Helena Järnström

Infant exposure to emissions of volatile organic compounds from crib mattresses

Infants spend most of their time sleeping and are likely to be exposed to elevated concentrations of chemicals released from their crib mattresses. Small-scale chamber experiments were conducted to determine the area-specific emission rates (SERs) of volatile organic compounds (VOCs) in a collection of twenty new and used crib mattresses. All mattress samples were found to emit VOCs and the mean values of total VOC (TVOC) SERs were 56 μg/m(2)h at 23 °C and 139 μg/m(2)h at 36 °C. TVOC SERs were greater for new mattresses compared to used ones and were influenced by the type of foam material and the presence of mattress cover layer. A variety of VOCs were identified, with polyurethane foam releasing a greater diversity of VOCs compared to polyester foam. Large-scale chamber experiments were conducted with an infant thermal manikin. TVOC concentrations sampled in the breathing zone and interior pore air of the crib mattress foam were found to be greater than the bulk room air by factors in the range of 1.8 to 2.4 and 7.5 to 21, respectively. The results suggest that crib mattresses are an important source of VOCs and infant exposure to VOCs are possibly elevated in their sleep microenvironments.

The Impact of Emissions from Structures on Indoor Air Concentrations in Newly Finished Buildings — Predicted and On-Site Measured Levels

The impact of surface emissions (VOCs, ammonia, and formaldehyde) on the indoor air quality (IAQ) in newly established buildings was examined. Six apartment buildings, in which low-emitting, classified building materials were used, were investigated 0, 6, and 12 months after completion of construction work. The predicted indoor air concentrations based on the on-site measured emissions (floor, walls, ceiling) and air exchange rates were in general lower than the measured indoor air concentrations. The contribution of other sources was on the average about 50% for VOCs and 25—35% for ammonia and formaldehyde. The ceiling structure was the main source of pollutants throughout the first year. PVC floor covering affected IAQ significantly in the newly finished buildings. The contribution of walls was relatively low in spite of large surface area. The impact of VOC emissions from surfaces on indoor air clearly decreased during the follow-up period whereas the impact of ammonia and formaldehyde emissions remained about the same. Higher SVOC concentration was measured in the buildings with PVC flooring compared to the rooms with parquet flooring in the 0 to 6-month-old buildings.

Indoor Air Quality in New Residential Buildings and Behaviour of Materials in Structures

A research project was initiated in order to collect numerical reference data on material emissions during the time of construction and to follow up indoor air quality in new buildings. Seven measurement sites representative of current construction practice in Finland were chosen for investigation. Material emission measurements for surfaces were made during construction using the field and laboratory cell (FLEC) technique. The emission rates for volatile organic compounds (VOCs), formaldehyde and ammonia and the relative humidity of the floor structure were measured for the floor structure build-up stages. In addition, decay behaviour of the emissions of underlying floor structures was investigated. The concentration of VOCs, formaldehyde and ammonia in indoor air and the air exchange rate were defined for the newly finished and 6 month-old buildings. The results were compared to indoor air concentration and emission rate target values defined in the Finnish “Classification of Indoor Climate 2000”.