Certain Metals and Sulfates in Air Pollution May Significantly Increase Asthma Hospitalizations

Recent research led by Harvard T.H. Chan School of Public Health highlights the crucial role of specific components within fine particulate matter (PM2.5) in contributing to asthma-related hospitalizations. The study identifies metals, particularly nickel and vanadium, along with sulfate particles, as the primary agents that amplify the risk of severe asthma attacks leading to hospitalization. The investigation reveals that these pollutants are major constituents of air pollution that, when present in higher concentrations, substantially impact respiratory health.

While it is well-known that exposure to PM2.5 is linked to increased asthma symptoms and emergency visits, this study enhances understanding by pinpointing which elements within PM2.5 are most harmful. Utilizing advanced machine learning techniques, researchers analyzed data on various chemical compounds forming PM2.5, such as bromine, calcium, copper, organic carbon, lead, silicon, sulfate, vanadium, zinc, and others. They produced annual estimates of these pollutants at a zip-code level across the U.S. and examined their association with asthma hospitalizations from 2002 to 2016 in eleven states.

The findings demonstrate that for every decile increase in the mixture of harmful pollutants, there was an approximate reduction of 10.6% in asthma hospitalizations among children and about 8% among adults aged 19 to 64. The compounds contributing most significantly to this association include nickel, vanadium, sulfate, nitrate, bromine, and ammonium. These pollutants are largely generated from activities such as fuel oil combustion, coal burning, and industrial processes.

Prof. Joel Schwartz emphasized the importance of targeting these specific pollutants: "Controlling emissions from burning fuel oil, coal, and other industrial sources could markedly lower the prevalence of severe asthma cases. Reducing metal contaminants in fuel oils and implementing scrubbers in coal plants are effective strategies for mitigation."

The researchers stress that further studies are necessary to understand how short-term exposure to these particle components affects asthma exacerbation. Their work aims to guide public health policies and pollution control measures to better protect vulnerable populations from harmful air pollution components.

Source: https://medicalxpress.com/news/2025-08-metals-sulfate-air-pollution-mixture.html