in Lombardy – a case-crossover spatiotemporal study,
Global Challenges (2025), DOI: 10.1002/gch2.202500241
Journal
Global Challenges
Method of Research
Data/statistical analysis
Subject of Research
People
Article Title
Short-Term Effect of Air Pollution on Out of Hospital Cardiac Arrest (OHCA) in Lombardy—A Case-Crossover Spatiotemporal Study
No comments:
Post a Comment