STAMFORD — When you look up at the night sky, you should be able to see at least 2,500 stars.

In a typical American suburb, however, you can see just a few hundred.

In a big city, you’d be lucky to see a few dozen.

The information comes from the National Conference of State Legislatures and was included in the research used to make the case for a light-pollution ordinance in Stamford.

The law, proposed by Land Use Bureau Chief Ralph Blessing, will go to a public hearing this month — no date has been set yet — and will establish regulations for exterior lighting citywide.

One goal, Blessing said, is to address the big picture — light pollution in all its forms. According to the research, that includes sky glow, which is brightening at night over inhabited areas; light trespass, which is light shining where it is not needed; and glare, which is excessive brightness that causes visual discomfort.

Another goal, Blessing said, is to address smaller-picture problems, such as when a floodlight on one house illuminates the bedrooms of the house next door; when a development project creates too much brightness in a residential neighborhood; or when lighting is excessive and wastes energy.

“This was driven by both types of things,” Blessing said. “We would hear from someone that their neighbor’s light shines into their back window, and we couldn’t do anything because we had no law we could enforce. We also did it for environmental considerations, what is known as ‘dark skies’ legislation.”

About a third of states, including Connecticut, have enacted ‘dark skies’ legislation to improve energy conservation, public safety, aesthetics and to aid astronomical research.

A number of U.S. cities have also set light-pollution regulations. In Connecticut that includes Milford, New Haven and Newtown, Blessing said.

If it passes, Stamford’s ordinance will set maximum light levels and restrictions for placing and aiming light sources; regulate types of lights, including signs; cap the height of light poles; require that lamp casings direct light downward; and more.

It will includes modifications for ballfields, gas stations, drive-up windows and similar uses. It will also set exceptions for ornamental lighting, seasonal displays, and events such as concerts and festivals.

The ordinance will require that developers file lighting plans with their project proposals, which some already do, Blessing said.

“We’ve been reviewing development projects for light, and the Zoning Board has been putting conditions on lighting for projects,” Blessing said. “This sets a standard for everyone to abide by. This formalizes it.”

The regulations will be enforced by the building department. Inspectors who find a violation will at first issue a notice that gives the property owner time to correct it. If there is no progress after 30 days, the owner will be fined $100 a day for one-, two-, and three-family buildings, and $100 per lighting unit per day for all other types of buildings.

According to the International Dark-Sky Association, the widespread use of artificial light at night increases energy consumption, disrupts the ecosystem and wildlife, and harms human health by impairing sleep, which increases risk for obesity, depression, diabetes, cancer and more.

Around the world, light pollution is cited in natural problems that include the decline in the number of lightning bugs, the death of birds during migration, and the disorientation of newly hatched sea turtles, which kills them. Florida, for example, sets guidelines for beachfront lighting to protect baby sea turtles and seabirds.

Texas has laws designed to reduce light pollution around military bases. Excessive light can interfere with training, much of which is conducted after dark using night-vision equipment to simulate combat conditions.

Connecticut’s light-pollution laws set restrictions for lighting along state highways and on the grounds of state buildings.

Blessing said the decision to pursue a Stamford light-pollution law was partly inspired by a zoning case.

A year and a half ago, the Board of Representatives reversed a Zoning Board decision to allow large fitness centers to be built in the city’s struggling office parks, which are mostly set in residential neighborhoods.

In this case, residents were fighting the owner of High Ridge Office Park, who wanted to build a big indoor-outdoor LifeTime Fitness center, part of a high-end chain. One reason for the residents’ objections was the amount of nighttime light the project would create. The owner is appealing the decision in court.

“During that discussion we realized there wasn’t anything that governs light pollution on the city books, so we started looking at ordinances from other places for ideas,” Blessing said.

acarella@stamfordadvocate.com; 203-964-2296.