Smooth Trend

Select a site by clicking on it. This tool is capable of plotting multiple sites together. To choose multiple sites, first select a single site, then hold the CTRL key while clicking additional sites.

Select a pollutant variable by clicking on it. The pollutants available will depend on the selections of other parameters (e.g. site and date range selected). This tool is restricted to plotting one pollutant at a time.

Choose to enter either 'Specific Dates' or 'Specific Years'. 'Specific Dates' allow you to choose day, month and year to start and stop your analysis. 'Specific Years' will allow you to quickly choose the years of interest to you and the analysis will commence on 1st January and run until 31st December of those selected years.

Use this drop-down menu to select the way you want your data conditioned. The default option will produce a single plot covering the entire range of the data. Selecting 'Hour' will produce an individual plot for each of the 24 hours throughout the day and so helps to represent diurnal differences. Selecting 'Weekday' will produce an individual plot for each day of the week and so is helpful in highlighting differences throughout the working week and weekends. Selecting 'Season' will split the plot into proper seasons showing the trend within seasons. Selecting 'Wind Direction' will split the trend plots into eight compass point sectors using the modelled wind direction from the UK air quality forecast.

Checking this option will amend the plot to account for statistically calculated seasonal variation. If this option is not selected, then a single plot of the original data will be plotted.