Jalisco authorities issued a stage three smog alert early December 25, after air pollution spiked in most zones of the Guadalajara metropolitan area.
Readings of fine suspended particles – or PM10 – at the monitoring station located at Las Pintas in the south of the city peaked at 324 Imecas, the highest recorded level for more than a decade.
The smog alert was extended to the entire metropolitan area as readings continued to rise at the city’s eight other stations. During a stage three alert, residents are advised not to undertake activities in the open air, to keep the doors and windows of their homes closed, only use vehicles if absolutely necessary, and be especially vigilant over the young and elderly, and those who may be susceptible to respiratory aliments.
In large part, authorities blamed the high air pollution levels on people lighting bonfires and setting off fireworks throughout Christmas Eve and into the early hours of Christmas morning. Although the metro area’s streets were mostly deserted as dawn broke December 25, a ghostly pall and scorched odor hung over the city.
Meteorologists said the pollution on Christmas Day was exacerbated when the suspended particles became trapped in thermal inversions, which occur when warmer air is held above cooler air.
Particulate matter can get deep into the lungs and cause a broad range of health effects, in particular respiratory and cardiovascular illnesses.
The alert was lifted December 26 after being in effect for 20 straight hours.
Fearing a similar scenario over the new year holiday, the Jalisco Fiscalia (state police) and Civil Protection have organized “brigades” to scour various zones of the city for stashes of illegal pyrotechnics. Municipal police will also be busy throughout the metropolitan area on December 31 to discourage the lighting of bonfires.
The number of days with bad quality air in the metropolitan area increased this year to 227, up from 135 in 2017.