Issue link: https://hi.iaq.net/i/191637
Climate Change, the Indoor Environment, and Health 166 CLIMATE CHANGE, THE INDOOR ENVIRONMENT, AND HEALTH increased use of air conditioning and dehumidifiers) could lead to a shift in the types of dust mites that are found in northern latitudes. The long-term outlook would be for increased numbers of dust mites and a wider variety of dust mite species in northern climates. However, that is speculative and does not consider adaptation measures. Adaptation More air-conditioning and dehumidifier use in summer In Ohio, Arilan et al. (2001) found that among three groups—those with only opening windows for cooling purposes, those with only air conditioning, and those with air conditioning and a high-efficiency dehumidifier—dust mite allergen concentrations in the homes with both air conditioning and dehumidifiers were less than 10% of concentrations in the other homes. Given that the monthly outdoor temperature in the Ohio summer months averaged 20.5–25.9°C (69–79°F), it is not clear how often the air conditioning was used in the air conditioning–only group. For that reason alone, the dehumidification (with only air conditioning) might not have been as much as could be expected in a scenario in which Ohio summers would be longer and warmer. Nonetheless, in a study that covered a wider geographic area of the United States, air conditioning was independently associated with lower dust mite allergen levels (Lintner and Brame, 1993). Furthermore, Swedish researchers found that mechanical exhaust and adequate supply ventilation in energy-efficient housing can decrease mite allergen concentrations substantially (Sundell et al., 1995). Air-conditioning use in the United States has steadily increased over the past several years, and it is likely that this adaptation measure will affect dust mite populations. More humidifier use in summer Humidifier use is an adaptation strategy for those in arid environments. A humidifier would need to run quite often to keep the humidity high enough to sustain a dust mite population, and there is some evidence that they are in some circumstances. Prasad et al. (2009) showed that evaporative coolers can increase indoor relative humidity to a point where the prevalence of patients who have asthma or allergic rhinitis with sensitization to dust mites increases. The researchers posit that it is an increase in dust mite allergen in the environment that is tied with the increase in sensitization, but they collected no allergen measurements. Nonetheless, it remains an interesting research question that warrants further investigation. Less heating in winter (because winters are milder) If winters become milder, some residents might use their heat less in the winter, and this could give rise to more dust mites and possibly a shift in the types of dust mites Copyright © National Academy of Sciences. All rights reserved.