This thesis examines how ambient temperatures and air pollution affect labour productivity and public health. It presents a comprehensive review of current evidence on the impacts of both high and low temperatures, as well as air pollution, on labour losses, such as reduced labour efficiency and working hours. Four original studies introduce a novel metric called the Productivity-Adjusted Life-Year (PALY) to quantify productivity losses resulting from premature mortality. The findings demonstrate that non-optimal temperatures and air pollution significantly reduce labour productivity, particularly in poorer regions. Furthermore, projections suggest that these impacts will worsen due to climate change, highlighting the need for the development of policies and targeted adaptation strategies.