Development of Spatio-Temporal Land Use Regression Models for Fine Particulate Matter and Wood-Burning Tracers in Temuco, Chile

Biomass burning is common in much of the world, and in some areas, residential wood-burning has increased. However, air pollution resulting from biomass burning is an important public health problem. A sampling campaign was carried out between May 2017 and July 2018 in over 64 sites in four sessions, to develop a spatio-temporal land use regression (LUR) model for fine particulate matter (PM) and wood-burning tracers levoglucosan and soluble potassium (Ksol) in a city heavily impacted by wood-burning. The mean (sd) was 46.5 (37.4) μg m−3 for PM2.5, 0.607 (0.538) μg m−3for levoglucosan, and 0.635 (0.489) μg m−3 for Ksol. LUR models for PM2.5, levoglucosan, and Ksol had a satisfactory performance (LOSOCV R2), explaining 88.8%, 87.4%, and 87.3% of the totalvariance, respectively. All models included sociodemographic predictors consistent with the pattern of use of wood-burning in homes. The models were applied to predict concentrations surfaces and to estimate exposures for an epidemiological study.<br/

Temporal and Spatial Trends of Adverse Pregnancy and Birth Outcomes in a Sample of Births from a Public Hospital in Chile

Understanding temporal and spatial trends in pregnancy and birth outcomes within an urban area is important for the monitoring of health indicators of a population. We conducted a retrospective cohort study of all births in the public hospital of Temuco, a medium-sized city in Southern Chile between 2009 and 2016 (n = 17,237). Information on adverse pregnancy and birth outcomes, as well as spatial and maternal characteristics (insurance type, employment, smoking, age, and overweight/obesity), was collected from medical charts. Home addresses were geocoded and assigned to neighborhood. We tested whether births and prevalence of adverse pregnancy outcomes changed over time, whether birth events were spatially clustered (Moran’s I statistic), and whether neighborhood deprivation was correlated to outcomes (Spearman’s rho). We observed decreases in eclampsia, hypertensive disorders of pregnancy, and small for gestational age, while gestational diabetes, preterm birth, and low birth weight increased over the study period (all p < 0.01 for trend), with little changes after adjusting for maternal characteristics. We observed neighborhood clusters for birth rate, preterm birth, and low birth weight. Neighborhood deprivation was negatively correlated with low birth weight and preterm birth, but not correlated with eclampsia, preeclampsia, hypertensive disorders of pregnancy, small for gestational age, gestational diabetes, nor stillbirth. Several encouraging downward trends and some increases in adverse pregnancy and birth outcomes, which, overall, were not explained by changes in maternal characteristics were observed. Identified clusters of higher adverse birth outcomes may be used to evaluate preventive health coverage in this setting

Spatial distribution of particulate matter on winter nights in Temuco, Chile:studying the impact of residential wood-burning using mobile monitoring

Temuco, a medium-sized city in the south of Chile, is heavily impacted by residential wood-burning particularly in winter, which causes strong episodes of air pollution. We spatially characterized the distribution of particulate matter (PM) during winter nights in Temuco using mobile measurements. In winter 2016 (June 8-July 15th), continuous monitors for PM ≤ 2.5 μm (PM2.5) and ultrafine particles <0.1 μm (UFP) were deployed in a vehicle along with a positioning system during 20 nights (20:00 to 2:00) in assigned routes that crossed the city and additional sampling was conducted at a central site. Measurements were expressed as concentrations and ratios to central site concentrations and collapsed by spatial grids of 50, 100, 200, and 400 m. Average PM2.5 concentrations were ∼100 μg m−3, while UFP ∼30,000 counts cm−3. Some neighborhoods had concentrations of PM2.5 nearly double those measured at a centrally located site, while other neighborhoods had less than half the measured level. We identified hotspots and cold spots of PM2.5 and UFP throughout the urban area—and observed some neighborhoods in which over 20% of the area was categorized as a hotspot for one of the pollutants (14 for PM2.5 and 11 for UFP out of 34). Using mobile monitoring—a relatively simple and inexpensive methodology— we characterized the spatial distribution of pollutants and likely clusters for the time period, which may guide future spatial campaigns and help targeting local interventions aimed at air pollution mitigation.This work was supported by “Impact of Wood-burning Air Pollution on Preeclampsia and other Pregnancy Outcomes in Temuco, Chile” (DPI2140093) by CONICYT and Research Councils UK. Estela Blanco, María Elisa Quinteros, and Salvador Ayala were supported by a doctoral scholarship by ANID Beca Doctorado Nacional, Chile No. 21201332, No. 21150801 and No. 21191111, respectively. Juana Maria Delgado-Saborit was supported by the European Union's Horizon 2020 research and innovation programme under the Marie Skodowska-Curie grant agreement No. 750531

Homomorphisms and Ramsey properties of antimatroids

SIGLEBibliothek Weltwirtschaft Kiel C132,202 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman