Environment experts say Hamilton's proposed bylaw to restrict industrial pollutants will be difficult to enforce and potentially costly to operate.

"The air quality equipments are set up more to see what the local air quality is, as opposed to who emitted what," said Lorraine Vanderzwet, professor of chemical, environmental and biotechnology at Mohawk College. "This is, of course, a big challenge determining the actual point source of the pollutant."

In addition to the difficulty of catching local offenders, Vanderzwet said that as much as 60 per cent of the air pollutants come from the U.S.

Councillors on Monday voted unanimously to develop a bylaw restricting the amount of fine particles. Coun. Brian McHattie introduced the motion, saying the bylaw will specifically target PM 2.5 — a fine particle formed by contaminants — that penetrates the respiratory system.

Despite the challenges, Vanderzwet said it is "very encouraging" that the city is looking at PM 2.5, because fine particles, especially those that are 1 micron or less in diametre, are the most harmful to residents.

But the smaller the particulate matter is, the more difficult it is for the city to measure, according to Joseph Castrilli, lawyer of Canadian Environmental Law Association (CELA).

Castrilli described the technology of measuring particulate matter as fairly "cutting edge." The city will have to acquire adequate equipment to accurately measure PM 2.5, he said.

But the cost of the equipment, called fine particulate samplers, can be hefty. According to Vanderzwet, they range from $30, 000 to $60,000. The more expensive kind allows online, real time data.

The city's air monitoring network currently tracks the emissions of most emitters in the area, but PM 2.5 is not one of the measurements.

Rare bylaw

Castrilli said although it is rarely done, municipalities can introduce environmental bylaws as long as doing so does not contradict provincial regulations.

"In situations where provincial air regulations are not as stringent as it should be, there's nothing in the constitution that prevents the municipality from issuing more stringent bylaws," he told CBC Hamilton.

In fact, the proposed bylaw will be the second of its kind in Ontario if it is passed. Oakville introduced a similar bylaw in 2010 to hold big emitters like gas plants accountable.

Ontario's Ministry of Environment typically does not get involved in municipal bylaw development or enforcement, said Lindsay Davidson, spokesperson for the ministry.

City staff will review Oakville's bylaw and find a way to implement a similar one in Hamilton. The motion must first be ratified by city council at Friday's meeting.