WASHINGTON — Construction activity was unchanged in August even though spending for residential projects posted the first increase in 17 months, a rare bit of good news in the midst of the worst housing downturn in decades.

The Commerce Department says construction activity was flat in August, a better-than-expected outcome than the 0.5 percent fall that economists expected.

The big surprise was a 0.3 percent rise in residential activity, the first increase in housing activity since March 2007.

CONSHOHOCKEN — The home furnishings retailer Ikea says it will no longer offer disposable shopping bags at its North American stores.In March 2007, the company said it would charge 5 cents per bag to discourage the use of disposable bags, with the proceeds going to an environmental charity. The company with U.S. headquarters in the Philadelphia suburb of Conshohocken says that cut bag use by 92 percent.Starting Wednesday, Ikea won't offer any disposable plastic or paper shopping bags. Sturdy, reusable shopping bags will still be available for 59 cents.

PITTSBURGH — Allegheny County Council is proposing its second tax rollback in as many weeks.Council may exempt nonprofit agencies from the $2-a-day rental car tax it enacted in January.The rental car tax, and a 10-percent tax on alcoholic drinks at bars and restaurants, were expected to raise $30 million a year to fund the county's transit agency subsidy.Last week, County Executive Dan Onorato asked fellow Democrats, who hold a veto-proof majority on council, to consider cutting the drink tax to 7 percent because it's bringing in more money than anticipated.Some council members say the nonprofit exemption should have been part of the original car rental tax. The county will lose about $750,000 a year under the exemption.

NEW YORK — A closely watched index released Tuesday showed home prices tumbling by the sharpest annual rate ever in July, and though the monthly rate of decline is slowing, there is no turnaround in sight.The Standard & Poor's/Case-Shiller 20-city housing index fell a record 16.3 percent in July from the year-ago month, the largest drop since its inception in 2000. The 10-city index plunged 17.5 percent, its biggest decline in its 21-year history.Prices in the 20-city index have plummeted nearly 20 percent since peaking in July 2006. The 10-city index has fallen more than 21 percent since its peak in June 2006.