Time Plot

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. If you choose multiple sites you will be limited to choosing a single pollutant below.

Select a 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 limited to plotting up to 10 variables together. To choose multiple variables, first select one then hold the CTRL key while selecting additional variables. If you have chosen multiple sites you will only be able to choose a single pollutant.

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 split. The default option will produce a single plot covering the entire range of the data. Where multiple sites are selected, this menu is greyed out, multiple plots split by site are produced. 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 'Month' will show twelve plots, one for each month, helping to visualise seasonal changes through the year. Selecting 'Wind Direction' will split into eight compass point sectors, and selecting 'Wind Speed' will split into four quartiles using the modelled wind direction or speed from the UK air quality forecast which can be useful in identifying particular sources.

Choose from the drop-down box an averaging period to be plotted. Hourly, daily, weekly, monthly, annual and seasonal averages are possible. A data capture threshold of 75% has been set for averaging.

Select from a variety of set colour templates.

If multiple years of data have been selected, this option shows a year at a time, making it easier to see detail in the plots.

This option allows you to compare the trends in pollutants with very different concentration scales (for example NO_X with CO) in the same plot. The variables are divided by their mean values in order to normalise them.