1.   A pollution alert was issued in Rome in early June because of rising ozone levels, with the elderly and children advised to stay indoors.

2.   Miners used to take canaries into the shafts as a primitive form of pollution alert.

3.   Pollution alerts are routine.

4.   Smoke from wildfires in Arizona, Colorado and other Western states even drifted over parts of Minnesota last week, prompting air pollution alerts.

5.   After two weeks of pollution alerts, French officials issued an unusual call for Paris residents to leave their cars at home and drive only in emergencies.

6.   It provides for a network of sensors around France and curbs on traffic during pollution alerts.

7.   Last summer, the city issued numerous high-level pollution alerts cautioning Parisians not to over-exert themselves, and warning the very young and very old to stay inside.

8.   Serious pollution alerts tend to occur when the weather is at its best, those stretches of glorious sunny days when there is little or no wind.

9.   The air pollution emergency alert was expected to continue Tuesday.

10.   The pollution alert has been caused by two weeks of no rain, authorities said.