Determination of carbonyls and their sources in three sites of the metropolitan area of Costa Rica, Central America

Abstract

Ambient levels of carbonyl compounds and their possible sources were studied at three places in the metropolitan area of Costa Rica, including a residential, an industrial, and a commercial downtown area with high vehicular flow, during the periods of April-May and September-December 2009. Fifteen carbonyl compounds were identified in the ambient air, of which acetone was the most abundant carbonyl, followed by formaldehyde and acetaldehyde. Concentrations were highest in rainy season at all sites and lower in dry season. These decreases in concentration are explained by the influences of both photochemical reactions and local meteorological conditions. The strong correlation between C1-C2 and C3 indicated a common origin for these carbonyls. The C1/C2 ratios varied between 0.49 to 1.05, values which can be considered typical of an urban area.

An Exploration on the Suitability of Airborne Carbonyl Compounds Analysis in relation to Differences in Instrumentation (GC-MS versus HPLC-UV) and Standard Phases (Gas versus Liquid)

“…The corresponding molar MDL's for HPLC/UV analysis of the L-WS aldehyde/ketone-DNPH mix are ~0.80 ± 0.02 pMol (see Table 5). The present work's MDL results are inconsistent with the almost constant MDL (0.04–0.06 mg L −1 ) reported for a 25  μ L L-WS HPLC injection of a CC-hydrazone mix [32]. The VA/FA molecular weight ratio is 86/30 = ~3.…”

“…The VA/FA molecular weight ratio is 86/30 = ~3. We make no attempt to reconcile our MDL results with the [32] data. The HPLC-MS MDL for PFPH derivatives (of FA, AA, PA, BA, and VA in gas samples) ranging from 0.21 ppb (FA) to 0.10 ppb (VA) [17] may generally reflect EI ionization efficiencies.…”

Diurnal and seasonal variations of carbonyls and their effect on ozone concentrations in the atmosphere of Monterrey, Mexico

“…In comparison with the results of Herrera-Murillo et al (2012) in San José, Costa Rica, Dai et al (2012) in Xi'an China, and Morknoy et al (2011) in Bangkok, Thailand, aldehydes presented higher concentrations, while ketones had a similar behavior in Monterrey.…”

“…Formaldehyde, acetaldehyde, and acetone are the most common carbonyls in the atmosphere Villanueva et al, 2013). The diurnal and seasonal variations have also been studied (Cerón et al, 2007;Wang et al, 2007;Lu et al, 2010;Herrera-Murillo et al, 2012;Ho et al, 2012). In Mexico, carbonyl concentrations have been measured mainly in Mexico City (Báez et al, 2000;Báez et al, 2001;Grutter 500 et al, 2005).…”

Evaluación de la concentración de los aldehídos en el aire en la Reserva Biológica Monteverde y en la ciudad de Heredia, Costa Rica

“…Las emisiones directas de las fuentes industriales y del tráfico vehicular podrían haber contribuido con la alta concentración de los aldehídos encontrados en el aire de Heredia. Además de ser emisores directos de los aldehídos, las fuentes fijas y las fuentes móviles emiten una gran cantidad de los NOx y de los COVs, los cuales son precursores de los productos del smog fotoquímico, que incluyen a los aldehídos (Altemose et al, 2015;Herrera et al, 2012).…”