Phoenix Regional Heat and Air Quality Knowledge Repository

There has been a wide range of low-carbon solutions proposed to mitigate climate change. However, such measures must be compatible with the local environment and living standards of residents to be brought to fruition. Measures that adversely affect residential environments will be difficult to implement, so the impacts of measures on the local environment must be taken into consideration during implementation. This study assessed the effects on urban heat islands of efforts to reduce CO2 emissions, as one environmental impact associated with climate change. A simulated assessment was conducted, using an urban canopy model coupled with a building energy model (CM-BEM), to evaluate the effects of five specific measures: solar shading of windows using curtains and blinds, improvement of the thermal insulation of building walls and roof surfaces, implementation of energy-saving measures related to indoor appliances, installation of solar photovoltaic (PV) panels, and adjustment of preset cooling temperatures. The study focused on these effects as they occur within typical urban districts of office buildings, fire-resistant housing, and wooden housing. Results indicated that many of the energy-saving measures have slight temperature lowering effects, but solar panel installation and improved heat insulation, both associated with changes in surface heat balances, tend to raise daytime temperatures to some extent. However, effects on daytime temperatures were in the range of 0.1–0.2 °C and, as such, none of the CO2 reduction measures considered was deemed a significant factor in raising urban temperatures.

In this study we characterized the relationship between temperature and mortality in central Arizona desert cities that have an extremely hot climate. Relationships between daily maximum apparent temperature (ATmax) and mortality for eight condition-specific causes and all-cause deaths were modeled for all residents and separately for males and females ages <65 and ≥65 during the months May–October for years 2000–2008. The most robust relationship was between ATmax on day of death and mortality from direct exposure to high environmental heat. For this condition-specific cause of death, the heat thresholds in all gender and age groups (ATmax = 90–97 °F; 32.2‒36.1 °C) were below local median seasonal temperatures in the study period (ATmax = 99.5 °F; 37.5 °C). Heat threshold was defined as ATmax at which the mortality ratio begins an exponential upward trend. Thresholds were identified in younger and older females for cardiac disease/stroke mortality (ATmax = 106 and 108 °F; 41.1 and 42.2 °C) with a one-day lag. Thresholds were also identified for mortality from respiratory diseases in older people (ATmax = 109 °F; 42.8 °C) and for all-cause mortality in females (ATmax = 107 °F; 41.7 °C) and males <65 years (ATmax = 102 °F; 38.9 °C). Heat-related mortality in a region that has already made some adaptations to predictable periods of extremely high temperatures suggests that more extensive and targeted heat-adaptation plans for climate change are needed in cities worldwide.