Retrospective assessment of pregnancy exposure to particulate matter from desert dust on a Caribbean island: could satellite-based aerosol optical thickness be used as an alternative to ground PM10 concentration?

Desert dust transported from the Saharan-Sahel region to the Caribbean Sea is responsible for peak exposures of particulate matter (PM). This study explored the potential added value of satellite aerosol optical thickness (AOT) measurements, compared to the PM concentration at ground level, to retrospectively assess exposure during pregnancy. MAIAC MODIS AOT retrievals in blue band (AOT470) were extracted for the French Guadeloupe archipelago. AOT470 values and PM10 concentrations were averaged over pregnancy for 906 women (2005-2008). Regression modeling was used to examine the AOT470-PM10 relationship during pregnancy and test the association between dust exposure estimates and preterm birth. Moderate agreement was shown between mean AOT470 retrievals and PM10 ground-based measurements during pregnancy (R2 = 0.289). The magnitude of the association between desert dust exposure and preterm birth tended to be lower using the satellite method compared to the monitor method. The latter remains an acceptable trade-off between epidemiological relevance and exposure misclassification, in areas with few monitoring stations and complex topographical/meteorological conditions, such as tropical islands.

Impact of Saharan dust episodes on preterm births in Guadeloupe (French West Indies).

OBJECTIVES: Large amounts of mineral dust are transported from their African sources in the Saharan-Sahel region to the Caribbean Sea, generating peak exposures to particulate matter ≤10 µm (PM10). This study aimed to investigate the impact of Saharan dust episodes on preterm births in the Guadeloupe archipelago. METHODS: The study population consisted of 909 pregnant women who were enrolled in the TIMOUN mother-child cohort between 2004 and 2007. Desert dust episodes were assessed from PM10 concentrations recorded at the unique background air quality monitoring station located in Pointe-à-Pitre. For each woman, the daily PM10 concentrations were averaged over the entire pregnancy, and the proportion of days with intense dust episodes (≥55 µg PM10/m3) during pregnancy was calculated. Weighted logistic regression models adjusting for known individual sociomedical risk factors were used to estimate ORs and 95% CIs for preterm birth. RESULTS: During pregnancy, the mean PM10 concentrations ranged from 13.17 to 34.92 µg/m3, whereas the proportion of intense dust events ranged from 0.00% to 19.41%. Increased adjusted ORs were found for both the mean PM10 concentrations and the proportion of intense dust events (OR 1.40, 95% CI 1.08 to 1.81, and OR 1.54, 95% CI 1.21 to 1.98 per SD change, respectively). Restriction to spontaneous preterm births produced similar ORs but with wider 95% CIs. CONCLUSION: Considering the personal and social burden of this adverse pregnancy outcome, this finding is of importance for both healthcare workers and policy makers to provide necessary preventive measures.