Kelley Christensen

Our planet may be experiencing its sixth known mass extinction event,1,2 with a precipitous loss of insects,3 birds,4 and other species.5 Unseen by our eyes, even Earth’s microbial biodiversity is decreasing.6,7 Yet human immune systems rely on microbial exposures to build up defenses.8,9 In a state-of-the-science review published recently in Environmental Health Perspectives,10 researchers assessed studies on the relationships between the inner and outer layers of microbial...

Abstract Background: More frequent and intense exposure to extreme heat conditions poses a serious threat to public health. However, evidence on the association between heat and specific diagnoses of morbidity is still limited. We aimed to comprehensively assess the short-term association between cause-specific hospital admissions and high temperature, including the added effect of temperature variability and heat waves and the effect modification by humidity and air pollution.

As urban temperatures rise, air pollution concurrently worsens—especially ground-level ozone1 and particulates2,3—because heat alters both atmospheric chemistry cycles and air circulation patterns.4,5 One population that is among the most vulnerable to the twin threats of heat exposure and air pollution is also chronically understudied and plagued by stigma: people experiencing homelessness.