The US government is trying to roll back the particulate matter limits set by former President Joe Biden. The 2024 rule had cut the allowable ambient concentration of PM2.5 from 12 µg/m³ to 9 µg/m³ — a move aimed at significantly reducing air pollution and protecting public health.
The Environmental Protection Agency (EPA), now headed by a director appointed by President Donald Trump, has asked a federal court to cancel a stricter air-quality standard for fine particulate matter (PM2.5) adopted under Joe Biden, arguing that complying with it would be too expensive for manufacturers.
Rollback
If the court agrees, the standard will revert to the older, laxer limit (12 µg/m³), effectively loosening regulation of fine particle pollution. This rollback is part of a broader deregulatory push: the EPA under Trump aims to reverse many environmental protections adopted over the past two administrations.
This isn’t the first time the Trump administration has rolled back or weakened environmental protection regulations. In July, Trump’s coal-fired power plants and other facilities were granted a two-year exemption from EPA environmental regulations.
PM2.5
PM2.5 – ‘fine particulate matter’ – is emitted by industrial smokestacks, power plants, vehicle exhaust, and other combustion sources; these particles are tiny enough to penetrate deep into the lungs and even enter the bloodstream.
Exposure to PM2.5 is strongly linked to a higher risk of respiratory illnesses (like asthma, chronic bronchitis), cardiovascular diseases, and premature death. Critics warn that particularly vulnerable populations (children, older people, and people with pre-existing conditions) will be hit hardest.
‘Lifesaving protections’
Environmental and public-health organisations and NGOs are strongly condemning the move. They accuse the administration of prioritizing corporate profits and economic arguments over public health and environmental justice. The claim is that this is “a rollback of lifesaving protections.”
The health effects that critics fear from loosening PM2.5 regulation in the US are not hypothetical — they already play out daily in Europe. Internationally, the rollback could also undermine US credibility as a climate and environmental leader — possibly weakening pressure on other countries to adopt stricter air-quality or climate policies.
Public-health concern
According to a 2025 report by the European Environment Agency (EEA), in 2023, about 92% of monitoring stations across Europe recorded PM2.5 levels above the WHO guideline value. That means the vast majority of Europeans — especially in urban areas — are exposed to levels of PM2.5 considered harmful.
Even in a (relatively) ‘clean’ European country like Belgium, air pollution remains a public-health concern, with elevated risk of asthma, respiratory and cardiovascular diseases — especially for vulnerable populations.
