Intake Fraction of PM10 from Coal Mine Emissions in the North of Colombia

Intake fraction was determined in this study to provide insight into population exposures to PM10 that is effectively inhaled due to emissions of an opencast coal mine. We applied the CALPUFF model to a coal mine in Northern Colombia, which has 6 active pits with an annual production of 33.7 million tons. We estimated the intake fractions for 7 towns through the integration of dispersion model results over the population data. The resulting average intake fractions were between 6.13 × 10−9 and 3.66 × 10−8 for PM10. 62.4% of the intake fractions in the domain were calculated within a 23 km radius from the coal mine and coved 44.3% of the total population in this area. We calculated an estimate point for morbidity impacts using standard epidemiological assumptions. It is estimated that there were annually 105835 restricted activity days and 336832 respiratory symptom cases due to the direct impact of the opencast coal mining. These data also provide a framework for improved understanding of the effect of coal mining in Colombia.

Performance of Coaxial Ceiling-Mounted Personalized Ventilator for Comfort and Good Air Quality

The aim of this work is to study the performance of a novel ceiling mounted coaxial personalized ventilator that can be used as an add on to the conventional ceiling diffuser in providing the thermal comfort and air quality needs to occupants in office building. A detailed 3D CFD model is coupled to a bioheat model to improve prediction of the microenvironment conditions around the human and the associated local and overall thermal comfort. Extensive simulations were performed to assess the effect of nozzle supply temperature and flow rate on the performance of the cooling system and on occupant comfort. The localized air conditioning system reduced the energy consumption by up to 34% when compared with conventional mixing systems providing the same level of thermal comfort. The proposed system also achieved high air quality in the occupant breathing zone with 45% ventilation effectiveness at fresh airflow rate of 10 L/s/person and attained 2°C between the occupant’s comfortable microenvironment and the rest of the space. In addition, the canopy of the angled diffuser was effective in reducing the migration of particles from the macroclimate to the microclimate region and low intake fractions of 1.90×10−4 were achieved.