Indoor Heat Exposure: Links to Weather and Housing Characteristics

Heat exposure of a given population is often estimated by applying temperatures from outdoor, central site monitoring stations. However, this can lead to misclassification as residents may not live close to the monitoring station and, perhaps more importantly, they spend more time indoors than outdoor. Here, we examine summer time temperatures measured inside homes of a vulnerable population (children with asthma in low-income households) living in inner-city Baltimore, and compare with temperatures from the NOAA weather station in Baltimore and from a low-cost monitoring network installed in East Baltimore. There is large variability in the indoor temperatures, both with time and between the different houses sampled. There is a weak correlation between the indoor and outdoor temperatures, suggesting that factors other than weather conditions play an important role in determining indoor heat. Analysis of a variety of house characteristics indicates that the availability of air conditioning is a key factor, with houses with central air generally being consistently cooler than outdoor while those with no air conditions are generally consistently hotter. This highlights need to better define the relationship between indoor climate and contribution of housing characteristics to improve modeling of heat exposure.