WILDFIRES in Los Angeles have caused a steep rise in the amount of lead in the city’s atmosphere, new data shows.
Measurements taken during the recent wildfires in the Pico Rivera suburb of Los Angeles by the Atmospheric Science and Chemistry Measurement Network (ASCENT) reveal that atmospheric lead levels rose to more than three times the amount considered safe by the US Environmental Protection Agency (EPA).
Lead particulates in Pico Rivera peaked at 472 ng/m3 on 9 January, reducing to their normal levels on 11 January. The EPA says the average atmospheric lead concentration over a three-month period should be no greater than 150 ng/m3. Atmospheric lead levels in Los Angeles were virtually zero prior to 8 January, one day after the Palisades wildfire was first reported.
ASCENT was launched in May 2024 and is funded by the US National Science Foundation. It records real-time concentrations of particulates less than 2.5 micrometres in diameter – known as PM2.5 pollutants – in the air at 12 locations across the US. The Los Angeles data has not yet been fully quality tested.
As well as the Los Angeles monitoring station, PM2.5 levels were also measured at sites in Riverside, around 50 miles east of LA, and in the Joshua Tree National Park, around 125 miles east of LA, to study the transport of pollutants across southern California. Neither station recorded spikes in atmospheric lead.
It is thought that such a dramatic increase in atmospheric lead was caused by older buildings containing leaded paint and pipelines catching fire. Prashant Kumar, an expert in air quality at the University of Surrey, told TCE that in the future “it is crucial to ensure that wildfires do not reach areas with lead-laden materials present.
“This could involve stricter building codes to prevent structures from burning during wildfires, properly disposing of materials that contain lead and ensuring they are not burned.
“Also, air quality monitoring during and after wildfires can help to indicate the increase in ambient lead levels, providing an opportunity to take relevant response measures.”
Kumar noted that “wildfires can also produce secondary particles through chemical reactions occurring in the atmosphere. Emissions during wildfires, for instance, can interact with other compounds in the air to create PM2.5 particles”.
Other PM2.5 particulates, including chlorine and bromine, also peaked on 9 January. The total PM2.5 concentration reached 258 ug/m3 on 9 January – more than seven times greater than the average amount over a 24-hour period the EPA considers safe, and almost 30 times greater than the average annual limit.
Exposure to lead can affect the nervous, kidney, immune, reproductive, developmental, and cardiovascular systems. It is also linked to neurological and developmental issues, such as reduced IQ, especially in children.
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