Short-term dynamics of indoor and outdoor endotoxin exposure: Case of Santiago, Chile, 2012
| Autor: | Francisco Barraza, Héctor Jorquera, Johanna Heyer, Marcelo Muñoz, Gonzalo Valdivia, Ana María Edwards, Wilfredo Palma, Lupita D. Montoya |
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| Rok vydání: | 2015 |
| Předmět: |
010504 meteorology & atmospheric sciences
Meteorology 010501 environmental sciences Atmospheric sciences 01 natural sciences Linear regression Humans Relative humidity Potential source Chile Cities lcsh:Environmental sciences 0105 earth and related environmental sciences General Environmental Science lcsh:GE1-350 Air Pollutants Contribution function Dust Environmental exposure Environmental Exposure Endotoxins Air Pollution Indoor Environmental science Spatial variability Trajectory analysis Seasons Elemental carbon |
| Zdroj: | Environment International, Vol 92, Iss, Pp 97-105 (2016) |
| ISSN: | 1873-6750 |
| Popis: | Indoor and outdoor endotoxin in PM2.5 was measured for the very first time in Santiago, Chile, in spring 2012. Average endotoxin concentrations were 0.099 and 0.094 [EU/m3] for indoor (N = 44) and outdoor (N = 41) samples, respectively; the indoor–outdoor correlation (log-transformed concentrations) was low: R = −0.06, 95% CI: (−0.35 to 0.24), likely owing to outdoor spatial variability.A linear regression model explained 68% of variability in outdoor endotoxins, using as predictors elemental carbon (a proxy of traffic emissions), chlorine (a tracer of marine air masses reaching the city) and relative humidity (a modulator of surface emissions of dust, vegetation and garbage debris). In this study, for the first time a potential source contribution function (PSCF) was applied to outdoor endotoxin measurements. Wind trajectory analysis identified upwind agricultural sources as contributors to the short-term, outdoor endotoxin variability. Our results confirm an association between combustion particles from traffic and outdoor endotoxin concentrations.For indoor endotoxins, a predictive model was developed but it only explained 44% of endotoxin variability; the significant predictors were tracers of indoor PM2.5 dust (Si, Ca), number of external windows and number of hours with internal doors open. Results suggest that short-term indoor endotoxin variability may be driven by household dust/garbage production and handling. This would explain the modest predictive performance of published models that use answers to household surveys as predictors. One feasible alternative is to increase the sampling period so that household features would arise as significant predictors of long-term airborne endotoxin levels. Keywords: Endotoxin exposure, Indoor and outdoor air quality, Endotoxins and combustion particles, Household features, Wind trajectory analysis, PSCF |
| Databáze: | OpenAIRE |
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