Nature World: This past week the San Francisco Bay Area has declared three consecutive "Spare the Air" alerts, showing that even with a harsh winter just behind us, things are already heating up for the west coast of the United States.
In the wake of a prolonged stretch of high temperatures and low winds, the Air Quality Management Districts for Sacramento and the Bay Area have both declared "Spare the Air" alerts for their regions, warning people who go outside that the air may be unhealthy for sensitive groups....