Variability in quartz exposure in the construction industry: implications for assessing exposure-response relations

Area of Science:

• Occupational Health
• Environmental Science
• Epidemiology

Background:

• Construction workers face significant exposure to respirable dust, including quartz.
• Variability in dust exposure and characteristics impacts the reliability of epidemiologic research.
• Understanding exposure heterogeneity is crucial for accurate risk assessment in this population.

Purpose of the Study:

• To assess the impact of inter- and intraindividual variation in respirable dust exposure on epidemiologic studies.
• To evaluate the influence of dust characteristics heterogeneity on research findings.
• To determine optimal grouping strategies for construction workers in exposure research.

Main Methods:

• Collected full-shift personal respirable dust and quartz exposure measurements from 34 construction workers (n=67).
• Utilized mixed models to estimate between-worker and day-to-day exposure variances.
• Employed electron microscopy and electron spin resonance to analyze dust characteristics.

Main Results:

• Grouping workers by job title reduced expected attenuation by 2-fold (respirable dust) and 3.5-fold (quartz) compared to individual approaches.
• Materials worked on explained most between-worker variance, but this grouping is impractical for past exposure assessment.
• Dust samples contained significant aluminum silicates and small particles (D50: 1-2 µm), indicating potential toxicological potency.

Conclusions:

• Job title grouping offers a practical approach for exposure groups in risk analysis, despite introduced errors from dust heterogeneity.
• Grouping by materials worked on is superior for exposure and risk assessment but not feasible for retrospective studies.
• Construction site dust contains factors that can modulate toxicological potency, necessitating careful consideration in epidemiologic research.