She's been studying the impact of litter on our communities in terms of physical and mental health.
"It can have effects on respiratory complications disease from rat infestations, and more commonly what we see are the links between litter and behavioral health," says Soya.
Soya has found that trash strewn in the street discourages feelings of safety and security, in turn, increasing feelings of stress.
"We see a rise in crime in areas that are highly litter inundated. Also, the effects on mental health and mental health disorders. Increased levels of stress, a lack of social cohesion in a neighborhood, a lack of pride in a neighborhood, feelings of depression and then of course, fear of crime as well," says Soya. "If the neighborhood is clean and there is a lack of litter, it brings out positive mental health effects. People are more likely to be outside, neighbors are able to spend time on their porch, on their steps and they are likely to spend more time engaging."
Community engagement is one way to disrupt the pattern of litter in Philadelphia. Ed Mitchell is a living, breathing example of that.
"I can't work a regular job," said 62-year-old Mitchell.
He has developmental delays, which don't slow him down in the least. For more than 25 years, Mitchell has been walking more than a half-mile stretch along Bustleton Avenue in Northeast Philadelphia daily, picking up litter.
He now does so with a walker.
"There isn't much for me to do and it gets me out of the house," says Mitchell.
Cleaning the neighborhood of litter comes naturally for Margaret Livingston who grew up on the 4600 block of Locust Street, in the Walnut Lane neighborhood. Her five siblings also own properties on the block, she jokes it should be renamed to Livingston Way.
Livingston's mother is her role model. She carries on the tradition of keeping her block immaculate.
"She would come outside and sweep up, every neighbor knew her, every neighbor. Everyone knew Marjorie Livingston," said Margaret.
Livingston is one of the 1,500 volunteers who have pledged to keep their block clean with the "Not in Philly" project. The non-profit was developed by Dave Brindley who moved to West Philadelphia 10 years ago, after living in Shanghai for two years. When he did, he quickly noticed the difference in cleanliness.
"I've seen kids play around litter, I think it's just a sign that nobody cares for their community. It's a very hopeless environment. And there's probably not going to be a good effect on how they view their future, their possibilities in life," said Brindley.
"Not in Philly" is encouraging others to sign up to become an active participant and fight against neighborhood litter.
"Once we launched, it was so encouraging to see so many people say, 'Yeah, I don't care if it looks a little weird to go out and pick up the litter on my block. I hate the presence of litter in our community, and I want to do something about it" said Brindley.
You can sign up to make a pledge to your block.
Keep Philadelphia Beautiful is another non-profit organization which was established more than 25 years ago. Kelly Offner is the executive director, she says changing litter habits starts with education.
"We've always been focused on litter and behavior change around folks' habits when it comes to littering and how they recycle. We aspire to convene, equip, and inspire Philadelphians to take part in the civic process and in their communities and keeping things beautiful, clean and green," said Offner.
To change a behavior, it's important to start young. Keep Philadelphia Beautiful partners with the school district to reach the youngest and most impressionable Philadelphians.
"Working with students to help change their attitudes around litter and really helping them feel like they have a stake in a say in their community. Even though they're small or young, they still can help take part in cleaning up their street. That starts with their behavior and with how they interact with their fellow students and friends," said Offner.
Keep Philadelphia Beautiful also supports community development corridors providing grants for trash and cigarette butt receptacles--many of which are unique to the fabric of the community.
There is some branding that feels more like their neighborhoods.
In Fishtown, for example, all the receptacles have fish stickers on them. Chinatown did their own contest, where they invited students to create illustrations that are on their receptacles. And it's made a difference in terms of the amount of cigarette litter in the areas that they're being installed. And a lot of these community development corporations have continued to install receptacles beyond what our funding provided," said Offner.
One community development corporation that has cashed in on the grants is in Mayfair. This year, the Mayfair CDC installed 10 cigarette butt disposal containers near SEPTA bus stops. The funding came from a $1,200 grant.
"We clean them out at least once a week and they're always full," said Mayfair CDC executive director, Marc Collazzo.
In South Philadelphia, Megan Farrell aims to tackle the issue of litter in her neighborhood by creating less trash. She took us on a tour through her kitchen and has essentially done away with anything that is not reusable. She says she subscribes to the "low waste" lifestyle.
"I feel like we can pick up trash all we want but if we don't change our habits in our home then there's going to continue to be trash on the streets," said Farrell.
Farrell always carries bamboo utensils, a steel mug with a lid, and a metal straw with her. She buys her groceries in bulk, lugging glass bottles with her, and always carrying reusable cloth bags. She admits living low waste can be difficult and suggests starting small.
"You don't need to buy new things--that is still creating more waste. Use what you have. It doesn't have to be Instagram-worthy, perfect or new and shiny. Old jars work, an old t-shirt ripped up to clean with works," said Farrell.
She's already seen the fruits of her labor, right at home.
"We're only putting out one trash bag a week, where it used to be two, along with a ton of recyclables. I would say we cut it in half. We're not there yet, little by little, but definitely a big improvement," said Farrell.
Less waste, less opportunity for trash to litter our streets.