<Li> Solar ultraviolet radiation </Li> <P> The WHO developed a methodology to quantify the health of a population using summary measures, which combine information on mortality and non-fatal health outcomes . The measures quantify either health gaps or health expectancies; the most commonly used health summary measure is the DALY . </P> <P> The exposure - based approach, which measures exposure via pollutant levels, is used to calculate the environmental burden of disease . This approach requires knowledge of the outcomes associated with the relevant risk factor, exposure levels and distribution in the study population, and dose - response relationships of the pollutants . </P> <P> A dose - response relationship is a function of the exposure parameter assessed for the study population . Exposure distribution and dose - response relationships are combined to yield the study population's health impact distribution, usually expressed in terms of incidence . The health impact distribution can then be converted into health summary measures, such as DALYs . Exposure - response relationships for a given risk factor are commonly obtained from epidemiological studies . For example, the disease burden of outdoor air pollution for Santiago, Chile was calculated by measuring the concentration of atmospheric particulate matter (PM10), estimating the susceptible population, and combining these data with relevant dose - response relationships . A reduction of particulate matter levels in the air to recommended standards would cause a reduction of about 5,200 deaths, 4,700 respiratory hospital admissions, and 13,500,000 days of restricted activity per year, for a total population of 4.7 million . </P>

​which of the following have the highest level of adverse impact