Climate change is impacting human health. An obvious effect of a warmer environment is more frequent and severe heat waves. During the European heat wave of 2003, there were an estimated 35,000 more deaths than normal in the first two weeks of August. Many of the deaths resulted from cardiovascular complications among the elderly. As heat waves become more commonplace in the future, so will the number of heat strokes and the onset of other cardiovascular problems. Higher summertime temperatures also increase tropospheric ozone concentrations which in turn affects people with asthma and causes lung and heart damage. Increases in the levels of photochemical pollutants like ozone are associated with a warming world.