A critical appraisal of epidemiological studies investigating the effects of ultrafine particles on human health

Background Though several reviews investigating the health effects of particulate matter on human health exist, none of them focus exclusively on the impact of particulate matter in the ultrafine range. Objective This research consists of a critical appraisal of qualifying studies that investigates the impact of ultrafine particles on cardiopulmonary and circulatory health among humans. Methods The published articles were obtained from a search of electronic databases and bibliographies of identified articles. The critical appraisal was conducted using an Epidemiological Appraisal Instrument. Results Seven articles satisfied the inclusion criteria adopted in this research. The assessed quality of the published studies ranged from marginal to good. Conclusions The appraisal reveals that ultrafine particle exposure has different consequences compared to fine particle exposure. Also, it is likely that ultrafine particles do pose a health risk to human subjects who are already susceptible to cardiopulmonary disease. Further research is needed to extrapolate findings from lab studies and to determine the exact biological mechanism by which ultrafine particle exposure results in cardiopulmonary symptoms. Significance The reported findings indicate the need to investigate standards for ultrafine particle exposure and to list the three major cardiopulmonary symptoms resulting from ultrafine particle exposure. (c) 2008 Wiley Periodicals, Inc