Nursing homes have been one of the most prominent targets of the COVID-19 coronavirus in Spain. The factors that have determined that this is the case are very diverse. In this study, physical agents and chemical pollutants, population density, and different capacities of the residences are analyzed to see their influence on the number of elderly people who have died in the geriatric centres in the different autonomous communities (AACC) of Spain. A statistical analysis has been carried out on the variables observed. The conclusions show that in many places where this overflow of deaths has occurred, the residences were private, with some exceptions. The influence of physical agents and pollutants has been shown to be a determining factor, especially for the communities of Extremadura and Castilla-La Mancha, although it is true that the large number of factors makes the study complicated. The dilemma between air quality and energy efficiency is of great importance, especially when human health is at stake.
TopIntroduction
Today, in developed countries, 80-90% of people's time is spent indoors (Klepeis et al., 2001), especially in the home, as the presence in the home varies between 60% and 90% of the day, and 30% of the time is spent sleeping (Wargocki, 2016; Borsboom et al., 2016). For this reason, homes contain the air that is inhaled, constituting the interior spaces of greatest exposure. The indoor environment in the home should benefit rest and recovery (Wargocki, 2000, Nathanson, 1987); therefore, poor air quality (IAQ) prevents this purpose as it has harmful effects on health).
Since the energy crisis of the 1970s, buildings have become increasingly airtight, leading to the appearance of IAQ-related diseases such as sick building syndrome (SBS) (Cao et al., 2014). In addition, the relationship between air movement in buildings due to ventilation and the spread of infectious diseases has been demonstrated (Li et al., 2007; Deisy et al., 2003). In this context, the benefits of indoor air exchange have been demonstrated, although the influence of ventilation on the spread of infectious diseases is not clear (Cao et al., 2014). Consequently, since there is no quantitative influence of airflow rates on health, ventilation rates specified in different regulations are usually set according to confort criteria (perceived conditions) (Wagner et al., 1993; Wargocki, 2015, González-Lezcano et al., 2016, WHO, 1987).
However, a healthy indoor environment can be achieved by applying the necessary strategies to improve the IAQ which are, in addition to increasing the supply of fresh air, controlling pollution from emission sources, cleaning the air and improving the efficiency of ventilation (Yocom & McCarthy, 1991; Spengler et al., 2000, Hormigos-Jiménez et al., 2018a). Therefore, indoor air quality (IAQ), especially in indoor residential spaces, has a strong influence on human health; therefore, it is essential to design adequate ventilation, which ensures good IAQ, since the main purpose of ventilation is to dilute or remove indoor contaminants by providing outdoor air (Turiel, 1986; Berenguer et al., 1994; Wadden & Schelf, 1983; Dimitroulopoulou, 2012; Van Buggenhout et al., 2006; Xu et al., 2020).
The values set for air renewal to ensure comfort and odour elimination have been modified over the course of history according to variations in ventilation theories. Nowadays, in the case of Spain and for residential buildings, the Basic Document HS 3 Indoor air quality, included in the Technical Building Code (DB-CTE-HS3, 2018), provides data on minimum ventilation rates depending on the room of the dwelling. In European countries, in addition to the EN 15251 standard (which should be used in case no national standard is available), there are also state regulations that, like the Spanish standard, show data on minimum ventilation rates based mainly on body odours with CO2 as an indicator and, to some extent, also established according to primary emissions from some building materials (Fernandez, 2008; RITE, 2020).
On the other hand, even if the regulations are complied with, indoor air quality may still be inadequate if stagnant air zones are generated, and therefore health and comfort problems may develop (Namiesnik et al., 1992; Knoppel & Wolkoff, 1992; Davidson et al., 1987; Kwon et al., 2011; Liu et al., 2010). In-depth research in this field is still needed; therefore, the debate on how much ventilation is sufficient to achieve good indoor air quality, capable of preventing both odours and the emergence and spread of diseases, is still ongoing.
In Spain, one of the countries most affected by the Covid-19 coronavirus pandemic, according to data provided by the Spanish Ministry of Health's Centre for the Coordination of Health Alerts and Emergencies (CCAyES, 2020), the number of deaths as of 16 May 2020 was 27,563 and 230,698 people were infected.