The project investigated the individual and joint effects of exposure to multiple pollutants (particulate matter, carbon monoxide, ozone, nitrogen dioxide, and sulfur dioxide) and fires on adverse birth outcomes such as prematurity, low birthweight, and congenital malformations and on the principal causes of hospitalization in the under-five population). The proposed methodology used the new database of the Environmental Information System (SISAM), which contains daily measurements of exposure to the target pollutants in Brazilian municipalities and the national databases Information System on Live Births (SINASC), Information System on Hospitalizations (SIH), and Mortality Information System (SIM) in Brazil’s 5,572 municipalities from 2012 to 2018. The analyses performed were highly robust due to the amount of data analyzed and allowed the greatest contribution to the area, which is the recommendation for the revision of the critical limits on exposure to pollutants, which is important information for drafting public policies in the environment and health
The odds ratios were calculated using a logistic regression model within an ecological study design to assess the relationship between exposure to ambient air pollution (PM2.5, CO, NO2, O3) and fire outbreaks during pregnancy. The selected outcomes included prematurity, low birth weight, congenital anomalies, and hospitalizations in children under five years old. Following this, the results were compared with the air quality standards established by CONAMA and those recommended by the WHO (interim targets). This comparison allowed for the calculation of the percentage of cases attributed to these outcomes and the estimated number of preventable cases if the standards were revised.
The study examined exposure rates to pollutants and fires, as well as the average exposure to key pollutants by municipality, highlighting the variability in exposure levels. It analyzed maternal and child health outcomes from 2012 to 2018, considering changes in how gestational age was recorded in the SINASC system since 2011. A total of 17,393,005 live births in Brazil were included in the analysis.
The impact of exposure to multiple pollutants and fires on maternal and child health was assessed, focusing on both individual and collective effects of exposure by state and municipality. The results indicated that exposure to pollutants significantly affected birth outcomes and hospitalizations, leading to issues such as preterm births, congenital anomalies, and increased hospital visits. Additionally, low birth weight was found to be directly correlated with prematurity.
The study noted that the critical limits set by CONAMA are considerably higher than the acceptable exposure levels. Therefore, it used the values recommended by the WHO in the revised air quality guidelines from 2021. Notably, there are no proposed guidelines from the WHO or CONAMA regarding fires.
To enhance understanding and alert policymakers to the severity of the situation, the results were presented in the form of odds ratios and confidence intervals. Additionally, the findings included the percentage of cases attributed to pollutant exposure and the number of cases of each outcome that could be prevented with a one-unit reduction in pollutant emissions