Air quality in Ecuador: a perspective from observations in Quito and the Galapagos Islands

In this work we present efforts to understand the origin and levels of air contaminants in Quito and Galapagos through multi-year data collected at stations run by Universidad San Francisco de Quito (USFQ).

Quito is located at high altitude on the Andes and on the equator. In spite of plentiful UV radiation and urban emissions, ozone levels are usually at or below the 8-hour Ecuadorian air quality standard, which meets the World Health Organization (WHO) guidelines of 100 μ g m^-3 in standard conditions (50.9 ppbv). Given that precursors are available, these peculiar ozone levels have their origin in atmospheric chemistry. We present observations between 2014 and 2018 taken at USFQ's Atmospheric Measurement Station (EMA, Spanish acronym) to characterize ozone levels in Quito's eastern valley and to explain the unique conditions, often associated to wild fires, under which ozone levels are episodically high.

On the other hand, at USFQ we are putting forth significant efforts to characterize for the first time levels of species relevant to air quality in the Ecuadorian province of Galapagos. We present ambient PM_2.5 concentrations derived from in situ measurements combined with aerosol optical depth taken with a sun photometer (AERONET) deployed at USFQ's Galapagos campus (San Cristobal Island). In addition, we present boundary layer ozone in Galapagos using data from the SHADOZ (Southern Hemisphere Additional Ozonesondes) public archive. Satellite data was also used to estimate typical levels of other gases in the ambient air. Specific scenarios, related to transport of pollution, that lead to high ozone or increased levels of particles in this pristine environment were identified and will be discussed.