Characterizing Particle Removal and Cleaning in Texas Border Housing PDF

A project to evaluate on-site environmental assessments and recommended, cost-effective corrective measures in 60 lowincome border houses in Laredo, TX over a 12-month period has been completed. As part of the project, the effectiveness of particle removal and cleaning by high efficiency vacuum cleaners and room-sized air cleaners, and usage by the occupants was studied. A high efficiency vacuum cleaner was provided to each family, along with a HEPA-equipped air cleaner for use in the bedroom of a child with asthma. Usage of the appliances was monitored with run-time and watt-hour meters, while the mass of vacuumed material was determined by collecting and weighing vacuum cleaner bags at approximately two-month intervals. Floor dust recovery sampling (in homes with carpet) and airborne particle measurements were also conducted before, during, and at the conclusion of the study. Occupant utilization varied widely, as did impacts on measured floor dust and airborne particle levels. The geometric mean (GM) for vacuum cleaner usage was 7.3 min/week (GSD of 2.24), while the GM cleaning rate was 420 g/ hr (GSD of 3.16). For 19 of the homes with carpet, the carpet dust recovery was reduced from a GM of 43 g/m² (GSD of 4.81) to 19 g/m² (GSD of 3.09). The median percentage of time that the air cleaners were on and being used at all speed settings was 82%. Surprisingly, the air cleaners were turned off during approximately 15% of the testing periods. Various factors impact occupant use of air cleaners, but noise is the most common obstacle to their use, especially in bedrooms. Overall, recommended cleaning activities resulted in lower particle levels in the houses, as evidenced by 1) a reduction in floor dust recovery from carpets of approximately 56%, 2) an increased number of occupants reporting more frequent vacuum cleaning (from 43% to approximately 80%), and 3) a significant reduction in the indoor/outdoor PM2.5 ratio.

IAQ 2007 Conference held in Baltimore, Maryland, October 14-17, 2007

Units: SI