Dust emissions occur at all works as a result of construction activities. However, due to the region where the work is located, these emissions were accentuated by the shortage of rainfall, characteristic of the province of Guanacaste and a predominance of silicic soil with little organic matter that favours infiltration.
Another problem encountered during the execution of the work was the fact that vehicles used to transport materials in the work generally did not respect the speed limits and sometimes they were switched on unnecessarily. These two circumstances contributed to increasing atmospheric emissions in the form of combustion gases, and dust.

To solve the problem of dust emission due to construction work, a number of mitigation measures were implemented. The first was to establish the obligatory use of tarpaulins during transportation of materials, and another was the irrigation of works roads.

On the other hand, the problem of excess speeding of vehicles and their unnecessary ignition presented an added difficulty, since the road is 50 km long, and one of the country´s main commercial and tourist routes, making the control of heavy machinery circulating the works very complex. The solution adopted was the installation of a GPS in vehicles and the preparation of weekly reports, including vehicles exceeding the established speed limits of 80km/h when transporting concrete (as high temperatures could affect the material) and 60km/h for all other vehicles. This was reinforced using speed limit signposts at 1km intervals and 500m before a turn off. These signposts were placed at 100m intervals for diversions.

In order to further reduce GHG emissions from transport, vehicles parked with the engine running for longer than 15 minutes were monitored. These events were also incorporated into the report prepared by the Security Department.

Drivers, who exceeded the speed limit and/ or left the vehicle running unnecessarily for too long, received a written warning. This was allowed up to 3 times per driver, and after this point, they were considered repeat offenders, and withdrawn from the work.

Dust emissions during construction fell sharply to reach the objective set, in part due to implementation of good practices and also due to controlling vehicle speed. This speed control, together with the control of unnecessary engine ignition times, resulted in a decrease in fuel consumption, which meant a reduction in emissions of pollutant gases into the atmosphere.