Health officials issue air quality warnings

Residents of Orange County and Los Angeles County, California, are being urged to stay in their homes and lock up windows and doors as unhealthful air caused by wildfires blows across the region.

Local health officials warned that those living in the area need to take precautions in light of the poor air quality - instructions that appear to have been heeded by a number of sports organisations that cancelled games and matches over the weekend.

As well as recommending that residents avoid making any unecessary trips out of their homes, the experts suggested that they do not use candles, fireplaces or air conditioning systems that lack recirculation options and only draw in air externally.

Those who do not have air conditioners capable of removing particles from the air were advised to consider going to places with such a system.

Wildfires have become a regular occurrence in southern California in recent years, with an outbreak in October 2007 forcing governor Arnold Schwarzenegger to declare a state of emergency.