Ozone's Threat Hits Back Mexico City
Abstract
Last March the Mexican authorities activated after 13 years the environmental alarm when ozone (O3) reached 210 ppb. The emergency measures created confusion among the public, who had lost memory of previous air quality crisis. Despite Mexico City has experienced a significant progress towards achieving cleaner air during the last 20 years, a recent relaxation in traffic regulations and meteorology favorable for photochemical activity triggered this new episode. All criteria pollutants of primary origin have been controlled and are in compliance with the Mexican Air Quality Standards. However, O3 and fine particles still exceed the standard threshold concentrations. For instance, 49-64% of the days have exceeded the 1-hour O3 standard of 95 ppb during the last 5 years. The current control policies, which responded to the integration of air quality information by authorities and scientists, have apparently started to lose effectiveness. Although precursor gases, such as alkanes and aromatics have shown an important decrease, reactive olefins have gained importance. The increase of motor-vehicles in recent years seems to fuel again the atmosphere's reactivity. This paper analyses the effectiveness of the emergency measures during the crisis based on the knowledge obtained from previous large field studies and the comprehensive data collected by the local air quality monitoring network. It is 10 years from MILAGRO, the last interdisciplinary study that examined the air pollution of the most populous city in North America. We call for a new collaborative research initiative based on a major field measurement campaign with the target of revealing new insights into the meteorology, emission of primary pollutants and precursor gases, photochemical production and formation of secondary particles in the atmosphere of Mexico City to improve its air quality, as well as of similar cities in the developing world.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2016
- Bibcode:
- 2016AGUFM.A14A..02V
- Keywords:
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- 0312 Air/sea constituent fluxes;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0345 Pollution: urban and regional;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0365 Troposphere: composition and chemistry;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0428 Carbon cycling;
- BIOGEOSCIENCES