Long-term airborne particle pollution assessment in the city of Coyhaique, Patagonia, Chile

An air pollution assessment in a small city located in the heart of Chilean Patagonia is presented. Seven years (2014-2020) of PM concentration levels retrieved from two monitoring stations permits an evaluation of the city's pollution variability, the effect of meteorological variables and long-term trends of air pollution. The highest PM concentration levels observed during the coldest months are mainly related to an increasing emission associated with the intensive use of firewood for residential heating and cooking. The most polluted days are associated with low temperatures, low wind speed and high PM2.5/PM10 ratios, which is consistent with the predominance of local firewood sources over background emissions. A decrease in both PM fractions over time has been estimated (PM10: -4.1, CI99%: -5.7 to -2.9 and PM2.5: -2.2, CI99%: -3.5 to -1.3 mu g m(-3) year(-1)). However, the annual average PM mass concentrations in Coyhaique exceeded both national and international air quality thresholds. The city reported a percent of annual exceedances of the daily WHO guidelines of 57% for PM10 and 77% for PM2.5. These numbers highlight the serious air pollution problem of the city of Coyhaique, which exhibits air pollution levels comparable to those of many polluted megacities in the world.

Automated summary

An assessment of air pollution in a small city in the Chilean Patagonia was conducted using PM concentration data from two monitoring stations over a period of seven years. The study analyzed the city's pollution variability, the impact of meteorological factors, and long-term trends. The results showed that the high PM concentrations observed during the coldest months were mainly due to the use of firewood for heating and cooking. The most polluted days were associated with low temperatures, low wind speed, and high PM2.5/PM10 ratios, indicating a dominance of local firewood sources. Despite a decrease in PM concentrations over time, the annual average PM levels in Coyhaique exceeded national and international air quality thresholds, highlighting the severity of the air pollution problem in the city.