Cleaning and Special Environments: understanding the science

Eugene C. Cole, DrPHThis article is reprinted with permission from the issue 4, volume 1, of the Cleaning Science Quarterly, the official peer-review journal of the Cleaning Industry Research Institute (CIRI).Special environments are those that harbor individuals who are considered susceptible to negative health effects associated with the accumulation of indoor contaminants and pollutants, and therefore present a notable challenge. They include schools, daycare, healthcare facilities (e.g.,hospitals, rehabilitation centers and long-term care facilities [LTCFs]), and some home environments. Such populations include individuals with severe allergies and hypersensitivities, to include asthma, as well as those who are immunosuppressed or immunodeficient and therefore at-risk for a variety of potentially life-threatening opportunistic infections caused by otherwise innocuous indoor contaminants such as environmental molds. Children and especially young children have immature immune and organ systems and are therefore at risk during their growth and development, especially from pollutants such as heavy metals and chemical residues that may be present in everyday house dust. Similarly at risk are the elderly, with their waning immune function and susceptibility to drug-resistant bacterial pathogens and respiratory viruses, in conjunction with a variety of chronic illnesses that often renders them even more vulnerable to indoor environmental contaminants. This article draws from the available scientific data necessary for an understanding of the complexities of special environments, in order to provide a basis of guidance for cleaning and restoration professionals. The Indoor Ecosystem Each indoor environment is an artificially created ecological system comprised of a nonliving or physical component intertwined with a living or biological one. The physical environment includes structural, finishing and furnishing materials, and their paints, coatings and sealants, a variety of contents, and a climate as measured by temperature, relative humidity and airflow. The living or biological indoor environment typically includes microorganisms, insects, plants, rodents, pets and humans. This indoor ecosystem is comprised of an interrelated complex of smaller microenvironments or habitats, each of which has its own mix of physical and biological factors, and can serve as reservoirs for a variety of pollutants that can potentially affect the quality of the air in occupied spaces. Some microenvironments are structural components such as interior and exterior wall cavities, ceiling spaces, air-handling systems, and crawlspaces. Others serve as reservoirs that readily collect particulates such as dust, fibers, soil, and debris that can harbor a variety of chemical and biological pollutants, such as pesticide and lead residues, along with microbial, insect and animal allergens. Examples of such microenvironments include textile floor coverings, upholstered and hard surface furnishings, bathroom surfaces, and food preparation and pet areas. If the accumulating particulate burden of these reservoirs is not regularly reduced through a removal process known as cleaning, they may quickly become sources of indoor contamination through airborne dissemination resulting from occupant activity and mechanical airflow. Such dissemination can seed previously uncontaminated areas as well as degrade air quality, leading to occupant exposures and adverse health effects in susceptible individuals. The latter, in particular, are considered at-risk in the aforementioned special environments that present significant cleaning challenges. The general population often incurs health risks in high occupancy indoor environments such as office buildings, hotels, and cruise ships. The focus of this discussion will be on special environments. However, the home, where everyone typically has their highest occupancy time, presents the greatest risk because reservoir reduction through cleaning is often the least well managed. Many of the principles covered here also apply to home cleaning.CleaningCleaning is a systematic, science-based process of managing unwanted matter, so human activities can take place in a healthy environment2. Effective cleaning requires an understanding of the science of particulate deposition and retention on various surfaces. Effective cleaning also chooses those practices and procedures necessary for maximizing pollutant removal while containing the process and minimizing cross-contamination. In all cases, cleaning needs to maintain and preserve the integrity of the surface or material being treated. It is heavily dependent on frequency of implementation and the efficiency of the equipment and cleaning products being used.SchoolsPublic school facilities present a particular challenge in regard to cleaning and overall environmental management due to budget constraints and resultant shortages of facilities maintenance and janitorial staff, outdated and ill-functioning cleaning equipment, and poor  cleaning products and staff training. Additionally, many schools are poorly designed and constructed, and ageing, making adequate inspection and appropriate subsequent cleaning  a significant challenge. Thus, not surprisingly, available evidence suggests that poor indoor environmental quality (IEQ) in schools is common and adversely influences the performance and attendance of students, primarily through health effects resulting from exposure to indoor contaminants and pollutants3. Lack of proper cleaning permits dust-collecting reservoirs to become sources of insect, animal, and microbial antigens that can trigger asthma and respiratory allergies, and possibly induce respiratory inflammation, which may predispose students to infectious respiratory illness, especially during the cold and flu season.4, 5, 6, 7Major dust reservoirs/sources in schools that typically lack effective cleaning and maintenance include carpet, animal cages, and HVAC systems. Additionally, inattention to moisture intrusion or accumulation throughout a facility may lead to microbial growth and quality and greater student exposures to respiratory health risks. On the positive side, the value of effective cleaning has been demonstrated, as increased effort at improved cleaning of floors and desks in schools has actually been demonstrated to reduce upper respiratory symptoms8.Cleaning for Health. Recent studies have collectively indicated that enhanced hygiene in schools, and targeted cleaning of biological residual contamination related to frequent-contact points, resulted in reduced illnesses tied to bacterial contamination reservoirs (MRSA, shigella outbreaks), reduced sick building syndrome symptoms, and reduced absenteeism due to infectious illnesses9, 10, 11, 12. And while school hygiene programs such as handwashing promotion are admirable and well-intentioned, they typically neglect the rapid recontamination of hands via high contact touch points that are usually poorly cleaned. Thus, student illness and absenteeism rates fail to change13, 14. While classrooms and hallways remain major dust reservoirs in school buildings, other subcompartments of the ecosystem (e.g. food preparation areas, restrooms, locker rooms, gyms) require similar attention to cleaning, with an additional targeted focus on reducing the infectious disease potential. School kitchens and related areas, as obligated by public health code, must be cleaned and sanitized to prevent environmental contamination and transmission of bacterial pathogens such as E. coli, Listeria, and Salmonella. Similarly, restrooms must be effectively cleaned and monitored for effectiveness to prevent exposure and resultant student illnesses from a variety of pathogens, both enteric (e.g. noroviruses, E. coli) and respiratory (e.g. cold, flu viruses). This is emphasized by results of a study in two daycare centers where 19% of surfaces tested were positive for rotavirus15. Rotavirus contamination was found on drinking fountains, water play tables, toilet handles, and telephone receivers. There can also be other consequences associated with poor cleaning of school restrooms, with students describing them as “unpleasant,” “dirty,” “smelly,” and “frightening,” and refusing to use them while at school, thus suffering consequences such as constipation, urinary tract infections, and incontinence16, 17.Likewise, school locker rooms and gymnasium surfaces and materials, if improperly cleaned and sanitized, can increase transmission of infectious agents such as athlete’s foot fungi, Staphylococcus aureus, and Herpes viruses. Absent effective cleaning, there is the potential for widespread outbreaks among students, as occurred with methicillin-resistant S. aureus (MRSA) in a college football team18. A recent extensive review of the significance of fomites (inanimate surfaces) in the spread of respiratory and enteric viral disease, stated that “the rapid spread of viral disease in crowded indoor establishments, including schools, day care facilities, nursing homes, business offices, and hospitals, consistently facilitates disease morbidity and mortality.” Further, it concluded that “level of cleanliness” is one of a number of factors involved19.Carpet. Although carpets in schools are usually cleaned by an extraction process once each year, the lack of effective maintenance with efficient vacuuming throughout the year permits the carpet dust reservoir or “sink” to fill and become a source. Carpeted classrooms are typically crowded with student desks and other furniture, and manpower is usually lacking to rearrange it to effectively vacuum the carpet even once per week. Additionally, some vacuum cleaners are inefficient at dust capture and lack appropriate exhaust filtration. Thus they serve as aerosol generators, collecting carpet dust and its pollutants, and aerosolizing them back into the environment. As carpet becomes a source, children can be exposed to very fine or respirable particles (