Carnival Cruise Lines’ announcement last week that it plans to install new technology to reduce air emissions on 30 of its ships means more to its shareholders than it does to the people of Charleston who are concerned about dangerous pollutants.

The company will install scrubbers to cut sulfur oxide emissions and filters to capture soot. It is cheaper than and expected to be as effective as using federally mandated cleaner fuel, according to the EPA.

And it still leaves Charleston in need of plug-in power for cruise ships while they are docked here.

When Carnival’s Fantasy is at dock for debarkation and embarkation, it continues to idle so that the air conditioning and lights will be operational. While it idles, it emits particulate matter. Even using the cleaner fuel that federal regulations will soon require, emissions would be a problem. The Port of Long Beach, Calif., (which is switching to shore power) estimates shutting down auxiliary engines for a day is the equivalent of taking 33,000 cars off the road.

That’s not good enough.

Other ports have installed shoreside power and required cruise ships to use it. It has worked, and Charleston deserves no less.

As a matter of fact, it’s of particular concern here because the port is adjacent to dense residential areas, often crowded with visitors.

Those kinds of emissions have been connected to lung disease, heart disease and cancer. Both the Charleston and the South Carolina medical associations have called for shoreside power.

The health risk is one reason preservationists, neighborhood associations and environmentalists have sued Carnival.

Other reasons are the ship’s impact on congestion as thousands of passengers come and go, noise from loudspeakers, and its visually overwhelming profile.

Soot also has been a major complaint. Maybe the new scrubbers will ease that problem.

But altogether, the fear is that the city’s important heritage tourism will be diminished.

Opponents haven’t asked that cruise ships be banned, only that they agree to reasonable, enforceable limitations as to the size of the ships, the number of passengers they hold and the frequency of visits here.

The city of Charleston has failed to go along.

The port has made some strides in addressing air pollution.

For example, it has implemented a program to provide financial incentives to encourage truckers to replace their old diesel rigs with more fuel-efficient trucks.

Plug-in electrical power is another effort that the port could make that would improve the livability and the health of its neighbors.