Launched with the aim of reversing the trend of deteriorating air quality in the Valley of Mexico metropolitan area, the programme Proaire has influenced the lives of 21 million residents in total, including those of Mexico City and fifty-nine surrounding municipalities.

The programme concerns 5.3 million vehicles, 2,410 businesses and regulated services, 1,935 industrial facilities and 5.8 million homes.

The project began at the end of the 1980s, when pollution had reached unimagined levels. “It was an emergency situation which brought together many public and private institutions, both national and international, to initiate this pioneering project,” said Antonio Mediavilla Sahagún, the programme’s director.

Before the programme’s implementation, the city registered extremely poor air quality almost every day. 25 years later, only 29% of days in the year are affected by bad ozone levels.

How does Proaire contribute to reducing pollution and protecting the health of the population? Mediavilla Sahagún, also the general director of Air Quality Management at Mexico City’s Environment Department (Sedema), explained that Proaire involves concrete actions for the control of air pollutant emissions, and is a key element that operates within a wider strategy, which also incorporates diagnostics and agreements.

He noted that firstly, weather, climate and air quality must be monitored, “over several seasons, along with an inventory of emissions.” These three factors are input into a pollutant dispersion model using software that converts the emissions (waste from automobiles, smokestacks and other sources of pollution) into levels of pollutants directly experienced by human beings. These results are then compared with the monitoring data; if the two are the same it means the system is working.

With Proaire, he says, policies can be implemented at theoretic level: “This is where proposals come from, for example, regarding restrictions on vehicles. We can model what would happen to pollution levels if this or that policy were implemented. We can analyse the resulting levels to see if they are in alignment with the standard or not, and this is where this programme comes in.”

The goal of the authorities is that 100% of days of the year are clean of contaminants. In addition to the programme “Hoy No Circula” (No-drive days), over the past 25 years, measures taken have included improving the quality of fuels, modernization and control of emissions in the industrial sector (for example the closure of a refinery in the Azcapotzalco district in 1992); reforestation of wooded areas surrounding the city and, since 1991, the use of two-way catalytic converters in motor vehicles.

More recent measures have focused on mobility; from the expansion of Mexico City’s STC metro system, urban mobility programmes such as Ecobici (a bike-sharing system), the introduction in 2005 of the Metrobus system and its extension in the State of Mexico, to the development of suburban trains and the renovation of taxi fleets and public buses.

How is it implemented ?

This is the fourth version of Proaire, the project having spanned several presidential terms. It began in 1990, then called the Integrated Program against Atmospheric Pollution (PICCA), and became Proaire in 1995. The latest period covers the years from 2011 to 2020. As a management tool, Proaire involves 116 actions, 81 measures and eight strategies, which are shared between the federal government and local governments, with the latter carrying out the majority of implementations.

A number of institutions are involved, with Sedema (Mexico City’s Environment Department) being the most important. The others include the departments of Mobility, Housing and Urban Development, Public Safety and Works and Services, as well as Metrobus and the Modal Transfer Centre (Cetram). As of September 2016, Proaire has been 41% implemented and with four years remaining until its conclusion, this is considered a “positive evaluation.”

Mediavilla Sahagún says that Mexico has made great improvements over the last three decades that have reduced pollution considerably, but that the challenge is increasing, as the population, along with the number of registered vehicles, continues to grow.

He asserts that the introduction of lead-free petrol in 1991 and the installation of catalytic converters in cars “was the most important environmental policy of the 90s for the reduction of emissions,” along with emissions regulation of the industrial sector. “Today, despite media reports that air quality is the worst it has been in many years, it has clearly improved.”

He added that pre-contingency phases no longer exist today, and environmental contingency has become stricter, with lower pollution concentration levels activating alert phases. “What triggered a phase one contingency in April of this year would not have even triggered a pre-contingency fifteen years ago.” Mediavilla Sahagún believes that it is essential to become even more restrictive in order to achieve the goal of 100% clean days.

Mediavilla Sahagún concluded that ensuring the continuity of the programmes over an expanded area is a key challenge, since they are now not just for Mexico City and its surroundings but also for the Megalopolis that covers six states. “We have to broaden the scope to include a much larger region, because the atmosphere does not have any borders.”