As the mercury climbed around the Bay Area Tuesday, at least one temperature record was broken by early afternoon and others were likely to fall as officials called a “Spare the Air” alert for the second straight day Wednesday as the hot weather made for unhealthy air quality around the region. The high for Tuesday’s date in downtown Oakland, an admittedly low 76 degrees, had stood since 1977 but was broken relatively early with temperature gauges reading 84 by midday, said Steve Anderson, a forecaster at the National Weather Service. The record of 88 degrees at San Francisco International Airport, set in 1954, was hanging by a thread by mid-afternoon with readings of 86 degrees by 1 p.m.