That Big Apple fresh air is getting fresher.

There have been significant decreases in harmful chemicals and particles in the atmosphere, according to an annual report released this week by the city’s health department.

Sulfur dioxide levels have plunged 68% since 2008, the biggest drop in the report, due to new regulations on heating and energy sources, according to the New York City Community Air Survey (NYCCAS).

Despite the advancements citywide, certain neighborhoods in the South Bronx and Manhattan still emit dangerous levels of pollutants, however.

“We’re pleased that we are making progress, but as a public health agency we are not satisfied.,” said Thomas Matte, an assistant city health commissioner who specializes in air quality.

The survey, which began in 2008 under Mayor Michael Bloomberg, collects data samples from sites across the city. This year’s report, covering through 2014, also found a 21% drop in nitrogen dioxide and a 24% drop in nitric oxide.

Ozone levels throughout the city leveled off during the six-year period, according to the report.

Holger M. Eisl, a research professor at Queens College, which helped conduct the survey, credited the city’s efforts to phase out older oil heating systems and upgrade properties to greener options.

“Building owners realized they are victim of that air pollution and accelerate the program,” he said.

Lou Strenger, 66, of Greenwich Village, remembered that his father had to change his clothes because of the soot in the air.3

“I feel OK because it’s not a threat to me and it’s getting better for everyone else,” he said.

That quality, however does seem to be a different story depending on where you are in the city. The NYCCAS maps show that Manhattan and the South Bronx lead the five boroughs in concentrations of the harmful materials.

Matte and Eisel said the areas’ concentration of larger buildings, businesses and vehicular traffic were the biggest factors in the larger share of pollutants.

The average sulfur dioxide levels were close to 6.7 parts per billion on the Upper East and West sides compared to 0.6 ppb in neighborhoods like Bay Ridge, according to the report.

Some New Yorkers, like John Petrocelli, 60, of SoHo said they can tell the difference between boroughs.

“I know every time I leave (Manhattan) it looks like I’ve taken 10 years off my face and I can breathe better,” he said.

Manhattan Borough President Gale Brewer said no amount of building upgrades can counter the exhaust from trucks, especially the ones that travel through the borough to avoid tolls.

“The trucks are big pollutants and one way to change that is to have a different pattern for their driving,” she said.

Steps have been taken to reverse the trend in the badly affected areas. Mayor Bill de Blasio set up a program to help upgrade heating systems from Number 4 oil to cleaner alternatives.

Bronx Borough President Ruben Diaz Jr. established an initiative where new developments in the borough must be certified green before his office will fund them.

“We’re making important progress by creating programs to lower the carbon footprint of our community,” he said in a statement.

Last week, the Manhattan Borough Board adopted a resolution that would encourage future developments to build to the “Passive House” code, which emit less pollutants and generate less electricity.

Matte said the city supports any idea that would reduce the pollution and expects further progress in the years ahead.

“There are reasons to be optimistic for the future,” he said.