Association between exposure to different stone aggregates from asphalt and blood coagulability: A human exposure chamber study.

A large fraction of particulate matter (PM), especially PM10, concentrations are due to non-exhaust emissions, such as road abrasion and wear on tires and brake pads. Concentrating on road abrasion, we aimed to investigate blood coagulability in healthy adults after exposure to two types of stone materials commonly used in asphalt on Norwegian roads. This study followed a randomized, double-blind, cross-over study design. Using an exposure chamber, 24 healthy young volunteers were exposed to aggregates of two different types of rocks and placebo dust: quartz diorite, rhomb porphyry, and lactose (placebo dust). Each exposure session lasted for 4 hours (h), and blood samples were collected before exposure (baseline), 4 h post-exposure, and 24 h post-exposure to analyse potential changes in the von Willebrand factor (vWF) as well as of fibrinogen, d-dimer, leukocytes, and thrombocytes. The dust concentration in the exposure chamber was measured with real-time instruments and gravimetric samples of total dust, respirable dust, PM10, PM2.5, and ultrafine particles (UFP). The results were analysed using a linear mixed-effect model. Leukocyte blood counts increased post-exposure for all exposure materials; however, none of the increases were statistically significant. The concentration of fibrinogen increased after exposure to quartz diorite, while it decreased after exposures to rhomb porphyry and lactose. Type of material was a statistically significant explanatory variable for the concentration of fibrinogen, with the most significant increase occurring 24 h post-exposure to quartz diorite. After exposure to the three materials, vWF decreased. For the thrombocytes, an increase in blood count was observed 24 h post-exposure to quartz diorite and rhomb porphyry, with a modest (p = 0.09) positive association for quartz diorite. Although the results are limited, we conclude that the different effects observed post-exposure to quartz diorite support considering potential health effects when choosing materials in the production of asphalt.

Covariation amongst pool management, trichloramine exposure and asthma for swimmers in Norway.

The association between asthma and exposure to the air in swimming facilities has been acknowledged. However, the variation in, long-term exposure to and management of the respiratory irritant trichloramine (NCl3) is not well understood. In this study, 313 swimmers above 18 years of age licensed by the Norwegian Swimming Association answered a questionnaire about health and swimming. The prevalence of asthma amongst the most-exposed swimmers was 36%. Two facilities, those with the highest and lowest reported prevalence of asthma, were chosen for further investigation. For each facility, a one-week-long monitoring campaign was performed, during which pool management, air and water quality were investigated. The results of this study showed that time of day, occupancy and pool management affect the concentration of NCl3, which ranged from 58 µg/m3 to 461 µg/m3. Furthermore, in one of the facilities, the concentration of CO2 was measured to evaluate whether this contaminant could be used to predict the number of pool occupants as well as the concentration of NCl3 in the air. The concentration of CO2 was significantly correlated with occupancy level (ρ = 0.82, p = 0.01) and NCl3 concentration (r = 0.80, p = 0.01). Furthermore, according to the random intercept model the concentration of CO2 explained 52% of the variation observed in the air concentration of NCl3. CO2 sensors to control the air supply can help reduce the air concentrations of NCl3 and balance the air supply based on occupancy level.

UV treatment and air quality in a pool facility.

We investigated how UV treatment of indoor pool water affects the concentration of trihalomethanes (THMs) and chloramines (NCl3) in the air above one therapy pool. One-hundred and sixty-two samples of tTHMs (sum of the four most common THMs in swimming facilities) and thirty-six samples of NCl3 were collected simultaneously at poolside and in the extract channel in a room with one therapy pool for 2 days a week over a period of 5 weeks. When the UV lamp was on, the concentration of combined chlorine in the water decreased 58%, the concentration of tTHMs in the air increased 37%, and the concentration of NCl3 in the air decreased 15%. Between 42% and 56% of the gases in the air are recirculated back into the poolroom along with the recycled air. The correlation between NCl3 and THMs in the air was stronger when the UV treatment was on (r2 = 0.963) compared to when the UV treatment was off (r2 = 0.472). Using a linear mixed model, 30% of the variability in THMs was attributed to UV treatment. For NCl3, the number of bathers was the most important predictor variable. UV treatment has a limited effect on airborne NCl3 but increases the air concentration of tTHMs.

Determinants of Exposure and Variability of Trihalomethanes in the Air of Three Indoor Swimming Pools.

INTRODUCTION: Negative health effects related to long-term exposure to volatile trihalomethanes (THMs) formed during the chlorination of pool water is recognized, but the determinants causing the concentrations to vary within and between sampling locations have not received much attention. METHODS: One hundred and twenty air samples of four THMs were examined in three Norwegian indoor pool facilities. In each facility, repeated samples were collected above a sports pool and a therapy pool, 0.05 and 0.60 m above the water's surface. A linear mixed model (LMM) was used to identify determinants of exposure and the variability in THM concentration within and between sampling locations, days, and heights in pool facilities. RESULTS: The within variability of days, sampling locations, and heights was greater than between days, sampling locations, and heights. Determinants contributing significantly to the exposure were pool facility, height, swimming pool, day of the week, time during the day, and number of bathers. These findings limits how exposure categories should be defined to be able to identify the real long-term exposure and to propose suitable exposure limit values. DISCUSSION: These determinants could help future research be designed with effective sampling strategies and to collect information about the real long-term exposure, which is important in terms of establishing a dose-response relationship and exposure limit values. CONCLUSIONS: If unbiased exposure assessments are to be conducted among the different users of the pool facility, air samples should be collected over time and for different exposure scenarios.