Assessing the outdoor biometeorological conditions of the elderly commuters in a hot-arid desert city of Jodhpur, India

Low-income areas in developing countries face the challenges of resource inequality and uneven distribution of growth. Under one such circumstance, extreme weather events can cause significant heat stress and heat-related mortality and morbidity if adaptation and mitigation strategies are not designed appropriately. Outdoor occupants are especially vulnerable to this, such as outdoor vendors, athletes, pedestrians, and travelers. In one such context, we seek to explore the thermal comfort perception of elderly adults in the hot-arid city of Jodhpur,India using microclimatic observation, questionnaire surveys and health data from wearable devices. Jodhpur exhibits extreme heat conditions with summertime high air temperatures frequently reaching upto 48^OC. We conduct a random sampling of over 400 people aged over 50 with self-reported healthy conditions willing to travel in public transport. A subjective questionnaire survey involves collecting information on travel patterns, and outdoor thermal comfort perception, supported by objective microclimatic field observation collected using Kestrel 5400 heat stress trackers. We simultaneously collect corresponding health data (SPO2, heart rate, and skin temperature) from wearable devices. Further, through statistical data analysis, we identify personal, socioeconomic, physiological, and psychological variables impacting thermal comfort perception and travel mode choice. We further enumerate the acceptable and neutral thermal range for the elderly commuters from this. We report that the acceptable and neutral thermal range of Physiologically Equivalent Temperature (PET) is much higher in Jodhpur compared to other existing studies from hot-arid cities. We also report that socio-economic, and psychological factors impact the travel mode choice and outdoor thermal comfort perception significantly. The results obtained from our study can aid in formulating strategies for heat-resilient transit infrastructure design. The focus is on identifying and developing data-driven evidences to support formulating an appropriate heat risk assessment framework to ensure optimum thermal conditions for the elderly commuters during outdoor trips while using public transit.