ABSTRACT
Temuco is one of the most highly wood smoke polluted cities in Chile; however, there is scarce evidence of respiratory morbidity due to fine particulate matter. We aimed to estimate the relationship between daily concentration of ultrafine particles (UFP), with an aerodynamic diameter ≤ 0.1 µm, and outpatient visits for respiratory illness at medical care centers of Temuco, Chile, from August the 20th, 2009 to June the 30th, 2011. The Air Pollution Health Effects European Approach (APHEA2) protocol was followed, and a multivariate semi-parametric Poisson regression model was fitted with GAM techniques using R-Project statistical package; controlling for trend, seasonality, and confounders. The daily UFP were measured by a MOUDI NR-110 sampler. We found that results of the statistical analyses show significant associations between UFP and respiratory outpatient visits, with the elderly (population ≥ 65 years), being the group that presented the greatest risk. An interquartile increase of 4.73 µg/m(3) in UFP (lag 5 days) was associated with respiratory outpatient visits with a relative risk (RR) of 1.1458 [95% CI (1.0497-1.2507)] for the elderly. These results show novel findings regarding the relevance of daily UFP concentrations and health risk, especially for susceptible population in a wood smoke polluted city.
Subject(s)
Environmental Exposure , Particle Size , Particulate Matter/toxicity , Respiratory System/drug effects , Respiratory Tract Diseases/epidemiology , Smoke/adverse effects , Wood/chemistry , Adolescent , Adult , Aged , Child , Child, Preschool , Chile/epidemiology , Demography , Humans , Middle Aged , Regression Analysis , Risk , Time , Young AdultABSTRACT
The difference in performance of three differently designed circular secondary clarifiers in the same wastewater treatment plant was analyzed in this paper. Data obtained using flocculated suspended solids and disperse suspended solids tests were analyzed using statistical tools. The conventional clarifier showed more variability in the average effluent suspended solids concentration when compared with the flocculator-clarifiers. Furthermore, a difference in performance among the two different flocculator-clarifiers was found.
Subject(s)
Bioreactors , Efficiency , Sewage , Waste Disposal, Fluid/instrumentation , Waste Disposal, Fluid/methods , Flocculation , Models, Biological , Particulate Matter/isolation & purification , Sewage/chemistry , Tennessee , Water Purification/instrumentation , Water Purification/methodsABSTRACT
To address the lack of research on the pulmonary health effects of ozone and fine particulate matter (= 2.5 microm in aerodynamic diameter; PM2.5) on individuals who recreate in the Great Smoky Mountains National Park (USA) and to replicate a study performed at Mt. Washington, New Hampshire (USA) , we conducted an observational study of adult (18-82 years of age) day hikers of the Charlies Bunion trail during 71 days of fall 2002 and summer 2003. Volunteer hikers performed pre- and posthike pulmonary function tests (spirometry), and we continuously monitored ambient O3, PM2.5, temperature, and relative humidity at the trailhead. Of the 817 hikers who participated, 354 (43%) met inclusion criteria (nonsmokers and no use of bronchodilators within 48 hr) and gave acceptable and reproducible spirometry. For these 354 hikers, we calculated the posthike percentage change in forced vital capacity (FVC) , forced expiratory volume in 1 sec (FEV1) , FVC/FEV1, peak expiratory flow, and mean flow rate between 25 and 75% of the FVC and regressed each separately against pollutant (O3 or PM2.5) concentration, adjusting for age, sex, hours hiked, smoking status (former vs. never) , history of asthma or wheeze symptoms, hike load, reaching the summit, and mean daily temperature. O3 and PM2.5 concentrations measured during the study were below the current federal standards, and we found no significant associations of acute changes in pulmonary function with either pollutant. These findings are contrasted with those in the Mt. Washington study to examine the hypothesis that pulmonary health effects are associated with exposure to O3 and PM2.5 in healthy adults engaged in moderate exercise. .
Subject(s)
Air Pollutants/pharmacology , Inhalation Exposure , Lung/drug effects , Ozone/pharmacology , Adolescent , Adult , Aged , Aged, 80 and over , Exercise , Female , Humans , Lung/physiopathology , Male , Middle Aged , North Carolina , Particle Size , Tennessee , Time Factors , WalkingABSTRACT
A computer model called the Ozone Risk Assessment Model (ORAM) was developed to evaluate the health effects caused by ground-level ozone (O3) exposure. ORAM was coupled with the U.S. Environmental Protection Agency's (EPA) Third-Generation Community Multiscale Air Quality model (Models-3/CMAQ), the state-of-the-art air quality model that predicts O3 concentration and allows the examination of various scenarios in which emission rates of O3 precursors (basically, oxides of nitrogen [NOx] and volatile organic compounds) are varied. The principal analyses in ORAM are exposure model performance evaluation, health-effects calculations (expected number of respiratory hospital admissions), economic valuation, and sensitivity and uncertainty analysis through a Monte Carlo simulation. As a demonstration of the system, ORAM was applied to the eastern Tennessee region, and the entire O3 season was simulated for a base case (typical emissions) and three different emission scenarios. The results indicated that a synergism occurs when reductions in NOx emissions from mobile and point sources were applied simultaneously. A 12.9% reduction in asthma hospital admissions is expected when both mobile and point source NOx emissions are reduced (50 and 70%, respectively) versus a 5.8% reduction caused by mobile source and a 3.5% reduction caused by point sources when these emission sources are reduced individually.