Exposure information in environmental health research: Current opportunities and future directions for particulate matter, ozone, and toxic air pollutants

Abstract

Understanding and quantifying outdoor and indoor sources of human exposure are essential but often not adequately addressed in health-effects studies for air pollution. Air pollution epidemiology, risk assessment, health tracking and accountability assessments are examples of health-effects studies that require but often lack adequate exposure information. Recent advances in exposure modeling along with better information on time-activity and exposure factors data provide us with unique opportunities to improve the assignment of exposures for both future and ongoing studies linking air pollution to health impacts. In September 2006, scientists from the US Environmental Protection Agency (EPA) and the Centers for Disease Control and Prevention (CDC) along with scientists from the academic community and state health departments convened a symposium on air pollution exposure and health in order to identify, evaluate, and improve current approaches for linking air pollution exposures to disease. This manuscript presents the key issues, challenges and recommendations identified by the exposure working group, who used cases studies of particulate matter, ozone, and toxic air pollutant exposure to evaluate health-effects for air pollution. One of the over-arching lessons of this workshop is that obtaining better exposure information for these different health-effects studies requires both goal-setting for what is needed and mapping out the transition pathway from current capabilities to meeting these goals. Meeting our long-term goals requires definition of incremental steps that provide useful information for the interim and move us toward our long-term goals. Another over-arching theme among the three different pollutants and the different health study approaches is the need for integration among alternate exposure assessment approaches. For example, different groups may advocate exposure indicators, biomonitoring, mapping methods (GIS), modeling, environmental media monitoring, and/or personal exposure modeling. However, emerging research reveals that the greatest progress comes from integration among two or more of these efforts.

Ozone and cause-specific cardiorespiratory morbidity and mortality

“…A limitation of this and other time-series studies on O 3 is the validity of exposure assessment for O 3 , because there is lack of personal O 3 measurements 45. The measurements were performed outdoors while people spend most of their time indoors.…”

Quantifying human exposure to air pollution—Moving from static monitoring to spatio-temporally resolved personal exposure assessment

“…Environmental, meteorological and microclimatic influences, which are changing dynamically, add to the complexity as well as people moving in space and time, showing individual behavioural patterns (McKone et al, 2008). This means personal exposure is a function of concentration and time (Nuckols et al, 2004).…”

“…According to McKone et al (2008), personal exposures of individuals in a population can be lower, equal or higher than those derived from ambient pollutant concentrations.…”

Summary and findings of the EPA and CDC symposium on air pollution exposure and health

“…The recommendations are grouped and summarized under the following five categories. A number of these issues are further expanded in the accompanying symposium papers by Thurston et al (2008) and McKone et al (2008).…”