How to measure and reduce carbon emissions from digital out-of-home advertising

As an advertising channel, digital out-of-home (DOOH) brings large-scale digital ads to many simultaneous viewers in key public spaces. Think of the iconic digital billboards in New York’s Times Square, the LED screen at your local train station, or the digital banner wrapping around the Kansas City Chiefs’ GEHA field.

DOOH ads have three distinct differences from other digital channels like display and social. Here is what to keep in mind:

1. The infrastructure on which the ad is run is a large screen that is situated outdoors, as opposed to a TV or smart phone screen.

2. DOOH is a one-to-many channel; because of their unique form and placement in high-traffic areas, DOOH ads are viewed by multiple viewers at once, whereas social, display, or search ads target a single user.

3. DOOH ads don’t typically run alongside content, unlike CTV, display, or audio ads.

These distinctions clearly make DOOH unique from a measurement and targeting perspective, but they also impact the way it produces carbon and what levers can be pulled to reduce those emissions. Brands who understand the nuances can take the necessary steps to keep their campaigns on track to meet both their performance and sustainability goals.

Where DOOH emissions come from

DOOH screens, like other digital channels, require energy to display an ad. When talking about the carbon emissions of a DOOH ad campaign, the largest source of CO₂e comes from the electricity required to power the digital screens the ads run on. The highest source of emissions for DOOH ads occurs in the “use” phase of the ad’s lifecycle.

Here are some of the main factors that contribute to DOOH ads’ emissions:

1. Operating Hours: The bulk of emissions come from the energy consumption required to power screens. Keeping screens on for 24 hours a day drives up the emissions of DOOH ads.

2. Brightness settings: The brighter the screen, the more energy is consumed—and the more carbon is emitted. Screens that are set to a constant brightness level regardless of the time of day consume an outsized amount of energy—and produce more CO₂e—than screens whose brightness is adjusted based on the time of day.

3. Electricity grid mix: Location of the screen matters. A DOOH ad in a location whose energy is powered by fossil fuels will produce more carbon than a DOOH ad powered by a renewable energy grid mix.

These emissions factors can quickly drive up a campaign’s total carbon footprint. However, because DOOH is a one-to-many channel, it can be relatively efficient from an emissions perspective. A single ad played on a DOOH screen in a high-traffic area might be seen by tens of thousands of people per hour. While an ad run on a DOOH screen might use more energy than a display ad, its ability to reach multiple viewers in a single moment “makes carbon count” from a business outcomes perspective.

Scope3’s methodology for modeling the emissions of DOOH ads per mille hinges on the number of impressions “per play” and the use of the screen-specific average impression multiplier provided by media owners and platforms.

Embracing the power of collaboration, the Scope3 methodology is strengthend with data from our valuable partners. Since launching DOOH in Australia in 2023 with local industry leaders, we’ve expanded our DOOH modeling globally with the help of new partnerships. Most notably, Broadsign has partnered with us to provide inventory-based data across all of their regions and screens, to improve and refine our modeling, especially in the US and UK.

Steps you can take today to make your DOOH ads more sustainable

The many factors at play in the CO₂e emissions of DOOH ads may make decarbonization seem like a daunting task. However, there are a few simple steps brands can take to significantly reduce the emissions of their DOOH ads without impacting performance.

Partner with sustainability-minded organizations:

The first step is to partner with organizations that can provide you with verified screen level emissions data. Scope3 can help connect brands and agencies with a great deal of media owners and adtech platforms around the globe that help advertisers locate and buy the most sustainable DOOH screens.

Buy high-quality, low-emitting screens:

Once advertisers have identified their DOOH partners, they can shop around for screen packages that deliver higher impact for lower emissions. A large part of decarbonizing DOOH ads involves selecting quality screens that deliver on impressions and performance without ballooning carbon emissions.

Optimize for time of day:

Lastly, keep in mind that some hours are more sustainable than others. In some locations, the energy grid mix is likely to include a higher amount of renewable energy when the sun is shining, making the energy powering screens there more sustainable during the day. Or, there might be more people around screens during peak hours in a city’s business district and train stations, making the carbon produced by DOOH ads during those hours more worthwhile. Take these factors into account when planning DOOH campaigns.

Taking these steps greatly reduces DOOH ad emissions. Scope3 recently collaborated with OOH ad agency JCDecaux Australia to simulate carbon reduction methods for DOOH ads. One of the agency’s brands shifted 5% of ad plays to lower carbon screens and saw a massive impact on both emissions and performance: carbon emissions decreased 28% and impressions increased 18%.

DOOH is a powerful channel that can generate brand awareness on a massive scale. If you’re ready to go all in on a sustainable DOOH model, sign up for our Collaborative Sustainability Platform and reach out to Scope3 today.