ExpoApp: An integrated system to assess multiple personal environmental exposures

Area of Science:

• Environmental Health Sciences
• Epidemiology
• Mobile Health (mHealth)

Background:

• Assessing individual-level environmental exposures requires innovative methods and tools.
• Smartphone technology offers a platform for developing novel exposure assessment systems.

Purpose of the Study:

• To develop and evaluate ExpoApp, a smartphone-based system for individual environmental exposure assessment.
• To measure time spent in microenvironments, physical activity, and exposure to ultrafine particles (UFP).

Main Methods:

• ExpoApp integrates smartphone sensors (GPS, accelerometer), portable monitors, GIS, and user information.
• A panel study of 158 adults across five European cities deployed ExpoApp alongside reference tools (accelerometer, activity diary).
• System reliability and validity were assessed by comparing failure rates and agreement on microenvironment time and physical activity levels.

Main Results:

• ExpoApp demonstrated high agreement with reference tools for time in microenvironments (86.6%) and physical activity (75.7%).
• Participants inhaled an average of 16.5 × 10^10 UFP particles/day, with limited green space contact.
• Increased green space contact correlated with higher UFP inhalation, except in the Netherlands.

Conclusions:

• ExpoApp is a reliable and accurate system for individual environmental exposure assessment.
• The system's measurements can advance understanding of environmental exposures in disease etiology.
• This mHealth approach facilitates large-scale environmental health research.