• HISTORIC: The Mexico City metro area experienced Sunday one of its worst episodes of air quality with particulate air pollution exceeding levels considered extremely bad by international standards. Authorities attributed it to unusual windy conditions bringing dust from neighboring states.
• NUMBERS: Air quality in Mexico City was so bad that some monitoring stations recorded PM10 particle levels reaching 625 micrograms per cubic meter (µg/m3). Authorities consider any measurement above 235 µg/m3 as extremely bad and ask residents to remain indoors.
• WINDS: “These nanoparticles are not seen, but they always are. They are only perceived when there is this wind and basically they go directly to the lungs”, said Miriam Alfie Cohen, an environmental risk specialist at the Metropolitan Autonomous University (UAM) in Mexico City.
• MATTER: Particulate matter (PM) are minute particles present in the air and that are invisible to the naked eye. PM10 are particles approximately ten times smaller than the human hair. The World Health Organization (WHO) recommends PM10 daily mean values not to exceed 50 µg/m3.
