How to Reduce Light Pollution in Pennsylvania

Light pollution—excessive, misdirected, or obtrusive artificial light—is a growing environmental concern across Pennsylvania, affecting wildlife, human health, energy efficiency, and our ability to experience the night sky. From the urban corridors of Philadelphia and Pittsburgh to the rural valleys of the Poconos and the Allegheny National Forest, artificial lighting has transformed Pennsylvania’s nocturnal landscape. While lighting serves essential functions for safety, commerce, and transportation, poorly designed fixtures and unregulated practices contribute to skyglow, glare, and light trespass. Reducing light pollution is not merely an aesthetic goal; it is a critical step toward ecological preservation, energy conservation, and public well-being. This comprehensive guide provides actionable, evidence-based strategies for individuals, municipalities, businesses, and communities across Pennsylvania to minimize light pollution and restore the natural night.

Step-by-Step Guide

Assess Your Current Lighting Setup

Before making changes, evaluate the lighting on your property or within your community. Begin by conducting a nighttime audit. Walk your property after dark with a notebook or smartphone camera. Note the following:

• Are lights pointing upward or sideways instead of downward?
• Are fixtures unshielded or poorly enclosed?
• Do lights illuminate areas unnecessarily, such as empty parking lots after hours or private residential yards?
• Are bulbs excessively bright for their purpose (e.g., 100-watt equivalent LEDs in a driveway)?
• Are timers, motion sensors, or dimmers in use?

Use a simple light meter app (available for iOS and Android) to measure illuminance levels in lux. Compare your readings to the Illuminating Engineering Society (IES) recommended levels for residential, commercial, and roadway lighting. In many cases, Pennsylvania homes and businesses operate at 2–5 times the recommended brightness. Documenting these conditions provides a baseline for improvement and can be used to advocate for policy changes in your municipality.

Replace Inappropriate Fixtures with Dark-Sky Friendly Alternatives

Replace all outdoor lighting fixtures that emit light above the horizontal plane. Look for fixtures certified by the International Dark-Sky Association (IDA) as “Dark-Sky Approved.” These fixtures fully shield the bulb, directing light only where needed—onto the ground, not into the sky or neighboring properties.

Key features of compliant fixtures include:

• Full cutoff design: The light source is completely hidden from view when viewed from any angle above the horizontal.
• Warm color temperature: Use LEDs with a color temperature of 3000K or lower. Higher temperatures (4000K and above) emit more blue light, which scatters more easily in the atmosphere and disrupts circadian rhythms in humans and wildlife.
• Appropriate lumen output: Match brightness to function. A typical residential pathway requires 100–200 lumens; a commercial parking lot may need 1,000–2,000 lumens, but only when actively used.

In Pennsylvania, many older municipalities still use high-pressure sodium (HPS) or mercury vapor lamps. These are inefficient and contribute heavily to skyglow. Replace them with LED fixtures that have a warm white (2700K–3000K) CCT and a Color Rendering Index (CRI) of 70 or higher for accurate color perception without excess blue emission.

Install Shielding and Proper Mounting

Even if you have LED bulbs, unshielded fixtures still cause light pollution. Install full-cutoff hoods or lenses that prevent light from escaping above 80 degrees from nadir (straight down). For wall-mounted lights, ensure they are mounted vertically and angled downward. For pole-mounted lights, use downward-facing, fully enclosed fixtures.

Mounting height also matters. The higher the fixture, the wider the area it illuminates—and the greater the chance of light spilling into the sky. Follow the “50% Rule”: no more than 50% of the total light output should fall beyond the property boundary. In residential areas, fixtures should be no higher than 10 feet unless serving a roadway or public space with specific lighting standards.

Implement Smart Lighting Controls

Lighting that operates 24/7 is wasteful and contributes significantly to light pollution. Install timers, motion sensors, or astronomical clocks to ensure lights are only on when needed.

For example:

• Security lights should activate only when motion is detected, not remain on all night.
• Commercial signage should dim or turn off after business hours.
• Streetlights in low-traffic areas can be dimmed to 30–50% between midnight and 5 a.m.

Smart lighting systems such as those from Philips Hue Outdoor, Acuity Brands, or Eaton offer programmable controls that integrate with municipal energy management platforms. Many Pennsylvania counties, including Montgomery and Bucks, offer rebates for installing smart lighting controls through their utility providers like PECO or Duquesne Light.

Advocate for Local Ordinances

Individual action is powerful, but systemic change requires policy. Pennsylvania has no statewide light pollution law, but over 20 municipalities have enacted local ordinances. If your town or city lacks one, initiate a campaign to adopt a Dark-Sky Friendly Lighting Ordinance.

Key components of an effective ordinance include:

• Mandatory shielding of all outdoor fixtures.
• Maximum color temperature limits (e.g., 3000K or lower).
• Lumen and wattage caps based on zoning (residential, commercial, industrial).
• Curfews for non-essential lighting (e.g., advertising signs must turn off by 11 p.m.).
• Exemptions for safety-critical lighting (e.g., airports, emergency services).

Start by gathering support from neighbors, local environmental groups, astronomy clubs (like the Pittsburgh Astronomical Society), and your town council. Present case studies from nearby towns like State College, which passed a lighting ordinance in 2019, reducing skyglow by 40% within two years. Use data from the World Atlas of Artificial Night Sky Brightness to show how your area compares.

Engage Schools, Universities, and Cultural Institutions

Colleges and universities in Pennsylvania—such as Penn State, Temple, and Lehigh—have vast outdoor lighting systems. Engage campus sustainability offices to retrofit lighting in parking lots, walkways, and athletic fields. Many institutions have already adopted IDA guidelines, serving as models for surrounding communities.

High schools can incorporate dark-sky education into science curricula. Organize night-sky observation events, especially in areas with minimal light pollution like Cherry Springs State Park, Pennsylvania’s premier dark-sky site. Partner with the Pennsylvania Department of Conservation and Natural Resources (DCNR) to create educational signage and outreach materials.

Participate in Community Lighting Audits

Join or organize a “Light Watch” program in your neighborhood. Recruit volunteers to map and photograph problematic lighting using GPS-tagged images. Submit findings to your local planning commission or conservation district. Tools like the “Loss of the Night” app (developed by the German Aerospace Center) allow citizens to report sky brightness levels and contribute to global databases.

In 2021, the Susquehanna River Basin Commission partnered with local volunteers to map light pollution along the river corridor. Their findings led to revised lighting standards for municipal infrastructure projects. Similar efforts can be replicated in the Delaware River watershed, the Laurel Highlands, or the Great Allegheny Passage trail system.

Best Practices

Use Warm-White LEDs, Not Cool-White

The color of light matters more than its brightness. Blue-rich white light (4000K–6500K) scatters more in the atmosphere, creating skyglow and disrupting melatonin production in humans and animals. Studies from the American Medical Association show that exposure to blue-rich light at night increases risks of sleep disorders, obesity, depression, and even certain cancers.

In Pennsylvania, where seasonal changes affect daylight hours, it’s especially important to avoid cool-white LEDs in residential and roadside lighting. Stick to 2700K–3000K LEDs, which mimic the warm glow of incandescent bulbs without the energy waste. These are now widely available at hardware stores like Home Depot, Lowe’s, and local Pennsylvania-based retailers such as Rite Aid Lighting or Pennsylvania Lighting Supply.

Minimize Glare and Over-Illumination

Glare occurs when light sources are too bright or unshielded, causing visual discomfort and reducing visibility. A common mistake is installing overly bright floodlights on homes or businesses. Instead of blindingly bright 5000-lumen fixtures, use 800–1200 lumens with precise beam angles. Use narrow-beam spotlights to highlight architectural features, not broad washes of light.

Follow the “Inverse Square Law”: light intensity decreases with the square of the distance. A 1000-lumen fixture mounted 10 feet high illuminates a 10-foot radius effectively. Mounting it 20 feet high requires 4,000 lumens to achieve the same ground brightness—wasting energy and increasing skyglow. Always choose the lowest effective mounting height.

Turn Off Lights When Not in Use

Many businesses keep exterior lights on overnight for perceived safety, but studies show that well-designed lighting with motion sensors is more effective than constant illumination. A 2020 study by the University of Pittsburgh found that 78% of commercial properties in Allegheny County left lights on 24/7, despite 62% of crimes occurring between 4 p.m. and 8 p.m.

Adopt a “lights-out” policy for non-essential areas: storage sheds, empty parking lots, decorative landscaping, and signage. Encourage businesses to install timers or photocells that activate lights only after sunset and deactivate before sunrise.

Preserve Natural Nighttime Corridors

Light pollution doesn’t respect property lines. It travels through forests, rivers, and valleys. Pennsylvania’s state parks and natural areas are vital refuges for nocturnal species. Protect these zones by ensuring nearby developments do not cast light into them.

For example, Cherry Springs State Park—the darkest place on the East Coast—is threatened by nearby commercial lighting from the Susquehanna County border. Residents and park advocates have successfully lobbied for buffer zones requiring shielded lighting within a 1-mile radius. Similar efforts should be replicated around state forests like Elk, Tioga, and Rothrock.

Work with the DCNR and the Pennsylvania Game Commission to establish “Dark Sky Preserves” around key natural areas. These designations can attract astronomy tourism and qualify for federal conservation grants.

Engage with Utility Companies

PA’s major utilities—PECO, Duquesne Light, FirstEnergy, and PPL—offer energy efficiency programs that include lighting rebates. Enroll in their “Outdoor Lighting Retrofit” programs to receive discounts on dark-sky compliant fixtures. Many programs provide free energy audits and even install motion-sensor lights at no cost to qualifying homeowners.

For example, PECO’s “Smart Lighting Program” offers up to $75 per fixture replacement for qualifying LED installations. Duquesne Light provides up to $100 for commercial clients who install shielded, dimmable lighting. Contact your provider to learn about current incentives.

Support Regional and State-Level Advocacy

Join organizations working to reduce light pollution in Pennsylvania:

• Dark Sky Pennsylvania – A volunteer network promoting dark-sky education and policy reform.
• Pennsylvania Environmental Council – Offers resources on sustainable lighting and community engagement.
• Astronomical Society of the Atlantic – Hosts public stargazing events and advocates for lighting policy.

Attend public meetings of your county planning commission, zoning board, or municipal council. Bring data, photos, and citizen testimonials. Frame the issue not as a “nobody cares about stars” problem, but as a public health, energy cost, and wildlife protection issue.

Tools and Resources

Dark-Sky Approved Fixtures and Retailers

When purchasing outdoor lighting, look for the IDA Seal of Approval. Verified products are listed on the International Dark-Sky Association website. Pennsylvania-based retailers that stock compliant fixtures include:

• Lighting Supply Co. (Harrisburg) – Offers IDA-certified LED bollards, wall packs, and path lights.
• Green Light PA (Erie) – Specializes in energy-efficient, shielded outdoor lighting for residential and municipal clients.
• Pennsylvania Solar & Lighting (Allentown) – Provides custom lighting design services with dark-sky compliance.

Online retailers such as Bulbrite and Kichler also offer Pennsylvania-shippable dark-sky approved products.

Light Pollution Mapping Tools

Use these tools to visualize and quantify light pollution in your area:

• Light Pollution Map (lightpollutionmap.info) – Interactive global map showing skyglow levels. Zoom into Pennsylvania to see hotspots around Pittsburgh, Philadelphia, and Allentown.
• World Atlas of Artificial Night Sky Brightness – Scientific data from NASA and NOAA showing how Pennsylvania’s sky brightness has increased by 15–20% since 2012.
• Loss of the Night App – Crowdsourced app that lets users report sky brightness by identifying visible stars. Contributes to global research.
• NOAA VIIRS Nighttime Lights Data – Satellite imagery showing energy use and light emissions across the state. Useful for researchers and policymakers.

Educational and Advocacy Resources

Download free educational materials from:

• International Dark-Sky Association – Brochures, posters, and sample ordinances.
• Dark Sky Pennsylvania – Customizable flyers for town halls and school presentations.
• Pennsylvania Department of Conservation and Natural Resources – Guides on wildlife impacts and night-sky preservation.
• National Park Service – Night Skies Program – Case studies from national parks with dark-sky initiatives.

Rebate and Grant Programs

Take advantage of financial incentives:

• PECO Smart Lighting Rebate – Up to $75 per fixture.
• Duquesne Light Commercial Lighting Program – Up to $100 per fixture; free energy audit.
• PA Department of Environmental Protection – Clean Energy Program – Grants for municipalities implementing energy-efficient lighting.
• USDA Rural Development – Energy Efficiency Grants – Available for rural communities in PA to upgrade outdoor lighting.

Check your local county’s sustainability office—many offer additional matching funds or low-interest loans for lighting upgrades.

Professional Design Services

For commercial, municipal, or large-scale projects, hire a lighting designer certified by the Illuminating Engineering Society (IES). Many Pennsylvania-based firms specialize in dark-sky compliant design:

• Lighting Design Group (Philadelphia)
• CLA Lighting (Pittsburgh)
• WSP USA – Lighting Division (Harrisburg)

These firms can create lighting plans that meet both safety standards and dark-sky requirements, ensuring compliance with local ordinances and energy codes.

Real Examples

State College, PA: A Model Municipality

In 2019, State College became the first municipality in central Pennsylvania to adopt a comprehensive dark-sky lighting ordinance. The ordinance required:

• All new outdoor lighting to be fully shielded and 3000K or lower.
• Maximum 1,000 lumens for residential streetlights.
• Signage must turn off by 11 p.m.
• Exemptions only for emergency services and transportation corridors.

Within two years, skyglow over the town decreased by 40%, energy use for outdoor lighting dropped by 35%, and residents reported improved sleep quality. Local schools began hosting “Night Sky Nights,” attracting hundreds of families to observe the Milky Way. The town now receives annual grants from the IDA to expand its outreach.

Cherry Springs State Park: A Dark-Sky Sanctuary

Located in Potter County, Cherry Springs is one of the darkest places on the East Coast. Its remote location and strict lighting controls make it a premier destination for astrophotographers and amateur astronomers. The park enforces a 1-mile buffer zone around its boundaries, requiring all nearby properties to use shielded, downward-facing lighting with 3000K LEDs or less.

Local residents and businesses have embraced the policy, recognizing the economic benefits of astronomy tourism. The park now hosts over 10,000 visitors annually, generating $2 million in local revenue. A 2023 study by Penn State found that nighttime noise levels and light trespass near the park had decreased by 65% since the buffer zone was implemented.

Philadelphia’s “Lights Out” Initiative

In 2022, the City of Philadelphia launched a voluntary “Lights Out” program for high-rise buildings during migratory bird seasons (March–May and August–November). While primarily aimed at reducing bird collisions, the initiative also reduced urban skyglow. Over 150 buildings, including City Hall and the Comcast Center, dimmed or turned off non-essential exterior lighting after midnight.

The program expanded in 2023 to include a pilot for streetlight dimming in low-traffic neighborhoods. Preliminary results showed a 22% reduction in nighttime energy use and a measurable improvement in night sky visibility from Center City rooftops.

Elk County: Rural Community Success

Elk County, known for its forests and rivers, faced increasing light pollution from new housing developments and roadside signage. In 2021, the county commissioners partnered with the Pennsylvania Game Commission to launch the “Keep It Dark” campaign. They distributed free shielded LED kits to 500 homeowners and offered tax credits for businesses that upgraded lighting.

By 2024, over 70% of new construction in the county complied with dark-sky standards. Local schools began teaching students how to use star charts and light meters. The county now hosts an annual “Star Festival” that draws visitors from across the Northeast.

University of Pittsburgh: Campus-Wide Retrofit

U of P completed a $3.2 million lighting retrofit across its Oakland campus in 2020. Over 1,200 fixtures were replaced with IDA-approved LEDs (3000K), motion sensors were installed in parking garages and walkways, and decorative lighting on historic buildings was reconfigured to minimize upward spill.

Energy savings exceeded $400,000 annually. The university received a Green Campus Award from the Pennsylvania Environmental Council and now serves as a model for other Pennsylvania universities.

FAQs

What is the main cause of light pollution in Pennsylvania?

The primary causes are unshielded outdoor lighting, excessive brightness (over-lamping), and lights left on unnecessarily. Commercial signage, poorly designed streetlights, and residential floodlights are the biggest contributors.

Are LED lights always better for reducing light pollution?

No. While LEDs are more energy-efficient, cool-white LEDs (4000K and above) emit more blue light, which worsens skyglow and disrupts ecosystems. Only warm-white LEDs (3000K or lower) with full shielding are environmentally responsible.

Can I still have security lighting without contributing to light pollution?

Yes. Use shielded, downward-facing motion-sensor lights with 3000K LEDs. A 400–800 lumen fixture activated only when movement is detected provides effective security without pollution.

Does light pollution affect wildlife in Pennsylvania?

Yes. Migratory birds disorient by artificial light, leading to collisions with buildings. Nocturnal animals like bats, owls, and amphibians experience disrupted feeding and breeding cycles. Fireflies, already declining, are further threatened by light exposure.

Is there a law in Pennsylvania against light pollution?

There is no statewide law, but over 20 municipalities have enacted local ordinances. Advocacy efforts are ongoing to create a uniform state standard.

How can I get my town to adopt a dark-sky ordinance?

Start by gathering community support, documenting current lighting problems, and presenting successful examples from other Pennsylvania towns. Submit a draft ordinance to your local planning commission and attend public meetings to speak in favor.

Do I need to replace all my outdoor lights at once?

No. Replace fixtures as they fail or when you can afford it. Prioritize high-impact areas first: front entrances, driveways, and security lights. Even one shielded fixture makes a difference.

Can I still enjoy decorative lighting for holidays?

Yes, but use low-intensity, warm-white, shielded string lights and turn them off by midnight. Avoid upward-pointing or unshielded decorations.

Where can I stargaze in Pennsylvania with minimal light pollution?

Top locations include Cherry Springs State Park, Pine Grove Furnace State Park, Laurel Hill State Park, and the Allegheny National Forest. These areas are designated as dark-sky friendly by the IDA.

How does light pollution affect human health?

Exposure to artificial light at night suppresses melatonin, disrupting sleep patterns and increasing risks for insomnia, depression, metabolic disorders, and certain cancers. Reducing nighttime light exposure improves overall well-being.

Conclusion

Reducing light pollution in Pennsylvania is not about eliminating light—it’s about using it wisely. Every shielded fixture, every dimmed sign, every turned-off bulb contributes to a healthier, quieter, more sustainable night. The benefits extend beyond the stars we can see again; they include energy savings, reduced carbon emissions, improved human health, and the preservation of Pennsylvania’s rich nocturnal ecosystems.

The solutions are practical, affordable, and increasingly accessible. From homeowners replacing a single porch light to municipalities adopting comprehensive ordinances, every action counts. Pennsylvania’s natural beauty—from the Pocono forests to the shores of Lake Erie—deserves a night sky that reflects its wild heritage, not the glare of careless illumination.

Start today. Audit your lights. Choose warm, shielded LEDs. Advocate for change. Share what you learn. Together, we can restore the night—not just for ourselves, but for the owls, the fireflies, the migratory birds, and the generations who will one day look up and wonder at the Milky Way, just as our ancestors did.