Gov. Bruce Rauner’s top environmental official is pressing to spend an anti-pollution windfall in the coming months, but critics say the rushed timetable is dictated not by sound policy but by the fall election.

Alec Messina, the Rauner-appointed director of the Illinois Environmental Protection Agency, wants to speed the handout of $109 million in legal settlement money — part of a $2.9 billion multi-state settlement with Volkswagen over an emissions-cheating scandal involving the German automaker’s diesel vehicles.

Messina says he wants to submit a final plan within a month to a national trustee and, as soon as August, start funding projects aimed at reducing air pollution in Illinois.

That timing could give Rauner good news to announce close to the November election — and help him in his tough re-election battle with Democratic challenger J.B. Pritzker.

Democratic lawmakers are trying to slow down and possibly alter Messina’s plans for distributing the money — plans that environmental advocates complain appear skewed toward helping big diesel-engine manufacturers while largely ignoring efforts to reduce the type of vehicle emissions central to the VW scandal.

The Illinois Senate passed a bill Thursday to require six public hearings on how to spend the money — and that a task force be appointed to decide on a plan.

Last week, Messina called it “frustrating” to be accused of playing politics with the settlement and argued the Senate legislation, if implemented, would delay distribution by up to a year.

“This is an important opportunity to make strides toward improvement in air quality,” he said.

Bill sponsor state Sen. Cristina Castro, D-Elgin, and others criticized Messina for holding private meetings with business leaders, including some from construction equipment manufacturing giant Caterpillar, while shutting out public input. Other states getting VW settlement cash, including Indiana and Ohio, have held public meetings on how to spend the money.

A number of health, environmental and clean energy groups have asked the state EPA to put the brakes on its high-speed spending plan and make the process more transparent to taxpayers.

“Clearly, they’re in a hurry to spend the money,” said Al Grosboll, legislative director for the Chicago-based Environmental Law and Policy Center. “We certainly appreciate the administration wants to begin moving money out the door but it’s really important that we get this right.”

Others are more pointed about the politics.

“They realize this is a fall election opportunity,” said Jennifer Walling, executive director of the Illinois Environmental Council, a coalition of dozens of advocacy organizations.

Messina’s EPA has put together a draft plan that must be blessed by a national trustee overseeing the VW settlement to make sure the state is spending the money to fight air pollution and not for unrelated purposes.

The draft has led to a philosophical fight with environmental and health groups that argue too much of the money is going toward trains, boats and other so-called off-road projects, and not on cutting air pollution from cars.

Indeed, the Illinois Manufacturers’ Association and the Illinois Chamber of Commerce praised the EPA’s draft plan, calling it a “policy that encourages business growth with smart environmental investment.”

The plan to emphasize off-road projects appears to draw from research by the Diesel Technology Forum, a Maryland-based organization of companies with an interest in diesel fuel, including Caterpillar.

In a statement, Rauner spokeswoman Rachel Bold echoed Messina’s defense: “This plan focuses on getting the oldest, dirtiest engines out of operation, and bringing significant air quality improvements to those citizens that need it the most. We need to move forward.”

Caterpillar has reiterated its position to invest in cleaner diesel engines for locomotives and tugboats. In a six-page letter submitted to the state EPA as part of public comments, a Caterpillar official knocked other ideas, such as electric school buses, as examples of “poor cost effectiveness.”

“Caterpillar and its dealers are ready to accomplish these replacements and emission retrofits,” Caterpillar Global Regulatory Affairs Manager Rey Agama wrote in the letter.

Messina has highlighted Metra as a potential recipient of Volkswagen settlement funds. Caterpillar restores diesel engines for the commuter rail system. Metra spokesman Michael Gillis said the agency is likely to replace or retrofit engines in its oldest locomotives, which are more than 40 years old.

Messina said he’s been transparent about the spending of settlement dollars — and told legislators he feared no one would show up for a public meeting on the subject.

Some lawmakers see things differently.

“The process is as important as the end result,” said Sen. David Koehler, D-Peoria, chairman of the Senate Environment and Conservation Committee. “You have to make people feel like they’ve participated and that hasn’t happened.”