This article is a commentary on the following study: Chen Y, Yang Q, Krewski D, Shi Y, Burnett RT, McGrail K. Influence of relatively low levels of particulate air pollution on hospitalization for COPD in elderly people. Inhal. Toxicol. 2004; 16:21-5. Its objective was to study the relationship between particulate pollution and emergency hospitalizations for exacerbations of chronic obstructive pulmonary disease (COPD) among people over the age of 65 in Vancouver, Canada, a city where pollution levels are relatively low. This study does not provide any new information beyond what is already known. It does indeed highlight an association between particulate pollution and hospitalization for exacerbations of chronic obstructive pulmonary disease, though it is not possible to distinguish the specific effects of particulate matter from the combined effects of the atmospheric mixture.