Nogales, Sonora, Mexico

Project for Air Quality Improvement through Street Paving in Nogales, Sonora

Status: Completed


The city of Nogales has approximately two million square meters (m2) or about 250 kilometers—of unpaved streets, which represents 65% of the city’s urban roadways. These unpaved streets constitute a serious public health problem, particularly during the summer months when the ground is dry due to lack of precipitation. The movement of private vehicles and public transportation, coupled with the area's frequent windy conditions, result in the suspension of fine dust particles in the air that are a potential source of respiratory illnesses (allergies, asthma, etc.) primarily among children and young adults. According to morbidity data from the Sonora State Office of Epidemiology, 61.8% of all illnesses recorded annually are due to respiratory problems and 15% are related to gastrointestinal and parasitic diseases, for which pollution is the main triggering factor.

The city’s unpaved roadways are the main source of an annual 8,896 tons of suspended particles (PM10), which is 26 times higher than the official norm. In addition, the region's prevailing southwest-to-northeast winds carry these contaminants across the border into Nogales, Arizona, creating a transboundary environmental air quality problem.

The Municipal Department of Urban Planning and Control has prepared a paving study, which is part of the city’s Urban Development Plan for the 2004-2007 period. The study identified 1,896 roadways in the city, 1,200 of which require paving. The most significant backlog of unpaved streets is in the northeastern (60%) and southeastern (40%) areas of the city.

The City is also using a binational air quality study (1994-1999) prepared by the Arizona Department of Environmental Quality (ADEQ), jointly funded by ADEQ and the Mexican environmental agency, Secretaría de Medio Ambiente y Recursos Naturales (SEMARNAT), to assist in identifying priority areas for paving.


The project consists of paving a surface area of 300,000 m2 of urban streets in residential areas of Nogales with reinforced concrete or asphalt. The streets to be paved are located in residential areas of Nogales that already have water and wastewater services installed. Priority will be given to roadways used for public transport.


Paving dirt streets will reduce air pollution from suspended dust particles (PM10) in the air basin shared by Nogales, Sonora and Nogales, Arizona, thus improving the overall health conditions for people residing in the area. In addition, having paved streets will increase public safety by facilitating the access of police, firefighters and ambulances.

Project Financing

Total Project Cost US 17.08M
NADBank Funding US 15.46M - NADBank Loan