Quaternary ammonium compounds, or quats, were widely used in many of the products investigated. Quats have been identified by Nielsen 2007 as one of the indoor agents that may promote development of airway allergy[27]. In his review, Nielsen summarizes the evidence from animal and humans studies that relates quats exposures with allergy-promoting effects. He concludes that the mechanism of asthma from quats remains unknown. One important consideration in the investigation of asthma symptoms from quats is the understanding of exposure routes in the workplace. Although several case reports identify an asthma-quats exposure relationship, they lack the clarification on how exposure had occurred [2, 5, 6]. In the second case report of a study by Purohit 2000, the nurse developed symptoms after entering the room that was cleaned with a surface cleaning product that contained benzalkonium chloride[5]. Because the nurse was not involved in cleaning activities the most probable exposure route would be inhalation and not through skin. A study by Vincent 2006 showed non-detectable levels of quats in the hospital indoor air [38]. Inhalation to quats may happen in two ways: 1) by inhaling aerosolized liquid particles generated during product application, or 2) by inhaling quats absorbed into the dust particles that are re-suspended in the air. Further quantitative workplace investigations of inhalation and dermal exposures will provide important evidence for understanding actual exposure routes for quats.

Mono-ethanolamine, used as surfactant, was found in most of the product types investigated, with exception of the floor cleaners. It has a boiling point of 171°C and dissolves very well in water. Exposures to its vapors can irritate the nose, throat, and lungs, causing coughing, wheezing and shortness of breath. The OSHA PEL for mono-ethanolamine is 3 ppm and the ACGIH 15 min short term exposure limit (STEL) is 6 ppm. Exposure to mono-ethanolamines from cleaning agents have been related to occupational asthma [4]. To understand the exposure response relationship and the mechanism of asthma, it is necessary to investigate exposure patterns in the workplace including short term peak exposures. Dermal exposure assessment should be considered in further workplace exposure assessment strategies, given the concern that mono-ethanolamine can be absorbed through the skin [19].

Fragrances were used commonly in bathroom cleaners. Exposure to fragrances is a topic of special interest because they may cause secondary emissions due to reactions of the primary exposures with oxidizers present in indoor air (e.g. terpenes, a family of chemicals common in fragrances, reacting with ozone in indoor air) [39]. These reactions can produce secondary gaseous and aerosol ultrafine particles that may be responsible for the airway irritation symptoms [40, 41]. Very recently, Wolkoff (2008) found that gaseous products generated from ozone-limonene reactions are causative of acute irritation effects measured in a mice bioassay[42]. Another important consideration related to fragrance use in cleaning product is the presence of odor during and after cleaning. Even at low concentrations, the presence of compounds with low odor thresholds may cause perceived respiratory irritation because of odor annoyance[41]. Furthermore, this is a topic of special interest due to the reported sensitization effects associated with the fragrance use [43].

Surprisingly, bleach was not used in any of these products compared to findings from other studies, which found that bleach can be responsible for asthma symptoms among domestic cleaners [14, 44].