Air quality management is a serious challenge, especially in middle-income countries, where resources are limited and there are widely varying geographical, meteorological and economic conditions. In this study, air quality data obtained in the period January–April, from 2012 to 2019, were compared with the results obtained in 2020, to assess the impact of urban mobility restrictions on the emission sources and air quality in the city of Rio de Janeiro, Brazil. The results provided a clear indication of the impact of vehicle emissions in different areas of the city and also showed the contribution of other sources (largely industrial and biogenic). The results showed that the sharp reduction in traffic flow was not effective in reducing levels of the main pollutants, particulate matter and ozone. Furthermore, the restrictive measures showed that, although previous emission inventories provided evidence that vehicular emissions are the main source of pollutants, improving air quality requires the control of both stationary and mobile sources, and an awareness of meteorological and transport factors, which have a considerable impact on ozone precursor levels and the shift in the ozone production regime. The different conditions within the city were assessed, as well as the pollutant emissions that affected each area and a list of necessary measures has been compiled. The results may help local authorities to fully assess the situation and take appropriate action. The approach adopted here could be extended to other cities with similar features, particularly in countries where complete emission inventories and modelling results are not available and there is limited funding for research and environmental management.

空气质量管理是一项严峻的挑战，特别是在资源有限且地理、气象和经济条件千差万别的中等收入国家。本研究将 2012 年至 2019 年 1 月至 4 月期间获得的空气质量数据与 2020 年获得的结果进行比较，以评估城市交通限制对里约热内卢市排放源和空气质量的影响。巴西，热内卢。结果清楚地表明了城市不同地区车辆排放的影响，并显示了其他来源（主要是工业和生物源）的贡献。结果表明，交通流量的急剧减少并不能有效降低主要污染物、颗粒物和臭氧的水平。此外，限制措施表明，虽然以前的排放清单提供证据表明车辆排放是污染物的主要来源，但改善空气质量需要控制固定和移动源，并了解气象和运输因素，这些因素对臭氧前体水平和转变具有相当大的影响在臭氧生产体制中。评估了城市内的不同条件，以及影响每个区域的污染物排放量，并编制了必要措施清单。结果可能有助于地方当局全面评估情况并采取适当的行动。这里采用的方法可以扩展到其他具有类似特征的城市，