Arlington County and Alexandria are taking great strides toward sustainable communities, but environmental advocates say more can be done.

The Sierra Club protested to shut down the coal-burning power plant in Alexandria. The Green Party recently pressured the Arlington County Board to ban plastic bags and plastic foam.

“On the whole, I think we’ve been successful,” said Chris Zimmerman (D), Arlington County Board chairman. “The people in our community recognize it makes sense and are, frankly, demanding we continue to make progress in this area.”

And Arlington officials are pushing to do more. The county’s four-year-old Fresh AIRE initiative has decreased carbon emissions from its buildings to levels from the year 2000, but county officials still must cut 10 percent more to reach their goal.

“It remains a challenge,” said John Morrill, Arlington’s energy manager, who added that the county saves about $400,000 a year in energy costs, removing the equivalent of 2,000 cars off the road. “We’ve essentially got the needle moving in the right direction.”

Nearly $2.1 million in American Recovery and Reinvestment Act grants will help the county move the needle further. Streetlights are being converted to efficient LED — or light-emitting diode — bulbs, solar panels will top the central library roof, and public education is planned.

“Part of our approach is to say, ‘Look, we are not asking people to do things differently from what we are doing ourselves,’ ” said Morrill, who tracks county efficiencies in a series of online report cards.

Curbside infiltration systems, rain gardens and other storm-water management ideas are being incorporated into neighborhood conservation projects and retention ponds, said Jeff Harn, Environmental Management Bureau chief. Stream restorations and wastewater treatment- plant improvements target water quality, he said.

At the same time, sustainable living among the private sector is promoted by organizations such as Arlingtonians for a Clean Environment.

The group hosts a household Green Living Challenge, Green Living Expo and the Solar Raisers Project, where volunteers install solar hot-water heaters for Arlington families.

Neighborhood contests help people “find those practical solutions, but also work with their own mini-communities, places of worship and school and offices, so they are really making that individual difference,” said Elenor Hodges, ACE executive director.

Alexandria officials agree and developed a “holistic sustainability approach” with their “Eco-City” charter. Adopted in 2008, the charter includes advancements in transportation, water quality, and climate, said William J. Skrabak, the city’s Office of Environmental Quality director.

“One thread that is weaved throughout is that the government can’t do it all,” he said. “Obviously the government has a role, but if we want to truly become an eco-city, the community needs to do their part.”

Nearly $1.4 million in American Recovery and Reinvestment Act funds will be used for home-greening lectures for residents. Green-building standards are in place for all new buildings, and guidelines for historic buildings are in the works. More hybrid vehicles for the city’s fleet are being purchased while traffic and streets lights test LED bulbs, among other plans.

The school system has been using environmentally friendly designs in school construction, said Peter Pennington, a member of Alexandria’s Environmental Policy Commission. Green roofs were installed at several schools. Geothermal wells heat and cool campuses such as the Minnie Howard campus of T.C. Williams High School.

Pennington said costs can be prohibitive, but Alexandria is tackling the issues step by step, such as starting a green business certification with the Chamber of Commerce.

GenOn, owner of the coal-burning power plant, set aside about $34 million to install “the full Rolls Royce treatment” to mitigate pollution from the plant’s smokestacks because of the city’s protests, Pennington said.

But for the Sierra Club, the new smokestack technology is not enough.

Coal is full of toxic metals, such as lead and mercury, and there are radioactive components to the smoke, said Jim Dougherty, conservation chair of the D.C. area Sierra Club.

“None of these things are removed from the cleaning system,” he said. The plant is “one of our biggest public health threats.”