The burning of fossil fuels for transportation and industry is a major contributor to air pollution emissions such as Nitrogen Dioxide (NO2). The Covid-19 pandemic and associated restrictions changed the transportation patterns and therefore could have had an impact on the pollution levels measured at roadside.
In Trafford, after the start of the Covid-19 pandemic and during the associated lockdowns and restrictions the NO2 levels measured at the roadside site on the A56 have been lower compared to periods with no restrictions. The spring and summer months of 2020 presented lower NO2 monthly means compared to the same seasons in 2019 and 2021, visible in the chart below in light blue. Consequently the level of pollution appears to be higher after the staged end of restrictions during spring and summer 2021 compared to the spring and summer months of 2020. The winter months of 2020/2021 registered the lowest levels of monthly mean NO2 compared to the previous two winters.
In addition to man-made emissions the measured pollution levels for a specific location are affected by other factors such as weather conditions like wind speed, temperature, sunlight, and humidity.