Peaks, Means, and Determinants of Real-Time TVOC Exposures Associated with Cleaning and Disinfecting Tasks in Healthcare Settings

Abstract

Cleaning and disinfecting tasks and product use are associated with elevated prevalence of asthma and respiratory symptoms among healthcare workers; however, the levels of exposure that pose a health risk remain unclear. The objective of this study was to estimate the peak, average, and determinants of real-time total volatile organic compound (TVOC) exposure associated with cleaning tasks and product-use. TVOC exposures were measured using monitors equipped with a photoionization detector (PID). A simple correction factor was applied to the real-time measurements, calculated as a ratio of the full-shift average TVOC concentrations from a time-integrated canister and the PID sample, for each sample pair. During sampling, auxiliary information, e.g. tasks, products used, engineering controls, was recorded on standardized data collection forms at 5-min intervals. Five-minute averaged air measurements (n = 10 276) from 129 time-series comprising 92 workers and four hospitals were used to model the determinants of exposures. The statistical model simultaneously accounted for censored data and non-stationary autocorrelation and was fit using Markov-Chain Monte Carlo within a Bayesian context. Log-transformed corrected concentrations (cTVOC) were modeled, with the fixed-effects of tasks and covariates, that were systematically gathered during sampling, and random effect of person-day. The model-predicted geometric mean (GM) cTVOC concentrations ranged from 387 parts per billion (ppb) for the task of using a product containing formaldehyde in laboratories to 2091 ppb for the task of using skin wipes containing quaternary ammonium compounds, with a GM of 925 ppb when no products were used. Peak exposures quantified as the 95th percentile of 15-min averages for these tasks ranged from 3172 to 17 360 ppb. Peak and GM task exposures varied by occupation and hospital unit. In the multiple regression model, use of sprays was associated with increasing exposures, while presence of local exhaust ventilation, large room volume, and automatic sterilizer use were associated with decreasing exposures. A detailed understanding of factors affecting TVOC exposure can inform targeted interventions to reduce exposures and can be used in epidemiologic studies as metrics of short-duration peak exposures.

Keywords: cleaning products; healthcare; modeling; peaks, real-time exposures; tasks.

Figure 1.

Scatter plot of full-shift average TVOC concentrations from time-integrated canister and full-shift average PID samples (a) mobile-area samples and (b) personal samples.

Figure 2.

Posterior distributions of the cTVOC summary measures for tasks showing: (a) GM and 95% CI, (b) P95 and IQR, and (c) GSD and 95%CI. Footnotes: Open diamond = mean; open circle = median; intervals around the GM and GSD are 95% CI; intervals around the P95 are inter quartile range (25–75%); model parameters are exponentiated to get GM, GSD, P95. A1: Alcohol Skin Wipe; A2: Alcohol Surface Cleaner; B1: Quats Bathroom Cleaner; B2: Quats Floor Cleaner; B3: Quats Skin Wipe; B4: Quats Surface Cleaner; C1: Phenolics Cleaner; D1: Chlorine Surface Cleaner-Bleach; D2: Chlorine Skin Wipe; E1: Iodine Skin Wipe; F1: Ethanolamine/Glycol Ether Floor Stripper; F2: Ethanolamine/Glycol Ether Glass Cleaner; F3: Ethanolamine/Glycol Ether Surface Cleaner; G1: Detergent Bathroom Cleaner; G2: Detergent Skin Cleaner; G3: Detergent Surface Cleaner; G4: Detergent Instrument Cleaner; H1: Enzymatic Instrument Cleaner; I1: High-Level Instrument Cleaner; J1: Dental Product; K1: Solvent Cleaner; L1: Formaldehyde in Laboratory; L2: Non-Cleaner in Laboratory; L3: Non-Cleaners in Dialysis; L4: Non-Cleaner Medication; L5: Other Non-Cleaner; M1: No Product Used.

Figure 3.

Posterior distributions of the GM (top panels), and P95 (bottom panels) of cTVOC summary statistics for selected (a) patient cleaning, (b) surface cleaning, and (c) instrument cleaning task-occupation combinations. Footnotes: Open diamond = mean; open circle = median; intervals around the GM are 95% CI; intervals around the P95 are inter quartile range (25–75%); model parameters exponentiated to get GM and P95; CLT = clinical laboratory technician; CAN = certified nursing assistant; DA = dental assistant; DLT = dental laboratory technician; ET = endoscopy technician; FSW = floor stripper/waxer; HK = housekeeper; LPN = licensed practical nurse; MAT = medical appliance technician; MEP = medical equipment preparer; PHT = pharmacy technician; RN = registered nurse; RT = respiratory therapist; and ST = surgical technologist.