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Cleaning and other household products
Cleaning is a necessary activity to maintain the functionality, appearance and appropriate hygienic condition of our homes. In general this mainly involves the cleaning of surfaces, particularly floors, furniture, sanitary fittings and windows. This can be done by dusting, wiping, sweeping or vacuuming, but is usually done with the aid of (chemical) cleaning products. Apart from those used for the cleaning of surfaces, several other types of chemicals are applied in many households. The most common include laundry products, air fresheners and pesticides.
Alkaline-based soaps have been used for centuries for general cleaning purposes. During the second half of the twentieth century, many cleaning products for specific purposes were introduced, increasingly containing synthetic chemicals including disinfectants, agents for surface care and other additives.
To date most evidence on the adverse respiratory health effects of cleaning products comes from occupational studies. Professional cleaning is common, both as a job and as a major activity in many other occupations. Presumably also the majority of the general population is to some extent exposed to cleaning products and other household chemicals. Apart from housewives and househusbands, most people actively do some cleaning in their homes. Household members may also be passively exposed to volatile agents from cleaning products when present in the home during or shortly after the application of these products. This indicates that the potential health consequences of the use of cleaning and laundry products comprise an important public health issue.
The purpose of this chapter is to provide a concise overview of the most common cleaning agents and other household chemicals and to describe factors that determine respiratory exposure. The major acute respiratory effects and chronic respiratory disorders associated with these chemicals will be reviewed, and practical measures to reduce exposure to household chemicals will be discussed.
Purposes
Cleaning products are commonly used on a variety of surfaces and have four different, often supplemental, purposes. Obviously the main goal of using cleaning products is to facilitate the removal of surface contaminants. This is based on physical and chemical processes, including the dissolution of deposits of minerals, fat and inorganic salts by acid-base reactions or by the forming of complexes (‘micelles’). A second purpose is surface care – maintenance of the material and/or making it appear shiny. Thirdly, certain products aim at the disinfection of the surface. Finally, cleaning products may be used to introduce a pleasant smell, and perhaps even to mask an unpleasant smell. An overview of the most common cleaning products applied for surface cleaning in homes is given in Table 4.1. Several products can be used for different purposes, probably including situations where this is not recommended.
Consumption
The individual exposure to cleaning products depends on the frequency of use and the amount of product used on each occasion. The latter is likely to be extremely variable between individuals, between countries/cultures and between purposes and applications, and is in general difficult to estimate. Product labels typically contain instructions for use, including recommended amounts and grade of dilution. It is, however, not unusual for these products to be used in higher concentrations or larger amounts than necessary. This may be related to the deep-rooted though unfounded belief that cleaning is done better and/or more quickly this way.
The frequency of use of cleaning products may vary significantly across geographical areas. In the framework of the second phase of the European Community Respiratory Health Survey (ECRHS II), study participants in 10 European countries were asked if they did the cleaning or washing in their own homes and, if so, how often they used each of a selected list of products. More than half of all study participants indicated that they carried out cleaning and washing at home, with large differences in the frequency of use of products such as bleach, ammonia, glass cleaning sprays and furniture sprays.
The consumption of cleaning products at the population level can be estimated using the marketing reports of manufacturers. For hypochlorite bleach these confirmed the findings of the ECRHS that bleach use is more common in southern Europe than in Nordic countries. Following both methods, the highest use of bleach was reported for Spain, with a per capita consumption of 12 litres per person per year in the early 1990s. More than 90% of the Spanish ECRHS participants reported ever using bleach in their homes, while almost 80% used bleach on a weekly basis. An increasing trend of aerosolized (spray) application has occurred over the last decade: over 1 billion household aerosols (the vast majority for cleaning) were produced in Europe in 2006.
Chemical components
Depending on the type of surface to be cleaned and the purposes of application, as outlined earlier, products contain a wide variety of chemical components. The most important are listed in Table 4.2. There are many qualitative and quantitative differences between products, but basically all contain a variety of substances from different chemical families. Few products contain (almost) exclusively one agent; an example is bleach which is basically an alkaline-buffered solution of sodium hypochlorite.
Table 4.2 Main chemical components of cleaning products
| Type of agent | Aim or mechanism | Examples |
| Detergents (surfactants) | Lower surface tension of water | Fatty acid salts (soap), organic sulfonates |
| Complexing agents (water softeners) | Dissolve and bind calcium and other cations; regulate the pH | Ethylene diamine tetraacetic acid, tripolyphosphates |
| Alkaline agents | Dissolve fatty substances, disinfection, inhibit corrosion of metal surfaces | Silicates, carbonates sodium hydroxide, ammonia |
| Acids | Dissolve calcium | Phosphoric-, acetic-, citric-, sulfamic-, hydrochloric acid |
| Solvents | Dissolve fatty substances | Alcohols, glycol ethers |
| Corrosion inhibitor | Protection of metal surfaces | Ethanol amines |
| Film formers, polishes | Surface care | Wax, acryl polymers, polyethylene |
| Disinfectants | Destroy bacteria and other microorganisms | Hypochlorite (bleach), aldehydes, quaternary ammonium compounds |
| Preservatives | Avoid microbial growth during product storage | Benzalkonium chloride, isothiazolinones, formaldehyde |
| Perfumes, scents | Introduce pleasant smell | D-Limonene, terpenes (pinene) |
Reproduced from Occupational and Environmental Medicine, Zock, J.P. 62: 581-584, © 2005, with permission from BMJ Publishing Group Ltd.
The labels of household chemicals typically contain limited, ambiguous, nonquantitative information on chemical components. The information provided focuses on compulsory consumer information: whether the product is inflammable, corrosive and/or toxic. According to recently introduced European Union regulations, the ingredients of consumer products must be publicly available on the internet. In relation to this, the Human and Environmental Risk Assessment (HERA) on ingredients of European household cleaning products project is noteworthy (www.heraproject.com). This is a voluntary industry program to carry out human and environmental risk assessments on ingredients in household cleaning products. HERA is a European partnership established in 1999 between the formulators and manufacturers of household cleaning products and the suppliers and manufacturers of the raw chemical materials for the chemical industry.
4.2.2 Determinants of respiratory exposure
Respiratory exposure occurs due to evaporation of volatile components, especially enhanced when applied on large surfaces such as floors. The personal (effective) exposure will depend on the amount of cleaning product and the concentration of the active ingredients, temperature, humidity and ventilation, among others. The use of products in spray form (either propellant-based aerosols or bottle pump atomizers) facilitates inhalation of liquid aerosols containing both volatile and nonvolatile agents.
A comprehensive overview of chemical exposures was provided by Nazaroff and Weschler [1], including both chemical ingredients and secondary pollutants created by chemical reactions with airborne oxidants or surface contaminants. There is relatively little data available to describe the exposure patterns associated with the use of different cleaning products, and there are few experimental studies on emissions and exposures, which mainly focused on volatile components after application of cleaning products. Most exposure studies were done under experimental conditions. Volatile chemicals under study included ammonia, ethanol, 2-butoxyethanol, terpenoids such as α-terpineol and limonene, among many others. Models have been developed to assess airborne exposure to volatiles from cleaning products. In a small study, personal exposure to ammonia and chlorine was measured continuously during common household cleaning activities. Peaks were identified and related to specific cleaning tasks and products. Finally, several studies have measured common volatile organic compounds that may originate from several sources, including household chemicals and furniture, carpets and building materials.
Events involving acute inhalations of large quantities of chemicals (gases or fumes) have been frequently described, in both occupational and nonoccupational settings, including the household. In relation to cleaning products, these acute high-level exposures are mainly caused by inadequate mixtures of incompatible products, and to a lesser extent by spills or highly intensive contact with released airborne irritants. The most commonly reported mixtures include hypochlorite bleach with acids (e.g. phosphoric acid from toilet bowl cleaner; hydrochloric acid from decalcifiers), leading to a release of the strong airways-irritant chlorine. Mixing bleach with ammonia leads to the release of chloramines with irritant properties, predominantly the most volatile and less watersoluble trichloramine. The latter is also produced, albeit to a lesser extent, after mixing bleach with dishwashing liquid.
4.2.4 More information and data on exposures
REACH is a new European Community Regulation on chemicals and their safe use (EC 1907/2006). It deals with the Registration, Evaluation, Authorization and Restriction of Chemical substances. The new law entered into force on 1 June 2007 (http://ec.europa.eu/environment/chemicals/reach/reach_intro.htm) and requires the coordination of the in-depth evaluation of potentially hazardous chemicals and the maintenance of a public database in which consumers and professionals can find hazard information. This can be particularly helpful when the chemical constituents are known (for example through the HERA project, as mentioned earlier). Another helpful database is the European Chemical Substances Information System (ESIS), which contains diverse information on chemicals (http://ecb.jrc.it/esis).
4.2.5 Other household chemicals
Apart from cleaning products, several other chemical-based products are to some extent applied in many households. The most common include laundry products, air fresheners and pesticides, shoe care products and drain cleansing agents.
Laundry products
Washing powders (laundry detergents) typically contain soaps, decoloring agents, perfumes and enzymes. In detergent manufacturing workers, inhalatory exposure may cause enzyme sensitization, even with encapsulated enzymes. Respiratory exposure related to household use is generally considered to be low, in particular in liquid formulation. Apart from detergents, exposures from fabric softeners and refreshers and laundry bleaching agents may be relevant.
Air fresheners
Air fresheners with fragrances are commonly used in homes. There are various methods of application, including aerosols and plug-in air fresheners (with an electrical element) that guarantee a continuous release of airborne perfume. Apart from the perfumes (deodorizers), air fresheners contain a variety of volatile chemical compounds. The use of air freshening sprays in toilets and other confined spaces may lead to temporarily high airborne concentrations.
Shoe polishes
Shoe care products are used for material care (typically leather) and/or to make the surface impermeable or waterproof (impregnation of material by water and soil repellents). These products are available as creams, polishes and sprays (either aerosols or nonaerosolized atomizers). The latter may lead to relevant inhalation of volatile chemicals, including organic solvents, in particular when used in large quantities and/or in poorly ventilated spaces.
Pesticides
This is a large group of chemicals with the main purpose of killing a variety of unwanted organisms. Pesticides are typically used in the home to control mosquitoes, cockroaches, flies, fleas, ants and rodents. Some are used to treat (preventively or actively) pets like cats and dogs, or ornamental plants. Some specific products containing fungicides are used to treat surfaces like walls or ceilings of bathrooms that are infested with mold. Aerosolized applications are common and involve inhalatory exposure during and shortly after use. Pesticides may contain a variety of active ingredients such as organophosphates and carbamates, among others. Residual exposures may be relevant for a longer period.
Drain cleansing agents
Drain cleansing agents (sink decloggers) are highly corrosive chemicals that dissolve material obstructing a drain. They typically consist of caustic soda (almost 100% sodium hydroxide), although some are based on acids or other chemicals. Exposures are typically occasional and acute but may be massive in accidental situations.
4.3 Diseases associated with exposures
The active use of cleaning products and other household chemicals usually involves the highest exposures and users therefore form the main population at risk. In addition, other household members should be considered at risk due to passive exposure to chemicals from these products during or shortly after use. The most susceptible groups probably include children and those with chronic respiratory or allergic disorders. It has also been suggested that prenatal exposure related to the use of household chemicals by the mother during pregnancy may be relevant.
There is growing evidence that professional cleaning involves an increased risk of asthma. Epidemiological studies have identified specific professional cleaning products associated with asthma, including bleach and several sprays. Most of this evidence has been based on lower respiratory tract symptoms suggestive of asthma, and in fewer studies also on bronchial hyperresponsiveness. The mechanisms are largely unknown, but both irritant-induced asthma (due to either acute high-level or recurrent moderatelevel exposure to irritants) and sensitizer-induced asthma have been hypothesized. Most case studies on asthma in relation to cleaning products are related to acute inhalations, either on the job or in private households. Only very few studies have evaluated asthma and other respiratory health effects of common household use of cleaning products.
Active users
An analysis of the risk of asthma by occupational groups using participants from 12 countries of the ECRHS I showed that housewives had a 20-30% increased risk of asthma when compared with nonmanual workers. This was suggestive of an increased risk of either new-onset asthma and/or exacerbated asthma related to household work. In the follow-up study (ECRHS II), the frequency of use of specific cleaning products was assessed for those who did the cleaning in their homes. The incidence of asthma was higher among those who frequently used sprays (Table 4.3). This risk was predominantly found for the commonly used glass cleaning, furniture and air refreshing sprays. Cleaning products not applied in spray form were not associated with asthma in this study.
Table 4.3 Relationships between the use of household cleaning sprays and the incidence of asthma. European Community Respiratory Health Survey II, n = 3484 participants doing the cleaning and/or washing in their homes and had no asthma at baseline
Relative risks or hazard ratios with 95% confidence intervals from log-binomial or Cox’s proportional hazards regression models, adjusted for sex, age, smoking status, cleaning job and study center.
Reproduced with permission of the American Thoracic Society, Zock, J.P., Plana, E., Jarvis, D. et al. (2007) The use of household cleaning sprays and adult asthma: an international longitudinal study. Am. J. Respir. Crit. Care Med. 176: 735-741. © American Thoracic Society.
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