Drivers in Yorkshire are being asked to turn off their car engines while waiting in traffic as part of Clean Air Day, an air pollution campaign, organised by Global Action Plan.
In York the council recently introduced a fine of £25 if drivers refuse to switch off their engines after being observed idling on public roads for more than two minutes.
Meanwhile drivers in Harrogate are being asked to switch their engines off while waiting for trains to pass at the Starbeck junction and sound their horns to show their support.
Leeds, which is one of Europe's most polluted urban areas, is closing 11 roads near schools and giving people the chance to try out electric bikes.
Leeds City Council were asked to tackle air pollution as a priority after roads in the cities were identified as likely to fail legal air quality levels by 2020.
In Calderdale today awareness banners are being put up outside schools which carry tobacco-style health warning pictures.