While the number of deaths as a result of air pollution across the USA has dropped in recent decades, some areas still need stronger pollution control to protect vulnerable populations living with chronic diseases, reveals a comprehensive and updated analysis, published in the September 2025 issue of the independent, peer-reviewed RCP journal Clinical Medicine (ClinMed).
Authors Manan Raina, Jieji Hu, Raghav Shah, Max Gilliland and Sanjay Rajagopalan analysed data from the Global Burden of Diseases (GBD) 2021 study to assess the health burden of chronic diseases (including COPD, stroke, type 2 diabetes and heart disease) attributable to air particulate matter (specifically PM2.5).
They looked at the number of deaths and disability–adjusted life years (DALYs) from 1990–2021 across the USA. Their study not only provides an insight into the positive actions that the country has taken to reduce the chronic disease burden from air pollution – including the US Clean Air Act, as evaluated in 2020 – but it also highlights inequalities, as some US states perform better than others.
What’s the problem?
Air pollution is a global crisis – it is the largest environmental risk to health. In 2021, an estimated 8.1 million preventable deaths globally were reported to be associated with breathing toxic air, as set out in the RCP’s 2025 report, A breath of fresh air.
The economic implications are also stark. As Raina et al note, the cost to the USA is billions of dollars, due to the strain on healthcare services, productivity losses and the long-term burden of treating diseases related to air pollution, such as respiratory and cardiovascular disease.
The vulnerable communities left behind
The GBD 2021 study shows that the chronic disease burden from air pollution in the USA has declined over recent decades. US policy has been instrumental in this decline. The 2020 Clean Air Act regulates air emissions from all sources, sets standards for air quality, provides a framework for states to implement these standards and, in doing so, is expected to prevent 230,000 premature deaths. However, the positive results of this policy are not seen nationwide, as was intended.
This new analysis of the GBD 2021 data sheds light on the inequalities of the air pollution health burden. The largest and fastest declines in death rates due to chronic diseases attributable to PM2.5 tended to be in higher-income states. However, deprived communities tend to be more vulnerable to air pollution-related diseases for several reasons: their exposure to air pollutants is often greater, their general health is usually poorer (making them more susceptible to the harms of air pollution) and their access to healthcare can be more limited.
The authors of this study highlight the need to focus efforts to reduce air pollution at a regional or state level, through policy interventions, targeted public health initiatives and research.
RCP associate global director for the Americas, Professor Hariharan Iyer, said: ‘This paper addresses an important and relevant issue related to global health – the air that we breathe. The short- and long-term adverse consequences from air pollution and particulate matter leading to decreased life expectancy and poorer health have been shown consistently by numerous studies over the past few decades.
‘Vulnerable populations such as people from areas with a lower sociodemographic index or limited access to healthcare face disproportionately higher health hazards. A large proportion of the population across the world would fall into this “vulnerable population” category, highlighting the need for targeted public health interventions and policy endeavours to minimise the risk burden. The findings in this paper have wide-ranging ramifications on global health outcomes.’
A major new RCP report on air quality published earlier this year, A breath of fresh air, has warned that in the UK alone, around 30,000 deaths per year are attributed to air pollution, with those from more deprived and vulnerable backgrounds disproportionately affected.
This 2025 RCP report found that the health impacts of toxic air go far beyond respiratory disease: in fact, evidence now shows that air pollution affects almost every organ in the body, with harm evident at every single stage of the life course, including before conception, during childhood and into old age. Furthermore, it reveals that in the UK, the cost of air pollution is estimated to amount to more than £27 billion annually.
Read the full study by Raina et al and their findings in the September 2025 issue of ClinMed: The health burden of chronic diseases in the United States attributable to air particulate matter.