Analysis of urban - industrial expansion and increasing level of ozone concentration as subsiding an environmental management plan for the east of Rio de Janeiro metropolitan area – Brazil

•The objective of this research work is to identify and evaluate the threshold values of the O3 concentration pattern in the expanded region of the Rio de Janeiro Metropolitan Area (RJMA).•Excess concentrations of O3 were registered to occur every month and across all weather seasons, mainly from October to March.•Regarding the legislative rules of a programmatic nature, their implementation still depends on the union efforts of the federal agencies, so that more time and resources in research and monitoring are invested in the area.•It is also necessary to expand the local network to better portray the occurrences of violations of air quality standards, as well as to establish protective measures and promotion of rural areas.