Measurement of household concentrations for estimating PM2.5 exposures in pregnant women: Preliminary results from the SICAPHE study

Abstract

Background: Only a few efforts have been undertaken to assess PM exposures in pregnant women, especially in developing countries. We report preliminary results from PM2.5 measurement exercises in the newly established South Indian Cohort for Air Pollution and Health Effects (SICAPHE) study aimed at generating exposure-response relationships for air pollution and select birth/early childhood outcomes. Aim: To conduct repeated measurements of area concentrations in multiple household micro-environments with time-activity records for estimating daily average PM2.5 exposures in a pregnant mother cohort in South India. Methods: We measured 24 h PM2.5 area concentrations in a rural-urban cohort of pregnant women enrolled in the SICAPHE study (n=724 out of total recruitment target of 1200) and collected detailed time-activity information. 2- 4 repeat measurements were performed in each household covering kitchen, living and outdoor areas using gravimetric low volume samplers. Results: The highest 24h PM2.5 concentrations were recorded in the kitchens (380, 91.8 and 75.8 mg/m3, in biomass, kerosene and LPG using households respectively) with much lower concentrations in the living and outdoor areas. Kitchen PM2.5 concentrations were significantly (p=0.014) higher in rural households as compared to urban households and higher in urban households located in commercial areas as compared to residential areas. Kitchen PM 2.5 concentrations measured in rural (n=399) and urban (n=209) households across the three trimesters were not significantly different from each other (p=0.827 and p=0.284). The time-activity data (n=724) found the profiles to be similar for both urban and rural women with activities in the kitchen and living areas accounting for 20 and 75% respectively during their daily routines. Conclusions: The measurements represent one of the most extensive datasets for estimating PM 2.5 exposures in pregnant women in India. Efforts are underway to perform exposure reconstructions and build exposure models as a function of multiple household level determinants.