PM1 Pollution Drives Respiratory Hospitalizations

Air quality has a huge impact on health, with exposure to particles with an aerodynamic diameter of Respirology examined 408,658 patients from Guangdong Province, China, who were hospitalized for respiratory conditions between January 2016 and December 2019, highlighting the link between PM1 exposure and respiratory health risks.

“Numerous epidemiological studies have shown that exposure to fine particulate matter (PM2.5) is closely associated with several diseases such as chronic obstructive pulmonary disease (COPD), pneumonia, and asthma,” explained the study’s authors, led by Chenghui Zhong, from Guangzhou Medical University in Guangzhou, China. The research team noted that smaller particulate matter, such as PM1, is considered more toxic than PM2.5, due to its ability to carry toxic carcinogens and settle deeper in the respiratory system.

“The acute effects of pollution from chest dust (PM10) or fine dust (PM2.5) pollutants regulated by European directives and described by the World Health Organization (WHO) guidelines on hospital admissions for respiratory diseases have been well documented in the scientific literature for decades,” Giovanni Viegi, MD, PhD, past president of the European Respiratory Society (ERS), told Univadis Italy, part of the Medscape Professional network.

Viegi, a senior research associate at the National Research Council’s Institute of Clinical Physiology and Institute of Information Technology, was awarded the ERS Life Achievement in Epidemiology and Environment in 2024. He is also active in national pneumology and allergology societies, including the Italian Society of Pneumology (Società Italiana di Pneumologia), Italian Association of Hospital Pneumologists (Associazione Italiana Pneumologi Ospedalieri), and Italian Society of Allergology, Asthma and Clinical Immunology (Società Italiana di Allergologia, Asma e Immunologia Clinica).

Viegi explained the impact of both short- and long-term exposure to air pollutants on health with a focus on European and global regulations.

Study Findings

Zhong and colleagues revealed that each 10 μg/m³ in PM1 was significantly associated with a 1.39%, 1.97%, and 1.69% increase in odds of hospitalizations for total respiratory diseases, COPD, and pneumonia, respectively, with older patients (over 75 years) experiencing a greater negative effect.

These data showed the acute effects of PM1 exposure. Viegi emphasized that “acute effects,” such as hospitalizations occur either on the same day or within a short delay of up to 7 days following the measured concentration of air pollutants.

“In recent years, the chronic effects of pollution, based on spatial variations in exposure, have also been studied extensively,” Viegi added, noting that while air pollutants are monitored continuously, clinical effects are not evaluated systematically.

“Most of the information on the environment-health relationship is collected from ad hoc scientific studies, but for some years the European Environment Agency (EEA) has been publishing annual reports that provide not only information on the temporal trend of pollutant concentrations but also estimates of health impacts. These include metrics such as early deaths, years of life lost, and hospital admissions,” Viegi explained.

The latest EEA report dated December 10, 2024, stated that in 2022, Europeans remained exposed to concentrations of air pollutants significantly above the levels recommended by the WHO. Reducing air pollution could prevent a substantial number of annual deaths in the European Union (EU) Member States: 239,000 from exposure to fine particulate matter, 70,000 from exposure to ozone, and 48,000 from exposure to nitrogen dioxide.

The EEA report also highlights a positive fact: Between 2005 and 2022, the number of deaths in the EU attributable to PM2.5 decreased by 45%, bringing Europe closer to the 55% reduction target set in the 2030 Zero Pollution Action Plan.

Data from a recent study from Italy confirmed the findings in Europe: Increases in PM lead to an excess risk for hospitalization for respiratory issues, particularly among older individuals. Nearly 5000 hospitalizations can be avoided each year by reducing pollution.

Practical Steps

Zhong and colleagues concluded that their findings highlight the importance of reducing environmental exposure to PM1 as a possible strategy to reduce hospitalizations for respiratory diseases. Furthermore, the exposure-response relationship between PM1 and hospitalizations for respiratory diseases could provide valuable data for refining air quality standards for PM1.

National and international authorities must pay closer attention to the link between air pollution and health, and periodically update guidelines to indicate maximum tolerable exposure thresholds for various pollutants. For example, the WHO’s Air quality guidelines established in 2021, along with the European directive, set new air quality standards across the EU that will come into force on January 1, 2030.

Surprisingly, the thresholds set by the WHO were lower than those set by the European directive. Viegi explains that this discrepancy arises because the WHO evaluates only health-related aspects, while Europe must also consider other factors, such as economic factors leading to a “compromise” and acceptance of higher tolerable thresholds. However, this does not justify the lack of commitment to adhere to the directives.

Viegi believes that substantial and decisive actions to improve air quality can no longer be delayed. “By investing in these environmental aspects, you invest in health,” he explained, “also obtaining economic benefits for the reduction of direct and indirect health costs of diseases linked to air pollution.”

Practical Advice

How can the impact of pollution on human health be reduced? Here are the expert’s recommendations.

• Prioritize prevention

  The best way to address these environmental risks is to cut them. This requires changes in the political, economic, and social contexts. This can be achieved by adopting the principle of “health in all policies,” which means considering health in all collective decisions.

• Transition from fossil fuels

  Avoiding fossil fuels as energy sources is essential from a health perspective.

• Change transportation habits

  Reducing the use of private transportation and prioritizing public transportation is crucial. This shift also implies changes in personal habits.

• Increase green spaces

  Adding more green areas to neighborhoods can significantly improve air quality. To follow the 3-30-300 rule, every city dweller sees three trees from their window, lives in a neighborhood where 30% of the area is wooded and has access to a park or forest within 300 m of home or workplace.

• Limited personal exposure

  Individuals can take steps to reduce their exposure to pollutants. A workshop organized by the American Thoracic Society provided valuable tips for minimizing the risks associated with outdoor air pollution.

• Stay indoors when pollution levels are high.
• Maintain indoor air cleanliness with proper ventilation systems and air purifiers.
• Choose alternative modes of transportation whenever possible.
• Adjust the times and locations of outdoor activities to ensure that these changes do not interfere with regular physical exercise.
• Limit strenuous activity during periods of high pollution and near pollution sources.
• Consider using respirators to reduce the exposure to high concentrations of particulate air pollution.

This story was translated fromUnivadis Italy using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.