Parameters for health risk assessment associated with chronic exposure to hydrogen sulphide in ambient air

High levels of chemical pollution in ambient air due to industrial emissions can facilitate development of functional disorders in various organs and systems. They are a significant component to be considered when assessing health risks under exposure to combined multi-factorial pollution. However, the issue of methodical approaches to assessing possible effects on health under exposure to combinations of chemicals has not been studied enough as regards public health risk assessment. Given that, we suggest a trend to develop the methodology that involves revising and substantiating indicators applied in health risk assessment. This should be done as new research data on influence exerted by chemicals on health (including exposure to levels higher than reference ones) become available. We have substantiated a system of quantitative indicators (including additional reference concentrations) for health risk assessment under chronic exposure to hydrogen sulphide in ambient air (including its elevated levels). Points of departure and modifying factors were established by analyzing studies on effects produced on health by hydrogen sulphide. On their basis, we developed parameters for non-carcinogenic health risk assessment. The reference concentration equaled 0.002 mg/m3 (the critical systems were respiratory organs and the nervous system). The additional reference concentration for risk assessment under elevated exposure to hydrogen sulphide was substantiated as equal 0.07 mg/m3 (impaired development being the critical system in the case). The suggested system of quantitative indicators enhances and specifies parameters for health risk assessment. This makes it possible to perform more adequate assessment of health risks under combined exposure to chemicals in ambient air including those contained in levels higher than reference ones. The suggested system of quantitative indicators was tested properly; as a result, the system was established to give an opportunity to obtain more comprehensive and accurate results of health risk assessment under combined exposure to chemical pollutants.