Formaldehyde levels in FEMA-supplied travel trailers, park models, and mobile homes in Louisiana and Mississippi.

In 2006, area physicians reported increases in upper respiratory symptoms in patients living in U.S. Federal Emergency Management Agency (FEMA)-supplied trailers following Hurricanes Katrina and Rita. One potential etiology to explain their symptoms included formaldehyde; however, formaldehyde levels in these occupied trailers were unknown. The objectives of our study were to identify formaldehyde levels in occupied trailers and to determine factors or characteristics of occupied trailers that could affect formaldehyde levels. A disproportionate random sample of 519 FEMA-supplied trailers was identified in Louisiana and Mississippi in November 2007. We collected and tested an air sample from each trailer for formaldehyde levels and administered a survey. Formaldehyde levels among all trailers in this study ranged from 3 parts per billion (ppb) to 590 ppb, with a geometric mean (GM) of 77 ppb [95% confidence interval (CI): 70-85; range: 3-590 ppb]. There were statistically significant differences in formaldehyde levels between trailer types (P < 0.01). The GM formaldehyde level was 81 ppb (95% CI: 72-92) among travel trailers (N = 360), 57 ppb (95% CI: 49-65) among mobile homes (N = 57), and 44 ppb (95% CI: 38-53) among park models (N = 44). Among travel trailers, formaldehyde levels varied significantly by brand. While formaldehyde levels varied by trailer type, all types tested had some levels ≥ 100 ppb.

Use of oral montelukast in the treatment of asthma.

Montelukast, a new leukotriene modifier, has several benefits in the treatment of asthma in adults and children including improved relief of asthma symptoms, rapid onset, a safety profile comparable with placebo, and oral, once-daily dosing means excellent adherence.

Effects of montelukast (MK-0476), a new potent cysteinyl leukotriene (LTD4) receptor antagonist, in patients with chronic asthma.

BACKGROUND: Cysteinyl leukotrienes mediate signs and symptoms of asthma. In a double-blind, placebo-controlled, crossover study, a new potent and specific cysteinyl leukotriene (LTD4) receptor antagonist, montelukast (MK-0476), was evaluated for tolerability and clinical efficacy in patients with chronic asthma (receiving and not receiving inhaled corticosteroids). METHODS: Twenty-nine nonsmoking patients with asthma (15 treated concomitantly with inhaled corticosteroids) with FEV1 percent predicted values between 50% to 80% received MK-0476, 200 mg, or placebo three times daily for 10 1/3 days (31 doses) in a random, crossover manner, after a 2-week, open, baseline period. Comparisons in FEV1 (mean percent change from baseline after the first and last dose), mean daily daytime asthma and nocturnal awakening scores, and mean daily beta-agonist use were made between treatment periods. RESULTS: Montelukast, compared with placebo, caused improvements in FEV1 (mean percentage point difference of the percentage change from baseline) 3 and 4 hours after dosing on day 1 (hour 3, 9.0%; 95% confidence interval [CI] 0.53, 18.72; hour four, 10.9%; 95% CI -0.25, 20.20) and day 11 (hour 3, 14.0%; 95% CI 0.76, 31.43; hour 4, 13.4%; 95% CI 1.24, 28.83). Reductions were observed in mean daily beta-agonist use (1.0 puff/day [95% CI -1.61, -0.26]), mean daytime symptom scores, and nocturnal awakenings over the 10 1/3 day treatment period. There were no important differences between the groups receiving and those not receiving inhaled corticosteroids. Montelukast was well tolerated with no serious clinical adverse events reported. CONCLUSIONS: In this study Montelukast, 200 mg, administered three times daily for 10 1/3 days, compared with placebo, was generally well tolerated and resulted in significant improvement in chronic asthma, irrespective of the presence of inhaled corticosteroids.

Estimated workplace protection factors for positive-pressure self-contained breathing apparatus.

An analytical model is presented that estimates the distribution of workplace protection factor (WPF) values for positive-pressure respirators. Input for the model is (1) the instantaneous facepiece pressure measured as a function of time and (2) the distribution of WPF values for a negative-pressure version of the respirator. As an example application, the model was applied to 57 measurements of facepiece pressure made in a previous National Institute for Occupational Safety and Health study called "Firesmoke." That study involved professional firefighters wearing positive-pressure self-contained breathing apparatus (SCBA). During Firesmoke, there were four donnings in which facepiece pressure momentarily went negative one or more times during use. The purpose of the effort described here was to assess the significance of these momentary, negative excursions in facepiece pressure. To that end, an analytical model was developed that estimates the ratio of the mass of contaminant that enters the facepiece during these negative excursions to that which would be expected to enter a negative-pressure respirator utilizing the same facepiece. Thus, the performance of a positive-pressure SCBA can be determined relative to the performance of a negative-pressure respirator with the same facepiece--either a negative-pressure SCBA or a negative pressure air-purifying respirator. The NIOSH-assigned protection factor (APF) for a negative-pressure full facepiece is 50; the APF for a positive-pressure SCBA is 10,000. The results of the application of this analytical model are consistent with the current NIOSH APF for a positive-pressure SCBA.