Airborne particulate matter (PM) is the result of industrial development, coal smoke, motor vehicle emissions, and other pollutant activities. In China, concerns are high regarding poor air quality – including PM and the potential health threats it poses. Working with Dr. Guanghui Dong (principal investigator) and his team from Sun Yat-sen University in Guangzhou, China, University at Albany School of Public Health environmental health sciences Drs. Michael S. Bloom and Shao Lin collaborated on a study of children and adolescents in China, assessing their exposure to PM of different sizes in relation to their respiratory health; the resulting publication appears in the November Environment International. The study found that long-term exposure to PM1 (ultra-fine particles (UFPs) with aerodynamic diameters of 1μm or less) may increase the risk of asthma and its related symptoms, specifically among boys and those who hold allergic predispositions.
Substantial research has been conducted in evaluating the effects of PM2.5 (fine particles with aerodynamic diameters of 2.5μm or less) on asthma and allergies. However, little research has assessed respiratory health impacts for the smaller, and potentially more toxic UFPs. These smaller particles have the ability to penetrate deeper into the lower respiratory tract, which may lead to more pronounced health effects. Additionally, UFPs have a greater surface area to mass ratio compared to larger particles, providing a larger area to adsorb condensed toxic gases or metals and to interface with pulmonary surfaces. Given these characteristics, researchers have hypothesized that the UFPs might be responsible for many of the observed health effects of PM.
This study looked at a sample of 59,754 children and adolescents from across 27 urban districts in seven Chinese cities. Detailed information about children’s respiratory health was collected using the Epidemiologic Standardization Project Questionnaire of the American Thoracic Society. Each participant’s home address as a geographical longitude and latitude was superimposed over a map of daily PM1 and PM2.5 concentrations predicted using a novel machine learning method that employed municipal air monitoring station data. This gave insight into the PM exposure each child faced. The researchers examined the exposure data for a four-year period (2009-2012).
The study found positive associations between PM1 or PM2.5 exposure and asthma and asthma-related symptoms in both boys and girls. Although PM1 exposure had slightly stronger associations than PM2.5, it was not found to be statistically significant. The positive associations were consistently stronger in boys than in girls, with boys being more susceptible to adverse respiratory effects. In addition, those who had a family history of allergy or asthma showed stronger associations with PM and respiratory health issues, potentially due to PM levels enhancing the allergic inflammatory response.
The study results also suggest that PM1 may account for the majority of PM2.5 concentrations in China, therefore indicating that the adverse health impacts of PM2.5 could be attributed to PM1— making it a critical area of study for further work on air pollution and health.