The airborne dissemination of Clostridium difficile (C. difficile) endospores (spores) in healthcare environments is documented in multiple studies. Once airborne, spores have the potential for transport on air currents to other areas. This study compared the methods in the collection of C. difficile spore aerosol. This study determined the relative efficiency of commonly used bioaerosol air sampling methods when characterizing airborne C. difficile spore concentrations. Air samplers evaluated in this study were the AirTrace slit-to-agar impactor, AGI-30 impinger, SKC BioSampler impinger, and a 47-mm mixed cellulose ester (MCE) filter cassette. Non-toxigenic C. difficile spores were nebulized into an enclosure contained in a biological safety cabinet. Side-by-side air samples were drawn from the enclosure. The slit-to-agar impactor, successfully used in previous studies to collect airborne spores, served as the reference method. Relative efficiency for the 47-mm MCE filter cartridge was higher than the slit-to-agar impactor (mean 136.6%, 95% CI 124.7–148.5%). Efficiencies of the impingers were similar and were low (mean 4.13%, 95% CI 2.27–5.99%). Impingers failed to maintain culturability of C. difficile spores during sampling. This study is the first to compare the efficiencies of commonly used bioaerosol sampling methods to collect airborne C. difficile spores. Filter air sampling provided the greatest collection of airborne spores. Slit-to-agar air sampling may underestimate the number of airborne spores present. Impinger air sampling could significantly underestimate the actual number of airborne C. difficile spores present or fail to detect airborne spores.

Little is known about the cleaning products used by early care and education programs that contribute to childhood asthma, particularly in Oklahoma where rates of uncontrolled asthma are higher than national rates (60.0% vs. 50.3%, respectively). We conducted a cross-sectional study of cleaning products used by Oklahoma-licensed family child care homes (FCCHs) (n = 50) to characterize and identify potential respiratory-health risks associated with chemical contents. Overall, 386 chemicals were abstracted from the 132 reported products. Of these, 100 unique chemicals were identified. Four percent (4.2%) of providers used a product with a sensitizer that may cause allergy or asthma symptoms if inhaled and 35.4% used a product with an irritant that may cause irritation to the respiratory tract. Most (62.5%) reported using a product with a chemical that had a C=C double bond in its molecular structure that may make it highly reactive with other substances in the air and produce secondary air pollutants and 83.3% reported using a sodium hypochlorite containing product. Twenty-three percent reported products that contain carcinogens. Policy, educational, and technical assistance interventions are needed to promote the use of safer products and reduce respiratory and other health risks posed by chemicals in Oklahoma FCCHs.

The National Institute of Occupational Safety and Health procedure No. TEB-APR-STP-0059 recommend of measuring the respirator filtration efficiency using sodium chloride aerosol with count median diameter of 75 nm ± 20 nm and geometric standard deviation ≤1.86. This study showed that this method would overestimate the respirators’ ability to protect against submicrometer particles. In this study, we converted both mobility diameter and equivalent volume diameter to aerodynamic diameter for comparison. The results showed that one unqualified KN95 respirator (with the filtration efficiency of 72%±3% for ≥300 nm sodium chloride aerosol) still passed the test with a measured overall filtration efficiency of 98%±3%, due to its larger most penetrating particle size compared to the typical N95 respirator. In addition, after three cycle H ₂ O ₂ plasma vaporous sterilizations, the most penetrating particle size for the N95 grade respirators also shifted to 250 nm – 500 nm, in which size the particles carried the peak concentration of the SARS-CoV-2 in hospitals. This size shift caused the significant difference between the size specific (250 nm – 500 nm) filtration efficiency and overall filtration efficiency using the same NaCl test aerosol. For example, after three cycle H ₂ O ₂ plasma vaporous sterilizations, the size specific filtration efficiency of the N95 was 55%±2%, however, the measured overall filtration efficiency was still 86%±5%. The size Specific filtration efficiency of the KN95 was 69%±2%, but, the measured overall filtration efficiency was still 90%±3%. In order to protect health care personnel adequately, we recommend increasing the test aerosol size, and measuring the size specific filtration efficiency to evaluate the N95 alternatives (e.g. KN95), and the reuse of N95 level respirators. In addition, multi-cycle sterilization with ultraviolet germicidal irradiation appears to have fewer negative effects than H ₂ O ₂ .