The Alaska Department of Environmental Conservation regularly monitors smoke from cruise ship and ferry stacks through our commercial passenger vessel environmental compliance program. Since the summer of 2000, we have taken an average of 100 opacity readings per year on large cruise ships in a combination of Juneau, Skagway, Ketchikan, Whittier and Seward.
A contractor, four certified smoke readers on staff, along with our partners at the U.S. Forest Service take readings. DEC follows through with enforcement actions when necessary. Visible pollution or haze does not necessarily translate into a violation of a standard or a threat to human health.
A trained observer judges the compliance of a ship’s stack emissions with air quality requirements. When there is more than one ship in the harbor, as occurs in Juneau, each ship might individually meet air quality standards, but the emissions collectively can be very visible. The wet weather does not help as water vapor will attach to particles in the air, increasing their size and making the pollution more visible.
In 2000, the department conducted ambient air quality monitoring to determine whether multiple ships discharging simultaneously in port could have a negative health impact. The studies indicate that all air quality health criteria were met. We are looking at updating that study to account for any increases in ship traffic.