Effect of Nearby Forest Fires on Ground Level Ozone Concentrations in Santiago, Chile

Abstract

On 4 and 8 January 2014, at the height of the austral summer, intense wildfires in forests and dry pastures occurred in the Melipilla sector, located about 70 km to the southwest of Santiago, the Chilean capital, affecting more than 6 million inhabitants. Low level winds transported the forest fire plume towards Santiago causing a striking decrease in visibility and a marked increase in the concentration of both primary (PM 10 and CO) and secondary (Ozone) pollutants in the urban atmosphere. In particular, ozone maximum concentrations in the Santiago basin reached hourly averages well above 80 ppb, the national air quality standard. This ozone increase took place at the three sampling sites considered in the present study. These large values can be explained in terms of high NOx concentrations and NO 2 /NO ratios in biomass burning emissions.

Soccer games and record-breaking PM<sub>2.5</sub> pollution events in Santiago, Chile

“…The western part of the city seems much more affected by the event than the eastern part. This comes from the diurnal wind cycle in Santiago, which features prevailing easterlies during the nighttime contributing to the renewal of air masses in this part of the city (Rutllant and Garreaud, 1995). The meteorological conditions observed at the location of the strongest peak during our period of interest are shown in Fig.…”

“…regularly faces high levels of fine particulate matter (PM 2.5 ) pollution in winter. The city is located in a confined geographical basin surrounded by the Andes cordillera in the east, a coastal range in the west, and transversal mountain chains in the south and north (Rutllant and Garreaud, 1995). The induced poor ventilation in wintertime combined with significant anthropogenic emissions lead to high average levels of PM 2.5 (Barraza et al, 2017;Mazzeo et al, 2018) as well as peak events (Toro A et al, 2018).…”

Soccer games and record-breaking PM<sub>2.5</sub> pollution events in Santiago, Chile

“…Besides meteorology, advection of a PM plume over the city could be a candidate cause for such events. For instance, wildfires occurring in the forests surrounding the city occasionally explain major peaks of particulate matter in Santiago (Rubio et al, 2015;de la Barrera et al, 2018), but these events mostly take place in austral summer, and no such event was reported during our period of study. In addition, the strong concentration gradients observed between nearby stations ( Fig.…”

Ecological Impact of Forest Fires and Subsequent Restoration in Chile

“…This damage begins with vegetation removal, leads to erosion, the excess of salts, pollution, and physical, biological and chemical degradation follows [15]. Furthermore, forest fires release carbon dioxide contained in trees which stays in the atmosphere if vegetation does not recover [1,16].…”

“…Fire has been one of the principal agents that affect the global ecosystem, damaging recovery cycles and altering the atmosphere [1]. The fire-ecosystem relationship is reflected in the response of ecosystems to natural fire episodes.…”