By 43 to 34 per cent , a plurality of Americans feels that the quality of life in this country has grown worse compared with 10 years ago, while another 19 per cent feels it has stayed about the same.

The result of this latest Harris Survey of 1,533 adults nationwide are roughly in line with the prevailing mood of the country over the past four years. Last April, with the new administration in Washington, the number of Americans who thought the quality of life was improving climbed briefly. But a sense of pessimism has once again taken over.

Asked why they feel the quality has grown worse, many Americans cite the unusal experience of a high inflation rate occuring at the same time as a high unemployment rate. Also discouraging is the sense that the physical environment has not improved, despite efforts to clean up fouled air and polluted waters.

A third factor is the public's growing lack of faith in the justice of the economic marketplace. As consumers, the people feel by a wide ratio of 3 to 1 that they are consistently short-changed on product quality and product safety, by shoddy repairs, by warranties and guarantees that are not what they are supposed to be and by manufacturers who are perceived as generally not really caring about the customer. The country is in the throes of a deep-seated consumer revolt, which is likely to grow and have a greater impact in the years ahead.

Although people feel that the quality of life has grown worse, they still beleive that they can make things better by their own actions. Thirty-seven per cent say they would take to the streets to protest against a manufacturer of a unsafe or poor quality product. A sizable 63 per cent report having a bad experience with a product purchased in the past year.

On a regional basis, Easterners are most upset by their quality of life, with 48-to-28 per cent plurality saying that it was declined. In the South, a narrow 39-to-38 per cent plurality feels that things have gotten better.

Young people, who were most disenchanted in the 1960s, now are most optimistic, with a 37 to 37 per cent standoff. People over 50 feet by a wide 49-to-30 per cent that the quality of life has become worse.

By 47 to 32 per cent, women feel it has declined over the past decade. Men agree, but only 39 to 37 per cent.