Hester Van Hooven Ward is pretty hard to miss when she greets you on the street with a wave and a big smile, then launches into her "rap": "Hi! How are you? Do you have a minute for the environment today?" she calls out to strangers.

Most of the time her rap ends there, cut off by a mumbled "No thanks" or "Not today," or a sheepish grin and quickened pace. But often enough a passerby will pause for a moment, and that's all Hester needs to launch into her pitch on energy efficiency.

Hester, 21, is from Vermont, but she is in Boston for the summer, working as a street canvasser for the Massachusetts Public Interest Research Group (MASSPIRG) -- one of more than 25 state-based PIRGs across the United States that are linked under the auspices of USPIRG.

Founded in 1972 by students at the University of Massachusetts, MASSPIRG describes itself as "an advocate for the public interest."

"When consumers are cheated, or our natural environment is threatened, or the voices of ordinary citizens are drowned out by special-interest lobbyists," it says on its Web site, "MASSPIRG speaks up and takes action."

Today the group has a staff of more than 20 fulltime researchers, attorneys, lobbyists and fundraisers working on campaigns that range from protecting forests to food safety to new energy solutions. More than 60 percent of the organization's funding comes from private citizens -- the rest is raised by university student chapters and through foundation grants -- so members are key to MASSPIRG's survival. That is where Hester and the street canvassers come in.

"This is a grassroots organization, so we get the public involved and aware, and we get them to become members. Members give small monthly contributions, so they're our lifeblood," Hester explains. Hester is a third-year student at the College of Wooster, in Ohio, where she majors in history and minors in political science. "I'm studying what I love and I'll go to graduate school for what I want to do, but I don't know what that is yet," she says.

Wearing jeans, big silver earrings, a wide leather belt and a bright blue T-shirt with MASSPIRG written across the front, Hester chats comfortably and laughs often as we talk. "I came to Boston this summer for an internship with a public relations firm," she explains. "But I decided that at this point in my life, when I don't have any responsibilities -- and it's such an important political year -- I need to do my part and get active. This is a good way to get involved. So I quit my internship and I've been doing this for about three weeks."

Many passersby assume that MASSPIRG canvassers are volunteers, but they receive a small commission based on how much new members pledge. "We have to make money," Hester says with a grin, noting that if the commissions can pay a living wage, that surely helps motivate canvassers.

MASSPIRG Director, Leighanne Cole, 24, says street canvassing goes on year-round in Boston, with a team of 10 to 20 people. There are also about 100 door-to-door canvassers working statewide, and together these two groups hope to raise $1.1 million in 2004, Cole said.

The street canvassers work five days a week, from 9 to 5, spending about 25 hours on the sidewalk. They visit different neighborhoods each day and, though they work whether rain or shine, Hester loves it. "I feel really good about how I'm spending my time," she gushes. "Sometimes people aren't very responsive, but I'm sad I have to go back to school. I love this, I definitely do."

When I ask her if she believes she can really make a difference, she looks at me incredulously for a split second. "Oh, definitely," she replies. "I know I can. Just talking to people on the street, and giving them information about, say, energy efficiency, something that they may never have heard of before. Also, MASSPIRG has a long history of bringing about change in the public interest, from bottle recycling to homeless shelters, so this is not wasted effort."

Hester's main personal concern is clean energy. "There is a lot of airborne mercury coming from coal-burning power plants, and one in six women in the United States has unsafe levels of mercury in her blood," she says. Hester is particularly worried about women's consumption of mercury-tainted fish, and she eats little fish herself. She also tries to be environmentally friendly, by buying organic foods and using recyclable containers. "I reuse a lot of stuff, take public transportation, and I try to inspire others to, as well," she adds.

Most days, Hester will greet hundreds of people, but only 20 to 40 will stop and chat. Of those, about 30 percent will become members. Hester tries to raise $200 a day, but some days she brings in as much as $500 from new memberships. As a team, the street canvassers aim to raise $110,000 by the end of the summer -- a target they will reach in just a week or two.

As I watch her work, most people just pass by, but quite a few stop to chat and the majority of those who do are genuinely concerned. Glenn Grieves, a 36-year-old IT manager, speaks with one of Hester's colleagues before making a $20 donation. Even though he has his hands full, with a golden retriever on a leash and a 3-month-old in a carriage, he seems unfazed about being approached on the street.

"I don't mind and it's a good cause. Anything for the environment is a positive thing," he tells me. Meeting thoughtful citizens, such as Grieves, Hester learns as well as teaches.

"The reality is that a lot of people do stop, and you find that people from all walks of life are concerned about the environment. Environmental issues affect everybody, involve everybody, and I have been given more hope working with MASSPIRG, because I know that people really want to get involved. It's been a great experience for me," she says before dashing off to greet another stranger.

Which leaves me thinking: If the hot, dusty streets of Boston are giving Hester and her friends hope, then there certainly is reason for all of us to be a little more hopeful, too. There's even reason to hope that someday soon, Japanese young people, too, will take to the streets for the environment.