Various municipalities have today exceeded ozone limits, meaning the air within them can cause health problems. Advice is for people in those areas not to indulge in ‘intense physical exercise outdoors’ and to stay inside as much as possible. A safe ozone level is one below 180 micrograms per cubic metre. Today in Coimbra, for example, ozone levels reached 240 micrograms/ cubic metre. Municipalities worst off are Coimbra, Almada, Vila Franca da Xira, Ílhavo and Aveiro.