Population exposure to hazardous air quality due to the 2015 fires in Equatorial Asia.

Vegetation and peatland fires cause poor air quality and thousands of premature deaths across densely populated regions in Equatorial Asia. Strong El-Niño and positive Indian Ocean Dipole conditions are associated with an increase in the frequency and intensity of wildfires in Indonesia and Borneo, enhancing population exposure to hazardous concentrations of smoke and air pollutants. Here we investigate the impact on air quality and population exposure of wildfires in Equatorial Asia during Fall 2015, which were the largest over the past two decades. We performed high-resolution simulations using the Weather Research and Forecasting model with Chemistry based on a new fire emission product. The model captures the spatio-temporal variability of extreme pollution episodes relative to space- and ground-based observations and allows for identification of pollution sources and transport over Equatorial Asia. We calculate that high particulate matter concentrations from fires during Fall 2015 were responsible for persistent exposure of 69 million people to unhealthy air quality conditions. Short-term exposure to this pollution may have caused 11,880 (6,153-17,270) excess mortalities. Results from this research provide decision-relevant information to policy makers regarding the impact of land use changes and human driven deforestation on fire frequency and population exposure to degraded air quality.

Premature thelarche in Puerto Rico. A search for environmental factors.

Pediatric endocrinologists in Puerto Rico reported a threefold increase in the number of patients with premature thelarche seen between 1978 and 1981. A matched-pairs case-control study was conducted to evaluate associations with potential environmental exposures to substances with estrogenic activity, as well as with familial factors. Analysis was performed on 120 pairs, the case subjects of which were selected from those diagnosed between 1978 and 1982. In subjects 2 years of age or older at the onset of thelarche, no significant associations were found. In subjects with onset before 2 years of age, significant positive associations were found with a maternal history of ovarian cysts, consumption of soy-based formula, and consumption of various meat products. A statistically significant negative association was found with consumption of corn products. These statistical associations are probably not sufficient to explain the reported increase because in over 50% of the case subjects there was no exposure to any of the risk factors for which statistical associations were found. Exposure to other substances with possible estrogenic effect, such as waste products from pharmaceutical factories and pesticides, was also excluded as a possible cause. These findings suggest that better diagnosis and reporting, or conceivably the presence of entirely new, unsuspected factors, could account for the reported increase.