Characteristics of patients with work-related asthma seen in the New York State Occupational Health Clinics.

OBJECTIVE: The objective of this study was to characterize the work-related asthma population seen by the New York State Occupational Health Clinic Network (OHCN) to determine which industries, occupations, and causal agents are associated with work-related asthma in New York State (NYS). METHODS: The OHCN patient database was analyzed to identify those patients with a diagnosis of work-related asthma and medical charts were then abstracted for data on demographics, clinical history, disease severity, industry, occupation, and putative agent. RESULTS: The OHCN patients with work-related asthma were most commonly employed in the service and manufacturing industries. Common occupations included teachers, farm operators/managers, and construction trades. The most frequently reported putative agents associated with work-related asthma were dust, indoor air, mold, and solvents. CONCLUSIONS: Our findings suggest the potential importance of prevention of workplace exposure in reducing adult asthma in NYS.

A simple and inexpensive method for determining the effective ventilation rate in a negatively pressurized room using airborne particles as a tracer.

The ventilation rate within a negatively pressurized room is usually determined by measuring the exhaust air flow rate. This method does not account for air mixing factors and gives limited information on ventilation efficiency within the room. Effective ventilation rates have been determined using tracer gases such as sulfur hexafluoride (SF6). The objective of this study was to determine whether artificially generated airborne particles could be used as a tracer to directly measure ventilation efficiency. We monitored the decay of artificially generated particles within negatively pressurized rooms. Separate trials were conducted at air exhaust rates ranging from about 6 to 20 room air changes per hour. Particles were generated to a minimum of 20 times the ambient concentration using a simple ventilation smoke bottle and measured with handheld light-scattering airborne particle counters. Data were obtained for aerodynamic particle size ranges of: 0.5 micron (microM) and larger, and 1.0 microM and larger. The time rate of decay of particles was plotted after subtracting the background concentrations. Results were compared with simultaneously conducted tracer gas decay analyses (ASTM method E741-95) using SF6. Particle concentrations followed an exponential decay (R2 = 0.98-0.99+) and mirrored the decay curve of the tracer gas. The air change rates predicted by the particle count procedure differed from the tracer gas results by a mean of 4.0 percent (range 0%-12%). The particle count procedure was substantially simpler and less expensive than the SF6 tracer gas method. Additional studies are needed to further refine this procedure and to explore its range of applicability.